Need Engine expert advice, budget building a 2.2 race engine.

[Olsen911]

Guys.

New poster, however long time reader of these forum's. Thanks for all the help so far.

I would like to introduce myself - My name is Tommy Olsen and i are from the other side of the world but share the same interest as you guys.
I have a porsche 911 T in 1972, originally born with a 2.4 with mfi.

I've attended a couple of hillclimbs this year in my country, I made a small website where I participate in a couple Hilclimbs. See link:

Itgracingteam.dk - IL TEMPO GIGANTE RACING TEAM -

But I want to move up in historic motorsport class 68-71, which is why The Shell are being rebuilt into a 1971, so it's under control for now.
To participate in the class 68-71, I should follow the homologation certificate No. 3025 issued by the FIA. From this, Fia requires that the engine should be a 2.2 S or 2.5 ST to participate in class 68-71.

Besides that, our country's domestic rules state, that the engine may be built with all the used or new parts which have been previously used for racing or from that time period, except that the 915 gearbox is not allowed.
It donīt need too be original parts and there is no limit to how many hp and revs the engine produces, as long as it does not exceed the engine volume of 2.2 or 2.5.

This Is what i have:

A complete 1971 2.2 T with Carp, completely original and has not been running for 10 years.

A complete 1973 2.4 E with MFI - engine damaged - valve in the piston.

To build a 2.5 ST, is a possibility, but it gets too expensive with double the ignition and so on. So it is put on waiting list, till I win the lottery.

The question is whether we can build something good out of the 2 motors, with a minimum of new - used parts. And how I get a proper result with such a good engine as possible, without rasing up the engine volume over 2.2.

I hope, you guys will help me with advice and guidance, and if you have some spare parts lying as I could use, so please let me know. it will be a budget build, with that in mind, I know that it will cost some, so all help is appreciated.
Hope you have time to help.

Thanks Tommy Olsen

P.S: I've probably forgotten something, but just ask.

[Schmierung]

Cheapest would be to put the T heads with the E cams on the 2.4 E, find a used set of 2.2S pistons to raise compression significantly. Some more money, repair the damaged E head and use the E heads for more flow. MFI is good.

Significant more money would be to get aftermarket high compression pistons, regrind cams to a modified S, and recalibrate MFI pump to match. I bored out the cylinders to 85mm and ran in the bare steel without any problems.

I have had similar engine configurations with very good results

[rexav8r]

I'm not going to pretend to be an expert (there are plenty of GREAT, REAL experts for that), but I will share my experience...

I literally JUST had my 2.2E rebuilt. (Blew it up at a DE, but that's another story)
The first thing I believe you need to accept is that you are talking about rebuilding a Porsche engine, not a small block Chevy or Ford motor... You can easily rebuild one of those pretty much anywhere in the world for a few grand and get really good if not great performance results, but it's still going to be a Chevy or Ford.

Any Porsche motor rebuild is going to cost you some bucks to do it right. You either spend the money and do it right now or spend a LOT more money and fix it again later...

I'm sure you will get this input eventually: You have to figure if you want to build a RACE motor or a STREET motor. In either situation, if you are using a donor case, unless you know it to be perfect is going to need work. I had the case done, the oil pump bypass case mod done, the cams (E) gone over, the crank rebuilt (donor from an S since I trashed mine) and a set of S rods reconditioned (trashed one of those too). All of that set me back about $3,300.

A very good Street motor can for sure be used for 'race' events or time trials and can last 150,000 - 200,000 miles or more, and could cost $6,000 to $10,000 to really do it right. A true 'race' motor especially a 2.5 done right, would be a BLAST to have but would require routine tear-downs and maintenance which really drives up overall operating costs and the experts can correct me but I'd say would be hard to build a competitive motor for less than $18,000 to $25,000.

Every time I go over to the Track Rat garage where 'THE man' is building my motor, 'the guys' find it more than easy to spend TONS of money for me building a monster twin-plugged beast for my baby.... In the end, I stuck with a basic 2.2E, E cams, I did upgrade to the 3.2 style internal oil pump. The P & C's are not original, I think they may have a bit more compression, but don't think they're S. Before I shelled out the motor it ran like a scalded ass ape !! Let's hope it does again...

Best of luck on your choices !

[Olsen911]

Thanks for the reply.

Schmierung: how much do you get from your setup.? is the engine good for revving.?

I think I will go for this solution:

using 2.2 T case and crank, use the original BiRAL cylinder from 2.4 E, get aftermarket high compression pistons, bored out the E heads to S specs. Regrind cams to a modified S, and recalibrate MFI pump to match.

What do you guys think.?

Is there anything I should be particular attention to with this setup.?

I started disassembling the 2.4 E engine today and the cylinder and heads looks to be in okay condition, however, the cylinders needs to be bored out.

I've measured the cylinder to be about 84.1 mm.

If I bored them out to 85 mm. do i so exceed 2.2 liters.?

[jluetjen]

You might want to use the T cylinders since they are steel. Yes, they are not as light as the Birol piston, and don't convect quite as much heat, but the they may be more stable (especially after the rebore) and thus promote better piston ring performance.

As far as boring the heads to "S" spec, check your throttle-bodies and intake trumpets to make sure that they can be expanded that far. I don't know this off the top of my head, but I'm pretty sure that it's been posted here in the past. The last thing that you want is to have a constriction at the throttle bodies, and then have the ports open up between the throttle-bodies and the valves, resulting in a loss of charge velocity. I would also recommend that you not open the intake ports up to a full 36 mm used in the 2.4S and 2.7RS. Given that you're racing in a hill-climb, you might want to spec your motor with 34 mm intake ports to keep the velocity up. You'll lose a little bit above 7000 RPM, but will gain flexibility below 4500 RPM where the S cams usually kick in. Not needing to rev your engine above 7000 RPM will also add to the longevity of your engine.