do my cylinders need honing?
10-02-2004, 11:06 AM
#1
Race Car
Thread Starter
do my cylinders need honing?
i am in the process of rebuilding my S engine (spun #2 rod bearing at 126K miles), and the block has been cleaned by the machine shop. according to them, the cylinders and pistons look really good, and the factory manual says to hone only if replacing the cylinders to help the rings seal. he has found the appropriate honing solution, but doesn't think it is necessary to hone.
what do you all think?
otherwise, the engine is close to going back together. the crank has been ground, the rods need to be examined, and the head needs all the valve guides replaced, plus two valves replaced. it should be good to go within the next month.
what do you all think?
otherwise, the engine is close to going back together. the crank has been ground, the rods need to be examined, and the head needs all the valve guides replaced, plus two valves replaced. it should be good to go within the next month.
10-03-2004, 11:21 AM
#6
Race Car
Thread Starter
thanks, then "nope" it is. engine should be going back together soon.
yee-haw (that's oklahoma talk for "i'm gonna build a sick ride")
yee-haw (that's oklahoma talk for "i'm gonna build a sick ride")
10-03-2004, 11:03 PM
#7
Drifting
No...and thats good! An Alusil engine job is a time-consuming, expensive process. Make sure the crankshaft is polished, though. Better yet- pay the extra saved by NOT rebuilding the motor and get it lightened, or spin-balanced to 0. It will be so smooth. They say if an Alusil engine block is treated right- the re-application of Silicon may not be necessary for many thousands of miles later.
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10-03-2004, 11:54 PM
#8
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Um.... Alusil is not a coating. The silicon particles are mixed in with the molton
aluminum and are in all the block, through and through. You only hone if you
want to go up to the next size (over sized, 100.00, 100.5,etc) piston $$$.
If your bore is within spec as you said it was then you can just re ring your
pistons and go but the factory says to buff (cyl) with a silicon paste to achieve a
dull or matt finish. This dull finish will help break in your rings properly.
This buffing removes very very little metal. If your mech doesn't know this,
IMHO either educate him or get a new one. (SUNNEN is a good source for silicon paste)
This seems to be a subject that confuses and a typical V-8 cast iron block
kind of machinist can ruin an alloy aluminum block in a $econd.
Back to lurking now.............LP '86 951
aluminum and are in all the block, through and through. You only hone if you
want to go up to the next size (over sized, 100.00, 100.5,etc) piston $$$.
If your bore is within spec as you said it was then you can just re ring your
pistons and go but the factory says to buff (cyl) with a silicon paste to achieve a
dull or matt finish. This dull finish will help break in your rings properly.
This buffing removes very very little metal. If your mech doesn't know this,
IMHO either educate him or get a new one. (SUNNEN is a good source for silicon paste)
This seems to be a subject that confuses and a typical V-8 cast iron block
kind of machinist can ruin an alloy aluminum block in a $econd.
Back to lurking now.............LP '86 951
10-04-2004, 12:05 AM
#9
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HI, this link explains clearly the diff between cast iron and aluminum with the silicium compound in the alloy. http://www.babcox.com/editorial/ar/ar90058.htm It helped me to know that a good cylinder wall doesn't look shiny and smooth, but needs to be crosshatched. Wore out cylinders look smooth. In the porsche engine, just the step that re-exposes the jagged silicium molecules the then slightly smooths these jagged peaks will be good.
robin
robin
