Mack e7 rebuild.

[mackmanb61x]

Looking at rebuilding my 94 E7 350 to a better speced engine. Already did a little research and found that it is using a 240GC2246AM piston. Now doing a little digging I found a 95 E7 454 and that uses a 240GC2248AM piston. Does anyone happen to know the difference between these two? Obviously it's probably compression ratio. I was just wondering if there is an ideal piston to order when Rebuilding an E7 so we can get the most out of this unit. Here's Mack muzzleloader chart, looks like there is only 4 options to choose from.

[mackmanb61x]

Don't worry guys! I figured it out. Gonna give you all the specs incase you guys didn't know. This is the compression ratio of each crown.

240GC596 15.3:1

240GC597 15.7:1

240GC598 16.5:1

240GC591 16.9:1

[luke andres]

i too have a 94 e7 350 that i plan to put the bosch 7100 p pump from my 91 em7 on      id like to know what turbo and injectors you end up using on yours     id like to get a little more out of this engine as far as horsepower   

[mackmanb61x]

Already have Rochester stage 3s but they smoke constantly under full fuel. Experimenting with turbos right now. Had their performance turbo on it but it never cleaned up the smoke. They use a K31 style turbo. I was getting around 45psi out of it with the wastegate blocked. Egts were up to 1400 pre turbo on a long pull.  I will let you know when I find a nice combination. 

[brettj3876]

On 1/15/2020 at 4:52 PM, mackmanb61x said:

Already have Rochester stage 3s but they smoke constantly under full fuel. Experimenting with turbos right now. Had their performance turbo on it but it never cleaned up the smoke. They use a K31 style turbo. I was getting around 45psi out of it with the wastegate blocked. Egts were up to 1400 pre turbo on a long pull.  I will let you know when I find a nice combination. 

S475 (171702) on a vmac1. 15.3 pistons and rochester stg 2 injectors with blixxton does 42-43 and besides mashing it before the turbo spools their isnt much smoke at all. You can find em for $650.  1.32 A/R  75/96mm. 

I always wondered what their turbo was. Do you know the A/R and wheel sizes on their turbo. 2200 is a bit much. Prob making a cool 1000 on each turbo.

 

Edit: post turbo egt tops out around 975-1000 on a very hard pull and takes a good 3-4 minutes to get up that high. A little laggy but once it hits 1400 it takes off like a raped ape pulling 43psi @ 1375 on up

Edited January 17, 2020 by brettj3876

[mackmanb61x]

Lol I have allot of theories in my head.... If I had to guess I would say it's a K31 with a A/R 1.28 wastegate housing Turbine 77/86 compressor 71/100 which is a great setup. But I like pushing the limits. 

So early E7 engines are similar to the 12v Cummins that every one seems to play with. Now coming from a few years or experience in the pick-up truck world a fixed timing engine will not spool a turbo up as well as a variable timing engine. Which is what surprised me about other people's turbo options. An Etech engine is vastly different than a mechanical E7 but they offer the same turbo for all. I ended up doing the s475 turbo and installed the smaller a/r housing on it I believe it's a 1.15 that way we still have decent low end torque. That 1.32 a/r housing was really doggy. We have some work on Tuesday with the truck so we will see. I'm curious about the drive pressure though. I think I'm going to put a gauge on it.

[brettj3876]

Did you get a chance to test the new housing? I would love to hear your opinion. I personally don't lug it below 1400 anyways. Don't wanna put more stress than necessary since she's already turned up. Coming out of jersey on I-80 into PA where it meets 380 i can pull that hill about 58mph with 40k in the box. Only have to split from 8L to 7H

We do mostly highway miles so the slight laggy-ness of the 1.32 isn't a hindrance for us. If we were doing stop and go local work all day it'd be a diff story tho. Prob would swap to 1.15 or 1.25 a/r.

[kscarbel2]

The ideal piston is the one your spec engine is supposed have. In your case, 240GC2246AM.

[mackmanb61x]

Well the smaller housing definitely brought back some low end power! It's definitely taken some from the top end but most of my work is running in and out of NYC all day so that doesn't bother me to much. We are usually hauling way over 80k I still can't believe she's holding together after all this abuse lol!