chris_mack

chris_mack

New Member
As above.

When I come home to the UK from Oz, Il be looking to buy another V8 to rebuild and put into my 110. The engine in that is ok, but perhaps a little tired.

So which is the best, I guess a 3.5 on carbs is the most reliable, and obv being a straight swap would be the easiest to fit.

In terms of the later models 3.5i 3.9i, 4.0, 4.6 etc which is the best and most reliable?

I seem to remember some of them suffer from cracked blocks due to being bored out or something is that correct?

If I were to go for something like the 4.6, would the extra power tear any manual gearbox to shreds, meaning I would have to go auto or would the santana box be ok?
 
My 3.5 was smoother running than my 3.9. I did't know the 3.5 was running some times untill turned the starter Oops. I believe that unless the engine overheats big time there won't be any problems with liners.
 
3.5 gets my vote although my 3.9 is still going and I think it had been badly beaten before I got it.
 
I have a 3.9 fitted to my 90, it is a huge improvement on the 3.5.

Having read lots of posts of unreliable electronics on this forum, I kept the carbs fitted.

Cannot rate it highly enough.
 
3.5disco said:
All except the 3.5 can slip a liner unless you have the block top-hatted
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This take (some engine re-builder's make a point of it in their ads) on the problem always puzzles me. Given it's when the block cracks, the bore no longer 'grips' the press fit liner thereby allowing it to move in the first place. I can see how a 'top-hat' design would prevent liner movement, but how does it prevent the block cracking? Anyway long live the 3.5, like many things in life the original remains the best - but then having had three of them & one 3.9 (groan) I would be biased!
 
Last edited:
The 3.5 in Disco 1 fitted with the hotwire efi. It has the reliable 87.5mm bore block and a half decent injection system with proper idle control and a choice of open or closed loop operation.
Not many left now tho.....
 
norseman said:
This take (some engine re-builder's make a point of it in their ads) on the problem always puzzles me. Given it's when the block cracks, the bore no longer 'grips' the press fit liner thereby allowing it to move in the first place. I can see how a 'top-hat' design would prevent liner movement, but how does it prevent the block cracking? Anyway long live the 3.5, like many things in life the original remains the best - but then having had three of them & one 3.9 (groan) I would be biased!
Click to expand...

the only reason for the slipping of the linner is the cracking but this is in part due to the engine running hot which gas and closed loop emissions set up cause most non cat engines and not converted to gas run fine for many many miles without an issue
 
vougese39 said:
the only reason for the slipping of the linner is the cracking but this is in part due to the engine running hot which gas and closed loop emissions set up cause most non cat engines and not converted to gas run fine for many many miles without an issue
Click to expand...

You could well be right, my 3.9 (another groan) ran well for the first year after I bought it, then I had it converted to LPG. Within 10k it had slipped a liner (#3) & although there was no direct evidence that the gas caused the failure.....:( Interestingly enough the same thing happened to a mate's 3.9, so it's the original bore & no gas for me these days plus the fact that with the mileage I do it would take me over four years to break even.
 
so 3.5 CARB would probably be the safest/most senisble option.

I know there are many debates about gas, but does it have a history of causing problems with the 3.5 or only the later models?
 
chris_mack said:
so 3.5 CARB would probably be the safest/most senisble option.

I know there are many debates about gas, but does it have a history of causing problems with the 3.5 or only the later models?
Click to expand...
I recently sold my 97 3.9 disco on lpg, lpg was fitted in 2000 on just over 20k miles and was still sweet as a nut at 105k
 
3.5 seems more resistant from all reports I have gathered.

Alot depends on which brummie bastid built it and and what mood he was in. also the year as the tooling getts more knackered as it gets older and tolerances grew!!

I have to say my 2.5 on carbs is very nice although I am just starting out with it after (still) running a 3.9 for a year and a bit.
 
I now always steer clear of twin carb setups after my years of MGs it seemed that they had to be ballanced every month. Never had an probs with a pair of Webbers though :D
So I would go with the EFi now but a carb V8 sounds better at the tail pipe to me.
 
I am thinking of rebuilding the 3.5 carb in my spares 79 rrc into a long stroke motor, so I keep the block and liner standard but get a bit more displacement which will hope fully last the gas!

Got plenty of time now with that nice new 3.5 already in my 72
 
fett said:
I am thinking of rebuilding the 3.5 carb in my spares 79 rrc into a long stroke motor, so I keep the block and liner standard but get a bit more displacement which will hope fully last the gas!
Click to expand...

A LR mechanic I knew a few years ago stroked his 3.5 to 4.3L using a kit from 'real steel' but whilst being impressed with the extra grunt he managed to blow the A pack of the ZF 'box whilst towing his caravan!
 
fett said:
3.5 seems more resistant from all reports I have gathered.

Alot depends on which brummie bastid built it and and what mood he was in. also the year as the tooling getts more knackered as it gets older and tolerances grew!
Click to expand...

You're right there Fett;) I'm also given to understand that more care was taken with the balancing of the 3.5's by fitting 'matched' pistons/rods etc. rather than the practice of balancing the later completed engines by fitting weights to the crank pulley (?) Mine was built in the mid-eighties.
 
I have a 4L v8 with a 5 speed manual in my 90. It goes like stink but does run a little hot.... Sounds good with the straight through
 
888crewcab said:
I have a 4L v8 with a 5 speed manual in my 90. It goes like stink but does run a little hot.... Sounds good with the straight through
Click to expand...


You don't want it to " run a little hot " normal tempreature is best so fit a bigger rad or bigger fan :)
 
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