That's the theory anyway with the slipped liners. As the LPG gas burns hotter, the block can't disperse the heat properly as it simply can't cope with it, and as the liners are a different metal to the block, you end up with the possibility of a liner moving under certain conditions.

Mark Adams tells me the liners were frozen to insert them into the blocks and I guess the thought was that they'd stay there for 200,000 miles of normal tested use. That and the fact the casting of the blocks was so poor, it's no wonder there are problems.

Really it boils down to wrong fuel in a badly manufactured engine. If LR had originally built the 3.9, 4.2, 4.0 and 4.6 RV8 using the same method as Richard Turner does now, then there would still be plenty of them running on the road.
 
WSLR said:
That's the theory anyway with the slipped liners. As the LPG gas burns hotter, the block can't disperse the heat properly as it simply can't cope with it, and as the liners are a different metal to the block, you end up with the possibility of a liner moving under certain conditions.

Mark Adams tells me the liners were frozen to insert them into the blocks and I guess the thought was that they'd stay there for 200,000 miles of normal tested use. That and the fact the casting of the blocks was so poor, it's no wonder there are problems.

Really it boils down to wrong fuel in a badly manufactured engine. If LR had originally built the 3.9, 4.2, 4.0 and 4.6 RV8 using the same method as Richard Turner does now, then there would still be plenty of them running on the road.
Click to expand...

But slipped liners are by no means confined to engines running on lpg. Probably way more non-lpg converted engines have suffered the same problem, along with cracked & porous blocks.

Guy
 
The stats may show this in the past, but I'd say there are more LPG'd p38's now, most of which are run on LPG at over 75% of the time.

The past failings have been the hose recall which contributed to the fate of some engines. Then the radiator problem with the cores clogging up. That was a second problem although LR didn't want to know at this point.

Last summer I got stuck in a traffic jam in Belgium. The engine for the first time started running hot. That's the point at which I knew the block was (or had just become) cracked. I ran it without any problems (except having to top up the coolant every week) 'till finally the coolant ran out faster than I could top it up.

I think the issue is that the engine was floored on manufacture. Yes, a petrol only engine will fail eventually, but an LPG engine will fail faster.
 
WSLR said:
The stats may show this in the past, but I'd say there are more LPG'd p38's now, most of which are run on LPG at over 75% of the time.

The past failings have been the hose recall which contributed to the fate of some engines. Then the radiator problem with the cores clogging up. That was a second problem although LR didn't want to know at this point.

Last summer I got stuck in a traffic jam in Belgium. The engine for the first time started running hot. That's the point at which I knew the block was (or had just become) cracked. I ran it without any problems (except having to top up the coolant every week) 'till finally the coolant ran out faster than I could top it up.

I think the issue is that the engine was floored on manufacture. Yes, a petrol only engine will fail eventually, but an LPG engine will fail faster.
Click to expand...

Not convinced. Most of the blocks that fail are flawed at manufacture and will be a failure waiting to happen regardless of fuel type.

I have no doubt that there are more lpg'd V8s now than there used to be, but what does that prove?
 
buick knew it was an issue years ago and any overheating incident is cause for concern
 
fanatic said:
buick knew it was an issue years ago and any overheating incident is cause for concern
Click to expand...

Buick dumped the design because their aluminium casting techniques weren't good enough and they couldn't actually make it. Rover, on the other hand, had a lot of experience in aluminium casting during the war and made it work well.

It's only the crap quality introduced by later penny pinching accountants that ruined it. Same with most things.
 
kooky_guy said:
Buick dumped the design because their aluminium casting techniques weren't good enough and they couldn't actually make it. Rover, on the other hand, had a lot of experience in aluminium casting during the war and made it work well.

It's only the crap quality introduced by later penny pinching accountants that ruined it. Same with most things.
Click to expand...


3.5 ltr service engines were well know to drop liners (previous overheating)

LPG also exacerbates this
 
fanatic said:
3.5 ltr service engines were well know to drop liners (previous overheating)

LPG also exacerbates this
Click to expand...

Really? I've never heard that. I understood that the original 3.5s were bomb proof. Hang on, what's a 'service' engine?

I cut my teeth on 3.5 V8 Rover P6s and I NEVER heard of a slipped liner. The odd head gasket problem, but that was about it. It's only since I started with P38s that I've come across it.
 
How to Power Tune Rover V8 Engines ... - Google Books page 23

I have experienced 4 3.5 v8 liner slips
1) bad fuelling cooked up-ran like bag of **** at 90mph so I was told
2) replacement block in 3.5 rr (like gold or silver seal engine)
3)kit car with coolant loss-ie driven with core plug failure and cooked I towed in rv8
4)One I'm planning to dump out of one of mine-place your bets, I guarantee it has slipped a liner

I agree 3500 v8 are a lot less likely-but not immune, carb v8 the fueling was richer and I agree that 94mm blocks are known issue. I think the p38 cooling system doesn't help and LPG and water loss= disaster
 
Last edited:
kooky_guy said:
Really? I've never heard that. I understood that the original 3.5s were bomb proof. Hang on, what's a 'service' engine?

I cut my teeth on 3.5 V8 Rover P6s and I NEVER heard of a slipped liner. The odd head gasket problem, but that was about it. It's only since I started with P38s that I've come across it.
Click to expand...

I agree cannot remember any real problems with the 3.5 litre engine IF it was looked after. It seems to me all the problems started when the went from the old cooling system with the conventional thermostat to the seperate one. Maybe barking up the wrong tree but it looks that way to me. Also the older engines ran a cooler stat than they do today. Engines now run a lot hotter than they used to to cover emission demands.
 
fanatic said:
How to Power Tune Rover V8 Engines ... - Google Books page 23

I have experienced 4 3.5 v8 liner slips
1) bad fuelling cooked up
2) replacement block in 3.5 rr (like gold or silver seal engine)
3)kit car with coolant loss I towed in rv8
4)One I'm planning to dump out of one of mine
Click to expand...


I guess that I (and everyone else I knew in the owners club at the time) were just lucky then. I've only had 3 V8s (4 if you count my parents' RRC) and they were all fine.

Not seen that book. Is it any good?
 
kooky_guy said:
I guess that I (and everyone else I knew in the owners club at the time) were just lucky then. I've only had 3 V8s (4 if you count my parents' RRC) and they were all fine.

Not seen that book. Is it any good?
Click to expand...

Not a bad book, I will agree that 3.5 are rare in liner failure.


Interestingly although TVR suffered RV8 liner slips, the 3.9 classics didn't seem as affected as p38.

that leads me to think that the p38 cooling system design has exacerbated it along with dubious casting quality possibly
 
As just mentioned - pollution reduction.

The p38 V8 engine management tries to run the engine at 96C. IIRC, the RRC runs at 85ish? Not sure. The 4.4 V8 in the L322 won't run coolant through the radiator 'till 106C.

It's all about emissions and saving the world from people driving 4x4s. :5bbanghead:
 
WSLR said:
As just mentioned - pollution reduction.

The p38 V8 engine management tries to run the engine at 96C. IIRC, the RRC runs at 85ish? Not sure. The 4.4 V8 in the L322 won't run coolant through the radiator 'till 106C.

It's all about emissions and saving the world from people driving 4x4s. :5bbanghead:
Click to expand...

As i said earlier it's down to reducing pollution by hotter burn. In the old days engines had big rads and no pressure cap. Then they introduced smaller rads with around a 7lb pressure cap. Engines ran with i think a 84 degree stat in winter and you changed the stat in the end of winter service for a summer stat at 74 degrees. Now they run all year round on one stat with small rads and 15lb caps. Any sort of a pressure leak on a hot summers day with the engine working hard will cause problems. Maybe not immediatly, but over time something has to warp or crack due to expansion and contraction. The V8 is an old design and was never supposed to run at these temperatures. Maybe over boring the blocks without any other redesign also contributes.
 
dannydimps said:
Im after a P38 rangey but not sure which one to go for ie Diesel or Petrol with LPG. Can people give me advice please on what they think is the best all rounder and what to watch out for???? Just got to get rid of my sports car then i can go out and buy :)


Many thanks

Dan
Click to expand...


hi i have a p38 2.5 dse in green 1996 mot and tax i have a problem with the suspenion welcome to come and have a look!!
 
Last edited:
marky69 said:
hi i have a p38 2.5 dse in green 1996 mot and tax i have a problem with the suspenion welcome to come and have a look!!
Click to expand...
He must have found one by now or given up this is an old thread.
Fix your suspension, it's easy:)
 
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