S3/S4 Engine Rebuild, Potential?
#1
Rennlist Member
Thread Starter
S3/S4 Engine Rebuild, Potential?
Hello guys, had a questions about the rebuild I’m working on for the 87 S4 I started a while ago. As some of you might recall I stained my block and so I got another one from S3 but the 5.0 32 valve. So been chatting with Mark Kibort about the potential mix of some parts and wanted to see what most of you thought about the idea I have.
So we are on the same page the car I have is a 1987 S4 5.0 32V automatic with block #M28/42. Engine I purchased was a long block 86 5.0L 32V with motor #M28/43.
So was thinking I’d use the block, pistons, crank, oil pan, camshafts and chains from 86 M28/32 and then use the heads and intake from the 87 M28/42. Any thoughts about that?
In the conversation I was having with Mark he mentioned the higher compression rate I might possibly get using that combo as well as reading that S3 camshafts are more agressive which leaves me to wonder and ask what negatives that results in?
Also, what modifications am I looking at doing to injectors? Higher compression requires different grade fuels? Any thoughts ideas and chiming in would be awesome, thanks guys.
Ricardo Vega
1987 S4 Black/Plum
125,XXX
So we are on the same page the car I have is a 1987 S4 5.0 32V automatic with block #M28/42. Engine I purchased was a long block 86 5.0L 32V with motor #M28/43.
So was thinking I’d use the block, pistons, crank, oil pan, camshafts and chains from 86 M28/32 and then use the heads and intake from the 87 M28/42. Any thoughts about that?
In the conversation I was having with Mark he mentioned the higher compression rate I might possibly get using that combo as well as reading that S3 camshafts are more agressive which leaves me to wonder and ask what negatives that results in?
Also, what modifications am I looking at doing to injectors? Higher compression requires different grade fuels? Any thoughts ideas and chiming in would be awesome, thanks guys.
Ricardo Vega
1987 S4 Black/Plum
125,XXX
#2
The 1st obstacle is that the S3 cams will not bolt directly into the S4 heads.
#3
Drifting
Rebuild the engine to S4 specs; do it right!
#4
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You're going from bad to worse.
Not to be offensive, however, when I read back through your posts, I'd go out on a limb and say you probably don't have the required skills to play around with swapping pieces from one generation engine to the next.
Find a correct S4 short block.....they are not all that rare.....yet.
Sell the incorrect S3 parts.
Attempt to re-assemble.
Not to be offensive, however, when I read back through your posts, I'd go out on a limb and say you probably don't have the required skills to play around with swapping pieces from one generation engine to the next.
Find a correct S4 short block.....they are not all that rare.....yet.
Sell the incorrect S3 parts.
Attempt to re-assemble.
__________________
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
#5
Rennlist Member
If you put an S4 top end onto an S3 bottom end you will end up with 12:1 compression. That is not a good thing as you will need to run race fuel or ethanol to make the engine viable.
I would do what Greg says and get the correct S4 bottom end.
I would do what Greg says and get the correct S4 bottom end.
#6
Nordschleife Master
I do however agree that this is a big commitment to buying tools, spending time learning, mocking it up, etc.
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#8
Drifting
#10
Rennlist Member
As an advocate for Greg Brown and living thru the S3/S4 build he did on my car this is not for the faint of heart. It was a head scratcher ( maybe beard puller) even for Greg. He had to come up with innovative solutions to make perfect. Listen to him and take his advice. The last thing you want to do is to be chasing issues for ever. Then you will loose interest and your time and investment is wasted.
#11
The Parts Whisperer
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#12
Rennlist Member
Thread Starter
Got it everyone! My block is group 1 tolerance. Thanks for advice, Mark. I emailed you guys this morning and Tom said you guys only had group 0 tolerance pistons, 8 of them.
RV
RV
#13
The Parts Whisperer
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#15
Drifting
RV, as stated earlier, the best way to go about this to maximize your probability of success is to acquirie a good S4 shortblock or longblock.