Turbo pistons and cylinders in 3.0 case?

[quattrorunner]

These work in my sc case?
http://cgi.ebay.com/ebaymotors/Porsche-911-3-3-Turbo-Mahle-Pistons-and-Cylinders_W0QQcmdZViewItemQQcategoryZ33623QQihZ015 QQitemZ250021327975QQrdZ1QQsspagenameZWD1V

I am going to be building my own turbo system using all factory parts and in time will be rebuilding the engine. I feel these would be good to use in my budget build. Am I right? Of course in addition to any machining needed and or wanted.
Thanks

[quattrorunner]

Will this make it a 3.1 liter?

[Carrera3.5L]

The 97mm 3.3L pistons use a 23mm wrist pin (different crank & rods than your SC), while your 3.0L motor's pistons/rods use a 22mm pin...

Change your crank & rods at the same time...?

At least you had the right idea with a lower compression ratio (7.0:1 for a 3.3L 930) so you could theoretically run higher boost levels with your SC-based turbo motor...

Ralph

[quattrorunner]

OK, thanks Ralph. Not exactly what I wanted to hear, but good to know. I'll add that to the list. And the 930 rods won't go on the sc crank? That 930 crank is pricy!

[iamchappy]

I am using the 3.3 turbo pistons and cylinder in my SC engine, All you need to do is have the wrist pin bushing modified so you can use the SC rods.

Henry at Supertec set me up.

Makes it into a 3.16.

Great price on those pistons and cylinders if there all in spec.

[Carrera3.5L]

Originally posted by iamchappy
I am using the 3.3 turbo pistons and cylinder in my SC engine, All you need to do is have the wrist pin bushing modified so you can use the SC rods.

Henry at Supertec set me up.

Makes it into a 3.16.

Great price on those pistons and cylinders if there all in spec.

He's absolutely right, with some machine work you can convert 22mm to 23mm and vice versa. Much cheaper than buying a used 74.4mm crank and appropriate rods although you would than have an even larger displacement motor...

Ralph

[quattrorunner]

OK, good info. I love it when everything is new and so much to take in. Gotta wright it all down though.

[Henry Schmidt]

David is correct.
97 mm 3.3 pistons can be used on a 3.0 crank by simply modifying the rods.
The end result is a fabulous little turbo engine.
In my opinion even better than the 3.3.
As most people familiar with Porsches know, the weak link in the 3.2, 3.3 and 3.6 engine is the crank and rod assembly.
The bolts on the rods are too small and the larger rod journals tend to have oiling problems. The factory never used the larger rod journals on their racing engines. They actually used the 3.0 journal on most of their racing cranks. 2.8 RSR, 3.0 RSR, 917, all 935, all 962, 956 and even the technology laden 959.
The other benefit is that the 3.0 rod length to stroke ratio is much better. This allows the engine to spin freer and attain a higher rpm with improved reliability.
As for larger displacement the difference in a turbo engine is negligible. 3.12 935s (97x70.4) made nearly as much power as the 3.16s. (95x74.4).

[quattrorunner]

Awsome news, thanks.

[iamchappy]

Henry , my engine is home and I will let everyone know very soon how she runs, many thanks for your guidance.

[mb911]

I am thinking of doing the same thing what does the rod Mod cost??

[911TT33]

Originally Posted by mb911

I am thinking of doing the same thing what does the rod Mod cost??

I know this is an old thread, but I thought I'd bump anyway.

Curious to know cost too

[quattrorunner]

Most the time people rebush anyway so it can't be too pricey eh? Just some machine work.

[911TT33]

Originally Posted by Henry Schmidt

David is correct.
97 mm 3.3 pistons can be used on a 3.0 crank by simply modifying the rods.
The end result is a fabulous little turbo engine.
In my opinion even better than the 3.3.
As most people familiar with Porsches know, the weak link in the 3.2, 3.3 and 3.6 engine is the crank and rod assembly.
The bolts on the rods are too small and the larger rod journals tend to have oiling problems. The factory never used the larger rod journals on their racing engines. They actually used the 3.0 journal on most of their racing cranks. 2.8 RSR, 3.0 RSR, 917, all 935, all 962, 956 and even the technology laden 959.
The other benefit is that the 3.0 rod length to stroke ratio is much better. This allows the engine to spin freer and attain a higher rpm with improved reliability.
As for larger displacement the difference in a turbo engine is negligible. 3.12 935s (97x70.4) made nearly as much power as the 3.16s. (95x74.4).

If someone were inclined to use the OEM 930 97mm P&C's in a SC motor for ~3.12 displacement, how much would one need to machine off the base of the cylinders to increase the static C/R to 8.0:1? 1.0mm taken off the base?

Also, could the top of the 97mm cylinders be machined to accept a similar sealing ring the OEM SC 95mm P&C's use? Just thinking of a better cylinder to head seal for such a setup. Btw, aftermarket fasteners will be used too.

[911TT33]

bump?

[Henry Schmidt]

Originally Posted by 911TT33

If someone were inclined to use the OEM 930 97mm P&C's in a SC motor for ~3.12 displacement, how much would one need to machine off the base of the cylinders to increase the static C/R to 8.0:1? 1.0mm taken off the base?

Also, could the top of the 97mm cylinders be machined to accept a similar sealing ring the OEM SC 95mm P&C's use? Just thinking of a better cylinder to head seal for such a setup. Btw, aftermarket fasteners will be used too.

Approximately .100" would need to be trimmed from the cylinder to produce 8:1 compression. That would product a negative deck of .60".

Rather than shortening the cylinders, a better method of compression increase would be to trim the perimeter of the piston dome to allow for longer rods. .040" to .060" can safely be removed from this area. By moving the piston deeper into the chamber you will increase the compression from between 7.14 and 7.45:1.

Machining the cylinder tops for CE rings is a poor idea based on your stated goal. The CE ring does not improve compression sealing and actually offers less sealing surface and reduced head stability.
The CE ring was used to prevent oil seepage during cool down not compression sealing.
Many high performance turbos were built using a flame ring which did aid in sealing compression when exposed to high cylinder pressures.
Many customers using Supertec head studs have reported greatly improved head to cylinder sealing based on greatly improved head stability.

[911TT33]

Thanks for the clarification, Henry.

How much does it cost to machine the SC rods for the 23mm wrist pins to mate with the 97mm turbo P&C's?

[Henry Schmidt]

Originally Posted by 911TT33

How much does it cost to machine the SC rods for the 23mm wrist pins to mate with the 97mm turbo P&C's?

$300 + or - a little.

[911TT33]

Originally Posted by Henry Schmidt

$300 + or - a little.

Pretty good. So if I use stock 90.4mm SC rods with 97mm P&C's, what's the best way to bump compression to 7.5 or 8.0? Trim the perimeter of the piston dome, or shortening the cylinder a bit?