cam bearing caps

[deanjohnson]

Yesterday after replacing the cam tensioner gasket and half moon, I was tightening down the cam bearing caps. I was following Audi's recommendation of using only caps 2 and 4, gradually tightening each evenly. Everything was going great until I encountered a little resistance on the frontmost cap. Suddenly, BAM! Big crack down one side of the cap. Now that cap is garbage, and I need a new cap.

I called the local dealer, but they will only sell me an entire remanufactured head for ~$1500 when all I really need is the cap. Any ideas where to get one from? Is it even possible to swap in a cap or are these things specific to my engine? Any help would be greatly appreciated.

[AlexHurley]

You could buy a used head for like $100-$300 and cannibalize the cap, although I think each cap is groved to the cam shaft overtime, similar to pistons in a cylinder, so not sure what you would have to do to make it all work. I don't know why they didin't use journal bearings, but i'm also not an Audi engineer.

Good luck, thats a shitty situation.

[julex]

Technically the caps wear down by your specific cam pressing on them for the life of engine but I don't see why you couldn't replace it with a cap from ANY engine. Otherwise it wouldn't be possible to install new/used cam in head when it is needed...right?

Just make sure to get a cam from relatively fresh engine though without any visible grooved wear on it.

Edit: and it sounds to me like you screwed up the installation though. Make sure to observe its orientation, depending on how new the head is, one hole might or might not be sleeved and I have a feeling you installed the cracked cap turned 180 degrees around trying to force sleeve dowel into a hole that isn't bored out for it...

[deanjohnson]

Thanks guys. I'm pretty sure I didn't mess up the orientation, but it is possible. I tried to be very careful laying each cap in order on the workbench in the orientation it came off. It could be that I was a little too aggressive in tightening it down as well. I might have to buy a head to grab the cap. I guess worst case, I'll have a spare head.

Thinking more about it, is there any reason to not tighten all the caps down at once? That way the inlet valve springs are pressing against all 5 cam caps instead of just two at a time. It seems like having all 5 distributing the load would be a better approach than just two. Thoughts?

Again, if anyone either has or knows where to find just the cap, please let me know.

[cinesnow]

I have a few 2.7 & 2.8 heads that i dont care about, if you pay the shipping i can send you the cam cap you need today

[deanjohnson]

I have a few 2.7 & 2.8 heads that i dont care about, if you pay the shipping i can send you the cam cap you need today

I just got off the phone with 034 and they said that each set of cam caps is line bored to the head, so if I tried to swap a new cap on there, I'd need to have it line bored to the head anyway. Any idea how true this is? I'm looking for the simplest, cheapest option to get the car up and running.

[cinesnow]

although they are line bored, i have swapped caps in a pinch and been ok. im my opinion a couple thousanths of an inch isn't a deal breaker but you can have the whole head if you want it.

[drdimick]

I just got off the phone with 034 and they said that each set of cam caps is line bored to the head, so if I tried to swap a new cap on there, I'd need to have it line bored to the head anyway. Any idea how true this is? I'm looking for the simplest, cheapest option to get the car up and running.

Typically this is true, main's are also line honed/bored while torqued to get true round. I wouldn't doubt these are any different, if I remember correctly Mitsu 4G63 cam caps have to be line honed. While I know thats a different animal, the cam cap design is similar. Plus 034 is a shop that I would take their word as fact.

But if you are willing to take a risk, the cam cap is aluminum and the cam is steel, I think. You risk snapping a cam in half, or pissing aluminum particles into the oil but you can just let the cam woller that bitch out to where it likes, that could be the trailer park coming out in me though.

[ddillenger]

You can't just swap the cam caps, just like you can't just swap main caps.

If you can find someone to line bore, go nuts. If not, replace the head.