2012年12月4日 · I was wondering if anyone knows the specs for the valve recess from the cylinder head deck... my head just got surfaced .008", but it's not the first time it's been surfaced, and from my understanding it's the valve clearance …

2013年5月10日 · I set the recession of the valve to .035 so that way when it's milled, the recession will be around .030-.032". The specs are .013"-.027" but there's been reports by many of piston to valve clearance issues on heads with valve recession well into the specifications.

2012年1月24日 · Valve Seat Alloys. Every valve seat supplier makes a big deal about the advantages of their proprietary alloys. And rightly so. The strength, hardness, wear resistance and thermal properties of a valve seat alloy can make or break it depending on the application.

2019年2月22日 · Full rebuild heads get seats intake and exhaust, along with new valves. Be sure to check pushrod/lifter preload as they are often close to being bottomed out. Use the .059" shorter 6.4 pushrods.

2017年3月7日 · All direct-injected Deere diesels got set with the valve-head depth (not valve seat recession) with the intakes at .030" and the exhausts at .050". We used to be able to get valves with extra thick heads from TRW that helped get the specs back without milling the head or installing new seats.

2015年11月13日 · All valves were below spec coming in between .009 and .012 of valve recession. He now has to recess the valves back into the heads. I just wanted to put this out there because people commonly say that up to .008 is ok on a virgin head.

2015年6月25日 · For those of you not familiar with valve recess, there is a spec for the amount of recess from the fire deck (surface) down to the valve head fully seated. It is .013-.027” (we use .020” +/-.002”) intake and exhaust valves.

A valve recess is a recess in the piston head. Since diesel engines have high compression ratios and small gaps between pistons and cylinder heads, they are provided with valve recesses to ensure that valves do not hit pistons when valves are lifted.

2018年6月18日 · A valve seat must actually do several things – it must support and seal the valve when the valve closes, it must cool the valve, and it must resist wear and recession. Consequently, a performance valve seat material should provide a certain amount of dampening to help cushion the valve when it closes at high rpm.

2015年8月1日 · Gave the heads to my machine shop and told him to deck, check thickness and valve recession. Says he took off .005 and were all good. Put back together and torque down, and of course one of the valves was hitting the piston.