Planning to put a 3.6 top-end on a 3.0 bottom end

[GT911]

Looking for a little advice or warnings of what I might be getting into. I realize there will be some machine work involved.

I have a street driven ’81 911sc with a 3.0, and the typical upgrades, steel head studs, 964 cams, and hydraulic chain tensionors. I have the engine out to begin a rebuild with new bearings, chains, seals etc…, but then begins the unconventional upgrades I have a ’90 3.3 turbo 115 amp alternator/fan that is a direct bolt in, I have a set of 964 heads, but plan on using the 3.0 cam towers and a 964 intake manifold and the early heat exchangers that will let it all breath. I realize there is some machine work required to make the heads fit, but that should be fairly easy for a competent machinist.

I’m looking for a 964 fan shroud that will fit the head pattern, and I’m also looking for an early air duct that will let me cut a square hole in the 964 shroud and bring air over to the oil cooler.

I’m also building a megasquirt EFI control system with an EDIS crank trigger ignition for the twin plug heads.

I would like to add some displacement, but not sure what the best options are to get the best bang for the buck.
I know your 98mm Max Moritz setup is a very easy upgrade, but what’s the possibility of adding the 964 100mm cylinders? I’m aware of the different stud spacing, but I also have read of members of the pelican community machining the 100mm cylinders, with 90mm stud spacing to fit the 86mm studs, and I already have to do this to the heads. Matting surfaces of the heads and cylinders would be easier with 964 cylinders. The next challenge would then be the pistons, I see the wrist pins are different, but could my 22mm rods ends be machined to 23mm? I certainly don’t want to save money on cylinders only to spend a fortune on pistons. I’m really at the far ends of my budget, but I don’t plan on ever going back into this so I really want to get the best bang for the buck as I can. Any advice is greatly appreciated.

[john walker's workshop]

sounds like a nightmare. buy a 3.6.

[James Brown]

im with John, 3.6 has all the goodies you need. and stay with the 915 tranny. that's what l want when my engine craps out. However, that should take place sometime around 2023!!!! i

[mytoy]

Originally Posted by GT911

Looking for a little advice or warnings of what I might be getting into. I realize there will be some machine work involved.

I have a street driven ’81 911sc with a 3.0, and the typical upgrades, steel head studs, 964 cams, and hydraulic chain tensionors. I have the engine out to begin a rebuild with new bearings, chains, seals etc…, but then begins the unconventional upgrades I have a ’90 3.3 turbo 115 amp alternator/fan that is a direct bolt in, I have a set of 964 heads, but plan on using the 3.0 cam towers and a 964 intake manifold and the early heat exchangers that will let it all breath. I realize there is some machine work required to make the heads fit, but that should be fairly easy for a competent machinist.

I’m looking for a 964 fan shroud that will fit the head pattern, and I’m also looking for an early air duct that will let me cut a square hole in the 964 shroud and bring air over to the oil cooler.

I’m also building a megasquirt EFI control system with an EDIS crank trigger ignition for the twin plug heads.

I would like to add some displacement, but not sure what the best options are to get the best bang for the buck.
I know your 98mm Max Moritz setup is a very easy upgrade, but what’s the possibility of adding the 964 100mm cylinders? I’m aware of the different stud spacing, but I also have read of members of the pelican community machining the 100mm cylinders, with 90mm stud spacing to fit the 86mm studs, and I already have to do this to the heads. Matting surfaces of the heads and cylinders would be easier with 964 cylinders. The next challenge would then be the pistons, I see the wrist pins are different, but could my 22mm rods ends be machined to 23mm? I certainly don’t want to save money on cylinders only to spend a fortune on pistons. I’m really at the far ends of my budget, but I don’t plan on ever going back into this so I really want to get the best bang for the buck as I can. Any advice is greatly appreciated.

How do you machine something that is smaller to something bigger? Do you mean machine down from 23mm to 22mm then yes but your machinest better be damn good to keep the centerline. If you are going from 22 to 23mm then you would have to build up the end and then machine down to 23mm. Again your machinest better be damn good. Why not just buy new rods to suit the application. I am sure even custom rods would cost about the same as going from 22 to 23mm. Or are you talking about the small rod eye dimension? If so then certainly you can enlarge the rod eye to 23mm.

[RWebb]

"there will be some machine work involved..."

why do you want to spend 3x what you could buy a complete motor for??

[JeremyD]

http://www.lnengineering.com/

Talk to charles - he'll give you a good idea on costs and reasonableness. But I agree with the others - it will probably make more sense to go with a 3.6

[Pazuzu]

Not only should you jsut go with the 3.6L...but you should also pass those 964 cams on to a highly deserving Texan, like myself