27th May 2024

MG Owners' Club Northern Ireland

Promoting the Enjoyment of MG Motor Cars

MGB Technical Tip

3 min read
MGB Technical Tip - MGOCNI
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Having owned various MGs for nearly as long as I have held a driving licence I have become very accustomed to the quirks they can periodically throw up, and most of which are easily rectifiable.

My current on the road MGB is one that was manufactured in 1968 and although there were no major changes to the basic B engine since the introduction of the five bearing crank in October 1964 one problem has always concerned me with the engines up to about 1970 that were fitted with the vertical oil filter housing containing a paper or other type of filter element.

The problem that I have encountered as I am sure many owners have noticed is the lack of initial oil pressure when starting the car after it has been sitting for days or weeks unused. I always turn the engine over without the choke out for what seems like a lengthy period of time trying to get the oil pressure needle to move before I pull the choke out and the engine fires this is certainly not good for the starter motor.

What happens is the oil drains out of the filter element and canister back into the sump and when starting the car from cold this unit has to refill before the oil can pass to the internal engine parts, bearings, etc. and this is the time when the greatest wear and tear can take place within the engine especially if the revs are lifted before oil pressure is showing on the gauge.

In about 1970 a dramatic improvement was made to the filter arrangement of the B engine by the fitment of a spin on oil filter element with a built in non return valve (part number GFE121) and this unit allowed the oil to be retained within the filter at all times so when starting from cold the stored oil in the filter was immediately pumped into the galleries supplying the internal engine parts therefore less wear and nearly immediate oil pressure.

This spin on filter unit has also a second advantage of a very easy replacement with far less oil spillage as the non return valve holds most of the old oil within the unit when it is removed as opposed to the removal of the original canister with separate internal filter cartridge the contents of oil has the tendency to go everywhere it shouldn’t.

Having tolerated this problem since the restoration of the car was completed I decided to deal with it before the starter motor objected with over use. A spin on after market conversion unit is available from MG parts suppliers and this unit mounts directly to the block and the filter hangs downwards again retaining it’s oil content at all times and although I have fitted this to the Twin Cam engine with great success I don’t think it’s right for the B engine when another alternative is available.

So in view of this I decided the way forward was to convert the existing set up to accept a GFE121 spin on filter and a telephone call to Alan of AC Restorations confirmed he had the part in stock off a later engine but he did quiz me as to why I wanted this conversion, As I was going to collect the part anyway I thought it sensible to let Alan fit it when there. It’s a very simple job and took less than an hour in fact the cup of tea and chat took longer and the difference it made was amazing with slightly better oil pressure and no more churning of the starter to build up oil pressure as it’s now nearly instantaneous.

Now to the purist or concours minded person this should not be done as you are taking away from the originality (always keep the original parts removed) but then owners fit radial tyres, halogen headlights, exterior mirrors, twin twelve volt batteries etc and these could all be regarded as incorrect for some cars but what an improvement for everyday motoring and I believe the safety of the occupants, reliability and health of the engine come before originality.

For my peace of mind this was a great and very successful improvement and yes I also have all the other items mentioned above fitted, my thanks to Alan Caldwell for his assistance.

Noel, MG Owners’ Club Northern Ireland

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