"Recorded" Wall Thickness

4.6 MGBegun · Post by **4.6 MGBegun** » Tue Apr 21, 2009 5:14 pm

I have a Rover 4.6 block from 1997 that I have been planning to use for an MG V8 conversion. I have removed the valley gasket and there is no sign of any wall thickness numbers or paint dabs anywhere on the valley wall. In "How to Power Tune Rover V8 Engines" it says that before the factory went to the paint dab method of grading they "started ultrasonic testing -by hand- of wall thicknesses of all engine blocks and recording what each blocks wall thickness was".

Does anyone know if this information was recorded on paper or just recorded on the block? If it was written down can Rover (maybe the traceability department) look up this information by the engine number?

crayefish · Post by **crayefish** » Tue Apr 21, 2009 6:39 pm

im afraid i cant shed any light on it but info recorded in those books isnt always entirely correct

i have it and its a good book, but unfortunately like most books of that type its a bit 'armchair mechanics'.

also it might have had hte paint dab and a previous owner might have removed it thinking it was a blemish or such like

however im sure one of the exerienced members of the forum will shed some light on it

RoverP6B · Post by **RoverP6B** » Wed Apr 22, 2009 9:27 am

At the same time, a block from 1997 will have had some use, and as such the environment within the engine will no doubt ensure that any paint applied has long since been washed away.

Ron.

CastleMGBV8 · Post by **CastleMGBV8** » Wed Apr 22, 2009 10:09 am

I think it is most unlikely that you will find any information as to the grade of the block.

If you are looking for confirmation that the block is sound then I can only suggest that you have it pressure tested.

A visual inspection with the heads off will show if there are any liners that have slipped lower in the bores, as will and signs of any of the cylinders looking as if they have been steam cleaned.

Kevin.

crayefish · Post by **crayefish** » Wed Apr 22, 2009 12:29 pm

As kevin said, pressure testing would be wise. or you could get it ultrasound tested to findout the wall thickness

most likely thing to have gone wrong in the casting process would be core shift. an ultrasound lest will tell you if one side of the wall is thicker than the other

4.6 MGBegun · Post by **4.6 MGBegun** » Wed Apr 22, 2009 5:19 pm

Thanks, but I'm pretty sure the block is sound and it only has 60k on it so it's pretty clean inside. I wasn't planning to do a rebuild so I don't think it's worth it to tear it apart just to have it ultrasonically tested. I just figured it would be nice to know the block grade for piece of mind.

ChrisJC · Post by **ChrisJC** » Wed Apr 22, 2009 7:26 pm

60K + clean doesn't mean that it's OK. Those blocks are notorious for failing. I would definitely take the opportunity to get it pressure tested whilst it's convenient rather than build it up only to find it leaks water internally somewhere!!

Chris.