AAZ vanagon project thread

[zuhandenheit]

Given the circumstances, should I just pull the head and start calling machine shops?

[zuhandenheit]

Here's a quick question: Assuming I can get it fixed, can I reuse the head bolts, since the engine hasn't been run?

[zuhandenheit]

So, I pulled the cam and checked it out. One of the bearing surfaces looks bad, but there wasn't much else to look at.

I pulled the followers and reinstalled the cam, and sure enough, with even a little torque on ANY of the caps, it won't turn. I guess that does suggest that the shop "faced" the head. If the caps were from a different head, I wouldn't expect them to all be slightly too small . . .

This looks bad to me, please let me know what you think:

[zuhandenheit]

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[92EcoDiesel Jetta]

I am no expert on machining heads. If only the piston side of the head is faced, it should not cause the cam journals to "tighten", should it?

[zuhandenheit]

No, it sure wouldn't, but I wonder if they did something to the top . . .

[Gizmoman]

I am no expert on machining heads. If only the piston side of the head is faced, it should not cause the cam journals to "tighten", should it?

I asked about the faced head because if it was warped from heat and was then faced without bolting it down to a solid fixture (using the same torque procedure as bolting it to your block), it then gets faced with a slight crown (due to the warp).
Now, when you bolt it to your flat block it bends the cam and causes it to bind. Keep in mind, we are only talking about a tiny amount.
EDIT If you don't know the head was faced, there's a very good chance your's is not.

If it were mine and I was as far along as you are, I would polish the rough journal(s) with some very fine emery cloth. If it's still stiff, try some aluminum foil shims between the caps and the head. You could also make a stud that fit the tapped hole in the end and drive it with a drill motor (not too fast) while you squirt oil in the journals and tighten the caps.

[zuhandenheit]

Aluminum foil shims? that's an interesting idea. It'd sure be nice to avoid pulling the head . . .

[zuhandenheit]

Well, I looked into line-boring / honing the head, but no one will do it. As far as I can tell, the only possible way to save this head is to try to shim the caps or something.

[zuhandenheit]

I've tried tightening the caps with feeler gauges between the caps and the head, and discovered that I need about .2 mm for them to clear. That's more than I might have hoped for . . .

Also, they all seem to be about the same, which is weird.

I could try making shims and using plastigage to check that the clearances are relatively even with the shims in place. I'm not sure what else to do.

[zuhandenheit]

Well, with shims I get pretty even clearance on the cam, but of course there's a little gap between the caps and the head, which is probably bad news.

[Gizmoman]

That's the beauty of the foil. Its so thin you can stack some on, put the cap on tighten it, and use an exacto knife around the cap.
2mm holy moly, that's a lot! Did you use two feeler gauges or only one in one side? Also, did you "polish" the journals?

[Smoker]

He said .2 mm, not 2 mm...  either way, that whole situation would be enough for me to start shopping for another head.  But that's just me.

[Gizmoman]

He said .2 mm, not 2 mm...  either way, that whole situation would be enough for me to start shopping for another head.  But that's just me.

Oops,
.007 is probably one or two foils per side unless its the heavy duty type

[zuhandenheit]

Well, I pulled the head, because this was enough to give me reason to distrust everything about the motor. Here's what I saw:






I'd love to hear your thoughts. I'm inclined to just buy a new head, but I want to get a sense of the trustworthiness of the rest of the motor, first.