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aigel aigel is offline
Now in 993 land ...
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Join Date: Mar 2003
Location: L.A.-> SF Bay Area
Posts: 13,544
While these look clean, I can hardly make out hone marks. Is that your camera, or is the cast iron harder than your average cast iron block and hence gets machined less by the hone?

I think what you have is what you will have to work with and as long as you do not expect 100k miles out of it, rather than about 50k, you should be fine.

If I were you, with the fine hone, I'd plan on breaking the engine in under load. That means having the car ready to DRIVE to break the engine in. This way the cylinders will see more pressure, pressing the rings harder against the cylinder walls. If you can't see yourself breaking it in driving, you may consider renting dyno time and breaking it in on a dyno - under load, of course.

Bore gauges are a must, otherwise you fly blind. Did you check piston to cylinder clearance? You can get a coarse idea by inserting a feeler gauge. The better way is to measure the pistons and the respective bores. You may be able to match pistons with cylinders for better tolerances.

You can measure overall taper of a cylinder with the "ring and feelergauge" method. You use a piston ring (new or old) and shove it into the bore. I like to use a piston to level it perfectly in the bore. Then measure the piston ring gap. Measure in 4-5 areas of the bore, from top to bottom. This basically leaves you with the variation in the circumference of the bore. It is not an accurate method but if you factor in a safety factor, this method is capable of giving you a go / no go for re-ring, at least regarding the taper, not really the out of roundness.

Report back the numbers and I will be happy to help estimate if your overall taper is tolerable by looking it up in my books.

Hope this helps,

97 993
81 SC (sold)

Last edited by aigel; 01-09-2005 at 11:36 PM..
Old 01-09-2005, 11:33 PM
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