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J and M Machine · 03-09-2015, 06:18 PM

I am currently working on two Jaguar 4.2 six cylinder engines.
The pistons are made by Mahle which purchased Clevite.

Since the spec was very tight clearance I decided to call and make sure if it was correct for an engine that was 47 years old.

According to the tech on the line that these pistons are designed for .001" "thousandths" clearance .
This is due to the fact he mentioned that they vibrate the mold at high frequency and the material used is very stout. He mentioned that the Aluminum used is very stable.
He also threw in that the new 4.7 Dodge engines pistons have a coating on and the clearance for those is tight enough to scuff off the coating during installation.!

03-09-2015, 06:18 PM	#5
J and M Machine Senior Member Join Date: Oct 2010 Location: 40 Mt.Vickery Rd. Southborough,MA 508-460-0733 Posts: 369	Re: Tight Piston Clearance, Not Model A I am currently working on two Jaguar 4.2 six cylinder engines. The pistons are made by Mahle which purchased Clevite. Since the spec was very tight clearance I decided to call and make sure if it was correct for an engine that was 47 years old. According to the tech on the line that these pistons are designed for .001" "thousandths" clearance . This is due to the fact he mentioned that they vibrate the mold at high frequency and the material used is very stout. He mentioned that the Aluminum used is very stable. He also threw in that the new 4.7 Dodge engines pistons have a coating on and the clearance for those is tight enough to scuff off the coating during installation.!