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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
just send them to me I can drop them off at the machine shop and they will drop them in the cleaner tanks overnight,
they will come out looking brand new and maybe the oil holes will magically apear
it's all a plot to make the cylinder walls last as long as possible...if they're slathered in oil constantly, the rings will barely wipe the alusil
if you have a moment (or maybe you have this on file) could you measure the compression height from piston pin center to top of piston? i would think it to be around 42.6mm.
In my opinion, and this is just an opinion, whether the oil holes are drilled thru or not depends on whether the piston designer wants more or less oil on the bore walls. Holes that go thru remove oil from the bore walls. Holes that don't go thru simply act as temporary reservoirs for excess oil. Personally, I think that 928 GT and S4 have too much oil on the bore walls even with those drain holes drilled thru and the pistons should have those holes drilled thru if factory doesn't do it. Otherwise, the excess oil on the bore walls leads to rings unseating, excessive blow by, breather system problems, and oil making it to the combustion chamber both thru the bore walls and thru the crankcase breather.
Is it possible to hold something that is round with an axe?
Yes, except Kibort will make 75 posts an hour in a new thread about how 2 cinderblocks and a come along will hold pistons without scratching only if he does it at the track, and the cinder blocks are lightly coated with amsoil.
Yes, except Kibort will make 75 posts an hour in a new thread about how 2 cinderblocks and a come along will hold pistons without scratching only if he does it at the track, and the cinder blocks are lightly coated with amsoil.
Or spend a couple weeks trying to lightly say that drilling the holes in the pistons caused some odd failure because they are different than what he runs. And keep repeating the same thing, in different ways, to try and get someone to reaffirm what he already believed to be true, even when it was wrong from the start.
05-31-2018, 07:46 PM
Fantastic Piston Update for '87-'91 Engines
