wildcat077

Hey guys,

Blew up my engine big time last weekend at Circuit Mont Tremblant ... now i need to start building another race engine and i have a choice of two running engines that i will tear down and rebuild over the next months.

One is an 86 and the other is an 87 , the current one in my car with a large aeration hole in the block is an 83 ...
Are there any pros or cons to either year ?

Thank you !
Phil

V2Rocket

No, the engines are 99% identical.
The only real difference is that the 87 engine will have a spring-type timing belt tensioner.

The spring is just an approximation of the correct belt tension - you still need to confirm actual tension by hand or by a gauge before tightening everything down.

The 86 will have the same type of tensioner as your 83 did.


For best results re-use all the wiring and sensors etc from the 83 engine...basically you are putting the 83 manifolds/accessories/wiring/etc onto an 86/87 long block.

SamGrant951

88 motor is best if staying/building 2.5 n/a, higher compression pistons (10.2) and DME had higher rev limit.

MAGK944

OP is Canadian. Is Canada US or ROW spec? if it's ROW their 83-87 motors had 10.6:1 compression ratios.

V2Rocket

Canada would be US spec...
by definition, it is "north America"

odonnell

87s also has revised oil systems. I'm not sure if there's anything as far as flow improvements.

I take it that a rod failed on the 83 motor? They're sinter forged, and supposedly a step up from later cast rods. I have a set on my shelf with 40k miles if you wanted to try your luck again with them in the new motor.

wildcat077

This is going to be my engine build ... the engine that came with the car was built in 2007 by the PO who outsourced the work !
I added some goodies over the years but this one will have mostly aftermarket performance parts , totally legal of course ... just like everybody else i race with !

MAGK944

Clever chap, but you should know that Porsche made our cars for the "US" market not the "North America" market, they were country not region specific. But you are right, they are the same

V2Rocket

splitting hairs, we both know Canada's not a real place, anyways.

CVR_Rally

Just curious what happened to cause the failed engine?

Chris White

a couple of points:
83s had forged rods.
83s also had the most oil system issues.
87 vs 86 - oil system was modified for 87 - worth getting that!

333pg333

Might be one or two pointers and good advice in this thread also.

https://rennlist.com/forums/944-turb...e-refresh.html

wildcat077

So it seems the 87 engine is the better choice due to improved oiling ?
I'm going to rebuild it completely anyways over the Winter ... not concerned about pistons, rods or cam , that is all addressed already , so basically the question was which engine year block is the better choice!

I suspect it's the infamous #2 rod that was the culprit although the rod bearings had less than 50 hours on them and they had the Calico coating.Yes my crank was also cross drilled and i'm sure it's toast as well.
My girlfriend will not let me take the car out of the trailer until after our vacation so i'll be tearing into the engine at the end of August, will keep you guys posted with some pictures !

GPA951s

What Exactly was the Difference in the oil system? other than a longer pickup tube and pan?

Chris White

3pcs vs 1 pcs Oil Pressure Relief Valve.
If I recall correctly the main oil galley was modified some time in 87.