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I just got a call to say that the engine on mine only has compression on one cylinder - so it is pretty sick!

The garage has suggested that I try and source another engine as they suspect the block is likely to be in a bad way.

I just thought I'd check to see if anyone on here had one? They come up on various P38 Facebook groups and obviously eBay, but I thought I'd check here first as it's a bit more of a trusted community!

Many thanks,

Mark

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MHT wrote:

I just thought I'd check to see if anyone on here had one? They come up on various P38 Facebook groups and obviously eBay, but I thought I'd check here first as it's a bit more of a trusted community!

For me it was a reason not to offer it on here, I just sold one. I've had it all apart and renewed conn bearings, mains, pistonrings, seals, gaskets and skimmed the heads but left the oilpump as it was, as the camshaft and valvegear.
It is sold 'as is', I did not want to sell it 'within the family'. I've been dissappointed myself too many times .

Tony.

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Ferryman wrote:

MHT wrote:

I just thought I'd check to see if anyone on here had one? They come up on various P38 Facebook groups and obviously eBay, but I thought I'd check here first as it's a bit more of a trusted community!

For me it was a reason not to offer it on here, I just sold one. I've had it all apart and renewed conn bearings, mains, pistonrings and skimmed the heads but left the oilpump as it was, as the camshaft and valvegear.
It is sold 'as is', I did not want to sell it 'within the family'. I've been dissappointed myself too many times .

Tony.

I can understand that Tony, but things go wrong and I'd rather buy from someone on here in good faith and take my chances than from eBay where someone is actively to bad faith me!

Would a 4.0 Thor work, or does a non 4.6 cause further problems?

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You can put a 4.0 in, and ideally change the option in the engine ECU so it know it is now a 4.0 instead of a 4.6.

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Ahhh.. the good 'ol rover block failing strikes again....

Surely if it's lost compression on all but 1 cylinder then that points more to the piston rings or valves in the heads not sealing?

It would have to be a REALLY fucked block to cause loss of compression on 7 of 8 cylinders...

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The mechanic I sent it to, who my bodyshop guy recommended, said he'd never seen one with commpression only on one.

He said he would expect to get compression on 6 or 7 as normal but this is the first one he's seen just with one.

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Has he broken his compression tester....?

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Personally... I would get a second opinion. I have never heard of a Rover V8 losing compression on all but 1 cylinder. down on a few, yeah as they get older and wear, but in my mind it would have to be a catastrophic failure to be that bad...

Also take into account in a diagnosis that most garages seem to hate P38's, and to them all they know about Rover V8's is that they will always fail, and in their eyes it's always the block.. or a liner slipping.. when a lot of the time it isn't actually that bad. Even if it was a HG failure, then it would have he to have failed between a LOT of cylinders to lose that much compression on that many cylinders.

I could be completely wrong, but something just sounds fishy about it to me.

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I've tested an engine, not a V8 but a 4 pot, and found compression on only one cylinder. That was because the cam belt had snapped so what valves weren't bent and not sealing weren't moving. Both valves were closed on one cylinder so that one had compression but none of the others did. I would suspect a cam chain failure personally.

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In saying that though, if the engine has been so neglected it's suffered a pretty catastrophic failure, then replacing it is probably a better option. There's more 4.6 engines about than 4.0 litre so they are more common but a 4.0 litre will go straight in as it uses the same block. The only difference between the two engines is the crankshaft, conrods and pistons so you could make up a 4.6 from a 4.0 block using the innards from your 4.6 (if it is a block problem).

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There is a write-up about differences in Rover engines that explains it all:
enter link description here

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I'd have it apart first, check out valve seats ect, it would be unusual for a block to fail on 7 out of 8 cylinders, rings, shells, even getting a few second hand heads, would still be cheaper than a second hand engine you know nothing about..

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Sloth wrote:

Has he broken his compression tester....?

I had exactly that problem when testing the compression on my 4.0. Borrowed a friend's compression tester and couldn't get compression readings on several cylinders. Then I remembered I had my own compression tester hidden away and using it, found compression to be good across the board.

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It would be interesting to see what kind of readings he's actually getting. These engines are pretty low compression compared to modern ones anyway.