What should I build?

[mudman]

I've got an original complete 2.4T CIS motor w/ a 7R case that was disassembled for broken exhaust studs, ran fine w/41K. I also have a 7R short block that may have some mods, haven't split the case yet. When I bought the second motor I also got a pile of parts:
unknown Mahle P+C set, bore measures 92mm, detonation damage to the cylinders, help ID with photos below

set of cams, see pics

two sets headers, 1 5/8 and 1 3/4, and a set of super trapps

set of heads, look to be freshly done but please give me your thoughts

cam housings

pressure fed 930 part# tensioners

solid tensioners or chain holders (???), alu body with bolt and locknut for adjust, I'll get pics later

carb intake manifolds

Budget is very tight. This will be for street, AX, and fun days at Waterford Hills. Any parts I have that won't be used for this build will be sold to help fund it, but I've not done a good assesment of my parts pile yet so I'm not sure what anything is worth.

[mudman]

[mudman]

Anyone able to ID those pistons or headers?

[Steve@Rennsport]

Mahle 92mm RSR P/C's 10.4:1 using RSR heads (early version with CE ring grooves). Thankfully, the late versions do not have them anymore. With 2.4 or 2.7 heads, your CR is around 11.2-11.3 and thats why it detonated, especially using single-ignition.

Headers kinda look like Bursch ones.

[mudman]

That is the worst cylinder I have pictured, does this set belong in the trash? I'll post some pics of the lot to get your input. The pistons look in ok shape, I haven't taken too close a look yet.

On the headers, you think both are Bursch? They have totally different collectors, I had figured different manufacturers but have no clue, thanks.

[euro911sc]

Cyls like that or anywhere near it are toast. You can have them re-plated though so don't totally trash them. If you do trash them I'll use them for various auto art projects I do so send them to me.

With single plug heads you do not want to go more than 9.8:1 and some prefer a little buffer and say 9.5:1 or even 9.3:1. You could twin them when you re-do the guides, but that is probably the cheapest part of going twin plug. So the heads and pistons do not really go together unless you twin the heads. there are a couple of nice engines with that combo running around this board I think.

1 3/4 headers are probably too big for anything that you might build with those parts. Sell them.

Do you have an induction system? The 2.4T CIS? Or will you have to buy something? Those manifolds should mount up to a nice set of 40 carbs.

-Michael

[911st]

If your budget was not tight a 2.7RS with about 9.5/1 CR would be a dream. It would require having the injection stacks opened up and the MFI pump rebuilt with a space cam to support it.

As budget is a concern it would be best to just rebuild it as a 2.4T motor if the P&C's are usable or somthing close.

You might be able to have the cylinders boored out to make it a 2.5 and increase the compression at the same time form 7.5/1 to about 9/1. This should let you keep you stock MFI system and pick up some HP. I would also replace the dist. rotor with one from an E to move the red line up from I think about 6800 to 7100. Could look for a set of 2.7 cylinders and build a 2.7T motor.

Having said that. You might put togeather a MFI conversion package with or without the heads and offer it for sale. The 7R small spigot case has value to the vintage racers. The 2.4/2.7 crank has value to. Part everything out and just buy a good running 3.0 CIS or 3.2 EFI motor.

It might be worth noting that you be aware of what class a modified motor might put you in. In some areas a stock rebuild w one point higher CR is still a stock motor.

[mudman]

The 2.4 is a CIS motor, not MFI

Can I bore out my cast iron cyls from the CIS motor and find an appropriate piston/cam/carb setup? I've seen some Webers and Zeniths that could be bought with funds from selling some of the spare bits.

What about using the 2.7 case with new cylinders for those pistons I have? Add cams and carbs and what could I get performance/value wise?

I'm not sure (yet) about selling the engine/parts original to the car, I've got a thing about that. The 'build' is something I'm looking forward to, If I could sell everything but the 2.4 case and a few other bits to have enough funds to buy a running motor that would be tempting - to have a running motor in the car while I build something with the original case.

Thanks for the help!

[mudman]

Oh yeah- no concerns about meeting class regs, if I do compete in the next couple of years it won't be with this car.

[911st]

If the 2.8 pistons are in good condition you can have a set of 2.7 cylinders bored out and plated. Contact EBS in Reno. Probably about $1200.

You will need to have the heads cut to fit them and will need a 1mm spacer under each cylinder to get compression in to the 10's. You will need twin plug ignition if you are going to run it on street fuel. Even then it will be on the edge. I did this with an RS MFI system and it was a hot little motor.

Or, You can bore out the CI cylinders for about a 2.5. Most the gain will be from a higher compression ratio custom pistons (about $1200) and bigger cams.

Nothing wrong with running a 2.5 or 2.7 CIS in autox. A set of SC cams would go well with it and it will remain more or less original which seems to interest you. Actually that is a good idea, get a set of 2.7 P&Cs and turn your 2.4 into a tuned 2.7 CIS original case motor with cams to fit and some compression. Should get you close to 200hp w sport exhaust.

Building anything correctly from what you have is going to be expensive to do it right. I would guess about $6-10k.

However, you may have some value in parting things out. Good used 3.0 should be under $5k and will plug righ in.

Good luck.