80 Vanagon It sounds like a compression leak

Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

I had a valve stem stripped off where the keeper goes on had that fixed and now it sounds like I have a compression loss when revved or put under a load http://www.thesamba.com/vw/forum/album_page.php?pic_id=235474

mightyart · Posted: Sat Oct 29, 2005 9:05 pm Post subject:

Do a compresion check, You probably have a dropped seat. Most broken valves I've seen have been caused by something, they usually don't just come apart. Valve damage can be caused by things like hitting the piston or stretching. Do you have a loss of power? Does it sound like it's missing?
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Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

The heads were repaired and had them off they look fine. I had the first time when I assembled it had used the metal gaskets that came in the gasket kit, I have done 1600's many times and never used a gasket between the heads and the cylinders but the machine shop and the parts house(Veeparts) in National City said you use them, so I did thats what I thought was the prob, so I removed them put it back together same problem. I replaced the rear seal on crankshaft seem to alot end play in the crankshaft. Is it possible I have the valves adjusted wrong and that would make it sound like a head leak or should I retorque the heads???? I'm stumped. Would'nt a leakdown test give me all the answers or would a compression check do the trick.

Randy in Maine · Posted: Sun Oct 30, 2005 2:24 pm Post subject:

Perry what year do you have?

You need to "zero out" those hydraulic lifters. http://www.ratwell.com/technical/HydraulicLifters.html

mightyart · Posted: Sun Oct 30, 2005 3:52 pm Post subject:

The shims between the head and the cylinders are supposed to be there, the auto parts place didn't fib. Zero out the valves like randy said and try again.
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Captain Pike · Posted: Sun Oct 30, 2005 5:26 pm Post subject:

LEAK DOWN TEST TIME Think

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Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

It is a 1980 with almost 60,000 miles on the rebuild in 1997. There was not gaskets or shims between and the top of the piston and the heads when I removed the heads. I did put the gaskets or shims on the bottom of the piston liners and the block. Do I need to put them back in ??? This was an engine purchased from Fast German Auto in Santa Anna I beleive it was rebuilt not an exchange with new AMC heads they nailed me 600$ on the core charge cause they said my old ones were no good. I did not leave the heads there I got them back and ended up using the valves out of the old heads when one of the cheap valves they used stripped the grooves out where the retainer clip holds on the spring. The old valves where orignal VW with the stamp on them. The machine Shop said they were of better quality so I used them with a couple of new seats and all new guides and grind job. I'll post a pic of the damaged valve tomorrow.

mightyart · Posted: Mon Oct 31, 2005 7:14 am Post subject:

I'm right in the middle of doing the same thing, kind of.
http://www.thesamba.com/vw/forum/viewtopic.php?t=139054
I had to look close at my old head when I took it off to see the shims, they just looked like part of the casting. The head I took off was a vw head, the used one I got was AMC, big differance in casting quality. Things like the spark plug holes, vw head nice and clean threads, amc treads pited and rough. Both plugs held in tight, but I can see someone striping the amc plug holes alot easier. As far as If you really need the shims for it to work I don't know, but the Bentley shows them too, so I made sure mine went back in. This head has to hold up just till, the first of Feb., When Uncle Suger gives back the extra tax money they took.
Them I'm at least getting a set of Jake Raby heads on this. Since It's the begining of winter with cooler air temps I'm not as worried as I would be in July. Wink

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Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

Can I just get away with compression check it my take awhile to round up a Leak Down Tester little short on funds
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Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

Have you seen this revision http://www.dolphinsci.com/techbull.html

mightyart · Posted: Thu Nov 03, 2005 3:39 pm Post subject:

that website only has half the thing about the aluminum shims.

"There is a technical bulletin published by Volkswagen in 1990 that describes a few changes they make upon reassembly. First, eliminate the head gasket and replace it with a 1.6mm aluminum shim (#071 101 34), or a steel one, at the base of the cylinder between the cylinder and crankcase. Increase the piston / cylinder clearance to .045mm +/- .005mm. Cut a 1.5mm deep oil groove in the large end of the connecting rods into the thrust surface on both sides to splash oil on the bottom of the pistons. For a more detailed description of these modifications, send an SASE to Bob Donalds, and he'll give you a copy of the bulletin"

this was taken off Boston Bob's website, lot's of good aircooled info there.
http://www.bostonengine.com/articles/finalt.html

check the shims you have with a magnet, if they stick they are steel.
the ones I put back in mine were steel.
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Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

did the compression check 100 on 1,2,3 and 110 on#4. It still sounds like the heads leaking when rev it quickly or put under a load. I'm going to check the exhaust nuts coming off the heads. Is there any way to retorque the cylinder heads without removing the motor. Pray

mightyart · Posted: Sun Nov 13, 2005 6:17 am Post subject:

I did mine with the engine in, you just have to remove some stuff to get to it. Did you zero out the valves with the engine warm, or after you ran it awile? the lifters need to be good and solid when you do it.
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Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

yes I did the zero of the lifters. I had one the #2 exhaust that took awhile to pump up. What is the most I could tighten the heads can I get away 30ft lbs of torque or do I have to stay at the max that Bentley say of 24ft lbs???? d'oh!

I Realize they do expand and tighten up but does everyone only torque them to 24 ftlbs and no further or do you maybe sometimes have to increase it slightly to make sure the heads will seal and not loose compression or leak.

Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

Randy in Maine · Posted: Sun Nov 20, 2005 7:18 am Post subject:

I would hold tight with the Bentley suggestion.

Nothing wrong with 100 psi and was there any change when you gave it the squirt of oil?

Perhaps a leakdown test would be of value.

Does thing thing have an EGR valve?

Perry Griffin · Samba Member Joined: October 29, 2005 Posts: 13

mightyart · Posted: Wed Dec 07, 2005 10:47 am Post subject:

a squirt of oil in the plug hole will seal any cracks that might be in the rings for a short time. So if you squirt oil in the hole and the compression goes up a good bit, your rings are the place you are loosing compresion not the valves. not very scientific, but it works ok.
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