Hi Guys,
I'm new to this forum, but were a member of disco2.com many moons ago (before it got hacked to pieces!) (I have also posted this topic on lro.com, but so far no responses.)
I own a 1999 Series II Disco V8 ES (A) with 270 000 km on the clock.
It suffers from a persistant misfire (that clears after a few seconds of elevated engine speed running) when the car is started after being switched off for a few minutes and a constant loss of coolant fluid. We have determined that coolant fluid is leaking into the Number 6 combusion champer (most likely source is from behind the cylinder sleeve, up over the top of the sleeve and into the chamber - the head gaskets were replaced about 10 000 km ago and the cylinder heads machined and pressure tested and found to be good). Ironically, the head gaskets were replaced BECAUSE of the loss of cooling water was blamed on a blown head gasket by the workshop I normally have my Disco serviced, etc. They failed to either check for or notice anything wrong with the block when they had the cyl heads off.
I'm fairly mechanically minded, so I have decided to tackle the engine rebuild myself as a home project. With this in mind, I have a few initial questions:
1. I have bought the LR Overhaul Manual for the 3.5, 3.9, 4.0, 4.2 & 4.6 V8 engines (Publication Numbers: LRL 0164 and LRL 0004), ISBN 1-855-20528-9. When I furchased it via the net, I was under the impression that it covered my car's engine. When I got the book, I noticed it was written in 1997/1999 and only covers the following:
3.5, 3.9 and 4.2 litre engines (with or without "B" engine number suffixes) fitted to Discovery, Defender and Range Rover Classic (Publication LRL 0164)
4.0 and 4.6 litre engines with Prefixes 42D, 46D, 47D, 48D, 49D, 50D and 51D fitted to "New Range Rover" (presumably the P38A), Discovery (NAS) 1996 MY onwards, Defender (NAS) 1997 MY onwards, Defender V8i Automatic. (Publication LRL 0004)
My Disco's engine number prefix is 55D.
Questions:
i) Can I use the LRL 0004 document in rebuilding my 55D engine?
ii) Is there a overhaul manual for the 55D engine? (I can't find one using Mr Google)
iii) What is the difference between the 55D and the other "D" engines listed above?
iv) Was the Series II Disco ever fitted with a 4.2 litre engine? (I've heard that the facelifted V8 (approx 2003 MY onwards), was a 4.2)
2. I was informed that the V8 engine's main "vulnerability" that prevents it from having a near infinite life, is this tendancy to have the cylinder sleeves "pull away" from the cast alu block and causing this sort of water leaks (mine leaks only into the No 6 combustion chamber. Engine oil shows no signs of water contamination).
Question:
i) Is this true? (Is this problem really so "common"?) (Or is someone trying to BS me?)
ii) Can such a block be effectively repaired? (New Liners fitted, etc) (I have also heard of companies fitting liners from a 2.0 litre Isuzu engine and having good results)
iii) What are the best non-OE pistons to fit? I've had varying success in finding out of Piston Manufacturers like Mahle, ATE and Kolbensmith produces aftermarket pistons for the 55D engine?
iv) Considdering the answer to (2-i) above is "YES", what is the leading cause for this mode of failure? Less-than-ideal cooling on the rear cylinders? Lean running conditions? (I had a UniChip fitted to my car about 50 000 km ago (at the time, it had no misfire/water consumptions problems) and it definately improved fuel consumption and my guess is the engine is running a bit leaner with the chip). How do I know if my engine is running TOO lean? (It still only gives around 6 km/l when driven sedately)
3. What items/areas are critical issues/pitfalls that one must be carefull of when rebuilding the 55D engine?
I know I've asked a lot of questions, but any help/information will be GREATLY appreciated!
Thanking you in advance!
Chris