Itinerant Air-Cooled

'77 fuel injected two liter bus with hydraulic valves

This engine certainly has had some drawbacks. Found it in a picknpull and sat in my garage for years.
I needed an engine and tried to put this one back in service. After new rings I scavenged two mismatched heads and had them rebuilt by a local builder. He said they were workable. I installed the heads andI couldn't get it to run and had it towed to this same vw garage and they couldn't get it to run much either. I got frustrated and brought it home.
Tristessa fooled with it and we got it running but it is difficult to start and runs weakly.
After being bummed about the situation I recently went back to basics, adjust the valves, where I found that I can't adjust them. Even with the adjustment screws backed all the way out the #1 exhaust, #2 intake, #3 intake, and #4 exhaust rocker arms are pressing on the valve stem. No clackety clack.
Did I waste my money on the heads or can I maybe use shims under the rocker arms?

Thanks

Joseph

You could, but it screams bigger issues. Take the rocker arm off and give them a look for excessive protrusion. I would think the heights of the valve stems coming out of the heads should be uniform. If they are longer, it suggests a dropping valve. But since the heads are fresh, it's an ugly thought you tell yourself couldn't be the problem. From my experience, it could be. Don't rule it out. Spacers could work, but that's a wide range of valve geometry that shouldn't be there.


neal

look to see if they used the aluminum pushrods vs the shorter steel ones for a hydraulic cam. The aluminum ones are for solid lifters and longer!

Mismatched pushrods could explain it.

neal

ruckman101 wrote:Mismatched pushrods could explain it.

neal

As could mis-matched lifters.

Checked and the pushrods are steel and I don't know how the lifters would matter as long as they were all the hydraulic type. And no I didn't mix them up.
I've about come to the conclusion that these heads just aren't going to work and i need to search for another pair.

Joseph

mentalQtip wrote:Checked and the pushrods are steel and I don't know how the lifters would matter as long as they were all the hydraulic type. And no I didn't mix them up.
I've about come to the conclusion that these heads just aren't going to work and i need to search for another pair.

Joseph

Shim the b*tches and run the da*n thing. Why not? Have fun. Experiment! If they are ALL whacko, that is a good sign that it is merely architectural idiocy, not some dire recessed valves.
Colin

Amskeptic wrote:Shim the b*tches and run the da*n thing.

That's pretty much what I told him the other night .. and apparently pretty much what his wife told him, too.

Ok, I scrounged and found washers that would fit all the way to the base of the studs and I adjusted them from no slack to 1 and 1/2 turns in. Started with difficulty but seemed to have a little more power than before. I've driven it several times now and it stays hard starting and doesn't really want to idle 'til warm. After idling awhile sometimes it just slows down and dies.

Joseph

mentalQtip wrote:Ok, I scrounged and found washers that would fit all the way to the base of the studs and I adjusted them from no slack to 1 and 1/2 turns in. Started with difficulty but seemed to have a little more power than before. I've driven it several times now and it stays hard starting and doesn't really want to idle 'til warm. After idling awhile sometimes it just slows down and dies.

Joseph

That makes this an open inquiry of vast possibilities. Do your due diligence. If it is running poorly cold but better warm, check the mixture when cold. It is either too lean or too rich. Pull off the vacuum hose that leads to the fuel pressure regulator from the intake plenum. Does the idle improve? Too rich. Does it die, might be too lean.

What is the idle speed when warm? Is it less when cold? It should be more. It has to be, to paddle through the thick cold oil.
AAR is responsible for a sufficient cold idle speed. Etc.
Colin

Ok then. Fired it up and ran back to the engine and pulled the vacuum hose. Rpm quickly jumped to about 1800+. It held for a little while and then dropped down and would have died if I didn't replace the hose. With the hose on it tends to idle at about 650 or just slows even more and dies.

Next went to AAR. 30 ohms resistance and test light while running verified current to heating element.
Can I consider the AAR as checked clear?
Also while running I checked the AFM wiper and pushing CCW caused an increase in rpm. This was with the engine somewhat warmed up.
So pulling the vacuum hose off increased the rpm when cold, meaning the engine is running rich. Moving the AFM wiper CCW increased rpm suggesting a lean condition.
Right?

mentalQtip wrote:Next went to AAR. 30 ohms resistance and test light while running verified current to heating element.
Can I consider the AAR as checked clear?

Umm, all you've done is confirm that the AAR heating element isn't open (as in open circuit, ie. infinite ohms).

You haven't checked that the AAR is open sufficiently when cold, or that it is closing up when warm. You'll need to pull it out of the vehicle to do that, or get creative with some inspection mirrors (removing the AAR will be simpler, and gives you the opportunity to inspect the pesky AAR elbow)

Note idle RPM when warm, shut off engine, remove and plug both ends of the AAR intake hose, restart engine and note RPM.

When cold, start engine with AAR intake hose blocked as above and electrical plug removed, and note idle RPM. Reconnect hoses, reconnect AAR plug, restart, and note idle RPM.

They should give extremely street readings on a yes/no condition of your AAR functionality. A true and proper test requires removing the unit and checking for open/close when cold/warm like SlowLane says. Here is a (greatly sped up) video of a Porsche AAR opening up over the course of 10 minutes or so.

https://www.youtube.com/watch?v=FO6BFmDrdSE


Good luck!
Robbie

Hello,

I just disassembled a '77 and it had solid lifters.... which seems to be correct based on the engine number. Are you sure you have hydraulic lifters? Solid lifters would require a matching cam shaft and push rods--and a different method of valve adjustment. Maybe a PO or uninformed shop did a mis-match? Might be worth checking. I'm particularly interested as I have and '80 that I'm thinking of converting to solid lifters as I only plan to use the vanagon occasionally during the summer and don't want to go thru the issues I've had with bleeding the hydraulic lifters.