V2Rocket

For your car, I suggest just finding a 944 head to directly swap onto the car and everything will work, for sure. You are still fairly new to 944 stuff so stick to the easy option for now.

When I get around to the 928 head (should be picking them up today!) on the 944 engine I will definitely share the results here on Rennlist.

chanothemekhanik

thanks it's gonna be awhile before I swap any head on I was just trying to gather info for the later future have to rebuild the engine in my garage before anything else

wpgshark

Are the camshafts not completely different?

mark kibort

I think they were talking about the cam shafts fitting, but certainly not interchangeable. 4 banger vs 8 cylinder is a HUGE diff.

mark kibort

that's right... the S2 944 and the 968 are both 104mm. are they both 3 liter too? so , besides the valves being larger in the 968, what is the difference in the piston? I seemed to remember that both could be used in stroker 6.5 L projects. but I forgot the differences.

Warehouse33.net

Couldn't you just get on CL and find one of the many ragged out 944's that set not selling for under $2000 and offer $750.00 and be ahead of the game?

-Jason

mark kibort

as i understand it, the 944S2 was a 2 valve head , so how could it have the "same " 37mm valves. it would be euro 928 style 2 valve sized at 40 and 45mm, right?

karl ruiter

Nope. S2 is a 16 valve motor. Unlike the 928 there was no S4 or anything like that, the S2 is the final iteration of the 944 motor before it went 968.

V2Rocket

The regular 944 from 82-88 had the equivalent of 928 euro 2v heads/valves. 45/40 valves.

1989 944 had a 2.7l (104mm) 2v engine with 48mm intake and 40mm exhaust.

The 944S was a 2.5 4v engine, heads very similar to the 928S4.

The 944S2 was a 3.0 4v engine. Heads were basically the same as the 944S but modified to fit the 944 3.0 block.

968 head was like the S2 but with 39mm intakes, larger ports, and modified tensioner boss for variocam.

928 cams come out, 944 cams go in.

chanothemekhanik

so would a s3 head be a better candidate or a s4? Cuz a complete s3 head goes for 400$ where I live and I'm pretty sure I could sell the 928 cams and save up for a pair of S cams or would S2 cams work?

chanothemekhanik

Or would a S2 head be a better candidate for a 16v head swap?

Vilhuer

Depends on what pistons are. S3 head works better with 2-valve heads. Compression ratio get to be interesting when '87+ 4-valve heads are mixed with 2-valve pistons.

Humboldtgrin

The 928 S4 head will work on the 944S with the coolest passage drilled out and the rear head addressed because it protrudes out. This is because once it's on the other side of the V-8 it sets back and has to have more meterial to line up the timing belt drive. If you have a 944S and want to fix it without messing around then find another 944S head. A 928 S4 head WILL work if you have to. But the rear of the head will need to be ground down an bit so it doesn't rub the DME wires going thru the firewall. The 928 S3 head is completely different at every side then the 944S head or the 928 S4 head. So far myself and Spencer are going to biuld a 16v turbo engine using the S3 heads. Also the S3 head uses a differant cam cover then all the 944S/S2 928 S4 heads. The seal makes a funny turn at the rear of the cover for the S3 head(rear being on the passanger side now). The 928S4 and 944S share the same valves and all the same features besides the drilling that would be required for the S4 head to mate onto the 944 block (it will still bolt up but this is for coolant purposes). The 928 S3 has a few mm smaller valves as pointed out and there shorter. However Ferrel is a valve company that will make custom S3 exhaust valves that will handle the turbo exhaust for under $65 ea. Not needed if not gong to a turbo. Also if your keeping the car as a N/A then don't use the S3 head. The intake runners are round not oval like the other 16v heads and the exhaust won't bolt up with any 16v exhaust without replacing the flanges on the 944S exhaust pipes. The cumbustion chamber is too big for a high CR needed for the N/A 944S. One thing I did notice in my parts book is that ALL of these head share the same cam followers. And 928 Motorsports sells lightwieght cam followers if one should chose to replace them with lighter parts. As far as the timing assy goes, the 944S bolts right up to all three heads without any issue. The most expensive part isn't the head, or having custom valves made. It's all the 944S timing assy parts! All of the parts! Don't expect to use a 944 2v timing anything on the 944S, not even the black plastic timing belt covers, any of them(it's wider at the top on the 944S. It's best to start with a complete used 944S engine with all the timing goodies regardless if your keeping it N/A or turbo.

Also it's best to ask these questions in our 944 specific posts. I had to do a search after talking to you for this post. Good question. Like to add a few more head facts, the 928 2v heads don't have the water port needed to be mounted to the 944 2.5 block, but the 4v heads do. And 944 S2 and 968 were both 3.0 liter four cylinders with 104mm bore and 88mm stroke. Using 944S Pistons in a 928 I believe drops the piston 2mm in the bore for you 928 guys that want to turbocharge your car. If a 944 enthusiast wanted to use 928 S4 Pistons then they would need purchase 2mm shorter connecting rods(LR has on hand for 944 engines), or offset the crankshaft 2mm shorter stroke and still get custom rods. Not recommended at all, or ever, by anyone.

V2Rocket

Humboldt - I'm not going to drill out that coolant passage, just going to route the coolant recirculation elsewhere. Some guys in AZ have had success blocking that passage off on the water pump side and putting the thermostat on the return path to the radiator, gives them cooler water temps (since hot water that just passed through the head isn't being recirculated rather than going to the radiator) and higher system pressure (since the pump inlet is not restricted by the t-stat anymore).

Also...If you grind the 944 crank journals to 2" Chevy size, run 5.7" Chevy inline 6 rods with pins drilled to 24mm for the Porsche piston pins, you could run the 928S3 piston in the 944 block with about 3mm of deck clearance and ~7.4:1 compression.

mark kibort

then, why the heck are we not building these euro 5 liter motors for the 928 with the '89 944S heads! 48mm intake valves???? wow, thats substantial, more than going stock US 43mm to euro 45mm!!