blown 944

I would measure where the worst runout is and polish that journal down a little. A little extra oil clearance on one or two main journals isn't going to hurt anything. However, wiping all the oil away with not enough clearance can.

333pg333

I know these bigger bore motors will have more torque but 6400 seems a tad low, no?

refresh951

Thanks Sid. This was my approach. Short block is assembled.

I really see no reason to go higher. I have looked at a lot of dyno sheets and it seems most motors do not make much more power above 6000 rpm. Top speed would be the only reason I could see going higher. Going higher without a dry sump also seems like it is asking for trouble especially if oil cavitation is a factor in the inherent bearing weakness in our motors.

refresh951

Completed the short block this weekend. I am amazed how long it takes to put the short block together. Very time consuming process that requires a great deal of patience. Pretty happy with the results. Everything looks good. Going to try to get the long block completed by next weekend and then start on the turbo/exhaust fab work.

333pg333

I suppose on a street car you're right Shawn. I found that I was still getting power over an indicated 6400rpm on my fairly stock 2.5 motor but in hindsight this shouldn't have been taken out so high by the non Porsche tuner. Next motor won't be an issue. Looking forwards to your results with this one, as I'm sure are quite a few others.

refresh951

The late NA cam may be perfect for me as I am running 47mm (+2) VTM intake valves and the OEM exhaust valves. Patrick posted specs on the late NA cam a while back and the extra exhaust duration may be a perfect combo in my case. This may result in more benefit from this camshaft than with a typical stock turbo head. Bought the late NA camshaft for $40 shipped so I will give it a try.

944 / 924S
Intake opens: 1¡ after TDC
Intake closes: 49¡ after BDC
Exhaust opens: 47¡ before BDC
Exhaust closes: 1¡ after TDC


944 Turbo
Intake opens: 1¡ after TDC
Intake closes: 49¡ after BDC
Exhaust opens: 43¡ before BDC
Exhaust closes: 3¡ before TDC

Thom

FWIW

https://rennlist.com/forums/10147203-post4.html

Dutch944

Wow.. I wish i was this far in my project.. The bushes still have to be ordered and the pistons have to be made.. And you are already building! I'm jealous!

blown 944

Good post. I would agree with that to a tee



The beauty of "off the shelf" parts. Along with having a trusted machinist to work with. Other than the block sleeving, these can be done in a couple weeks.

I'm glad Shawn ran with it so quickly

refresh951

Thanks. LOL...It seems like it is taking forever to me.

964-C2

What are the drawbacks with the NA cam?
Less HP at low rpm and slower spool up?

refresh951

"Clayed" the valves tonight. Build is a non-interference design. I appreciate Sid's input about running a bit down in the hole and going with a smaller inverted dome. The exhaust valves have about 0.05" clearance between the bottom of the exhaust valve and the piston. These measurements were with the OEM Turbo cam and no cam tower gasket. With the Late NA cam (additional 0.039" lift) it will be VERY tight. Also, if you go with an intake valve any bigger than 47 mm (+2) it will not clear the valve relief.

V2Rocket

how far shaved is the head?

refresh951

0.010"

blown 944

Looks like its coming together well. It will be close if the belt breaks, but let's hope it never gets tested. Looks like my next cam won't be non interference on the bigger engine .

I'm getting excited just watching your progress.

I did find some longer rods for your next build ... Lol

I'm thinking a 3.6 liter monster hybrid