Are there any parts that can be used off of a 7M-GE in a 5M-GE? For example the cams.

I used to have an '85, from what i remember, there aren't any parts off the head that can be swaped from 7m to 5m. I know the bottom end components are compatible though like the crank, and I believe the piston rods. the bearing for these should be compatible too.

The 7M-GE cylinder head design is completely different to the 5M-GE, so nothing is interchangeable (including cams). A 7M crank won't directly fit in a 5M block, although it could be done with some machining.

Norbie!
http://www.norbie.net

I was thinking about building up the 7m-ge that i have and just putting it in the car. Is this a hard swap to do and is it even worth doing. Also if I were to sell the 7m that i have how much should i be able to get for it (the only thing wrong is low compression)?
Thanx again,
Matt

It's not that hard to do if you mix'n'match components. A 6M-GE is a much easier way to get a 3 litre engine though, mostly because you don't have to touch the electricals.

Norbie!
http://www.norbie.net

well since you have a 7M engine and a 5M engine... then you can do a franky engine from the two... just use the 7M block, rods, and crank... while using the top end of a 5M front timing cover, machine 5M crank pulley, and also use 5M pistons to mate the 5M head design of valve reliefs... then your set to go and have a 6M on hand

JAY

"Road Racers Don't Need Girls.... I am a lonely driver!!!"

Or you could spend less money and just buy a 6M... your choice!

Norbie!
http://www.norbie.net

quote:

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Originally posted by Norbie:
A 7M crank won't directly fit in a 5M block, although it could be done with some machining.

Norbie!
http://www.norbie.net

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But will a 5M crank fit in a 7M block?

Again, it could be done, but it's not a direct fit. I'm not sure why you'd want to do that though?

Norbie!
http://www.norbie.net

I want to de-stroke my current 7M so it can live in the rpm efficiency range of the turbo I have in mind. Might you have any of the specifics? I gather the crank snout on a 5M is a smaller diameter.

What do you mean the "rpm efficiency" of the turbo? Turbos are powered by exhaust gas, and the amount of exhaust gas you have is related to the size of your engine. A smaller engine is going to take longer to spool any given turbo, and I can't see how that would be a good thing?

Norbie!
http://www.norbie.net

I understand the concept. That is why, if I can de-stroke the 7M I would accompany it with a 1-2 mm overbore. From my understanding the M block has room for an overbore like this.

It needs to rev if the turbo is not going to spool 'till 4 grand +

Have you ever seen a disassembled M block? There is very little space between the bored, which is most of the reason why they're known for blowing head gaskets. Overboring even 1mm is risky! On top of that, a 2mm overbore won't come close to making up for the capacity lost in de-stroking.

Norbie!
http://www.norbie.net

Thanks for your opinion. I guess you don't have the specifics, then?

Edit- specifics on the nessicary changes to install the 5M crank in the 7M. Good idea or bad.

Sorry norbie, I wasn't trying to be rude. I don't see the problem with an 85 mm bore, since the HKS gasket I plan on using has an 86 mm bore. There are no cooling passages in the narrow area between cylinders, and compression is sealed by the "fire ring" of the head gasket.I'm not concerned with 200,000 mile reliability either. I realize that will not entirely make up for the displacement lost by a shorter stroke. The cylinder head will recieve professional port work in order to maximize VE and airflow (exhaust gas to spin the turbine). I also have appropriate camshafts and valvetrain components lined up. It all hinges on wether or not I can use a reasonably priced crankshaft to reduce the piston speed of the 7M to some real world figures for a 4 valve engine.

I'm not just wondering, I have my 7M in a million pieces and would like some info. If nobody can help me out I will just have to go waste my money on a 5M crank and see if I can make it work or not. So politely this time, do you know? It does not appear this has been attempted seriously, so your scepticism is noted.

The 5M crank will fit, but IIRC you will need a custom front pulley ( the crank snout is smaller )...

I tried ~5 years ago in the garage, out of sheer boredom ( I had a bunch of 5M and 7M parts lying around )
Yes, the 5M crank will fit in the 7M block, anything else I can't tell you or remember ( journal clearances, front cover, etc ).

If anything, get a 5M crank from a parts store ( Autozone, etc ) that will accept it back if you don't use it.

I'm quite sure it can be done with a bit of effort if you really wanted to, but wouldn't it be easier just to put a 7M head on a 5M block? No machining required!

Norbie!
http://www.norbie.net

Well, I checked into the autozone crank idea and they want ~$330 for a crank " kit" plus ~$600 for a custom pulley from unorthodox racing (right on the Island w/ me ). Pauter will make me custom length connecting rods for the same price as standard ones ~$1000. With Ross pistons for a 7M this is still within my budget. I'm still shopping for a good cylinder head shop.

I'd like to know if I'm going to be able to swing this deal financially before I get too far into it. A 5M engine is not really in the budget and most used ones are ready for an overhaul anyway.

Norbie- Does that mean the mains are different sizes 7M to 5M? The local library was really no help. Does anyone have a good link with 5M engine specifications and tolerances?

Yes, I believe the mains are a different size. The best place to find specs and such is the TSRM.

Norbie!
http://www.norbie.net

I guess I could look it up at work if I ever remember.

Call me Crankshaft