1998 4.2 S8 ENGINE DIFFERENCES HELP
08-24-2004, 08:58 AM
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1998 4.2 S8 ENGINE DIFFERENCES HELP
JUST BOUGHT A 98 S8 (CODE AHC)WITH A BLOWN ENGINE, IT'S DROPPED A VALVE AND DAMAGED THE HEAD, PISTON AND ROD. QUESTION IS: I CAN GET MY HANDS ON A 4.2 V8 (CODE ABZ), WHAT WILL THIS PERFORM LIKE ONCE FITTED TO THE CAR, OR CAN I BUILD THE ABZ MOTOR TO S8 SPEC WITH EASE CONSIDERING I HAVE A DONOR S8 MOTOR ?? HELP PLEASE I NEED THIS S8 RUNNING.... THANKS, MIKE
08-24-2004, 09:17 AM
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Don't know
First, if you could post NOT in all caps, we would appreciate it.
Secondly, welcome to audiworld!
The pre facelift S8 has many different parts as compared to the ABZ engine.
Most of the people here are from the states, so we have never seen a pre face lift 32 valve S8.
"JeffB" has imported a motor from Europe and is retrofitting it to his 98 U.S A8.
Do a search on audiworld for "JeffB" and you'll find 60 hits, most of them his threads about his rebuild.....a lot of technical info there.
Good luck!
Another place you might want to ask is at the url below. Almost everybody is from Europe there.<ul><li><a href="http://www.tyresmoke.net">http://www.tyresmoke.net</a</li></ul>
Secondly, welcome to audiworld!
The pre facelift S8 has many different parts as compared to the ABZ engine.
Most of the people here are from the states, so we have never seen a pre face lift 32 valve S8.
"JeffB" has imported a motor from Europe and is retrofitting it to his 98 U.S A8.
Do a search on audiworld for "JeffB" and you'll find 60 hits, most of them his threads about his rebuild.....a lot of technical info there.
Good luck!
Another place you might want to ask is at the url below. Almost everybody is from Europe there.<ul><li><a href="http://www.tyresmoke.net">http://www.tyresmoke.net</a</li></ul>
08-24-2004, 09:46 AM
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See post below. Someone has a line on an S8 with eng compartment fire. Motor may be for parts OK!
<ul><li><a href="https://forums.audiworld.com/a8/msgs/73020.phtml">https://forums.audiworld.com/a8/msgs/73020.phtml</a</li></ul>
08-24-2004, 10:27 AM
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Stick to the same engine code if you can
You'll probably run into all kinds of trouble if you don't. ECU needs to match, as stated above, ECU and TCM need to be able to communicate, etc.
08-24-2004, 11:01 AM
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Re: Stick to the same engine code if you can
I was thinking that because the A8 and S8 are very similar engines except for compression ratios,solid lifters and camshafts, that the S8 would run an A8 motor without a problem... as far as I know they have the same engine electrics. Does anyone know how the compression ratio is changed ie; is it pistons,rods, crank or head ? Is it possible to fit the solid lifters and camshafts into the A8 motor ?
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08-24-2004, 11:10 AM
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Some info
To match S8spec on ABZ you need heads, intake manifolds with all on them from AHC/AKH.
You can use pistons & rods from ABZ to repair AHC.
If you drop ABZ to S8 body you must replaced ECU & TCU. Will tranny normal work in that case nobody knows. Another way replaced tranny too.
Simpliest way to repair - to find another AHC or spare parts.
You can use pistons & rods from ABZ to repair AHC.
If you drop ABZ to S8 body you must replaced ECU & TCU. Will tranny normal work in that case nobody knows. Another way replaced tranny too.
Simpliest way to repair - to find another AHC or spare parts.
08-24-2004, 11:17 AM
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Re: Some info
I think the inlet manifolds and throttle body are the same according to ETKA ? obviously I'll have to use the S8 injectors. What is the difference in the heads ?? One of my S8 heads is scrap, can I put the solid lifters and cams into the A8 heads ?
08-24-2004, 11:24 AM
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No it wouldn't
just run w/o a problem. The electronics wouldn't know what to make of it. Unless the parts are shared that is. You need to source ETKA or ETOS, then you can see if the heads, block, etc. are shared with the present engine. If so there will be no problem, as long as you use the present ECU and torque converter.
F.i., a (facelift) S8 with AQH can run perfectly with AVP - if you do as above - but don't try to swap the ECU. For one, the first has a single lambda, the other two, result: a confused ECU.
F.i., a (facelift) S8 with AQH can run perfectly with AVP - if you do as above - but don't try to swap the ECU. For one, the first has a single lambda, the other two, result: a confused ECU.