Project status....

[gruhsy]

Awesome info thanks

[michaelmount123]

Prepared a brand new cylinder head for the current engine. New casting, new guides, new valves, new lifters - all from spares. The casting was fully ported, but I don't know if Andial did it here in the US, or it was done in Germany. The port shapes looked good. I put it on a flowbench to get a sense of airflow capabilities and was somewhat disappointed. It's not a huge increase over what I get with a standard 944 2V head (ported) which was surprising. No worries, boost overcomes everything else.
Measurements on a 4 inch bore.
Intake valve: 48.5mm Exhaust valve: 42mm
Camshaft has .500" lift both intake and exhaust

Intake (radius at intake port):
LIFT CFM
.100 62
.200 125
.300 183
.400 234
.500 269
.600 283
Exhaust (bare port except as noted)
.100 61
.200 105
.300 150
.400 181
.500 206 (220cfm with 2" pipe added to port)
.600 206 (no increase)

[michaelmount123]

GTR front.jpg (2.9 MiB) Viewed 860 times

I alway promoted and applied the KISS principle. Clearly not everyone does...

[333pg333]

Prepared a brand new cylinder head for the current engine. New casting, new guides, new valves, new lifters - all from spares. The casting was fully ported, but I don't know if Andial did it here in the US, or it was done in Germany. The port shapes looked good. I put it on a flowbench to get a sense of airflow capabilities and was somewhat disappointed. It's not a huge increase over what I get with a standard 944 2V head (ported) which was surprising. No worries, boost overcomes everything else.
Measurements on a 4 inch bore.
Intake valve: 48.5mm Exhaust valve: 42mm
Camshaft has .500" lift both intake and exhaust

Intake (radius at intake port):
LIFT CFM
.100 62
.200 125
.300 183
.400 234
.500 269
.600 283
Exhaust (bare port except as noted)
.100 61
.200 105
.300 150
.400 181
.500 206 (220cfm with 2" pipe added to port)
.600 206 (no increase)

Those figures look pretty decent to me from others that I've seen Michael. I'm not sure quite how much advancement has been made since the days that this was designed and cast but for a 2v it seems pretty good. That's 100cfm over a stock turbo head iirc.

[michaelmount123]

GTR Lower Case Half.png (9.1 MiB) Viewed 644 times

Oil pan / lower case half cleaned and complete (old main bearings). Interesting piece.

[ROB III]

I take it the bolt in 'vent' panels are part of a "windage tray" program and the vents just drain into the oil pan. The material looks thicker than I would expect for that purpose, but perhaps I've miss-interpreted their purpose...I've never taken mine apart so seeing internals is always an appreciated educational journey. Thank you!

[Tom]

We're definitely not in Kansas anymore. Suffice to say yours doesn't look like that Rob. As best I can tell/guess, that's a special part Porsche made for the GTR. On our motors, instead of individual main bearing caps, we have a 'girdle' with all the main bearings caps in one piece that bolts to the block. The oil pan goes over all that. The girdle locks the crank in place and makes it strong like ox. This piece seems to take that to the next level, with the mains integrated into an even bigger casting that incorporates the dry sump oil pan. It's a very Porsche thing to do -- not too unlike the 911's left and right case halves that form the mains around the crank. I know some 944 engine builders put shuffle-pins in the girdle/studs because the crank purportedly starts to move above 5 or 600hp. This piece makes me think Porsche was concerned about the same thing.

Of course, I'm wildly speculating, so MM may come back and explain that's really the blinker fluid tank or something.

[michaelmount123]

Tom, you're right on the mark. There's a dual purpose for the louvered panels in the pan. First, they act as a wiper to strip the oil that wraps around the rotating crankshaft and channel it to the sump below to be scavenged by the external oil pump. It also acts as a "windage tray" to prevent the substantial wind generated by the spinning crankshaft from interfering with oil entering the sump for extraction. Like you suggest, the lower case half/oil pan is more like a 911 than any 944. The removable and slip-in cylinders are another 911-like feature. It makes me think that Hans Mezger had a hand in the very bespoke 944GTR engine design.

Yes, the aluminum panels in the pan are rather thick to withstand the tornado-like conditions in the pan at 7600 RPM.

Engine components that are standard 944: cam housing (although modified to allow access for valve lash measurement), balance shafts and covers, injectors (although two per cylinder are fitted), engine mounts.

Bespoke components are block and cylinders, billet crankshaft, Carrillo rods, Cosworth pistons, solid lifter camshaft, cam followers, cylinder head and valves, intake manifold and ITB's, plenum, Weaver dry sump pump.

I've become quite familiar with this fascinating engine, so if there are more questions, please fire away. Photos are also available.
MM

[gruhsy]

Any chance you are going to 3D scan the crank girdle?

I also keep think about Calico CT5 coating that piece

[333pg333]

GTR Lower Case Half.png

Oil pan / lower case half cleaned and complete (old main bearings). Interesting piece.

That looks like a very stout (multi purpose) pan there Michael! Another piece that I wish they had have incorporated more widely. I lost a 3.1lt 8v and the girdle was in pieces (even though it had been dowelled/pinned).

Nice to think that H.M. had his hands all over these motors.