3.2 engine build

dpetteng · 02-06-2015, 11:56 AM

So, I have just purchased a used 3.2 Carrera engine from a crash damaged 911 from 1987.

Its currently being shipped back to the UK and the plan is to rebuild and use in my 1971 VW bus conversion. I already have a 915 transmission.

So a couple of questions.

I have seen "Euro" and "USA" replacement cylinders and pistons with the Euro versions being rated to a higher BHP. Is this due to emissions and therefore can be replaced with the euro versions?

Next, I am converting to jenvey ITB's and Omex ignition and fueling. What cam would be well suited to this?

Last, I think the engine was originally fitted to a G50 transmission, what do I need to change to make it work with the 915?

Any help appreciated

JJ 911SC · JJ 911SC's Garage

Quote:

Originally Posted by dpetteng

... and the plan is to rebuild and use in my 1971 VW bus conversion. I already have a 915 transmission...

This is going to be fun...

In case you have not seen this: Porsche Powered Mid-Engine Double Cab

Also, you might want to post that question here: Porsche Engine Conversion Tech Forum - Pelican Parts Technical BBS

Jcslocum · 02-06-2015, 02:18 PM

Quote:

Originally Posted by dpetteng

I have seen "Euro" and "USA" replacement cylinders and pistons with the Euro versions being rated to a higher BHP. Is this due to emissions and therefore can be replaced with the euro versions?

Next, I am converting to jenvey ITB's and Omex ignition and fueling. What cam would be well suited to this?

Last, I think the engine was originally fitted to a G50 transmission, what do I need to change to make it work with the 915?

Any help appreciated

The euro pistons will fit. A slight bump on CR so the greater powah!

The 3.2 will fit the 915 but you will need a clutch kit from and '86 or earlier car and a flywheel too.

earossi · 02-08-2015, 04:08 AM

The 3.2 should make right at 235 hp in an American build config. I doubt that for your application in a bus, that any slight increase in power will be relevant. You are going to have a hot rod with either engine build! So, go for whichever build is the most economic.

dpetteng · 02-08-2015, 06:55 AM

Quote:

Originally Posted by JJ 911SC

This is going to be fun...

In case you have not seen this: Porsche Powered Mid-Engine Double Cab

Also, you might want to post that question here: Porsche Engine Conversion Tech Forum - Pelican Parts Technical BBS

Wow, that mid engine thing is awesome!

Thanks for the advice

dpetteng · 02-08-2015, 06:57 AM

Thanks guys, already looking at euro pistons and barrels. So what is the right cams to go with?

dpetteng · 02-08-2015, 07:01 AM

Oh and is there any difference between standard 3.2 barrels and pistons and Carrera ones?

Jcslocum · 02-08-2015, 07:10 AM

NO, not for that engine.

964 cams might be a good swap once you're in there.

dpetteng · 02-08-2015, 07:25 AM

great, thanks, so any 3.2 barrels and pistons for an 87 will work, great

Jcslocum · 02-08-2015, 07:30 AM

Yes, for any original 3.2 from 1984 to 1989 should all be good. New pistons will fit in your existing barrels BTW. You can have them replated.

dpetteng · 02-08-2015, 07:51 AM

Oh cool, didn't know that.

Is it a good idea to fit an external oil cooler or is the Porsche one ok? I come from a VW world where the internal cooling is not "optimal" for bigger engines.

dpetteng · 02-08-2015, 08:25 AM

Oh and another one... head studs. Do I need to replace and if so, what is a good replacement for the Dilavar ones that break?

Jcslocum · 02-08-2015, 09:00 AM

Yes, the 3.2 will need an external cooler. The one on the engine is not adequate for the 3.2.

The bottom head studs will need to replaced at a minimum. I''m using stock steel studs for my engine build, but if you want to go full Monty then Supertec studs or ARP studs. Works of are these are...

dpetteng · 02-08-2015, 11:22 AM

Quote:

Originally Posted by Jcslocum

Yes, the 3.2 will need an external cooler. The one on the engine is not adequate for the 3.2.

The bottom head studs will need to replaced at a minimum. I''m using stock steel studs for my engine build, but if you want to go full Monty then Supertec studs or ARP studs. Works of are these are...

Any idea where you can buy the stock steel studs?

Jcslocum · 02-08-2015, 04:22 PM

Right here at Pelican or many many other vendors.

Jcslocum · 02-09-2015, 05:18 AM

I'm using part number 911 101 17200

You need 12 of them

dpetteng · 02-10-2015, 03:49 AM

Thanks a lot, really helpful.

So, for the external oil cooler what is the routing? Engine to cooler and then back to tank or something else? And do I need an external oil thermostat?

Jcslocum · 02-10-2015, 04:12 AM

You can use the Porsche thermostat or one from say, Mocal and one of their coolers too. With all of the under floor space you may be able to mount it close to the engine and run an air duct to it to feed it while moving. Lots of ways to skin that cat and you will have to be good at fabrication too!

dpetteng · 02-10-2015, 07:13 AM

I have a great fabricator so no problem there. So how is would the oil line routing work? Would the line go from the engine outlet to the cooler and then back to the tank?

MST0118 · MST0118's Garage

I would be interested what other builders say, but I think that if you're going with Jenvey ITBs, then you might want to go with a more aggressive cam profile like a DC40 or modified S cam. The potential problem you might find is the piston to valve clearance with either the US or Euro pistons. For that reason, you might consider higher domed pistons like JE or another brand. Interested what others think. If you go with Motronic, then the US or Euro pistons would be great. Another option is to send cylinders to EBS and have them slightly bored and plated so that you can run 3.4 pistons, and then you can get new JE pistons. I think it is cost effective if you can find a cheap set of 3.2 cylinders..