I got an Idea, 1JZ it revs high, it flows well and its a lot easier than this idea. I mean it sounds cool but I just don't think it would be worth the hassles in the end.
5m crank in a 7m, or just go 5m?
- Thread starter bigaaron
- Start date
Wills7MGTE said:
I have a 1jz Supra already. I want to do something different for my 88, I want it to be M series, and I want to use the parts I already have in the car like harness, turbo, exhaust system, oil cooler setup, etc... Something like building the 7M engine I personally would want. I like the 7M for the challenge it presents, otherwise I would not have one in my car at all. Building this 5m/7m shortblock is really not hard for us at all, and I have no time limit. When it's done I just swap it in.
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7m head on 5m block? That's basically the same as a 5M crank in a 7m... You just loose the oil squirters (if 7mgte) and you only have 1 knock sensor port tapped. Either way, you still need custom pistons and/or rods (5m pistons have 2 valve reliefs). Oh, and 5m/7m oil pumps are basically the same -- the main difference is the pickup location (front for 7m, middle for USDM 5m)
5/6M pistons:
7m piston (ignore the hole):
Honestly the easiest way is probably going to be 7m engine with 5m crank, 7m pistons, and custom rods. But this setup will be far enough off stock maps, you will definitely want to go standalone...
5/6M pistons:
7m piston (ignore the hole):
Honestly the easiest way is probably going to be 7m engine with 5m crank, 7m pistons, and custom rods. But this setup will be far enough off stock maps, you will definitely want to go standalone...
ma71supraturbo said:
I have the Stinger standalone in the car already so the knock sensors are not going to be used at all, but I think it would be easier to go exactly with what you said: everything 7m but the crank and rods.
Aaron, that's what I'd do - 5M crank into a later 7M ('89+) block.
The 5m is an 85mm stroke crank, right? vs 91mm on the 7M crank?
so it's a 6mm de-stroke, and you'll need to increase either rod length, or pin height by 3mm.
A 6.1" rod should do the trick, don't you think?
I know you can get LS1 rods that are 6.1" Hell, Scat's got a set of 8 forged 4340 I beams on Summit for $245.
I retract my machining thoughts here! Call up Scat or Eagle, or whomever - you should have no problem getting a 6.1" rod with the big end, piston pin, and width needed!
What is our rod width, on the big end, anyway? I like this idea. Do a 2mm bore on the block, and have an 85x85 square bore setup. Oh snap, that's awfully close to another engine I can think of
The 5m is an 85mm stroke crank, right? vs 91mm on the 7M crank?
so it's a 6mm de-stroke, and you'll need to increase either rod length, or pin height by 3mm.
A 6.1" rod should do the trick, don't you think?
I know you can get LS1 rods that are 6.1" Hell, Scat's got a set of 8 forged 4340 I beams on Summit for $245.
I retract my machining thoughts here! Call up Scat or Eagle, or whomever - you should have no problem getting a 6.1" rod with the big end, piston pin, and width needed!
What is our rod width, on the big end, anyway? I like this idea. Do a 2mm bore on the block, and have an 85x85 square bore setup. Oh snap, that's awfully close to another engine I can think of
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Engine----------Disp---HP------Torque---Bore--Stroke--CR
5MGE DOHC 82 2759 145@5200 155@4800 3.27 3.35 8.8:1
5MGE DOHC 83-85 2759 150@5200 159@4400 3.27 3.35 8.8:1
5SFE DOHC 90 2164 130@5400 140@4400 3.43 3.58 9.5:1
7MGE DOHC 88 2954 200@6000 185@4800 3.27 3.58 9.2:1
7MGTE DOHC 88 2954 230@5600 240@4000 3.27 3.58 8.4:1
5MGE DOHC 82 2759 145@5200 155@4800 3.27 3.35 8.8:1
5MGE DOHC 83-85 2759 150@5200 159@4400 3.27 3.35 8.8:1
5SFE DOHC 90 2164 130@5400 140@4400 3.43 3.58 9.5:1
7MGE DOHC 88 2954 200@6000 185@4800 3.27 3.58 9.2:1
7MGTE DOHC 88 2954 230@5600 240@4000 3.27 3.58 8.4:1
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I think it would be around 5.75 to 1 if the numbers I run are correct. The Ls1 rods won't work with out welding the big end to make them wider they are narrower than the std gen1 sbc rod which is .940 the 7m rod is close to 1.00wide . The rod that might work with a few mods is the Olds 350 rods from when Olds made their own engines . they are slightly wider the the gen1 sbc,the big end is slightly larger in dia. they have a ctc lenghtof 6.0"and the small end is fairly beefy and might be able to be offset bushed for the right wrist pin dia. ,and placement. they're forged with 3/8" bolts and weigh close to the stock 7m rods .Donn't have any Olds rods on hand to check closer just going from memory
Doward said:Aaron, that's what I'd do - 5M crank into a later 7M ('89+) block.
The 5m is an 85mm stroke crank, right? vs 91mm on the 7M crank?
so it's a 6mm de-stroke, and you'll need to increase either rod length, or pin height by 3mm.
A 6.1" rod should do the trick, don't you think?
I know you can get LS1 rods that are 6.1" Hell, Scat's got a set of 8 forged 4340 I beams on Summit for $245.
I retract my machining thoughts here! Call up Scat or Eagle, or whomever - you should have no problem getting a 6.1" rod with the big end, piston pin, and width needed!
What is our rod width, on the big end, anyway? I like this idea. Do a 2mm bore on the block, and have an 85x85 square bore setup. Oh snap, that's awfully close to another engine I can think of
AMEN to all that!
suprarich said:
Interesting point. Is the dish height of the 5m and 7m piston comparable? (What would your CR be?)
C
cnewingham
Guest
Either that or the deck height of the 7M is taller in which case you would want to keep the 5M shortblock with a 7M head to avoid custom rods. One way or the other should work.suprarich said:
5MGE Rod Length: 6.1050
7MGE/GTE Rod Length: 5.9800
this may help for piston height, just skimmed through it quickly
http://forums.celicasupra.com/showthread.php?t=13293&highlight=piston+height
7MGE/GTE Rod Length: 5.9800
this may help for piston height, just skimmed through it quickly
http://forums.celicasupra.com/showthread.php?t=13293&highlight=piston+height
yep this is a sick idea aaron, im lovin it!! cant wait to see your progress and success (to be hoped):naughty:
good luck
good luck
cnewingham said:
It's going to be more of a rebirth then a retirement :biglaugh:
The 7m in the car now has been through lots of experiments with 4 different turbos and different fuel management setups and it's still running strong but it is starting to use a little more oil then it should. I think we were a little too generous with the ring gap from the get go, but that was the first 7m we built with Ross forged pistons so we just went with their recommendations.
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