diamond forged .020 pistons

[razorryan10]

in the middle of collecting parts for a lly motor build, question i have is how much daily driving can be done on a set of forged pistons piston/wall clearance is .006-.0065
power goal of a 1000hp and daily around 800hp

got a good deal on forged pistons only reason for going that route

 

[Chevy1925]

I’d tighten up piston to wall clearance a bit but there are guys that have put thousands of miles on forged pistons before. Rings just see more wear. I’ve not seen anyone do a ring gap comparison after high miles put on them. Might have been one or two in the past??? Can’t remember.

Most guys are on cast pistons in that range where it’s a non issue and much tighter piston to wall clearance.

 

[razorryan10]

alright sounds like a non issue for me to worry about, ill just tighten wall clearance up to .003-.004
over building it for my needs, planning for future upgrades

 

[Chevy1925]

.004 would be as tight as I go. There is no “range” if the machine shop is good. If you want .0042, they can hit that to the largest piston. The only range is the little bit of piston dia but you should see next to none on new pistons

 

[razorryan10]

alright thx

 

[Bdsankey]

If your goal is around 800whp with a couple trips to 4 digits IMO a cast piston would be better suited. As for PTW, my CP forged were recommended at 0.006-0.008 and provided a handy formula to punch in for diameter and usage. My pistons went in at 0.0065" based on their formula and conversations I had with other engine builders.


The problem with going outside the manufacturer's spec is that the forged pistons grow substantially with heat. I don't know what material Diamond uses but it may be worth looking at what the thermal expansion rate is on that material.

 

[razorryan10]

have talked with diamond they do recommended a .006-.007ptw for the pistons

 

[56taskforce]

Stay with cast for street driven. Unlike gas power the biggest drawback isn't cold piston slap. In deisel applications the big drawback to forged pistons is ring land wear.

 

[Fingers]

The problem with Forged on the street, IMO, is the blowby. To have enough clearance when you lean on them, you have to accept the looser clearances. Ring wear is another issue, but there are steel land forged available to deal with that.

Just know what you are getting into.

 

[razorryan10]

blowby im ok with it has alittle bit now as it is lol, if i can get 20k-25k kms out of them that will take 3 years or more by then the truck will be rutted out again anyway from being in canada