Ok, bore question

[DustyR/T]

What is the maximum bore feasible on the 3.0? I've heard .100 over. That was my original goal. Will it hurt the integrity of the block at all? I'm going w/ free floater JE or Venolia's and my machinist is very concerned that .100 over might be too much. Having never done something like this before, I don't know just how extreme .100 over is. I have heard of a few guys doing it, I just want to know if will hold what I want it to. He also estimates a displacement increase of .2-.3 liters which will be very cool. The rods will be shot peened and re-sized, the crank is getting blue-printed, and like I said-free floating pistons. He says it's good for RPMs and whatnot. He hasn't bored anything yet, and says it is going to be very difficult to get these pistons in this style. I tried asking brent, but he never got back to me. How the hell did he score such a good deal?! Who did he talk to, and can I get the same deal?

[c2xejk]

Take your block into your machine shop and have them tell you how far they can bore it... It will vary some from block to block.

You may have to have a headgasket made up for your application...

[DustyR/T]

already did. He is just curious because he has never worked this much out of a 3.0 Mitsu/chrysler.

[Harvii]

are you planning on running boost or NOS? If so I'd keep it as tight as possible so you keep your cyl strenght up. I don't think I've heard of anyone going more than .060 over tho.

[mwinkle353]

Brent went 0.096" over with his forged pistons. So, it is possible. As for cylinder wall strength; I'd say, "stay tuned for what's in store after he starts running boost through that monster of a motor."


Is it possible: Yes
Will it hold the pressure: Dunno yet

[Ondonti]

okay I dont know what you guys are getting at.


dohc 6g72 guys bore .100" or bigger and last time I checked the same guys make 500+WHP and I believe Ray Pampena who makes 1200+crank HP has a .120" overbore.

If you think you could possibly make too much power for a large overbore you are dreaming.

.100" overbore leaves .200" wall thickness which is enough for 700whp in a Non girdled low quality cast iron block.

Our block is much stronger inately then one of those low quality blocks.

many new engines come from the factory with stock wall thicknesses of .090" which in a 3.0L engine is still good for 300whp. 99.99% of 3.0 owners make less then 300whp. You could theoretically overbore .200" then if you didnt have any core shift. .

[Ondonti]

Since a lot of motors have stock wall thicknesses of .090-.150" overboring .100" would just not work. We have .300" wall thickness.

[Chief8one]

i bored mine to .08 if that helps... lol

[Ondonti]

Quote:

Originally Posted by Chief8one i bored mine to .08 if that helps... lol

You went against the BS law of never boring past .060"..........your motor will self destruct with only 150whp let alone you having a turbo.