combining newer with older

[svandamme]

I'm slowly gathering parts for a short stroke 2.9 on a 930/02 block. 66x97mm
Have 87 3.3 turbo heads
I'll run mfi, and twin plug on this thing.



1
Since i will be having new cams made, i was thinking about using later camhousings with 4 bearings.


But can those camhousings be modified/opened up so i can have an MFI drive on my left camshaft?? Or are those camhousings closed up?? Would i have to have em machined for this?

2
Any advantages in certain specific year camhousings?
3.2 ? 964 ? 993?


3
Would i need to get matching Chainhouses, or are all chainhouses supposed to be of equal spacing.


4
I know the 964 chain covers don't have the oil plug for the 3.2 hydraulic tensioners. looks like a completey different tensioning setup..

Has anyone ever tried 964 tensioners on a earlier model?
Any advantage or are they too expensive?



I personally don't care one way or another if it doesn't look early.
Just looking for the best possible combination from a technical standpoint, without going crazy in the $$$ department.

So i don't mind if i get modern valve covers like 965/993 has , those are Twinplug from the factory..
are they less prone to leak?
better when using them for lowers with twin plug??

Just need to make sure that
A it works with MFI drive
B fit's the 3.3 heads
C everything will fit, and the cam will not be twisted with the camhousing.


So if you got any feedback on this kind of neo retro combinations, i'de love to hear about them...

[Flat6pac]

I put the answers in by your questions. Bruce

I'm slowly gathering parts for a short stroke 2.9 on a 930/02 block. 66x97mm
Have 87 3.3 turbo heads The ports are too small
I'll run mfi, and twin plug on this thing.



1
Since i will be having new cams made, i was thinking about using later camhousings with 4 bearings.
There is 2mm difference in the housings between 3 and 4 with 4 being larger to allow the cam lobes access.


But can those camhousings be modified/opened up so i can have an MFI drive on my left camshaft?? Or are those camhousings closed up?? Would i have to have em machined for this?

There is a plug to knock out on the opposite end from the drive

2
Any advantages in certain specific year camhousings?

3.2 ? 964 ? 993?
you cant use the 993 the rocker area is different


3
Would i need to get matching Chainhouses, or are all chainhouses supposed to be of equal spacing.

All pre C2 are equal after 1968


4
I know the 964 chain covers don't have the oil plug for the 3.2 hydraulic tensioners. looks like a completey different tensioning setup..
The 964 is a completely different casting, it looks different because it is different.

Has anyone ever tried 964 tensioners on a earlier model?
Where are you going to get your oil from for the tensioners and cams, everything is different
Any advantage or are they too expensive?
The valve covers tend to be expensive because they fit only the 964 and earlier The 993 because of the hydraulic lifters look the same but dont fit.



I personally don't care one way or another if it doesn't look early.
Just looking for the best possible combination from a technical standpoint, without going crazy in the $$$ department.

The same engine was built for 25 years, the later ones for 4 or 5 years, so which ones has the parts available?

So i don't mind if i get modern valve covers like 965/993 has , those are Twinplug from the factory..
are they less prone to leak? If its got oil in it, it has oil on it.....
better when using them for lowers with twin plug??

Just need to make sure that
A it works with MFI drive If you have the drive put on the cam
B fit's the 3.3 heads But the ports are too small, try the Carrera heads for flow
C everything will fit, and the cam will not be twisted with the camhousing.


So if you got any feedback on this kind of neo retro combinations, i'de love to hear about them...
__________________
Stijn Vandamme

[svandamme]

yeah, i wondered about the 993 hydraulic lifter setup for some time, but as i read in another thread, they aren't as good with revs as solid rockers....
Those lower valve covers are cheap though, but the 964 ones , not so much

So realistically, i'm best to look for 3.2 gear, the newest latest that will fit for my application. And available in numbers...

Same for the oil pump (although later ones will probably fit as well, hear that even gt3 pumps fit, just to expensive for my taste )