head/cylinder replacement?

Feb 26, 2005 3 Replies

Hi all



In furthere stripping of my 75, I found that one cylinder has not been sitting right on the head because one can tell that this is where it must have lost compression. When I did a compression test, I found that cylinder lacking so now it makes perfect sense. The mounting nuts/studs withstood the mounting torque, so it wasn't due to a loose mounting nut.



My question is would it be best to just get the head machined or replaced? I've seen original German heads and cylinders for sale and was wondering if buying them is just a better option since machining comes at a cost, not everyone can do VWAC heads and most of the time you have to ship the hardware to get it done. Pricewise, it is almost a wash and there's nothing like shiny new hardware. :) Does this make sense or is it best to stick with the original equipment in this case?



Also, if I don't replace the cylinders, since I got the cylinders/pistons off is it just a good practice to replace the rings? They look good but it would be easy to do now, right?



Thanks, guys! Remco


I can't decide for you what to do, but this info: '75 FI heads are different from the earlier carb heads - valve size for one. I would carefully inspect that head for cracks, especially around the exh seat and plug hole. If you have to replace, do both sides.

If you re-ring, the cylinders should be honed. Most guys won't bother re-using old cylinders; if budget is tight, go for it...

Speedy Jim

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I heated up the head a little and think I found something that looks like a crack near the plug. Thanks, Jim, for the sanity check -- replacement was the direction I was leaning towards.

Also, after cleaning and looking at the rocker arm a little closer, I see blobs of small welds in some spots. One appears to have been ground down but not all the way, almost like it is a balancing method. It actually looks original and does not appear to be a fix -- what is this for? Is this some sort of way of balancing the rocker arm? (didn't think that was needed)

Remco

IIRC that was merely to close off a drilling for an oil passage. Nothing to worry about...

Speedy Jim

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