Need help, building a 3.6 with MFI

[911Switzerland]

Hi there

I'm building a 3.6 engine with MFI. Using a 3.2 Case, 964 Crank and Rods (76.4mm) with ported SC Heads (43mm In. and 41mm Ex. ports) 906 cam, Factory SCRS Headers, special MFI stacks (conical 43mm to 53mm), single plug (we have all over 98 octane here in Switzerland) lightened Flywheel, Factory RSR Aluminum pressure Plate, 4 puck Sachs clutch. 915 Tranny from 2.7 Carrera(7:31 R&P).

1974 Car, is relatively lightweight, bit under 2000 pounds.

Now I d'ont know which Mahle cylinders i have to use. Can anybody help me with a Mahle Serial No. or Andial No.? Want to go 10.3:1 - 10.7:1 CR. Where can i buy? Prices?
If i would go with dual Ignition, where can i get a distrubutor with centrifugal advance, d'ont need vacuum (not that 964 thing)? Sources? Prices?

Many thanks for your help in advance. (Sorry my bad english)

Regards from Switzerland,
Thomas

[Mr Beau]

Hi Thomas,

Just a note on fuel: 98 octane in Europe is approximately 93 octane in the US. So you have a big bore engine and are planning a lot of compression, without much better fuel than what is referred to by most people on this board. Twin plug would definitely be a good investment.

Sorry I can't help you with piston questions.

Definitely no problems with your English.

[Shuie]

100mm P&Cs on a 76.4mm crank gives you a 3.6.

I’ve never tried this before so I don’t even know if the pieces would actually fit together.

The stud spacing is different between a 964 3.6 case and the 3.2 case you have so you would need 100mm cylinders designed for the type 930 case. I don’t know the part number or if Andial sells these separate from the P&C set.

Andial lists 3 sets of 100mm P&Cs on their website:

Street 3.5L 9.8:1 part no. AND 103 981 10 (motronic)
Race 3.5L 10.4:1 part no. AND 103 962 12
Race 3.5L 10.3:1 part no. AND 103 962 SP


The 76.4mm rods use a different wristpin also, right? If so, I don’t think you can use the pistons from the above sets. You are going to need 100mm 964 pistons or custom J&E pistons to match the 964 wristpins. I also have no idea what compression ratio you could expect due to the lower volume of SC heads.

It may be worth it to find a source for a custom set of J&E P&Cs if you continue down this path.

Again, I’m not an engine builder. I don’t know if what I just wrote is even possible

[Carrera3.5L]

Originally posted by 911Switzerland
Now I d'ont know which Mahle cylinders i have to use. Can anybody help me with a Mahle Serial No. or Andial No.? Want to go 10.3:1 - 10.7:1 CR. Where can i buy? Prices?

Thomas,

3.6L conversions from 3.0/3.2 motors have been done since the 964 was introduced in 1989. Andial was the first to develop this conversion.

Andial sells a kit that includes the 76.4mm 964 crank, modified 100mm Mahle pistons and cylinders, and a special crank pulley.

Arnold (co-owner of Andial) ran the mule motor in his own '77 911 for a long time. The motor was based on a 3.0L SC and retained the CIS and single ignition. Other then additional oil cooling that was needed for the increased displacement, the motor ran without a hitch. I don't remember exactly, but I think the motor had 9.2:1 or thereabouts on single plug.

Many, many motors were built (normally aspirated and 930 versions) using any combination of CIS or Motronic, single or twin-plugs. At the time, this was the max displacement update for SC and Carrera owners.

The 100mm Mahle pistons and cylinders are the same ones used for the 3.2L to 3.5L conversion using the 23mm wrist pin. The pistons are then machined to work with the 3.6L crank. If you buy the kit from Andial, the pistons will already be machined by them or Ollie's Porsche Machining. If you source the 100mm P's and C's from others, I have the drawings for the machine work that is necessary if you need it.

I also have the Mahle internal piston and cylinder part numbers, but unless you can buy from them direct I don't think that they will do you any good.

Sounds like a fun project, keep us updated as things progress.

Ralph

[Shuie]

Good stuff, Ralph. Thanks. So the 100mm 964 pistons wont work in the 100mm 3.5 cylinders, or do they raise the compression too much?

[Carrera3.5L]

Originally posted by Shuie
Good stuff, Ralph. Thanks. So the 100mm 964 pistons wont work in the 100mm 3.5 cylinders, or do they raise the compression too much?

Good question, and I wish that I could give you an answer. But I don't know. I know very little about the 3.6L series of motors with what works and what doesn't.

I would speculate that someone has tried fitting 964 pistons into an earlier car but I have no idea what the outcome would be.

I am not a professional engine builder either or have vast experience with every motor combination feasible.

Ralph

[911Switzerland]

Matt,

Thanks for your fuel infos.

Sherman, Ralph

Will also thank you for good infos, much appreciated. I will call Andial and ask for the setup.

Noah,

I know many people have talked over the durability of the 915 with 7:31 R&P. A Friend of mine is using a mag case 915 with 7:37 R&P!!!!! and short gears for over 8 Years in Racing (Hill Climbing)
He won over 150 Trophys ( first and second places) in Switzerland, Germany and Austria.

He had no problem with the Gearbox.....

(3.6 engine with Motronic, 385 Horsepower)[img]

BTW. This is my car, at the moment there is a 3.2 engine with MFI installed (308HP)

http://forums.pelicanparts.com/uploads5/Porsche+17+10+2004+0051110709859.jpg[/img]

[Carrera3.5L]

Thomas,

Nice car. The 3.6L should have no problem supplying the punch needed for that car.

Sorry, I forgot to provide you the Andial kit number that you originally asked for:

AND 102 911 36

When you talk to Pete or Arnold at Andial, you may wish to ask them if you can buy just the modified 100mm Mahle pistons and cylinders and the crank pulley. You MAY be able to save a little bit of money by sourcing your own 3.6L crank. The Andial kit includes a new crank, but you may find a good used one for significantly less over in Europe. Or even a new one. Just a thought.

I don't know what the price of the kit is in today's dollars, but would figure somewhere around $7K US, especially with the strong Euro.

Good Luck!

Ralph

[WERK I]

Thomas,
Very nice car. Question to you or anyone out there; How do you modify the fuel curve on these MFI's to compensate for the increase in displacement?
Thanks

[asphaltgambler]

It's my understanding that the 3.6 build does not last. I posed a similar question months ago and more than a few people said that the 964 cranks need the dual-mass flywheel to keep harmonics in check.

That, in fact w/o it the engine will self-destruct. Any comments?

[camgrinder]

Why use the 906 camshaft?

[strokher racing]

Many of the 100mm combos on this type of setup have cracked. It is very common since the 100mm bore makes the spigots too thin. Just a heads up. That is why the 98mm setup is more popular.

Eric Hood

[Carrera3.5L]

Originally posted by strokher racing
Many of the 100mm combos on this type of setup have cracked. It is very common since the 100mm bore makes the spigots too thin. Just a heads up. That is why the 98mm setup is more popular.

Eric Hood

IMO, it has nothing to do with the 100mm "cracking", but more to do that the 98's do not require case machining or even a full teardown to install. A 3.4L can be easily made during just a top end rebuild on a 3.2L Carrera. It is a saving money issue more then anything else. Arnold's (and others) motor went over 100K with this conversion (driving in stop & go traffic much of the time BTW) which is acceptable in my eyes.

I don't think a long stroke 3.5L (98 x 76.4) is more popular then the full 3.6L conversion. I saw a heck of alot more 3.6L conversions being done then 3.5L long-strokes. The 3.5L long-strokes were generally done for 930 motors.

But I think unless there is some underlying reason, the price of the parts for these 3.6L conversion kits plus the extra machine work required makes simply transplanting a later 3.6L with the added benefits much more financially attractive, especially for a 3.0L SC owner where the 3.2L rods would also have to be sourced in addition.

Ralph

[911Switzerland]

Dave,

I'm not doing any work on the pump myself. There is a shop in Germany, where every European Porsche Engine Builder bring his pump to modify. (35 Years expirience in Bosch things)

PM me if you want that adress.

John,

Because i have only the 906 cam. What would you prefer for such a engine?

Thanks for reply.

Thomas

[BURN-BROS]

Thomas, RSR sprint cams or something even more aggressive would be more ideal for your displacement. John will have great specific advise for you.

[350HP930]

For the cost of trying to make a MFI work right on that engine I would assume an EFI solution would be better and a lot more tuneable.

[camgrinder]

I agree with Aaron, the Sprint RSR cam is better than the 906 for this application.
How high do you want the rpm band?

[911Switzerland]

John,

I d'ont want to rev. higher than 7500- 7600.
Because i run the car also on the street, still want some smooth idle and torque. Are you selling them? Price of a set to fit old chain housings and pulley for MFI Pump?

[dd74]

Bump - out of interest.

[Mr Beau]

Thomas,

I'd agree with the others that MFI is probably not the best choice for this project. Ad in the cost of a dual plug distributor (based on your WTB in the classifieds) and you'd be way ahead with an EFI system.