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MG MGB GT V8 Factory Originals Technical - Engine oil cooler - essential ?

I'm converting my 1979 MGB GT to V8 power using an engine from a SD1. Because of leg problems I'm also using the original V8 autobox which obviously needs it's own oil cooler.
What I'm wondering is an engine oil cooler essential when using the Rover V8 after all the SD1 donor vehicle didn't have one. Having just an autobox cooler would help keep the plumbing down !

Paul Humphries


I've been wondering the same thing as I plan my conversion. If you read Roger Parker's essay on the subject of conversions, he is not at all convinced about the need for an engine oil cooler, and I intend not to use one when I eventually get round to doing the job. The RV8 didn't use one.

Mike Howlett

From experience of running a factory V8 from new I would recommend an oil cooler - but only if you also use an oil thermostat.

This will avoid over-cooling in cold conditions, but provide some extra help on those hot days when cooling is marginal.


Nigel Steward

I've got an auto with an oil & a tx cooler fitted.The oil cooler fits under the front tray & the tx cooler from a Triumph 2500 fits neatly between the bottom of the radiator & the oil cooler.If I lived in a cooler climate, I'd probably opt for no oil cooler.Why not try it without an oil cooler at first & if you're not happy, then it's no big deal to fit one later. Barrie E
Barrie Egerton

My 2 conversions using Buick 215 motors did not need oil coolers. My GT with a 4.2 Rover definitely needed a cooler. My oft repeated suggestion is that without installing an oil temp gauge, you have no way to know if you need a cooler.

I am in the DC area, all my cars have A/C, & get driven on almost a daily basis in heavy traffic.

To repeat an earlier comment, an oil thermostat is essential, otherwise, in cold weather, your oil may never get up to the correct temp. I have bought 2 different versions made by Mocal.
Jim Stuart

An oil cooler is needed only if the performance of your cooling system is marginal. (Can you say MGB-V8?) Many of these cars will benefit from having one, as about the only way you can know for certain that you won't need it is if you have provided a way for the hot air to get out of the engine compartment, taken steps to ensure that hot air does not get recirculated through the radiator, made certain the radiator capacity is more than adequate, and provided better than good airflow through the radiator. And then tested it in hot stop and go traffic. I think the most crucial thing is a high exit from the engine compartment for hot air.

Jim Blackwood

The question is where the heck do you put it. I have a vertically extended V8 radiator and I'd be loathe to have it be swilling air from the leeward side of a hot oil cooler ... the very last thing it needs. One thought I had was to plumb a pair of oil lines all the way back to the unused driver-side battery box, which is empty. You could put a small oil cooler in there and hook a fan up to it to blow air through. Would expanding the oil system thusly create problems with oil flow/pressure?

The best place I have found for an oil cooler on a chrome bumper car, or a late model converted to chrome bumpers, is inside the front fender, either side, but the side closest to the oil filter reduces the length of the lines.

I found I could use a large hole saw & drill several openings behind the front bumper to allow a large air flow, & that the openings cannot be seen. Fresh air enters from under the bumper.

A Sebring style opening could also be made if you are not running a bumper.

No good suggestions for the rubber bumper cars.

I agree with the earlier post thay placing the cooler in front of the radiator is somewhat self defeating.
Jim Stuart

I mounted the oil cooler on my chrome bumper model off the steering rack mounting bolts. I fabricated brackets so it faces downward and has a shroud to direct air coming from underneath the radiator. I mounted the oil filter inside the fender on the left hand side to keep the piping to a minimum. The system seems to work really well.

Ted, to help reduce the losses in the longer length of pipe maybe go one or two sizes up in the tube dia. If you do that then check to ensure that the orifices in the fittings are larger as well and not too restrictive. Also maybe you could shim up the pressure relief spring to keep the pressure in the system up.

In my opinion the oil cooler inlet and outlet should be on top when the cooler is mounted. Then if pressure is not the greatest then the oil will still circulate fully through the cooler. If they are on the bottom I have seen cases when only the bottom two or three rows on the cooler have been effectively cooling the oil.

I hope this helps

Graeme Weston

Oil cooler or NOT to oil cooler?????? I have run a 74.5 GT 350,000 miles with a Rover 3500 for 20 years with a 3,000 lbs. trailer behind her ALL over the eastern 1/2 of the U.S., one time in 106 deg. temp for 6 hrs., with a stock V-8 raid. WITH NO OIL COOLER! I sold 1 chrome 73 G.T. with a 3500 Rover that I put 35,000 miles on her in 1 year & a 79 B with the same 3500 Rover & I put 80,000 miles on her, before they were sold & NO OIL COOLER. Then I put a 4200 Rover in a 74 chrome G.T. (225,000 miles in 7 years) & NO OIL COOLER. Oh, there is my 72 B that has a 4.9 with a 10-1 comp. ratio & hot cam & T-56 six speed trans & A 4.10 rear (& yes there is a trailer hitch on her) & I have put 75,000 miles on her. Tell me do you think I have an oil cooler on her??? NO WAY!!!! I had a 80 L.E. at my shop & she had an oil temp. gauge on board & on a 80 deg. night the oil temp NEVER got above 180 deg.with an oil cooler (to cold) & after he saw this he took the oil cooler off. All the above cars have a 180 thermostat. I put a 80 B together with a 4200 with 9.5 comp. & a hot cam, with the hot wire F/I & A.C.& the owner put a temp. gauge in her & the oil temp was 200 to 225 deg. (were it should be) & yes this car is PACKED FULL under the hood & she has a 195 thermo. in her. In my book if you think you need an oil leak, this would be a good reason to add an oil cooler. Before I put my first V-8 on the road I asked Dan at D&D fab. what he though & then Phil Backer & 2 others that have worked on these motors what they thought &
this is why NONE of the cars that I have built in 20 years have. NO BRA OR COOLER!!!!
Glenn Towery

Any competent radiator shop can install a transmission oil cooler in the lower radiator tank. This could be used for engine oil as well. Also many v6 and v8 engines use oil filter base coolers that flow water from the radiator to cool the engine oil. Marc
Marc Judson

What do Peter Burgess and Chris Cane at RPI have to say on the subject of wether an oil cooler is necessary on an MGBV8?


Good question.

Oil needs to be run hot 100c+ but engine lower say 80c.
With modern oils they can take heat.

So do you max out water cooling, Ali rad and avoid oil cooler, or if cooling marginal add oil cooler to help.

In a UK winter I cannot see a oil cooler as adding any value. In summer may be necessary. Is it better to run cold and change oil frequently or run hot and lose bhp.
Close call depending upon use.


Perhaps an oil cooler with a bypass line plumbed in parrallel with it? There could be a three way valve on it so that you could pump the oil through the cooler durring the summer, or flip the valve and bypass the cooler back into the engine in the winter. Could be a lot of plumbing for nothing though.
Anthony Morgan

This thread was discussed between 05/02/2003 and 10/02/2003

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