7.3 Low Compression Pistons

[IHDiesel445]

Does anyone know of a manufacturer who can supply otherwise stock pistons with a reduced compression height? I want to have them about 0.060 shorter to give about a 16:1 ratio. I'm looking for reasonably priced (as in not $250 a slug custom pistons) factory type pistons with the pin hole in a different place.

Yes, I am aware of the starting problems that may cause, but I'm looking to run a lot of boost on a rather large single turbo. Something like a 75-78mm S-400. I will also be taking appropriate measures to keep the other internals where they belong (head studs, fire rings, block filler, water injection, and possibly a main bearing girdle).

Also, does the highly acclaimed "Moose Pump" supply enough fuel to make 500-600hp?

As you can probably gather, I'm looking to build a streetable (relatively speaking) truck puller.

Thank you for any input!

Eric

 

[dyoung14]

Does anyone know of a manufacturer who can supply otherwise stock pistons with a reduced compression height? I want to have them about 0.060 shorter to give about a 16:1 ratio. I'm looking for reasonably priced (as in not $250 a slug custom pistons) factory type pistons with the pin hole in a different place.

Yes, I am aware of the starting problems that may cause, but I'm looking to run a lot of boost on a rather large single turbo. Something like a 75-78mm S-400. I will also be taking appropriate measures to keep the other internals where they belong (head studs, fire rings, block filler, water injection, and possibly a main bearing girdle).

Also, does the highly acclaimed "Moose Pump" supply enough fuel to make 500-600hp?

As you can probably gather, I'm looking to build a streetable (relatively speaking) truck puller.

Thank you for any input!

Eric

get a new set of stock pistons and take them and have them turned down, i really dont think 60 thousands will give you a compression ratio of 16-1 maybe take off like 120 thousands seems like i read somewere ken at dps did that to an idi with no problem except cold start problems, there will be alot of money in something like this and im not sure if 600hp would be possible and still be streatable and even then whos knows if the engine will hold up, and who knows how much fuel a moose pump will supply i dont think anyone has pushed theres to the absolute limit and dynoed it.

 

[IHDiesel445]

How exactly is the "turning down" accomplished? Can any machine shop do this?

 

[dyoung14]

How exactly is the "turning down" accomplished? Can any machine shop do this?

if they have a metal lathe then they can turn the tops down on them, but i really think you will be messing up by trying to build something like this, call hypermax engineering, ask them about the high performance bottom end parts for the idi, do you have any expierience on diesels?

 

[hesutton]

You might try and Email Ken at DPS. He's the only guy besides Hypermax to really push an IDI that far. His 600+ IDI puller apparently blew the crank mains out. He had them and basically everything else studded (head, intake, and what have you).

Can it be done........yes..........can it be streetable/drivable/reliable......unlikely.

Heath

 

[tractorman86]

i think if you had some kind of girdle and windage system made up and possibly like a splayed main cap the bottom would stay in it. then you have to fight the precup design...

 

[dyoung14]

i think if you had some kind of girdle and windage system made up and possibly like a splayed main cap the bottom would stay in it. then you have to fight the precup design...

last time i talked to hypermax the offered a main stud girtle for the idi, cant remember the price tho

 

[icanfixall]

Mahle offers a low comp piston. They mill the pin 10 thous higher up in the piston. When I talked to Eric, an engineer with Mahle he told me milling no more than about 15 thous off the top of any of there pistons. Any more and you will damage the top ring with all the heat its exposed to. All the pistons have a dome thickness of between 560 and 580 thous thick so there is enough material but. Doing it will cause trouble. You can and probably will do what you want but be warned first. Plenty of members will be watching and hoping it works for you. You may be the first to achieve this streetable too. Ken's motor making that hp pushed the crank out of the main caps. The studs pulled all the threads out of the block. Thats horse power.

 

[dyoung14]

there has been a couple of people who milled ther pistons farther than that and have not had any trouble, im not calling you rong, but i just dont think what mahle is saying is true.

 

[Agnem]

Right or wrong is measured in tens of thousands if not hundreds of thousands of miles. Just cause it works and has 20K on the rebuild, doesn't mean it will go as far as stock would. Not trying to play devil's advocate here, but I'm just saying that some things may take time to see if they really work out or not.

 

[dyoung14]

Right or wrong is measured in tens of thousands if not hundreds of thousands of miles. Just cause it works and has 20K on the rebuild, doesn't mean it will go as far as stock would. Not trying to play devil's advocate here, but I'm just saying that some things may take time to see if they really work out or not.

yes very true, but who builds a hot rod motor and expects it to last like a stock one would? no one i dont think cause you cant have power, and still expect longlivety and fuel milage, do you see what im saying?

 

[farriswheel]

does anyone know what ratio the 7.3 psd's have? just curious

 

[Chevyboy_0]

If I'm correct and please correct me if I'm not the PSD has a 16:1 or 17:1 CR

 

[discbrks]

As you can probably gather, I'm looking to build a streetable (relatively speaking) truck puller.

Can I ask... why an IDI? Wouldn't a cummins make more reliable h/p & torque with less money? I mean, don't get me wrong... I like the IDI's - but I just don't think they are the best choice as a performance platform.

So, IHDiesel, what's the reason for wanting an IDI?

 

[6.9poweredscout]

So, IHDiesel, what's the reason for wanting an IDI?

if u ask me i think u answered your own question there.... BECAUSE IT'S AN IH DIESEL!!! ....orr uhh at least that's why i'm putting one in the scout!

-Jon