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Heads for discovery 3.9.

Posted: Mon Jan 29, 2007 9:54 am
by Oil leaks
Hi, I have cooked the Disco! (1994/5 3.9 serpentine belt), (Wasn't my fault I promise!) and have dropped a valve seat. The rest looks ok, but who knows! I suspect that the way to go is an entire second hand motor but I'd like to get this one going and see and see what happens. 3.9 heads appear to be hard to come by and expensive so the question is can I use some good early 3.5 heads I have on hand? Id guess that they would need a shave to allow me to use composite head gaskets and a extra hole for the front power steering bracket has been mentioned, has any one any details of the mods required, comments, or advice on if it is possible?
Thanks for your help
David

Posted: Mon Jan 29, 2007 8:20 pm
by Tim D
i was told that 3.9 heads will swap onto a 3.5 without any mods,same size valves exept early 3.5 which had smaller valves.why use the composite gaskets as the tin ones appear too work/seal better?no help on the pwr str bracket.

Posted: Wed Jan 31, 2007 7:57 pm
by Philip A
Heads are probably the least problem area of a Rover V8.
why not take the heads to a reconditioning place for an assessment.
It only cost a couple of hundred for a clean/shave /grind if the guides are OK and a bit more to replace the valve seat.
They can also sleeve/knurl the guides if they are worn, but this is unlikely.
regards Philip A

Posted: Wed Jan 31, 2007 8:37 pm
by Reddo
Agree Phillip - was quoted 400 to get the heads done here.

Posted: Wed Jan 31, 2007 9:39 pm
by disco95
Just had mine off, valves were good, seats were good. $50 a head for a skim, Just spent a little time lapping the valves in again and cleaning things up. the old girl runs like a dream.

Posted: Thu Feb 01, 2007 11:45 am
by Loanrangie
disco95 wrote:Just had mine off, valves were good, seats were good. $50 a head for a skim, Just spent a little time lapping the valves in again and cleaning things up. the old girl runs like a dream.
thats all i did for the heads on my old 81' rangie, 270k on the clock and it still goes ok apart from the lifters that are noisy at startup due to worn cam/ lifters/chain.