Porsche 944S engine rebuild
Discussion
So, getting back to my earlier question 
Is the 8V block compatible with the 16V head. It looks like it may be, because instead of using a longer single cambelt for both cams, it looks like they just stuck with the arrangement from the 8V engine, and then put the chain on to drive the second cam.
It all comes down to whether there are any other differences there that might cause me trouble.
It would be useful if it would fit, as I've found somebody who has an 8V engine for sale.
James
Is the 8V block compatible with the 16V head. It looks like it may be, because instead of using a longer single cambelt for both cams, it looks like they just stuck with the arrangement from the 8V engine, and then put the chain on to drive the second cam.
It all comes down to whether there are any other differences there that might cause me trouble.
It would be useful if it would fit, as I've found somebody who has an 8V engine for sale.
James
james said:
It looks like it may be, because instead of using a longer single cambelt for both cams, it looks like they just stuck with the arrangement from the 8V engine, and then put the chain on to drive the second cam.
They did this to cut down on costs when they introduced the 32v 928 for the 1987 model-year (autumn of 1986), the same system was applied on the 16v 944 S instead of designing a proper head without any cam chain.
As far as I know there are two types of 944 block :
- 2.5 8v / 2.5 8v Turbo / 2.5 16v S : BxS = 100 mm x 78.9 mm
- 2.7 8v / 3.0 16v S2 : BxS = 104 mm x 87.8 mm
Unless someone else replies I will try to come back to you with the block numbers as I don't have them with me right now.
>> Edited by Thhom on Friday 17th October 12:04
james said:
There is that
I've got a Rover V8 sitting in the Ultima right now. Hmmm.... No, I think it's probably doing more good sitting in the Ultima, so I'll leave it there.
I's also need a seriously uprated gearbox to handle the torque.
How much does the Rover engine weigh compared with the 944S unit?
As far as I know the gearboxes were good for about 400BHP...AJLintern said:
There is that
I've got a Rover V8 sitting in the Ultima right now. Hmmm.... No, I think it's probably doing more good sitting in the Ultima, so I'll leave it there.
I's also need a seriously uprated gearbox to handle the torque.
How much does the Rover engine weigh compared with the 944S unit?
The turbo gear boxes probably were but the standard S box strugles with anything more than standard
james said:
So, getting back to my earlier question
Is the 8V block compatible with the 16V head. It looks like it may be, because instead of using a longer single cambelt for both cams, it looks like they just stuck with the arrangement from the 8V engine, and then put the chain on to drive the second cam.
It all comes down to whether there are any other differences there that might cause me trouble.
It would be useful if it would fit, as I've found somebody who has an 8V engine for sale.
James
Yes James, you can put a 16v head onto an 8v block. The problem will be with the cam belt. On the 16v the belt is thicker, and has a different tensioner: the 8v has a tensioner on a cam, the 16v has a tensioner which sits on a sping mounted plate.
In order for the correct belt to be used, you would have to use a 16v cam tensioner, but machine the hole into an oblong so you can tension the cam that way.
The other way would be to take the water pump jacket from a 16v (with the sping loaded tensioner assembly attached) and replace that as well. Then its entirely possible.
I know, because my 16V "S" had an 8v block, with a machined tensioner.
Any other questions, feel free to contact me
regards,
Will
ex-944S
Thanks for that. I'll probably go the route you suggest of swapping bits from my 16V block onto the 8V one to use the correct tensioner. It'll be the simplest way I think.
On the subject of gearboxes. My S had a replacement gearbox a couple of years ago, and it was replaced with one from an S2, so it should be able to take a bit more torque than the original unit.
Now. About that supercharger......
On the subject of gearboxes. My S had a replacement gearbox a couple of years ago, and it was replaced with one from an S2, so it should be able to take a bit more torque than the original unit.
Now. About that supercharger......
That's a bit of a bugger. How bad is it? Is it fixable, or is it a non starter?
Edited to add:
I just spoke to Kevin at EMC. He tells me that the blocks are identical between the 8V and 16V 2.5 angines. It's only the pistons that are different. This is good news, as I'll be able to make one good engine out of 2.
James
>> Edited by james on Friday 24th October 08:45
Edited to add:
I just spoke to Kevin at EMC. He tells me that the blocks are identical between the 8V and 16V 2.5 angines. It's only the pistons that are different. This is good news, as I'll be able to make one good engine out of 2.
James
>> Edited by james on Friday 24th October 08:45
)I've heard from and read in a couple of places (including Kevin at EMC) that the blocks are identical, and the only difference is the pistons.
I guess I'll find out tomorrow when I go to pick up the short engine
I'm going to end up with 2 blocks and 12 pistons (4x8V and 8x16V), so I should be able to make one decent engine out of all that.
Cheers
James
I guess I'll find out tomorrow when I go to pick up the short engine
I'm going to end up with 2 blocks and 12 pistons (4x8V and 8x16V), so I should be able to make one decent engine out of all that.
Cheers
James
Will do. I'll also need to head sort out the head. I'm going to need at least 4 valves, but the seats don't look like they were damaged (although I can't be sure until I've stripped them out and inspected it properly).
As I don't want to have to be rebuilding the engine again in a couple of years, I'd like to be as sure as possible that I don't suffer a cam belt snapping, like so many people seem to have done (cylinder heads seem to be in constant demand for just this reason).
What is the general consesnsus on when you really do need to change the cam belts? The Porsche recommended interval seems to be a bit long by the sound of things. Or is it that people do low miles over several years, so the belts age?
Cheers
James
As I don't want to have to be rebuilding the engine again in a couple of years, I'd like to be as sure as possible that I don't suffer a cam belt snapping, like so many people seem to have done (cylinder heads seem to be in constant demand for just this reason).
What is the general consesnsus on when you really do need to change the cam belts? The Porsche recommended interval seems to be a bit long by the sound of things. Or is it that people do low miles over several years, so the belts age?
Cheers
James
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