Carrera 3.0 Rebuild (burned cylinder)

tfmccoy · 01-05-2006, 04:32 AM

I split the case on my Carrera 3.0 rebuild on monday night, so at least I'm making progress. The reason for the rebuild is 8 broken studs lower studs.

Unfortunately, the top of one of the cylinders (#4) is a little burned from the broken studs. The outer ring on the top of the cylinder is missing a little material. The inner ring is OK. So, at this point, it looks like I need to replace one cylinder, the heads are fine. Any suggestions on my options? The size group is 1 and the height group is 6.

Is welding new material and machining a reasonable option? How hard is it to match a new cylinder? Does it have to be in the same size group?

Second question for those of you who have installed JE pistons...Can the pistons be made for the specific size group? As I understand the off the shelf JE pistons are for a set of zero size group cylinders..95.000mm....If anyone could share with me their experience with sizing JE pistons to their cylinders I would sure appreciate it.

My intent is to bump the compression to 9.8:1, use 964 cams, update the exhaust and retain the CIS.

john walker's workshop · 01-05-2006, 07:18 AM

all the cylinders that were affected by the broken studs are going to be beat up at the top. irregular. especially on the side toward the broken studs. the heads will be beat also, but they can be flycut to a point. i suggest that you bite the bullet and go new, or if that's out of the question, find an unabused used set. on occasion, i've taken 0.10mm off the top edge to true them up, using a lathe, if they were not too bad.

tom1394racing · 01-05-2006, 01:16 PM

Tom

You have a PM from me.

len911 · 01-05-2006, 01:44 PM

I feel your pain, just went through that with a 3.0l Euro I just bought due to not broken, but loose studs! #3 on my bit the dust due to a head gasket getting pushed out. I was able to get a used set of p/c. I have 5 Nickasils in group 6 and tol 1 available. Let me know... My machininst says he can salvage the head by shaving a bit off... Lou

tfmccoy · 01-06-2006, 12:43 PM

Thanks your comments and photos. Amazingly, the heads on my car appear to be fine, they are currently at the machine shop.

The top of my cylinder is nowhere near as bad as the one you sent in the photo. However, it is still unuseable.

I would be interested in talking to you about your cylinders. Please send me a pm.

thanks

dtw · 01-06-2006, 05:04 PM

Quote:

Originally posted by len911
My machininst says he can salvage the head by shaving a bit off...

Apologies if I am stating the obvious but make sure your machinist knows that all heads, at least all the ones on that bank, must be machined equally or your cam will bind...

len911 · 01-07-2006, 04:26 AM

Oh, yes! We have discussed that issue. My machinist is excellent and I trust his advice. Does most of the work for a lot of NJ based shops and for Peter Dawe. Thanks for bringing that up! Lou