I have a block being bored as I write this and I also talked to the machinist about cutting into the rods.020" toward the fat end to lower the compression and he sugested I use a steel racing headgasket that is machined to mate to my block.

The cost is a little more for the rod work but I thought I'd put this up incase anyone had an opinion about the headgasket or cutting into the rods to lower compression.

IIRC, Grape was going to do something similar about cutting the rods. The steel gasket he is talking about is probably going to need reciever grooves cut into your block to accept o-rings. I've heard it is very hard to get steel gaskets to seal good in daily drivers.

I know of a guy running the steel head gaskets QM, he's suppose to have one of the highest performance 6.5's around here, he can't keep gaskets in it and is using studs as well!

I have access to a company here locally that will make me copper head gaskets for the 6.2/6.5 if requested.

I agree that it probably wouldn't be that great for a daily driver situation.

I would suggest doing it the right way rather than trying to do something funky to save a buck, OR leave it at stock compression and moderate HP levels....

So what's the down fall on daily drivers? Expansion and contraction as opposed to down the track a couple times one day a week?

So what's the down fall on daily drivers? Expansion and contraction as opposed to down the track a couple times one day a week?

That's what I have heard, not specificly in the 6.5 application though. On anything, be it a tractor or diesel pickup the constantly changing rates of expansion and contraction apparenlty wreak havock on the oil and water port seals... The good new is that usually there are never compression leaks.:lol:

the rod thing will not save you money. there isn't but maybe .005" you could go at the most in a stock bushing before it becomes too thin on the bottom side. By the time you have your own bushings made with a larger OD to give you enough material to get the pin down, then having the rod re-sized, you will spend well over $200.

I talked with jamie at DD after i spoke with cometic about building a thicker head gasket that could withstand more power, and be a cheap solution, however you couldn't get all the way down to 18-1 with gasket thickness alone. Problem is, after the initial investment of 50 sets at $100 per set........it might work, and that's a big MIGHT. Not to mention increasing the squish on a 3600 rpm engine to over .040" is not exactly what you call efficient.

Thanks for the replies. With all the money that's already been spent on new pistons, rings, bearings ect I'm thinking about not spending anymore right now and just concentrating on getting it back together.

Not to mention increasing the squish on a 3600 rpm engine to over .040" is not exactly what you call efficient.

Sinking the piston down in the hole does the same thing...

Not to mention increasing the squish on a 3600 rpm engine to over .040" is not exactly what you call efficient.

Does squish even effect an indirect injected diesel?

Does squish even effect an indirect injected diesel?

Swirl does so IMHO, any movement of the combustion air will help. I feel that concentrating this air near the center of the piston is also helpful rather than letting it hang around out by the cylinder walls...

Air needs to be directed toward precombustion chamber as that is where the fuel is entering combustion chamber.

Sinking the piston down in the hole does the same thing...

boy i would have never thought that, thanks for clearing that up........:rolleyes:

I've heard of some 5.7D's built with copper head gaskets, ARP studs, o-rings in the block, etc. They still blow head gaskets when driven on the street!

I cut .010 off the stock pistons, used the 8716PT-1 (.010 thicker, 4.170 bore) head gaskets, ARP studs and got 76,000 miles before the head gaskets etched the block and blew. The etching is due to the head creeping and crawling around on top of the block. The gaskets have the stainless steel wire o-ring built into the combustion seal. The wire o-ring "eats" into the top of the block as the head crawls around, during normal expansion and contraction.

I finally gave up and sold the whole mess! I moved four 5.7D cars two weekends ago and got a months payment on a new truck for the whole pile! Live and learn!

I suspect the 6.2 would be relatively the same story over time due to similar disign and compression ratio.