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Old 05-10-2010, 06:17 PM   #83
PEI330Ci
58mm of Bliss
 
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Join Date: Jul 2003
Location: PEI,Canada
Posts: 3,991
My Ride: 330i, 330Ci
This is my own view on the topic, so please understand it is an opinion based loosely on my own experience and second hand information. I haven't done stress testing myself, so I don't have a solid answer.

I am told that when the block is overheated, the alloy softens. I confirmed with a number of professional race teams what this value was, and they all seem to agree that anything in the 240 degree area with regard to water temps was really bad.

Now I haven't experienced this myself with a running engine, but it does seem to be the case for those that have had to re-thread a block.

So in this case, if a person did have a stud pull out, it is my opinion that the block is compromised and should not be re-used.

If a person wanted more securely fasten the head to the block, it is my opinion that most direct way to do this is to use big (thicker) head studs. This does 2 things: 1.) Increases the tensile load capabilities of the fastener. 2.) Increases the total thread area in contact with the block.

#2 is basically what you are doing with a timecert, but then you are still using the same diameter fastener as before.

For those that have chosen studs and timecerts, it is going to be stronger than OEM. Even stronger would be larger head studs and no timecerts.

From weakest to strongest in my opinion:

1.) OEM
2.) 10mm Head studs (I prefer Raceware)
3.) 10mm head studs + timecert
4.) 11mm head studs

You can get 11mm head studs directly from Raceware for a little bit more than the normal 10mm head studs. With both timecerts and 11mm studs, you will have to re-thread the block. This is best done with the block completely torn down for other machine work like boring/honing for new pistons.
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