Broken head studs damaged cylinder

Jeff_Ragsdale · 07-30-2009, 12:19 PM

1982 911SC 3.0. It is a slippery slope, indeed. Two broken bottom studs on #6. As long as you're there leads to new clutch kit and heads machined. Upon further review, the mating surface on the cylinder was damaged from the stuff blasting out of the cylinder. Does anyone have any experience building up and re-machining the cylinder surface, or should I look for a single replacement? I don't have money in the budget for a new set of 6, I have two kids in college....

TibetanT · TibetanT's Garage

Hello there, Jeff:

I am no expert, but I do not believe there is anyone worth there salt that would do this. You will need a replacement 95mm cylinder.

What numbers are you looking for? Height? There should be a triangle with a number in it on the cylinder near the bottom which will give you this info. Also, most likely you have an Alusil cylinder. If so, I have a few of them and would be glad to help with that request. Height and weight grouping is important when reassembling since you want them to all line up properly with the cam housing.

You can PM me for details.

Welcome! You can find lots of help and wonderful people here especially when it comes to problems such as this.

Jeff_Ragsdale · 07-30-2009, 05:58 PM

Thanks. I have a reply from Bob Hindson Racing here in Kansas City that is promising. He told me to bring the old jug over and he would have a look in his inventory for a match. My shop works four 10s and takes Friday off. I will get the bad cylinder on Monday and report back.

Jeff_Ragsdale · 08-05-2009, 12:45 PM

The guy at Bob Hindson Racing said the damage was shallow and he could reface the mating surface. I found some double thick (0.5 mm) cylinder-to-case gaskets that should get it up to the proper elevation. We shall see....

john walker's workshop · 08-07-2009, 07:25 PM

you are machining all six, right?

Jeff_Ragsdale · 08-09-2009, 06:08 AM

We are machining all six heads, but only the top of one damaged cylinder.

john walker's workshop · 08-09-2009, 10:53 AM

not the way to do it. do all six. you rarely have to trim a whole 0.25 mm off them. usually way less, like no more than 1/2 of that. having one cylinder shorter than the rest is mickey mouse, regardless if you use a thicker base gasket. less than a precision job. i woudn't do it here.