2001 s8 4.2 engine swap???
02-11-2016, 04:39 PM
#1
AudiWorld Newcomer
Thread Starter
Join Date: Feb 2016
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
2001 s8 4.2 engine swap???
Hi im new to the audi world I work at at a vw dealership but im not a tech
I recently bought an 01' s8(did not have full coverage) and to put it bluntly I slid under a cherokee due to bald tires, the timing belt is all shredded up, quite possibly have valve and piston damage etc... on to the point
I was wondering if I could drop a 4.2 out of an a8 of the same year into it or even an a6 without any modifications or major issues.
ANY help or advice would be appreciated
I recently bought an 01' s8(did not have full coverage) and to put it bluntly I slid under a cherokee due to bald tires, the timing belt is all shredded up, quite possibly have valve and piston damage etc... on to the point
I was wondering if I could drop a 4.2 out of an a8 of the same year into it or even an a6 without any modifications or major issues.
ANY help or advice would be appreciated
02-11-2016, 09:25 PM
#2
AudiWorld Senior Member
S8 has different Cams, pistons (forged and higher compression), and intake manifold. You could swap the intake manifold, but you will still have less power. You might also be swapping over a bunch of sensors to make the wiring work. How certain are you that the heads/valves are damaged. I'd throw a new timing belt on it and see what you got first.
02-12-2016, 04:19 AM
#3
The C5 S6 engine however is identical to that in the S8, apart from the oil cooler and engine mounts and they are just bolt-on anyway. The 20hp difference is just in the software.
If it is just 'possibly' valve damage then I agree with Brian - throw a new belt on and see what it does. The 40V is remarkably tolerant to belt issues for such a complex engine. It can run a tooth out without any damage, so unless the belt is actually snapped and the crank has spun without the cams turning its possible it might still be ok.
Mine had the belt hanging slack between the two heads and not even touching the water pump, yet doesn't appear to have any valve damage at all, although for various reasons I am putting a brand new S6 engine in it.
If it is just 'possibly' valve damage then I agree with Brian - throw a new belt on and see what it does. The 40V is remarkably tolerant to belt issues for such a complex engine. It can run a tooth out without any damage, so unless the belt is actually snapped and the crank has spun without the cams turning its possible it might still be ok.
Mine had the belt hanging slack between the two heads and not even touching the water pump, yet doesn't appear to have any valve damage at all, although for various reasons I am putting a brand new S6 engine in it.
02-12-2016, 12:23 PM
#5
Over-stock from Audi UK. They had a load of them on the shelf left over from back when the C5s were new so sold them off cheap. £1800 instead of £13,600 list 
I had the heads off to check for damage following the slack timing belt and overheating issues courtesy of the PO, and was >£1000 in parts just to put it back together so the new one was a no-brainer.
I had the heads off to check for damage following the slack timing belt and overheating issues courtesy of the PO, and was >£1000 in parts just to put it back together so the new one was a no-brainer.
