Oil Pressure Warning Light for an MG T-Type

Photo 01: The author’s (David Ralph) TA (TA0312)

How often do you check your oil pressure gauge? The answer is probably not often enough. I regularly glance at the pressure gauge but last December it wasn’t often enough. Having spent the previous 3 months rebuilding the steering on my TA I took the car out for a test run.The steering was transformed and I was really enjoying the drive.

I called in to see someone who had just bought a dismantled TC to restore. Having sorted out the boxes of parts there were several items he couldn’t identify so wanted my help. He had a thorough look around my car, including under the bonnet, so I know the car was alright at that point.

As the temperature was dropping dramatically I wanted to dash home and I was concentrating on keeping warm rather than watching the pressure gauge. Just three miles later the engine started to rattle. I immediately dipped the clutch and that caused the engine to stop. I rolled to a stop and got out to investigate. As soon as I was out of the car I could see the nearside front wing had turned completely black with engine oil, which also covered the bonnet side, door and rear wing.

Opening the bonnet revealed that a soldered joint on the oil pressure gauge pipe had failed where it attaches to the engine block. The TA has the pipe going straight to the block rather than having the flexible hose fitted to XPAG engines. The dip stick didn’t show any oil so the sump had clearly emptied itself in less than 3 miles. Over a gallon of oil certainly makes a mess when it is being pumped out at 60 psi.

I tried turning the engine on the handle but it was virtually seized. I phoned the AA and requested recovery, explaining that an oil pipe had broken so I had lost all engine oil and seized the engine. I double-checked that they were sending a recovery vehicle rather than a patrol van. Whilst waiting I cleaned up the oil as best as I could. An hour later an AA van appeared. The patrol man took one look and said he couldn’t fix it so I needed recovery. Yes I knew that already and had asked for recovery. Another hour passed before the recovery lorry finally arrived. By now it was very dark and very cold.

The following weekend I removed the sump plug and drained out just half a pint of oil mixed with plenty of white metal from the bearings. The TA big end and main bearings are cast from white metal and machined to suit the crankshaft rather than having replaceable shells. Clearly the engine needed expensive repairs. Rather disappointing as when I bought the car 18 months earlier it had only covered about 40 miles since the previous owner had spent over £14,500 on having the engine rebuilt twice. The first time an MG specialist charged £5442 to rebuild it but less than a year later another MG specialist found major problems which necessitated another full rebuild which cost £9108!

With the engine out of the car and stripped right down I was very pleased to find that just the big end bearings had suffered. The main bearings, bores, pistons, camshaft had all survived undamaged. I carefully checked the crankshaft but this was perfect with less than half a thou of wear. So I just needed 4 new big ends made. The crank and rods were taken to John Kirby at Croydon.

While the car was stripped down I decided to have the radiator shell re-chromed as it had gone dull around the top. With the radiator slats out I re- sprayed them. I next looked at the gearbox as the gear selection was very notchy and synchromesh didn’t work. I found 6 separate problems with the gearbox even though it had been rebuilt just before I purchased the car. The selector forks didn’t line up so the selector lever didn’t move smoothly across the gate. The selector lever had been worn (they all wear) and it had been ground down to a smooth surface making it even smaller rather than building it up with weld and grinding back to original size. The bearings were very loose in their housings. The splines on the third motion shaft were damaged and the output flange had been hammered on instead of cleaning up the splines. When I turned the first motion shaft there was a horrible grinding noise which turned out to be the lay gears rubbing the gearbox casing. Unbelievable that it had been rebuilt like this by an MG specialist (Well, there are MG specialists and MG specialists! – ED) Luckily I have 4 spare gearboxes so all of these were stripped and assessed before the best one was overhauled.

Once the new big ends were ready, assembly of the engine was straight forward and it wasn’t long before it was back in the chassis. When purchased, the engine was finished in MG maroon whereas the TA should have a bright red engine. I took the opportunity to return it to the correct colour.

When I came to bolt the carburettors back on I checked them first and discovered that there was considerable wear in the throttle spindles. Dismantled I also found that the spindle bores in the bronze bodies were also very worn. Rebuild kits were ordered from Burlen Fuels. I made up a jig to bolt the carburettor bodies to so that I could accurately bore out the bodies to accept the new spindle bushes that come in the kits. I ordered new standard needles as the carburettors had been fitted with weak needles. The colour of the spark plugs and combustion chambers confirmed that the engine had been running too weak.

Photo 02: Boring out the carburettor bodies in order to fit the new spindle bushes obtained from Burlen.

The whole exercise had taken 3 months and cost £765. Not wanting to repeat this any time soon I felt it sensible to fit an oil pressure warning light, utilising the 30mph lamp. This lamp wasn’t connected up in my car and I doubt if many TA – TC cars have it working as intended. Being bright green and right in front of the driver it is perfect as an oil warning lamp.

Photo 03: The ‘Thirtilite’ which now serves as the oil pressure warning light.

On eBay I purchased a stainless steel braided hose and T-piece for £27 and a pressure switch for £7. For a live feed I connected a wire to the coil and ran it up to the 30mph lamp. Another wire ran from this lamp down to the pressure switch mounted on the front of the ramp plate. Earth return is through the switch body. Now with the ignition turned on the bright green light is very prominent and I am confident I will see it immediately if the engine loses oil pressure again.

Photo 04: Showing stainless steel braided hose from block to pressure switch.

I would certainly recommend this improvement to all T-Type owners. There isn’t enough space to fit a T-piece and switch directly to the engine so the TA needs a flexible hose. XPAG engines should already have a flexible hose so just a T-piece and switch are required which will cost about £15. TD and TF owners don’t have the 30mph lamp so would need to fit a warning lamp to the dashboard.

My brother once had the flexible hose split on his car but luckily he had travelled less than half a mile to a garage before he discovered it so no damage done.

David Ralph

2 thoughts on “Oil Pressure Warning Light for an MG T-Type

  1. Martin Moore says:

    I think this problem must have been realized by MG as my late TA chassis 3116 does have a factory fitted union and flexible hose . There are however a number of different failures that could cause loss of oil pressure and the fitting of the warning light is a great idea . Regards Martin .
    PS After avoiding many propriety brands of oil additives designed to reduce friction from Molyslip , Activate and Slick I fell foul of old age and having found Wynns very good in my 1950s Alfa duly poured some into the TA ! Don’t as I very quickly remembered the MPJG has an oil/ cork clutch and slip will occur !

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