chanothemekhanik

I own two 944's I'm looking for another head for my S which is the 16v dohc model. I know that the 928 gt4 uses the same head parts but when I saw a photo of the cylinder head on a 928 they look extremely similar will it work???

davek9

I've seen heads on 944's that are the exact same as 32v 928 heads, however I'm not at all familiar w/ all the 944 variants as to what MY's they were.

Maybe if you post the PN of the Head you are looking for, others here may be able to assist.

Also as far as I know there are no 928 GT4's, only 928, 928S, 928GT and 928GTS

hacker-pschorr

The 944S and S2 head from 87+ look identical to the S4/GT/GTS head, but they are far from the same. They can be made to work but not a 100% bolt on without some modification.

Something with the water jacket port is different, it's been a while since I looked into this.

The ports on the S head are also larger, not sure about the S2.

davek9

^^^Thanks ^^^ for clearing that up for me, AO and I were looking at one on a 944 and thought they were the same, the above makes sense, Also missed the S4 reference

James Bailey

The 944 head has no need for the water bridge between two heads and is quite different in how it hooks up to the thermostat housing....that is where it varies the most.

chanothemekhanik

have to bring the topic up again. But will it bolt up to a 944 block? And what mods would need to be done to make it work?

hacker-pschorr

I fail to understand why you would go through the trouble when 944S heads are out there.

There has been one for sale in the classifieds for 3 years with no buyers. $800 and it hasn't been installed since being refreshed:

https://rennlist.com/forums/for-sale...-16v-head.html

That one says "sale pending" as of 11/30 - send him a PM, see if it's still available.


I also pointed out above, the ports in the 928S4 head are smaller than the 944S head.


If that is outside of your budget, I dare ask what you think a good 928 head sells for?

chanothemekhanik

I seen a complete 928 head for 500$ and a 944S head only with valves and springs for 700$

GregBBRD

There's places to save money and places to not try to save money.

You are going to spend more than $200 getting the 928 head fit.

Buy the 944 head.

V2Rocket

Hacker,
Can't speak for the other guy, but there is a little bit of interest on our side regarding the 85-86 S3 heads, because they bolt-up to the 2.5L 944 block (all the coolant stuff lines up), the 944S/S2 cams appear to fit, and the combustion chamber is ~56cc like the 944 2-valve head, versus 42cc like the 944S/S2 head. So It's a possibility to get a 16v head without bumping up the compression a full point like the 944S head would do on a 951 bottom end (8:1 to 9:1).

Also, as you all know, the S3 heads have the 2-valve exhaust bolt pattern which takes out half the work of building a DOHC 944 turbo.

I just bought a pair of S3 heads to experiment.

Vilhuer

Problem with S3 heads are small valves. Using custom valves and porting head to S4 size cost $$$ so there is no easy way to get full benefits from 4-valve design.

V2Rocket

Hasn't it been proposed and supported as an idea that the valves of the S4 (same size as 944S) are perhaps TOO BIG for a 100x78.9 engine in this RPM range?

I am thinking the smaller valves (and smaller ports!) may help the lower/mid-range torque production compared to the HUGE ports on the 944 16v engines which are very weak below 4000+rpm.

And even if the S3 heads/small valves don't flow as much outright as the S4 stuff, it should be at least a fair bit more than the standard 944 2v head.

Like I said...it's an experiment...we won't know if it's worth doing, until it's been done

mark kibort

what about 968 heads, will they fit the S4? (then you get the bigger valves, right?) but i heard there is some water opening that needs to be closed off or some oiliing passage.

i thought the 944 was 2 valve euro size, no??

ok.. edit.. 944 is 2valve like the euro 2 valve, and 944 s2 is a 4 valve like the S4, but bigger valves... what about the 968 heads? are those valves even bigger?

I think the advice here is that water bridge plug for you , and create for the 928, is a non trivial procedure and that sounds like it would make sense to just find a 944s head, right??

V2Rocket

928S3 has 35mm intake valves.
928S4/944S/944S2 have 37mm intake
968 has 39mm intake, but the same bore as the 944S2 (104mm)

re:valve sizing, been doing some reading on that based on S3 concerns and found some interesting figures...i think the 35mm will work for my purposes and rpm range.
- honda s2000 (2.0 or 2.2L depending on year) has 36mm valves, sufficient for 8000+rpm and 240hp
- current Ford 5.0 Coyote (5.0L) has 37mm valves, good for 7000rpm, 420-450hp or so.
- 944S2, 3.0L with 37mm valves but a good tune and hot cams, 280whp (https://rennlist.com/forums/944-and-...big-power.html)


- on front corner of 944 head is a tab for coolant to pass through as a recirculating feature, on the 928 heads the tab is there but it is cast shut so no water flows. other coolant/oil passages should be similar between models.
--- this block-off could be desireable for us, as some experiments have been done blocking off this recirculation path on the 944 with a modified gasket, resulting in cooler, more consistent cylinder head coolant temps.
--- along with relocating the thermostat, higher system pressure/pump efficiency.


- 944 2v head is like the 928 Euro 2v stuff.

- 944 doesn't need a water bridge or anything like that - just reuse the 944S coolant parts on the 928S3 head (the coolant outlets on either end of the 928 4v head, where the 928 coolant bridge goes, the 944S has its upper rad hose on one port and the heater core hose on the other)


see some pictures in 1st post of this thread....
https://rennlist.com/forums/944-turb...-question.html

chanothemekhanik

So if someone could come to a conclusion on Wat head would theoretically work and Wat wound be needed and or changed? To work efficiently?