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MG MGB Technical - Engine Confusion

Hello,

I have been told my engine is no good by an engine machining company. Therefore I have located another engine and could do with checking it is a suitable exchange

My old engine no. 18GG RWE H 26557
Proposed engine no 19GG WE H 7108

I believe the R stands for overdrive, however I am unsure whether this has any significance on the engine? Can I fit my gearbox with overdrive to this engine?

Secondly, I have been told by the machinist that one of the bearing ends has cracked, and that in order to reuse my original engine (not use the proposed unit), I would have to have the block line bored, and that just fitting a new end cap is unlikely to run smoothly due to slight dissimilarities between the end caps. In this case should I only use the crankshaft associated with the proposed engine also?

Many thanks,
Alex Davies

Alex

I'm assuming that you mean one of the main bearing caps, as opposed to the big-end caps. If it is the former, you would need to source another cap and then have the block line-bored. If the latter, you would just replace the conrod.

When the block was originally machined, it would have been line-bored with the main bearing caps in place. If you then replace one of the caps, it is very unlikely to line up with the block.

Out of interest, who are you using for your machining?
Dave O'Neill 2

I'm using Autosprint in coleshill, they seem very genuine, just concerned I haven't supplied them with a suitable alternative block. Do you know the significance of overdrive in the engine number? In answer to your question it is the main bearing cap that has gone.

thanks,
Alex Davies

The R merely indicates that the car originally came with an overdrive transmission. The 2 transmissions, overdrive and non-overdrive, are interchangeable. If you have damaged a main bearing cap you will need to align bore the engine when replacing a single main bearing cap. RAY
rjm RAY

Hi Alex
The engine you have sourced 18GG not 19GG is perfectly suitable, the gearbox will bolt straight on without any problems.
There was no changes made to the backplate on 5 bearing engines, infact you'll not find any difference in the motors.
The bearing caps have to stay with the motor they were fitted to origonally but the crank could be used in another 5 bearing motor.
Hope this helps

Regards Pete
PJ Thompson

There is no difference between an engine on an overdrive car and an engine from a car without, only the additional letter just to show the original specification.
Mike Howlett

This thread was discussed on 30/01/2010

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