3.6, 3.7, 3.8 What recipe do I have?

[rick2]

I bought this "trade in" engine and am wondering what my final displacement is? Redline?

78 SC Case Sprigots bored 4mm
964 crank
Mahle 102mm pistons and cyl
3.2 rods narrowed at top to fit pistons (22mm If I remeber corectly)
heads twin plugged and massaged as well as D ported
Turbo Pump
TWM 3003s 48mm
Tech engine management

I am looking for definitive answers so please no guesses.
Thanks for the help,
Rick

P.S. Hoping to get the car down to 1800#s

[BURN-BROS]

It's a bit hard to give a definitive answer when you do not give a complete build list.

You have a 3.8.

Cams? rod bolts? Without knowing those you are at the stock redline for a 3.6.

[304065]

Well lemee see here definitive answers huh?

A 964 crank has a stroke of 76.4mm

Your pistons are 102mm

102 x 102 x 76.4 x 3.1416 / 4 * 6 = 3745cc lets call it a 3,8 same specs as the M64/20

[rick2]

Thanks for the help guys! Does this fall under short or long stroke? I usually run 2.8s and smaller so this is uncharted waters for me.

I have ARP rod bolts and need head studs, ARP or Raceware. I recently saw on a thread that Henry Schmidt had his own? Are they his own creation or is he a dist?

I have factory 73 S cams and 3 support towers but think maybe Woods GE100 or 80s may be better suited. Are Jerry's 4 bearing? I have solid tensioners.

A local builder chromes the journals on his early 74 cranks and swears by it. He also builds some crazy mod 4 cyl 356 stuff. Any advice on chroming my 964 crank?

There seems to be some discussion on the turbo pump compared to the GT3 pump. My case has already been modified for the turbo pump.

Thanks again for the help.

[BURN-BROS]

I will not ever use a chromed crank period. It is also the longest stroke and crapiest rod angles that Porsche has made. But 6500-6700 rpm should be fine for that build

Henry's head stud are his own design and based off of 935 factory studs as far as material goes. I believe it is the best product on the market in regards to head studs.

[kenikh]

Originally Posted by BURN-BROS

I will not ever use a chromed crank period. It is also the longest stroke and crapiest rod angles that Porsche has made. But 6500-6700 rpm should be fine for that build

Henry's head stud are his own design and based off of 935 factory studs as far as material goes. I believe it is the best product on the market in regards to head studs.

I'd love to know what the coeeficient of linear expansion is on Henry's studs.

[911st]

3.2 rods on a 964/993 crank???

Anyone know whats up with that?

Do the big ends fit?

Would the rod not be to long or is the attachment moved up on the pistons for a better angle?

I would think one would just use the stock 964/993 rods.

Thx.

[Bill Verburg]

Originally Posted by 911st

3.2 rods on a 964/993 crank???

Anyone know whats up with that?

Do the big ends fit?

Would the rod not be to long or is the attachment moved up on the pistons for a better angle?

I would think one would just use the stock 964/993 rods.

Thx.

3.2, 3.3 and 964 3.6/3.8 all use the same size rods interchangebly

993 3.6/3.8 use a different rod which is narrower and not interchangeable w/ the others

[BURN-BROS]

Originally Posted by kenikh

I'd love to know what the coeeficient of linear expansion is on Henry's studs.

I have not checked but it would be close to steel expansion rates if I were to guess.

[rick2]

If Henry recommends them then that's good enough for me.

The 3.2 rods I have, have been narrowed at the small end to fit the pistons.

Anyone used Smart Racing's rod bearings?