Valve Reliefs and Piston Work?

Kroner96

Kroner96

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Nov 27, 2007
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Im getting valve reliefs cut into my factory 12v pistons and wanted to know how much would be a good amount to take out? I was thinking .100 but want to get some oppinions before it gets done. Also I was told I could machine the lip out of the bowl. What kind of grind should I get and how much is safe to remove?
 
i bought mine fron haisleys. I had .200 valve release cut in them and the bowl opened up. And also .010 off the tops. these were a stock style 12v Mahle piston to start with


what are your plans for the motor is the question
 
Its a puller. I figured while the motors out I should put the reliefs in. I know they are not necessary for my h2 but I would like them just in case.
 
.250"?? And to think I thought .050" was enough relief for a pretty wild cam! lol. I think .100" would be plenty unless you are planning a 1k+ puller IMO. I am going to do .050"-.100" on my pistons just incase as well, wil give extra room for valve float or a bigger cam later on.
 
Adam is your stuff at farmers, he was working on a 12v head yesterday in said he had some pistons to work on too.
 
That being the case, I would go very conservative on the amount of material removed from the pistons. 2.6" trucks like higher compression ratios.
 
If you need to have valve reliefs deeper then .100, then the cam profile is wrong for a diesel. to tight of lobe separation angle , or too lazy.

In addition, on a 2.6 puller you need to keep as much compression as possible above 16 to 1
.
 
Pistons are still in the block Jordan, Not sure where they are going yet. I was told it would be better to machine the lip off and take the knob out of the middle of the bowl. Yes it will be a 2.6 puller.
 
Carl At Polydyne will plunge cut and coat pistons for you . They do a great job. they are not just some caotings place but where most of the NASCAR team get their work done , and well and a lot of the NHRA pro Stock and Comp guys

Performance Coatings by PolyDyn
 
Dang Adam are you going to be able to have it done before season starts back up. Are you going to be at sturgis march 20, dont look like im gonna have the cummins back up and going by then, so i may be playing with the dmax.
 
Im wanting to make sturgis but with my luck it will be june before its done. My clutch has been at a shop for close to 3 months now and they are still "waiting on parts". What is an ideal compression ratio to run in the 2.6 class?
 
haha yea I know that. The part they are waiting on is the flywheel insert, which has to be made since the SB insert wont work with my new discs. Should have been done a month ago but someone messed up when measuring and it wouldnt fit the first time.
 
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