Building an AutoStick Engine

[Bookwus]

Hiya All,

OK.............back to the thread already!

The pistons and cylinders are next up in the assembly process.  But before we go slapping these things on the case there is some prep that needs to be done.

First off, you need to determine which side of the piston faces the front of the engine.  Check the face/head of the piston and you'll notice an arrow..............



The arrow should be pointing to the front of the case.  I have been told that the reason for this is that the bore for the wrist pin is not exactly centered in the piston body.  Consequently, each piston has a top and bottom.  By arranging the piston so that arrow is pointing forward you have just made sure that the top of the piston is top and the bottom, bottom.

Next, the wrist pin needs to be started into the piston.  Be careful when placing the wrist pin into its hole in the piston.  It needs to be perfectly square with the hole when doing so.  Otherwise it may bind.  Its a very close tolerance.  When I do this I slightly twist the pin as I engage the piston hole with it.  Once the pin feels secure in the hole I tap it in so that a few millimeters of the pin protrudes from the interior piston shoulder..............



This allows me to place the piston on the rod and make sure that the wrist pin is in the connecting rod small end hole,  By the way, before you actually put the piston and wrist pin into place make sure that you have gooped up the wrist pin and the small end hole of the connecting rod with your assembly lube.  Seating the wrist pin into place is as simple as tapping it in with a mallet.  I also use a socket as a driver when the pin gets close to the piston body.  That way I can drive the wrist pin to its fully seated position INSIDE the piston.

That wrist pin also needs to be secured in place and that is done with piston clips.  Take a look........





Exercise some care with the piston clips.  Basically these guys are small springs.  If they go flying off your needlenose pliers they are headed for other universes, believe me.  Very hard to locate these things when they have taken to the air.  Been there, done that!
And a tip............Install one piston clip before you do any installation work with the wrist pin.  When you later go to tap in the wrist pin the installed piston clip will act as a stop.

One last job with the piston before we slide on the cylinder.  Make sure that the ring gaps are staggered.  Check this out......



The oil ring will be marked with a spot indicating that it (the spot) should be at the top of the piston.  The pistons I used in this build were Mahles and they use a red spot.  I have seen them in other colors.  The comression rings need to be staggered in opposite directions from the oil ring.  I never stagger these rings so that they are below the centerline of the piston.  Notice in the picture that they are at about 9 to 10 o'clock and at 2 to 3 o'clock.  Once you have the rings in their proper position slather some assembly lube all over them.  Then be sure to pull the piston you are working on out to its fullest extension.

Let's turn our attention to the cylinder.  Most old VW hands will use a cylinder gasket where the cylinder meets the case.  Lately it seems as if many have had just as good results omitting the gasket.  I'm of the opinion that the gasket can make up for any differences between the machining of the case and the cylinder, so I use it.



I goop a little Permatex on the seal and the cylinder is just about ready to install.  Just one last thing.........  I wipe assembly lube throughout the barrel of the cylinder.

Now the cylinder is ready to meet its partner, the piston.



Both my hands were full getting the cylinder on the piston so I couldn't take pictures.  But it's not rocket science at all.  The cylinder slides into position ahead of the piston on the cylinder head studs.  That you see in the picture above.  Then the ring comressor is placed around the piston and rings.  Clamped down it compresses the rings so that the cylinder can slide over them.  At this point it's a simple matter of tapping the cylinder back toward the case.  I do this with an open hand much as you might slap somebody.  As the cylinder moves toward the case it pushes the ring compressor off the rings.  Once the rings are all cleared the ring compressor can be removed and the cylinder driven home with a mallet.



All the rest of the piston/cylinder assemblies go in the same way.



Finishing off this job is an important step and NOW is the time to do it.  The air deflectors under the cylinders on each side need to be installed.



There's not much to these deflectors.  Basically, they are just a slightly angled piece of sheet metal.  But they are absolutely critical in the proper cooling of your engine.  They gotta be there!  Installation is easy they simply clip around the cylinder head studs between the two cylinders...........



Some folks have used a replacement for these OEM tins.  They are usually referred to as "Cool Tins".  They are in fact the under cylinder tins for Type 3.  Some say they work, others say they do not.  Do consider though that a Type 3 engine has an entirely different cooling "architecture".  The cooling is directed at surfaces from differing directions than that of a Type 1.

Next time:  Heads and pushrods/pushrod tubes.

[volkenstein]

Mike,
     

The arrow should be pointing to the front of the case

. We are talking "VW Standard"?, ie Front = front of car? Which means the flywheel end of the donk?

Just for us L6/V8 recidivists .

And...10mm case studs? Case savers or O.G.? Just out of interest...


Regards
Sean

[Bookwus]

Hiya Sean,

Front as in front of the car.  The arrow should be pointing toward the flex plate.

The studs on this engine are 10mm OEM.

[Bookwus]

Time to get the heads on this engine!

Before we get to the heads we need to do a little prep work on the pushrod tubes.  Pushrod tubes are, generally speaking, one of those parts that most folks reuse when they rebuild.  That's certainly the situation in my case.  So. I need to make sure that these reused tubes will not leak.  And there's a couple of items to check with the tubes.  [/img]
I don't want the seam of the tube on the bottom of the tube whan it's installed.  So, I arrange the tubes and make a mark on the tubes opposite the seam.  Take a look....



When I get into the installation process I'll make sure those marks are facing downward; more on that later.

Leaky pushrod tubes are a pretty common complaint.  Most folks think that they may have problems with the pushrod tubes seals, and they might.  But they also may have problems with the pushrod tubes suffering from compression.  That is to say, their length is compressed so that they are no longer long enough to span the distance between the case and the head in a satisfactory manner.  So, I make sure that the tubes are little too long before I start.  Each tube is suppose to be 7 9/16 inches long from the end of the accordian pleats on one end to the end of the accordian pleats on the other end.........



It's been my experience that most pushrod tubes are not quite this long.  So, with a pair of channel locks, I stretch them out a bit.......



I usually try to get them about 7 3/4 inches knowing that when I torque the heads in place they will compress the tubes in each position to a nice tight fit.  In this case, it's much better to be too long rather than too short!

Last thing to do with the tubes is to put the pushrod tube seals in place.  These doughnut like seals are placed on each end of the pushrod tube so that the beveled side of the seal is facing outward.......



This allows the seals to fit into the concave depression around the pushrod tube holes in the case and head.  Some folks use a sealant on their pushrod tube seals.  I do not.  By stretching the tubes and then torqueing down the heads I get a nice tight compression fit.  I have not had problems with leaky pushrod tubes.

The heads should be spotlessly clean like this one...........



Additionally, when doing a rebuild I'd recommend that you take the heads in and have good machine shop check 'em out.  Remembering that your pistons and cylinders are brand new, your cylinder heads are the outside "wall" of the combustion chamber.  As such it is imperative that they be in excellent shape.  VW heads often crack between the spark plug hole and the valves.  And that's bad news.  This phenoma is actually a bit more prevalent in dual port heads than in single ports, but either way it's the knell of death.  These cracks usually run pretty deep and welding, sometimes suggested as a fix, may or may not be effective.  Then too, valves that have seen action need to be evaluated.  You want your valves on good shape and able to make a good seal - a good reason for a valve job.  While most folks think of a nice tight seal when the valves close (and that is important) one should also realize that a proper seat insures that the valve has a chance to bleed off accumulated heat.  All in all, heads are both complex and important.  I wouldn't think of doing a rebuild without having my machine shop go through them from top to bottom.

So, the heads have been checked out and they're ready to install.

Slip the heads onto the cylinder head studs that run through the cylinders.  Put them on just enough so that the studs hold them; you do not want them touching the cylinders right now.

Now, with your pushrods in your right hand and your pushrod tubes in your left hand, begin to insert the pushrods into their holes in the head.  As you do so bring the pushrod tube up into its approximate finished place.  Then insert the pushrod into the pushrod tube (by the way, the pushrod tube does not have specific ends so it may be inserted either way.  And remember those marks we put on the pushrod tubes?  Don't worry about those right now) while you "aim" the case end of the pushrod tube at the proper hole in the case.  The pushrod, being longer than the pushrod tube, will hold now the tube in place until you get the head torqued down.



Once you have all four pushrod tubes more or less in place, move the head closer to the cylinders so that the threads of the cylinder head studs are visible in their appropriate holes in the head.  You may have to do some wiggling and tweaking of the pushrod tubes during this procedure.

At this point we are just about ready to finger tighten the nuts to the cylinder head studs.  But before we do that be sure to put a bead of sealant (I use Curil here) around each stud hole in the head........



Be sure you have those extra thick washers in place around the cylinder head studs.  Then finger tighten the nuts down.  Once you have the nuts all finger tightened, turn your attention to those pushrod tubes again.  Now is the time to make sure that the tubes are well seated in their respective positions and that those black marks are face down.

We are ready to torque!

First thing to know before getting out the torque wrench is that there are two torqueing patterns you need to use on the heads.  The first one.........



....serves to compress those pushrod tubes into place so that they do interfere with the final torque values.  Notice how the torque (I use 10ft/lbs for this pattern.  Most manuals recommend something a little less but my torque wrench only goes down to 10 ft/lbs.  Never had a problem with this approach) is applied to the bottom studs first?  That compresses those "too long" pushrod tubes snugly into place.

Now we are ready to move to a final torque on the heads.  Take a look at the pattern for the final torque............



The idea behind this pattern is to apply the torque in such a way as to not risk warping the head.  We're going to help reduce that risk even more.  The final torque on these nuts is supposed to be 23 ft/lbs (but check the manuals for your specific rebuild - there may be some variations) and we are going to get there in steps.

First of all, before applying that final torque make sure that you have the heads on both sides of the engine ready to go.  In other words, you have done the initial torqueing sequence to compress the pushrod tubes on both sides.

OK, now torque all the bolts (in their proper sequence) on one side to 15 ft/lbs.  Then move to the other side of the engine and do the same for the that head.  Now, go back to the original side and torque to 20 ft/lbs.  Again, go to the other side and torque those nuts to 20 ft/lbs.  Come back to the first side and torque to 23 ft/lbs.  Then go to the other side and torque up to 23 ft/lbs.

Then walk away.

Come back in an hour or so and torque the first side to 23 ft/lbs.  Then do the second side to 23 ft/lbs.  I come in the next day
and do this step one more time.  Kinda anal, but it does make me feel a bit more secure.

By the way, did you notice that I already had my spark plugs in the heads before I installed the heads?  I like doing that.  It saves me from doing the contortionist act later on and I can be sure that I easily get the proper torque on the spark plugs.
 

[CarlIseminger]

I am not up to speed on rebuilding a VW aircooled engine, but I enjoy following this thread as it explains how my car engine works.  I am curious, did I miss a step along the way somewhere?  Shouldn't there be some sort of gasket between the head and the cylinders?  Usually on water-cooled engines this would be the "head gasket" that keeps getting blown?  It would be great if we could get a shot or two of the valve side of the head before it is attached to the cylinders.

Keep this going.  I am learning quite a bit.

Thanks

[hercdriver]

Bookwus,

I agree with with Carl. This is a great learning tool. I too have a request.

Could you talk about how you prep the valves? Do you recommend a three angle job?

I'm also interested in measuring the volume of the heads. I think it's referred to as cc'ing? Is it a critical step? Or just an FYI issue?

Dave

[Bookwus]

Hiya Carl,

If you go back up a couple of posts and take a look at the portion where the installation of the cylinders takes place you'll notice that there is a paper gasket that I installed around the cylinders' base.  Also note that I mentioned the gasket was deemed uneccessary by some these days.  Indeed, many folks just glop some Permatex (or whatever sealant they might choose) around the cylinder base and shove it on.  It should be noted that whatever way one chooses to go, the cylinder should be sealed to the case.

Now, I'm guessing that this really isn't what you had in mind when you posted that question.  So, the answer to your question is basically, no.  There is no sealing device between the cylinder and the head.  It's a machined contact surface. The heads are then torqued in place to insure that "machined" seal.  However Carl, this does raise an interesting issue.  After the engine has been run in a bit (everything has "settled" into its natural working configuration), these heads should be retorqued.  That means pulling the engine at around 3,000 miles ands doing the retorqueing - most folks overlook that.

Finally, do know that there are shims for use on cylinders.  These shims come in varying widths.  They are used to adjust the volume of the combustion chamber.  One will frequently see these shims on a performance type engine.  They are sometimes used on stock type engines which have cases or heads that have been flycut.  Basically though, if you are using all stock parts and your aim is to build a stock engine these shims are not needed.   

[Bookwus]

Hiya Dave,

Definitely go with the 3 angle valve job.  Good point! 

The only reason I did not go into any depth with that aspect of the build is that the valve job is the domain of my machine shop.  Frankly, all of the work done on a cylinder head is way past my level of knowledge and available tools.  So when I take my heads over to them, I trust their expertise.

Measuring out the combustion chamber is actually quite important providing that you are not building a stock engine.  Even folks I know who are building a stocker will measure out the combustion chamber - peace of mind.  The information gathered from this measurement can then be fed into an engine spec calculator (these are a bunch of these around - here's one that I use - http://www.msgulfcoastvwclub.org/TechPages/Tech10.html) that can provide you with valuable info about the engine you are building.  Using this information for example, you can add the shims I mentioned in the post above to reduce the compression ratio.  Very neat.

And CCing (measuring the volume of the combustion chamber) is really not difficult at all.  A good micrometer, a graduated pipette, alcohol and food coloring can get you there - along with a smidgen of math.

I did not include the CCing in this series because I didn't do it.  Frankly, when putting a stock engine together (this assumes all stock parts and that nothing has been machined or altered) measuring the combustion chamber volume is not needed.  Once the rebuilder begins to change this or that, then the need for measuring those combustion chambers becomes more and more necessary.

[CarlIseminger]

Thanks for the update.  I never realized there were no "gaskets" between the head and the cylinders.  For us novices, this thread is wonderful.  I still wish, even tho you said you trusted the head work to a pro, you could have shown us a couple of shots of the other side of the head with the valves already installed.

Please keep this post going.

[Bookwus]

With the heads torqued, re-torqued, re-re-torqued, and maybe re-re-re-torqued (told you I was anal about this!) it's time to turn our attention to the rocker arms and setting the valves.  But we have a couple of small jobs to do before the rocker arms.

I put the intake manifold gasket into its place at this time.  On a single port engine it's as simple as placing the gasket (a metal doghnut type affair) into its recessed position in the head...........



The intake manifold gasket for a dual port is even simpler.  It just fits over the studs which you'll use to bolt down the manifold end castings.

The main pulley should also be on the engine now.  But before instyalling the main pulley, the under-pulley tin needs to be in place.....



This piece is held on by cheeshead tin screws on either side of the crankshaft.

The pulley itself is "keyed" so that it can be installed in only one way.  It usually needs to be tapped into place on the end of the crankshaft.  The pulley nut (don't forget the washer!) needs to be torqued down to about 35 ft/lbs.

And a hint:  It's a good idea to paint a single mark (for cylinders 1 & 3) at your engine's primary timing mark (the exact spot will depend on the engine you are building but a typical dual port would be 7.5 degrees BTDC).  And make a double line 180 degrees across the pulley from your first mark.  That gives you the secondary timing mark for cylinders 2&4.  Take a look...........



Rocker arm assemblies are usually a pretty dirty affair come rebuild time.......



I always clean these rocker arms up.  Actually, it's more than just a matter of being clean.  It's also prolonging their effective life.  Here you see a rocker assembly partly torn down.  



Pulling this assembly apart is really quite simple.  You'll find a squeeze pin at both ends of the rocker shaft.  Simply remove that squeeze pin and all the inboard parts will just slide off the end of the rocker shaft.  Notice that just inboard of the squeeze pin are three washers.  Two standard flat washers sandwich a wavy washer - they need to go back on in that order so don't forget their order.  I clean all the parts off the rocker shaft with a brass brush attachment on my drill.  They all need to be nice and shiny.  Once you have the parts from one end of the shaft clean turn your attention to the other end.  Same procedure there and same treatment.  

That will leave you with the dirty rocker shaft itself..............



See those brownish ares on the shaft?  That is accumulated dirt and burned on oil.  This accumulation can prevent oil from being disbursed to the shaft as it sits in its supports.  Bad news.  I clean the rocker arm shaft by sanding it with 220 grit sandpaper.  I hold the sandpapaer in one hand and pull the shaft through the sandpaper while I (and this is important) twist the shaft.  That will give me an even (as long as I pull evenly) diagonal sanding pattern on the shaft.  I repeat that step only this time I twist in the opposite direction.  The result is a nicely cross-hatched rocker arm shaft.  



Of course, at this point the newly sanded shaft needs to be scrupulously cleaned.  I wipe it down with brake parts cleaner several times at least until the rag comes out spotless.  This cross-hatching will now actually conduct the oil between the shaft and its supports.  And that's a very good thing!  Remember too to cross hatch the insides of the rocker arm shaft supports.

It's time now to mention an old rebuilding trick I always employ.  When I first remove the dirty old rocker arm assembly I make a mark on the outside left end of the shaft.  When I reassemble I make sure that the mark is on the inside right end.  In this manner I have turned the shaft so that the rockers will be mating up with unworn surface on the shaft.  With the rocker arm assembly all cleaned up and reoriented it's time to lube (use assembly lube) all the parts and reassemble.



Big difference between this and what we started with.  Nice and clean and well oiled, this rocker assembly is ready to get bolted into place.  Simply slip the rocker arm assembly onto the head studs.  Don't worry too much about the position of the rocker arms themselves right now.  Just tweak them enough to allow installation.  Then torque the rocker arm assembly down to 18 ft/lbs.  Alternate your torqueing from one nut to the other and do this torqueing in steps, 12, 15, 18.  

But be careful during this step also.  It is possible to get the rocker arm assembly hung up on a case stud.............



This happens when the case stud has not been fully seated in the case.  It may interfere with some of the rocker shaft hardware.  It's just one of those things to keep an eye out for.  Fixing this situation can be as simple as turning the case stud in a bit more (but never force it - the case will likely crack).

Let's set the valves............  grab the main pulley and turn it counterclockwise until you see that single painted mark at TDC (the case seam).  You now have either number one or number three piston at its firing position.  But which one?  You can easily check the distributor to see which position the rotor is pointing to.  And/or you can pull the spark plug from the number one hole and gently push a pencil down and into the hole.  If it immediately hits the piston top, you have number one up and in firing position.  If you don't feel the piston top you'll need to rotate the engine (remember, counterclockwise) 360 degrees so that the single painted mark is again at TDC and piston number one is up and in firing position.

Now, with a 13mm box end wrench loosen the valve screw adjusting lock nut.  You don't have to go far with this nut - you just want to break the contact between it and the valve screw.  Now turn the valve screw (you may have to retain your 13mm boxend on the locknut during this part of the process) so it is just barely touching the top of the valve stem.  Grab your .006 feeler gauge in your right hand, keeping the screwdriver in your left hand.  Loosen the screw just a smidge.  See if the feeler gauge will fit between the valve stem and the adjusting screw.  An excellent .006 fit will make the feeler guage feel as if it is being very slightly tugged as you m ove the guage between the two surfaces.  Once you have a good feel from the gauge go back to your 13mm boxend and attempt to tighten the locknut.  Be advised that the tightening the locknut will want to move the adjusting screw as well.  So you have to use your wrist strength to keep the adjusting screw in one place while tighteneing the locknut.

It's as difficult as it sounds.  And truthfully, the whole procedure is a bit of an art form.  So don't be too disappointed if it proves difficult to keep the valve adjusting screw in its .006 position.  This takes a bit of practice.

In any event, that just got you through adjusting one valve.  Seven more to go!  Adjust and tighten the other valve on the number one cylinder.  Then turn the main pulley (which way?) 180 degrees so that you bring up the double painted mark.   Now you are ready to do cylinder number two.  When you finish with number two rotate the main pulley up to the single mark and do the valves for number three.  After number three rotate counterclockwise (you didn't forget, did you?) to the double mark again so that it's number four's turn at valve adjustment.

For what it might be worth, after finishing the valve set procedure above, I go through them all over again - just repeating the process.  

[Bookwus]

At this point in our continuing saga this engine would basically be called a "long block"  A true longblock would also have valve covers and a flywheel (or in our case a flexplate) but it would not be sporting a distributor.  During this session we will add on those valve covers, the oil cooler, the fuel pump, the drain plate, and the oil pressure switch.

Let's get started with the valve covers.  The valve covers and the pushrod tubes are the two most common sources of annoying leaks.  We've already lengthened and then compressed the pushrod to minimize their chances of leaking so it is important that we take a good look at the valve covers.  

First off, know that most folks will reuse their old valve covers.  And that is fine as long as they are in pretty good shape.  They should be clean (spotlessly so on the inside) and undented.  You might want to set them down on a known flat surface to make sure they are not warped.  Most important they should have a clean and smooth mating surface where they contact the valve cover gasket.  Get yourself good valve cover gaskets.  The rubber/cork gaskets do very well for me.  Some like to use an affixative between the valve cover gasket and the valve cover itself.  Curil might be used in that sort of application.  I have never found it neccessary to use and affixative/sealant at this point of assembly.  That's because I make sure that the bails that hold the valve covers in place against the head are VERY tight.  One needs to use some muscle to force that bail into place with a long-handled screwdriver.  If that means buying new bails, so be it.  If the valve covers are in relatively good shape and the head mating surface is also in good shape, any subsequent leaks are almost sure to be due to a weak bail.

And a word or two about those super-groovy aluminum finned valve covers.  Don't bother with them.  They are notorious leakers.  The boys at Wolfsburg got it right the first time.  Go with the stock set-up at this point.

The stock VW mechanical fuel pump is a pretty reliable design.  However, there are a number of things that can go wrong.  We'll try to cover those problems as we add the fuel pump to the longblock.

The first thing to do is lay the bottom gasket on the case...........



Note that I have covered both sides of this bottom gasket with Curil.  Also note that this bottom gasket is mostly open in the center.  You will also need a top gasket.  The top gasket is the same shape as the bottom but it has only a small hole for the fuel pump pushrod.  Once that bottom gasket is in place it's time to drop the fuel pump stand into the case.  Take a look..........



........this fuel pump stand is made of a plastic compound.  It tends to have one big drawback.  Its rate of thermal expansion is somewhat different that that of the engine case.  Consequently, it is not at all unusual to find that the fuel pump stand becomes permanently affixed to the case.  That's due to the case expanding under heat and trapping the neck (blue arrow) in position.  To stop that from happening it's a good idea to sand down the neck of the fuel pump stand so it meets with no resistance at all when you drop it in the case.  If you can drop the fuel pump stand all the way into the case, you are in good shape.  Other wise do the sanding to narrow the neck a bit.

On top of then fuel pump stand goes the top gasket with that little hole for the fuel pump pushrod.  Lube up the fuel pump pushrod with assembly lube and drop it through that little hole (and in turn,) the fuel pump stand.   Let's turn our attention to the bottom of the fuel pump.....



Nice and shiny and ready to go.........NOT!  The fuel pump will benefit a great deal from doing a lube job on it right now.  That tongue looking piece of metal is the pump lever.  It's actuated by the fuel pump pushrod and it will never get any lubrication except what you give it right now.  So, cram a general purpose grease into the bottom of that fuel pump.  When you are ready to install the bottom of the pump should look like this........



Turn the pump over and line it up with the case studs on either side of the fuel pump stand.  You'll need to exert a bit of pressure downward on the fuel pump as you tighten up the nuts (don't forget the wavy washers) to 18 ft/lbs.

It should wind up looking like this.............



There has been much written about generator only fuel pumps and alternator only fuel pumps.  A generator style fuel pump is more upright that its alternator cousin.  That because the generator takes up less space than does an alternator.  An alternator's diameter is so large that its fuel pump must be bent or angled toward the distributor in order to fit.  And this is MOST IMPORTANT...........each style fuel pump has its own unique length fuel pump pushrod.  They must not be mixed up!

The fuel pump above, a relatively new design, is being sold by my friendly local auto parts store (FLAPS) as a generator style replacement.  However, I'd bet that it might well fit in an alternator application also.

The oil pressure switch appear to be a pretty straightforward installation.  And it is.  



But there is a caution involved here also.  The threads on an oil pressure switch are tapered.  If you tighten the oil pressure switch too much you stand a good chance of actually cracking the engine case at that point.  A good rule of thumb is to hand tighten the oil pressure switch as far you can.  Then wrench it another quarter turn.  That ought to do it.  Because of the taper a sealant is not needed but Curil could be used in this application if so desired.

The whole subject of oil cooler installation can get very involved.  Some folks like to change out their original oil coolers in favor of a doghouse style oil cooler (that is the way I went in this build), others use their originals and complicating all this is the fact that VW changed the size of the oil passages.  All this results in a number of different kind of oil cooler seals.  They can convert 8 mm to 10 mm, 10 mm to 8 mm.  Or they can be straight through 8mm or 10mm.  To make short telling of a long story its important that you know the oil passage size in your case, your adaptor (if you have one), and your oil cooler.  If you play it smart and you're lucky all the passages will be the same size.  In my case of converting a single port cooling system to a doghouse cooling system I got lucky in that my case has 10mm oil passages.  So also does my adaptor and oil cooler.  

I decided to convert to a doghouse oil cooler because this situates the oil cooler out of the direct airstream generated by the cooling fan inside the fanshroud.  This is important because the single port oil cooler which is situated inside the fanshroud blocks a good deal of cooling air to the number 3 cylinder.  This, to quite an extent, is a reason that number 3 experiences more failures than the other cylinders.  VW tried a number of approaches to dealing with this problem until 1971 when they implemented the doghouse.

Let's take a look at the oil cooler before we get into mounting it to the case......



In this picture the oil cooler has been mounted to its adaptor plate.  The adaptor plate is that portion of the assembly at the bottom of the page - more about it later.  The black piece of OEM VW tinware is the "Hoover Bit", named after Bob Hoover who called everybody's attention to its importance in the cooling of a VW engine.  It prevents cooling air from escaping the doghouse and forces air though the oil cooler.  Both very good things.  Make sure that you have a Hoover Bit in place when you assemble if you are using a doghouse set-up.

Notice also that the oil cooler has been wrapped with a thin (about 4 or 5 mm) covering of foam.  This also keeps air from bleeding past the oil cooler.  And the oil cooler has been scrupulously cleaned inside and out.  Little bad things sometimes found in the oiling system like to go to the oil cooler and hide.  If you are reusing your old oil cooler (and most folks do) the rule of thumb is that it cannot be too clean.  So that means clean, clean, clean and clean it again.  It took me 24 separate washings with brake cleaner to get the inside of my oil cooler to drain perfectly clear.

Here's my oil cooler adaptor plate.  



This is an original VW part designed to offset the oil cooler toward the front of the car.  You're looking at the surface that mates up to the oil cooler.  See the red seals?  They're the 10mm seals I was speaking of before.  Notice also the copper crush washers?  They are there to insure an even fit between the oil cooler and the adaptor...........



This picture shows the oil cooler in place, mounted to the adaptor and the adaptor attached to the block.  The red arrow designates one of those red oil cooler seals while the yellow arrow is showing how the copper crush washer makes for an even fit between oil cooler and adaptor.  But in actuality, before the the adaptor and oil cooler are bolted down to the case, another two oil cooler seals need to be placed on the case like so......



With those two seals in place on the case the oil cooler/adaptor assembly is lowered down and wrenched into place.  Be easy with this.  The seals need to be in place tightly but not so tightly that they distort.  Very delicate doings here.  Torque everything to around 5 or 6 ft/lbs and you'll be fine.

The oil drain plate is pretty straightforward but, like the oil pressure switch, opportunities for foul-up do occur here.  Here's how I go about the "straightforward" part of the business................

One drain plate gasket coated with Curil goes on the case slipping that gasket around the six studs.  The wire mesh strainer plate goes dome-in into the hole again tweaking it a bit so that it fits the six studs.  It's also important to make sure that the hole at the top of the wire mesh dome fits nicely around the oil pickup tube inside the case.  Another gasket smeared with Curil goes on over the base of the wire mesh strainer plate.  Then comes the drain plate itself.  It is held in place with six acorn type nuts.  They should be tightened to about 5 ft/lbs (figure finger tight plus a quarter turn with a 10 mm wrench) and the main drain plug should go in at 25 ft/lbs.  Take a look.........



And a couple of words about this drain plate assembly.  Leaks at this point are often the result of over tightening the acorn nuts.  Matter of fact, some folks like to wrench so hard on these little guys that they strip the studs right out of the case.  Not a good thing so be careful here.  And take a good look at the wire mesh on your strainer plate.  It should be a fine mesh.  There are aftermarket strainer plates out there with a wire mesh so coarse that small boulders could pass through.

Next time we'll look at generator stands, thermostats, and oil relief valves.    

 

[FlamingChris]

Superb write up, wish i'd had that when i was putting mine together (and someone about to tell me why i couldn't get the right end float - the crankshaft was too long).

[Bookwus]

Hiya Chris,

.......someone about to tell me why i couldn't get the right end float - the crankshaft was too long.

Ouch!  Wrong crankshaft, I presume?  A friend of mine was putting together his engine at about the same time I was building the engine in this thread.  He opted for an aftermarket counter weighted crankshaft from CB Performance, a reseller with a good reputation.  It turned out that his crankshaft also was a bit too long.  He had no problems with his endplay but did have a problem at the other end of the engine.  He could not get his main pulley to align properly with the generator pulley. 

By the way, how are coming along with your project?   

[Bookwus]

I do believe that I'll leave the thermostat and its hookups until a later installment.  Truth be told, some of the engine tin needs to be in place before dealing with the thermostat.  But we ought to be installing the thermostat in not too long a time.

So, we do need to need to install the generator stand.  A couple of words first..............  There is a physical difference between generator stands and alternator stands.  Fortunately for this series the differences are all in the portion of the stand that "marries" to the alternator or the generator.  An alternator has a bigger diameter than does a generator and the stands for those parts must reflect that.  However, the procedure for mounting the stands to the case are the same.

First thing to do is to lay one of the paper stand gaskets in place,  before I do that I place a bead of Curil around each stand stud and then link the four circles of Curil with a line of the same stuff.  Then I place the paper gasket home and I make the same Curil design on top of the in-place paper gasket, like so.............



Now we are ready to put the generator stand baffle in place.  This baffle is supposed to go in place in one way only.  Here's a tip for you..........  the four stand studs are not in an EXACT square.  Inside to outside the distance (center to center) is about 59mm.  Front to back the distance is just a bit shorter at 58mm.  The baffle goes over the studs easily when it is correctly oriented.  When it is not correctly oriented it can be forced into position.  This is also true for the paper gaskets involved in this installation.  So, take care and go nice and easy here.  

And about those vents.  The idea is that they should open downwards and toward the front.  You want to have oil drain into the crankcase freely and not get get hung up by the baffle.  Then too you also want the crankcase gases to be able to escape freely up through the baffle.  So the baffle fits down on stand gasket (and the Curil!) as in this picture...........



Note the Curil being forced up around the studs.  Another note on correctly placing the stand baffle.  You will find that if you attempt to orient the baffle 90 or 180 degrees out of the position above it won't want to sit inside the hole provided for it in the casehalf.  However it will sit there nicely in most any orientation if you turn it upside down (not a good idea for reasons stated above).

Anyway, once you have the stand baffle in place, do the Curil thing again on the metal baffle.  Then place another paper gasket down and again Curil the topside of that...........



That brings us to the generator stand itself.

But before we do the stand, a reminder on the order of sealing materials from bottom to to top.

1.  case
2.  Curil
3.  paper gasket
4.  Curil
5.  baffle
6.  Curil
7.  paper gasket
8.  Curil
9.  stand

You'll find that like the baffle and paper gaskets the stand only wants to go on one way.  I suppose you might be able to mount it reversed 180 degrees but that would put the generator right where the carburetor is supposed to be.  Not a good thing!
Once you get the stand in place wrench the four securing nuts (and their wavy washers) down to about 12 to 15 ft/lbs.  

By the way, I usually do not put the oil filler/road draft tube assembly in place at this time.  I'll wait until the rear tin pieces have been loosely put in place and then fit the oil filler/road draft tube assembly.  The darn thing just seems to get in the way for me.  However, you could put it on now if you wished to do so.

You'll likely be dealing with a dual relief case when you rebuild.  So what does that mean?  Take a look...........



The actual oil pressure relief valve lives in the case hole designated by the yellow arrow.  It's there because the oil pump doesn't have the smarts to know when the oil is thick or thin.  Pumping cold and thick oil under pressure can cause damage to fragile devices like oil coolers.  So the pressure relief valve shuts off oil from going through the oil cooler when the oil is still thick and cold.  As the oil warms up, the pressure relief valve opens up and allows the oil to flow through the cooler.

The valve sitting in the green arrowed casehole is not really a pressure relief valve in the sense that the other one is.  It's actually more of a pressure regulating valve.  And while we are here..........a single relief case will not have the casehole at the green arrow (it will also have 8mm oil passages in the case whereas a dual relief case has 10mm oil passages).  Generally, rebuilders would prefer to rebuild a dual relief case whenever possible.

The valves themselves are piston and spring affairs.........



The longer assembly is the pressure relief valve (gets installed at the yellow arrow in the picture above).  These valves are installed in their respective caseholes after receiving a good coating of assembly lube.  The piston which goes in the hole first has to be inserted into the hole so that the piston face enters the hole first.  You find that the springs will seem just a bit too long for the hole, but that's part of the design.  Get yourself the biggest screwdriver you've got and twist those caps into caps into place.  Make sure those caps are also wearing their washers.

For what it might be worth.........  the pressure relief valve for the ATF (located on the face of the oil/ATF pump) is the same design as these valves although not the same size.

When both valves are in place you should be seeing something like this on the bottom of your case...........

[volkenstein]

Mike,
     

Get yourself the biggest screwdriver you've got and twist those caps into caps into place.

Hmmm....getting them off can be an adventure in itself .

I wound up ordering two replacements from Aircooled.net that take an allen key (rather than a screwdriver type
arrangement) because I destroyed mine getting them out......

For anybody reading, if you can find what is known as a 3/4" draglink socket (essentially an ultra wide screwdriver bit) you'll be doing yourself a big favour!

Enough hijacking, I have a serious question.....why put the oil filler baffle plate (steel one) on the way you have? Most of the manuals I've perused (and done myself) have it at 90 degrees to the way yours is oriented. I don't see that it would make any difference either way....just curious...

Oh, BTW, when are we eating off that donk?

Regards
Sean