944S block with SOHC head??
#1
944S block with SOHC head??
Hi everyone,
first post here but I have a conundrum that I can't work out on my own.
I just started doing the cambelt on my 1983 2.5 Lux and when I took the timing cover off I noticed an autotensioner that I wasn't expecting.
Then looking for the engine number I found it was in the wrong place so turns out my engine is from 88.
The engine number is M44/40 42J01506
According to my research this means it is a 944S engine.
However...
Doesn't look like a DOHC to me...
Don't really know what my question is, I think I just need a second opinion on whether I've got this right or not so I can crack on with the work.
Seems like I need the timing gear from the 944S engine?.
Let me know your theories on what's happened to my engine!
My running theory is that someone with a 944S mashed their valves and replaced the head with a SOHC? then maybe the whole engine came out and went in my car. Don't know how feasible that is though.
Thanks for your help!
Joe
first post here but I have a conundrum that I can't work out on my own.
I just started doing the cambelt on my 1983 2.5 Lux and when I took the timing cover off I noticed an autotensioner that I wasn't expecting.
Then looking for the engine number I found it was in the wrong place so turns out my engine is from 88.
The engine number is M44/40 42J01506
According to my research this means it is a 944S engine.
However...
Doesn't look like a DOHC to me...
Don't really know what my question is, I think I just need a second opinion on whether I've got this right or not so I can crack on with the work.
Seems like I need the timing gear from the 944S engine?.
Let me know your theories on what's happened to my engine!
My running theory is that someone with a 944S mashed their valves and replaced the head with a SOHC? then maybe the whole engine came out and went in my car. Don't know how feasible that is though.
Thanks for your help!
Joe
Last edited by Joe Webb; 01-16-2019 at 05:37 PM. Reason: rookie mistake
#2
Three Wheelin'
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Yeah looks like m44/40 is the model for 87 and 88S models. The S block will take an NA head. So seems you have a hodge podge of parts there, do you have a small camera and could ge a shot of the piston? Wonder if the pistons were changed from the 4v to 2v as compression would be effected. Wiring harness is also different from 4v to 2v, so someone took some effort to swap things about.
#3
Rainman
Rennlist Member
Rennlist Member
most likely in my opinion is that they used an M44/40 BLOCK with SOHC pistons installed.
the SOHC valves would crash into the DOHC piston crowns without proper reliefs cut (unless somebody cut the reliefs?)
SOHC head on DOHC pistons would be around 9:1 compression give or take.
the SOHC valves would crash into the DOHC piston crowns without proper reliefs cut (unless somebody cut the reliefs?)
SOHC head on DOHC pistons would be around 9:1 compression give or take.
#4
Yeah I was wondering about that, I guess you would you be able to identify the piston from the presence or lack of reliefs? Also it would be interesting to see if they had witness marks from presumably crumpling the valves in the original head.
I'll see what i can do but I don't have an endoscope.
The car seems to run pretty well, although I didn't give it much welly with the uncertain cambelt condition. would the compression ratio really drop with DOHC pistons installed? seems to me if they are potentially fouling the valves the compression ratio would increase, no?
Maybe I'll borrow my friend's dyno when I get it running.
That autotensioner is a pretty big unexpected outlay, given the frankenstein nature of the engine I'm less keen to break my wallet over it. What are you guys' thoughts on reusing the old autotensioner? (with a new roller)
I'll see what i can do but I don't have an endoscope.
The car seems to run pretty well, although I didn't give it much welly with the uncertain cambelt condition. would the compression ratio really drop with DOHC pistons installed? seems to me if they are potentially fouling the valves the compression ratio would increase, no?
Maybe I'll borrow my friend's dyno when I get it running.
That autotensioner is a pretty big unexpected outlay, given the frankenstein nature of the engine I'm less keen to break my wallet over it. What are you guys' thoughts on reusing the old autotensioner? (with a new roller)
#5
Rainman
Rennlist Member
Rennlist Member
its not really an autotensioner.
it's got a spring to approximate correct belt tension, but tension still needs to be manually verified.
once set the tensioner gets locked down via bolt/nut and it doesnt adjust any more on its own.
standard procedure to just swap the roller for a new one.
it's got a spring to approximate correct belt tension, but tension still needs to be manually verified.
once set the tensioner gets locked down via bolt/nut and it doesnt adjust any more on its own.
standard procedure to just swap the roller for a new one.
#6
Instructor
its not really an autotensioner.
it's got a spring to approximate correct belt tension, but tension still needs to be manually verified.
once set the tensioner gets locked down via bolt/nut and it doesnt adjust any more on its own.
standard procedure to just swap the roller for a new one.
it's got a spring to approximate correct belt tension, but tension still needs to be manually verified.
once set the tensioner gets locked down via bolt/nut and it doesnt adjust any more on its own.
standard procedure to just swap the roller for a new one.
#7
That's what I thought, excellent news!
I have a tension gauge but it's a universal one rather than the porsche one.
OK I think I can get started while my new cambelt kit is on it's way. Thanks everyone!
I have a tension gauge but it's a universal one rather than the porsche one.
OK I think I can get started while my new cambelt kit is on it's way. Thanks everyone!
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#8
Nordschleife Master
The workshop manual was wrong from the start, those “self-adjusters” never worked accurately from the get-go and the timing belt was always checked using the factory tool #9201 at the dealerships.
#9
Oh wait, one last question:
am I right in thinking i need the cambelt from a 944S (944 105 323 02) or would it be better to go with the one from the 8v (944 105 157 04)?
Also what is the difference between the two?
thanks in advance
am I right in thinking i need the cambelt from a 944S (944 105 323 02) or would it be better to go with the one from the 8v (944 105 157 04)?
Also what is the difference between the two?
thanks in advance