59FORD

Anyone know the max over-bore on a 5.9 that you can get pistons for.

I am not sure if you can do a +.060 bore and find pistons at a reasonable price.

I have an evil thought for the P build.


59

PeytonMaterne

I'm not an expert but I have heard not to go more than .040, and most of the kits you see are .020 over. Why would you want to go .060 anyway? Unless the cylinder needs that much to clean it up, the increase in displacement isn't worthwhile. Plus pistons for these are expensive.

dpuckett

I agree, why are you over boring it, anyway? If there is that much wear, then I'd go for it. But you will get ZILCH for extra power by boring alone. It is all about fuel, air, and timing.

Daniel

59FORD

I am building a P motor and the block will more than likely
have to be bored. I wouldn't be afraid to take one to .060
there is plenty of meat. As far as expensive this will be my
3rd Cummins and I think they're priced cheap. My last VE build
had 2 sleeves in 1 & 2 and ran real strong. I just wasn't sure
on the over-bore size.

59

Begle1

Nonsense. There's no replacement for displacement.

More displacement means you can burn more fuel at lower pressures. Whether the extra ~.2 of a liter will make that much of a difference is questionable, however.

rockjeep73

Took the words right out of my mouth.

Someones not gonna tell me that you cant fit more air into a larger cylinder.

PeytonMaterne

The real replacement for dispacement is the turbo itself.

rockjeep73

Same turbo, two different engines, one with a .060" overbore. Which one is going to make more power?

vette95

I'm building my 5.9 right now and couldn't find .060 over pistons so I went w/ .030 and two sleeves. The brand that I was using was Mahle and wasn't availible. There may be other companies that do offer it since I didn't research heavily on the matter.

59FORD

Glad to see some folks are into my way of thinking.

I'd like to a 426 (non hemi) CUMMINS out of a 5.9 block.



Can you say

PeytonMaterne

If you mean 426 cubic inches, your not going to get that without a stroker crank. Look at the power guys are making with just the factory bore and stroke. I think you could use that money in another area and get more power and more return on your hard earned bucks.

PeytonMaterne

"I say you burned a piston or two. Don't keep starting it you will only risk cracking a cylinder and have to have it bored and sleeved, I know I been there, done that and it ain't cheap." Quote by 59 ford

59FORD

Uhhhhhhh yeah, I have burned more than a few pistons in my time. I
trust MY work on MY toys more than anyone out there. If I kill it, it's
mine and mine alone. IF you pay someone to build someyhing for you
it's either you can't do it or have too much money. You are trusting
that person with your parts and your money, if it BANGS who pays?

ALSO, The above piston and head are from my 5.9 that had 2 sleeves
in it and ran very strong. The dropped valve was not from anything I
did or didn't do. You can drop a valve on a $50,000 engine the first time
you fire it. Just ask the NASCAR boy's.

You can burn a piston and not hurt the block or head but a dropped
valve it another story.


BTW, what was ^ about???

59FORD

WHY NOT?? The Ford 7.3 is 444 inches and with very weak rods and walls.

Why not stroke a 5.9 ? Why not bore a 5.9 out to say .125 or even .250

Remember an overbore of .250 bore is only .125 off the wall NOT .250

The bore is measured across not from the center to the wall.


Just $ .02 more.

dpuckett

I was under the impression that FUEL made the power, not displacement. My mistake. I do like the idea of lower pressures to make the same power, as stated by Begle1. (many guys use marine pistons and lower the compression ratio) But, you add a turbocharger (or two), and displacement becomes secondary to fuel and air.

DP