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Join Date: May 2005
Location: Cambridge, Ontario (Ayr)
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Cylinder Measurements - Are these Good?
Hi Guys,
Last year I sent my max moritz pistons and cylinders to Henry Schmidt. He spec'd them out and reported they were good. Now I am looking to change the pistons that have deeper valve pockets. At this point I can install new pistons or replace the entire set. If I reuse the cylinders, how good are these specs, as I'm unfamiliar with the allowable tolerances? 
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05-29-2007, 01:10 PM
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Location: Momence, IL 60954
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Those measurements look fine to me. How do the pistons measure that you are going to use? I'm assuming they are used from another set. Just make sure they have the proper piston to cylinder clearance if they are from a different grouping.
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Charles Navarro President, LN Engineering and Bilt Racing Service http://www.LNengineering.com Home of Nickies, IMS Retrofit, and IMS Solution |
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05-29-2007, 01:22 PM
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Hi Charles,
I was looking to buy a new set of pistons, but wanted to make sure the cylinders are in spec. Can you or someone explain what grouping means? For example, I've heard the mahle cylinders can have a group of 0,1,2? Can one tell from the stamp on my cylinder? 
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05-29-2007, 01:31 PM
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Constitutional Liberal
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All those numbers are in mils. or 10,000th of an inch. All of these numbers are under .001".
Mahle calls out .004" as the wear tolerance. I would be surprised if brand new cylinders were any closer. Run them, they are great.
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Jim “Rhetoric is no substitute for reality.” ― Thomas Sowell |
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05-29-2007, 03:04 PM
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These numbers show almost no wear. The group numbers are next to the height numbers on the top of the base of the barrel. The height number is inside a triangle and is a 5 or 6. The group number for the bore size is listed in all the spec books. The total difference between groups is very small maybe .001 inches.
-Andy
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05-29-2007, 06:15 PM
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Henry did a scotch brite hone on these. I then ran them for 200 miles. Should I have them honed again? I will be pulling them out this weekend.
They would be going with a new set of mahle motorsport pistons.
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05-30-2007, 04:27 AM
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The scotch brite doesn't hone them - it's a deglazing more than anything. It wouldn't hurt to have them re-honed properly but more than likely, 200 miles on them didn't change the finish on the bore much. A photo of the bore would help clear things up if you have any doubt.
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Charles Navarro President, LN Engineering and Bilt Racing Service http://www.LNengineering.com Home of Nickies, IMS Retrofit, and IMS Solution |
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05-30-2007, 04:55 AM
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Pics of my 98mm Mahle Cylinders
Wondering if I should scotch-brite these and/or if these look good.
thanks! From the top of the cylinder:  From the bottom: 
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06-03-2007, 04:30 PM
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