Why most 911 leak oil trick to help
 

Just wondering if I’m the only one who does this when rebuilding a motor? i have not read or seen mention of it anyplace here.

A little trick my father taught me when i cut my teeth on my first 911 rebuild at the age of 17.. after i blew my 2.7l motor screwing around.

Use a perfectly flat piece of granite and some 220 to 600 sandpaper to block sand the piece that has gotten warped by years of over tightening i keep rotating the part by 90 deg every 30 seconds or so to avoid pressing on the same spot . sure beats spending $500 on a set of valve covers works well on all the covers and small parts it doesn't take much just hundred thousands of an inch or so and you don't have to get it perfect just the high spots.

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I've done that. If you go to a countertop store they often have chunks from sink cutouts or offcuts that they will either sell for cheap or give to you if you ask nice.

Great idea. Thick piece of glass will also work.

In my mind it is an excellent idea the question in my mind is how far can you go?

Can you do cam towers? How about engine cases? I am presuming that in any event one is cleaning the living heck out of everything afterwards, but would this help keep the case seam a little less leaky or are the risks of getting it uneven greater than any possible beneifit?

Dennis

I have never done cam towers or the case halves that would effect the bearings and typically those parts are not overtightened and warped if they are you have bigger problems. I typically do the chain housings all the covers valve and cam housings covers and that little end piece over the end of the intermediate shaft and the round piece that cover the cams cam headed and intakes ...

Agree with gorskined. If you have leak problems with the case halves or cam towers (or the tops of the heads), they aren't due to the warping covers (or things like covers, like the chain housings where they connect to the case) where we naturally try to stem the leak by applying more torque. It seems it is gasketed joints which can best use this cleanup occasionally. Just not joints sealed only with sealant.

It’s called hand lapping and I use it frequently and have forever. Even with four cylinder motorcycle heads. I like to move in a figure eight with light pressure letting the grit do the work. The issue with big pieces is finding large sheets of paper.