The V8 Owners Forum -

Richard P6 wrote:
In thought it was the same block? Just a longer throw crank.

They are the same block, but at the factory the blocks were tested for minimum cylinder wall thickness.

The thickest were used as 4.6s and the ones not good enough for them were used as 4s.

I have not owned a P38 Range Rover (maybe one day), but was not the failure of the top radiator hose a major cause of engine coolant loss, with repeated failures ulitmately resulting in cracked blocks?

I was also under the impression from talking to different people that that the frequency of cracked blocks impacting on the 4.0 and 4.6 litre engines reduced almost completely from 1999-2000 onwards when the engine managament system changed to Bosch...the same system as fitted to the BMW 7 series.

Ron.

ppyvabw wrote:

Richard P6 wrote:
In thought it was the same block? Just a longer throw crank.

They are the same block, but at the factory the blocks were tested for minimum cylinder wall thickness.

The thickest were used as 4.6s and the ones not good enough for them were used as 4s.

That's a little alarming as I have one of those.

Mine is the later 'coscast' block from MCT. I believe that 'coscast' means that the block was cast using methods developed by Cosworth, which includes actually casting the liners in, instead of machining the cast block and fitting the liners afterwards. ( I have been known to be wrong about these things though )

Does this suffer from the same problems?

Hello Richard,

I am not able to comment directly on the coscast blocks, but I expect that there would be too few about to be able to draw definitive statistics from on their failure rate,..assuming of course that there even is one.

To be always on the safe side,..can I ask what temperature thermostat you run?

Ron.

Richard P6 wrote:
That's a little alarming as I have one of those.

Mine is the later 'coscast' block from MCT. I believe that 'coscast' means that the block was cast using methods developed by Cosworth, which includes actually casting the liners in, instead of machining the cast block and fitting the liners afterwards. ( I have been known to be wrong about these things though )

Does this suffer from the same problems?

They used better casting techniques to ensure more uniform cylinder wall thickness because with the p38 castings the wall thickness could vary from 3mm to as little as less than a mm. So with a coscast block, you have the maximum cylinder wall thickness on each cylinder in principle.

I don't know how effective they are but better quality casting can only be a good thing so you're alright I reckon!

RoverP6B wrote:Hello Richard,

I am not able to comment directly on the coscast blocks, but I expect that there would be too few about to be able to draw definitive statistics from on their failure rate,..assuming of course that there even is one.

To be always on the safe side,..can I ask what temperature thermostat you run?

Ron.

Hi Ron

There are two over here for road cars, an 88C for the winter, and an 82C for the summer.

I run the 82C all year round and because it arrived without the little jiggle pin, I drilled a small (2mm) hole in it at 12 o'clock before fitting it.

I don't know why I had to drill it at that particular time of day, but I was advised to

I have fitted a 14" blower fan which comes on at 86C, wrapped the manis, and fitted an expansion tank. Manual switch will be fitted when I get time.

I may fit the 74C that you run if I get any problems, but I seem to have it under control for now and will be fitting a 1/2" thermal gasket on the eddy soon as well.

Im still of the poinion the liner problems are down to the short rods and rod angularity putting extra side loads on the bores.

ian.stewart wrote:Im still of the poinion the liner problems are down to the short rods and rod angularity putting extra side loads on the bores.

Would that not be accompanied by excessive bore wear also. Is that a problem with the long stroke engines?

RichardP6 wrote,..

Hi Ron

There are two over here for road cars, an 88C for the winter, and an 82C for the summer.

I run the 82C all year round and because it arrived without the little jiggle pin, I drilled a small (2mm) hole in it at 12 o'clock before fitting it.

I don't know why I had to drill it at that particular time of day, but I was advised to

I have fitted a 14" blower fan which comes on at 86C, wrapped the manis, and fitted an expansion tank. Manual switch will be fitted when I get time.

I may fit the 74C that you run if I get any problems, but I seem to have it under control for now and will be fitting a 1/2" thermal gasket on the eddy soon as well.

Hello Richard,

It certainly sounds like you will not have any problems with overheating, so the possibility of encountering liner problems from that angle should be very slight indeed.

Ron.