BC

The ports are different on the 968 heads, and the valves are already "big valves"

For someone planning a BIG motor, and if they can be patient to find the second head:

https://rennlist.com/forums/944-turbo-and-turbo-s-forum/419737-968-head-and-cams-for-sale-along-with-a-few-other-parts-from-my-968-a.html

They come up once in a while. How about a Vario-Cam 7L motor?

shmark

ummm...Sterling?

BC

Sterling did his with S4 heads welded and customized to fit the variocam system from the 968. His works great, and he did this 8 years ago.

This would actually (unless the head surface shape changing is insurmountable) be an easier and cheaper way of doing what Sterling did years ago as a pioneer.

hacker-pschorr

Are the water & oil passages the same on a 968 & a 32V 928? The 944 heads are not a direct bolt on to a 928.

Not only are the water passages just a bit different, the valves are actually further apart so they do not line up with the 928 cam lobes.

Not saying it cannot be done, there might be a few issues.

BC

Cams would be custom anyway. Sterling said something about the other stuff.

RyanPerrella

I guess the question then would be is there any benefit to the 968 heads that cant be done to S4 and later heads. It would seem that the money involved in making the 968 heads work for the 928 would cost quite a bit more then just the larger intake valves would be. This is $1000 for a single head. I think S4 heads run 1000 for a pair so your doubling your investment in heads right there and then need machine work in them to get them to work properly. Not to mention you MUST you use custom cams that would work ONLY with this engine, so if you ever wanted to change profiles your cams would be worthless to resell.

Of course if you want vario cam then maybe you do it. But I think it would be cheaper still to modify the 928 heads to allow for the variocam install. I think the Variocam requires another bolt hole on the opposite side of the tensioner. I think you could weld that tab on and machine it so that it works.

I wasn't aware of the water passage differences. Thanks for pointing those out.

And was it really 8 years ago Sterling, damn! That really is innovation, i had no idea you did that so long ago.

IcemanG17

The bummer is he is selling 1 head...928's need 2....I still think a 89+ head with bigger valves, porting and custom cams will flow more than enough to make silly HP.....

BC

Indeed. Sterling's idea and trying it again has merit though.

The port shape is more modern on the 968 heads as well. Alot of work would need to be done ($$$) on the 89 heads.

LT Texan

how about a flat (180 degree) crank and 968 cams?

BC

indeed.

RyanPerrella

Well Dan, thats an idea, i like that!

Vilhuer

While picking up S3 cams from local cam specialist he explained further how he had done adjustable gear into 944 S2 cam by machining original gear away. Once original was off he inserted new gear through rear end of the cam and secured it to what little original gear he left to cam. He thought inserting one teeth smaller 968 style gear in place of 928 or 944 gear would be impossible without either making cam lobes smaller or making gear from two pieces which probably wouldn't be very good idea. For fixed adjustment he favored changing up/down position of entire chain adjuster mechanism. For on the fly adjustable system like 968 Variocam he would perhaps try to make two piece can gear setup by machining gear teeths after pieces are mounted on the cam so that gear would be uniform. But in his opinion its way too much work for the gain to even try to change exhaust and intake cam relationship. Its simpler to just take few mm's off from cam base lobe and make new static profile than to do anything movable.

RngTrtl

single plane cranks on v-8s have tonnes of other issues...No way good idea

RyanPerrella

On an all out racing engine it could be worth it (Although I am still not entirely sold on the benefits)

Ferrari uses it in the 360 and 430, BMW uses it in their ALMS V8 M3's for a few years back. (Not sure the new M3 street car uses a flat plane crank though, I doubt it)

LT Texan

I do believe ferrari does it on street cars.

The suggestion is an enzo. search on it. Never picked up critical mass

for racing, no brainer if you ask me.

I'd give it a try on the street if I had the inclination or time for such a project.

But a stroker in a 928, come on, how much do you guys need?????

5.0 is enough

4.5 aint bad in a light old bugger