My New 68 Fastback

[supersuk]

Ok, I think I remember putting that crush ring thing. On second thought, i'll have to check. LOL

I haven't been able to clean the car up and take it out for some photos. One day when my son doesn't need as much supervision.

On another note, went for a fairly long drive today in the fastback. Everything was going great until I drove for an extended period on the freeway at 65mph. Noticed that the oil pressure started to slowly drop from about 25psi to about 12 psi at 65mph. So I slowed down to about 55mph and the oil pressure remained the same. Pushed the clutch in and the oil pressure dropped to about 5psi (hard to see the gauge). Got to my destination and opened up the engine bay....damn it was super hot in there! Couldn't even touch the oil without getting burned. I'm guessing the oil got super hot and thinned out enough to drop the oil pressure. Right now I have Brad Penn 10w-30 oil in there, no extra capacity sump, and no external oil cooler. I think I may need to install an extra oil cooler. What other things should I check? I'll have to check if the cooling air flaps are working. I checked the plunger thingie thing that expands, opening up the cooling air flaps when hot and it was fully expanded after the long drive. Hopefully the flaps aren't frozen. I read that I should check the oil plunger thing to see if one of them has a groove, which I don't remember at all. I'll search the performance forums for anything else to check. Any other suggestions?
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[W1K1]

mine was the same, my stock 1600cc I could drive all day long around town, and not have the oil temps go over 200, hit the highway and the temps climb into the 230 range after 1/2 hour of 65-70mph. I re-jetted, changed timing, tested gauges, all sorts of things. I built a new 1904cc, same thing, I said screw it and added the thermostat and a mocal cooler and no problems since.
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http://www.thesamba.com/vw/archives/manuals/jim_martin_engine_build.php

1973 super
1965 squareback 1500E
1971 bay window westy- subi swap

[supersuk]

I'm going to install an oil cooler and hope it helps.

I also found these things to check in the performance section:

Low pressure at hot idle is most commonly-
-oil pump radial and end play
-rear oil plunger loose fit in case
-lifter bores worn

I know I checked these, but doesn't hurt to check them again when I plan to tear the engine down soon. I currently building a 2276 that should be finished soon.
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[supersuk]

Decided to do some investigation today. Drained the oil and found no metallic particals nor anything strange in the oil. Magnetic drain plug was also really clean with almost nothing on it. The strainer was really clean. I’ll open up the oil filter to see what’s inside there when I have a chance. Removed the oil plungers front and back. First problem I see is that the oil plunger by the fan is extremely loose that it’s able rock back and forth in the bore. Also the up and down movement is really rough and seems to have a ledge of some sort that I can’t see. I think what’s happening is that the plunger is getting stuck in the bore, bypassing all the oil so that I have very little to no pressure at idle. On the flywheel side, the plunger Goes up and down smooth with very little movement, but the plunger does easily fall out so it seems the bore is a little worn. I’ve been reading about Adrian’s (headflow masters?) 5/8” ball bearing mod that would cure my problem. Anyone have any experience with that mod?


Also, the sealing surface for the aluminum crush washer is all buggered up. Looks like the machining didn’t go down far enough to remove the rough sand casting. Prolly could use some silicone to seal that up, but when I tear the engine down, I’ll get that portion properly machined.

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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[supersuk]

Got some measurements for the rear bore by the fan. At the very top of the bore (in between the two oil galley holes) I get 0.6285”. In the middle of the bore, just above the step, I get 0.630”. Right below the step, I get 0.645-0.647”. Right above the threads, I get 0.648. The plunger that was in the bore measures out to be 0.625-0.627”. Here is a photo of the bore that shows the step and the buggered up sealing surface. Is the step supposed to be there? I feel like the plunger is getting hung up on that step. Here’s some pics of the bore and the step.

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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[Clatter]

I have totally been down this road a couple of times now.

The rough step at the end of the bore can be problematic.
If the plunger doesn't seat home correctly, it can cause the cooler to bypass.
John at aircooled.net used to rent out a reamer that was the correct size, and had end-flutes square, with sharp corners to dress down the plunger bore bottom clean and fresh again.
It also had an adjustable collar stop you would set so it only did a clean-up cut, and got a nice finish as well.
Eventually, too many assholes kept them, so he doesn't do it anymore, unfortunately.
(The step at the bottom is supposed to be there, BTW).
You might consider getting an end-mill finish-ground to the correct size by a tool and die guy..?

When there are loose tolerances from the side of the plunger to the bore,
It can be corrected by reaming oversize and getting the next size plunger.


Adrian's ball-valve deal is a total hoax.
You will end up ruining your plunger bore when you pull it back out.

Honestly,
For a first thing to try,
(people will flame me for suggesting it),
If it were mine,
I would try one of those booster springs they sell in a cheapo blister pack.

Can't hurt to try... Flame suit on.
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Bus Motor Build

What’s That Noise?!?

[supersuk]

Ok, that’s something I’m willing to try. I’ll buy the Hd spring set and see what happens. If that works, then I’ll run it like that for a little while. Eventually I’ll have to get some machine work done. I’m not comfortable getting a tool made and doing it myself.

Do the bore and plunger measurements look good? I couldn’t find anything about wear specs in the Bentley, unless I’m blind?
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[Clatter]

I have heard of people taking a plunger,
And gluing a perfectly-trimmed piece of sandpaper to the end.
Then, a wooden dowel is trimmed to jam inside the plunger,
And the whole deal is used like a lap, like lapping valves,
To get the bottom seat area of the bore clean and square.

Better done with a bare case, though,
As you'll need a way to clean out the crud.


Ideally, the plunger is a tight fit, but free to move easily.
Any side-to-side rattle anywhere in there is bad.
If I'm interpreting your measurements right,
You have a bit too much side clearance right through the area where the plunger travels.
This might mean that it was run many miles, likely with dirty oil?
Was your case on it's third line bore, and ready to be done for good?
Or was this a fresh case?
Side wear from an old case might be harder to fix, with an oversize plunger,
And some machine work.

If this was a newer case (newer in time especially),
Some cases from various south and central American countries are the ones known for the rough/crooked bottom of the plunger bore.
That is good, because the fix is easier, and the case newer enough to be worth putting work into.

If you go and look at Brent's fastback build,
he chased an oil temp issue until he finally put a big ol' cooler and fan on.

There are several likely culprits for your condition,
And all kinds of speculation.
Some are really just bad news.
Like how Gene Berg said how line-bored cases can cause this..


An oil cooler isn't the end of the world.
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Bus Motor Build

What’s That Noise?!?

[supersuk]

This is the aluminum case that came with the car when I purchased it. I'm not sure how many miles it was used before I purchased it, but it looked pretty good when I tore it down. Some oil leaks here and there, etc. All the bearing saddles are standard and was in very good shape, as verified by a vw machinist here in Hawaii. Too bad I never had him check the oil plunger bores, that was my fault.

Well, at least I know that a tear down is in the near future and will have this corrected! I guess I was hoping that the ball bearing mod would help because then I wouldn't need to tear the engine down. Live and learn.
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[supersuk]

Just saw this full flow adapter from CSP

https://www.csp-shop.com/en/engine/full-flow-adapter-115-431-008-22198e.html

and thought that this would work great in my application. I can get rid of the stock oil cooler and just run everything through the external oil cooler. Of course i'll have to modify the factory tins to close up the gap where the factory oil cooler was. Also for guys who do not have a full flow system (I do) it allows you to easily run plumbing and eliminates the fitting on the block right behind the fan shroud. Think it'll work?
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[Clatter]

http://www.piersideparts.net/JC1013.html
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Bus Motor Build

What’s That Noise?!?

[supersuk]

Small update, I bought the empi oil pressure booster kit to see if the pistons measure out differently from the one that was currently in my engine. Turns out that the new pistons were basically a perfect match for the bores in my engine. When inserted, the pistons went into the bore really nice with a very slight drag. I could easily pull it out with a dowel. I'll be using these pistons with the OEM springs to see if that helps. An oil cooler is also on its way. I also purchased one of those oil filter sandwich/thermostat adapters that will help regulate the oil path when cold.

Clatter - I saw that filter adapter before, but since I have one of those berg oil pump covers that regulate pressure (100psi max?), figured I didn't need it. At what pressure is it unsafe for the oem oil coolers?
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[Clatter]

Berg cover makes it all safe.
They do, however, need to be clean clean.
Used ones have been reported to stick, or hold a bit open.
Might inspect that sucker for a clean (not dirty or pitted/nicked/flawed) ball seat and strong/long spring.
It might just be your culprit?

The Jaycee thing I linked is for you to eliminate your factory pressure relief altogether,
Using another place to return your oil to the case instead of the stock valve.
Maybe replacing your relief spring with a solid rod.

Kind of an extreme solution..

Keep us posted how it works out for you.
That plunger by itself might just be enough.
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Bus Motor Build

What’s That Noise?!?

[supersuk]

Just wanted to post an update on my oil pressure problem. I had previously stated that I changed the oil control piston with the EMPI one and wanted to report that it didn't help one bit. What i'm planning to do now is to block the hole for the oil control valve so that it acts as if the oil control valve is always closed. Since I have the berg cover with the pressure relief, hoping this works. If it does, then it shows that my problem is due to the oil control valve.

I plan to get a rod machined down so that it is almost the same OD as the oil control valve ID, with a groove machined around the circumference at the top so that I can install an oring to help it seal to the bores sidewalls. I just have to make sure its the proper length. Eventually, i'll have to disassemble the case to have it machined correctly with a new piston made so that everything works as it should. I will do this when i'm finished with the other motor that i'm building, prolly within a year. No rush for me.
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[T3Yoshi]

Sorry to hear you're still having problems with oil pressure.
There is a tech article in the March 2019 issue of Hot VW on the oil relief system. Not sure if it will help but its an interesting piece about the oil plunger options/problems.
Nice to hear from you. Great thread!

[supersuk]

Thanks for the info! Ill check it out. I recently cancelled my hot vw subscription so i never would've known!
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[T3Yoshi]

No problem. Ill PM you the info

[race2fast]

Hello, I know this is an old topic but can you give me the source for the 50mm throttle body modification that you used for this project?? I'm also using stock components but with a Microsquirt ECU on my EFI conversion. I'm installing it on my Type 3 fully automatic dragster. Carburetors just don't work well with my setup. Also what size injectors did you use??

Thanks in advance for your help.

[supersuk]

The throttle body was purchased on ebay. A 50mm throttle body was way too small for my 1904 engine and choked in the upper rpm. I was planning to go turbo with this setup, but that didn't materialize and ended up selling the car.
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68 Fastback Build: http://www.thesamba.com/vw/forum/viewtopic.php?p=5396323#5396323

[race2fast]

Thanks for the quick response. Other than the high rpm restrictions from the undersized throttle body, how did the car run with the modified throttle body and stock intake runners?? Also, what size injectors did you use?? I've only got a 1641 so maybe the 50mm might work for me. At moat a 60mm could work alright.