MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Sling the oil cooler underneath?

Sling the oil cooler underneath?


I would like to increase the cooling capacity of my 1965. I am thinking to mount the oil cooler through the same threaded holes, but under (rather than over) the sheet metal shelf. I see I would need new hoses, I think I can have these made very cheaply. Has anybody done this?
Frank Baker

That's how rubber bumper cars are, and you may be able to use those hoses. One difference is that forced air from the cooling fan(s) is not passing through the oil cooler when at a standstill. Furthermore the hot air from the engine compartment can only escape (mostly) from the bottom of the engine compartment, and some of this comes up the front of the car over the air cooler (and incidentally back into the radiator again). The upshot of this is that the hot idle oil pressure will drop noticebly more after idling for a while than with the cooler above the panel. No big deal, just don't panic if you see it. My RB V8 has a Sebring valance which ducts air into the oil cooler and lower 1/3rd or so of the radiator, this is much more effective at forcing air though these two when under way than the original 'curved back and under' front valance, as well as aiding front-end stability at speed. My car has a fibre-board duct behind the valance which ostensibly should duct all the air coming through the valance into the oil cooler and radiator, but as it described a gentle curve between the two instead of a rectangle it wasn't very effective. It's difficult to be certain, but since I put a brace round it to force it into a rectangular shape it does seem to have improved cooling and oil pressure in hot weather.
Paul Hunt 2

Just a few things to think about: Do you really need more cooling capacity? Are you having a problem? Is your radiator et al in good shape?

I'd suggest that you make sure that everything is working effectively before you go about modifying things....

HTH!
Rob Edwards

Racers have this as a de facto standard. Of course they will either be on the move, or out of the race so the forced air at a standstill does not come into it
Stan Best

Frank-
I've been running my oil cooler underneath inside a simple air duct for years. I use Mobil 1 synthetic oil which pretty much ignores heat and doesn't thin out at high idle temperatures. Don't forget to mount an oil thermostat!

Rob-
The cooling of the cylinders and the head is controled by the radiator, but the internal parts are cooled by the oil. Keeping the oil temperature constant helps keeps things operating within proper tolerances. Makes for a longer service life. Locating the oil cooler underneath where it can't feed already-heated air into the radiator matrix is a good idea on hot summer days.
Steve S.

Steve,
Overcooling oil prevents contaminants from being driven out quickly and leads to increased engine wear and decreased longevity. I also question how much or how necessary the additional engine cooling is, given that: a. later-model MGBs do not have oil coolers, and b. very VERY few modern cars have oil coolers, even though modern engines are much more highly stressed and put more demands on their oils. My belief is that oil coolers were initially installed on MGBs not because the engines needed additional cooling, but rather that the oils of 40 years ago could not take the heat and would coke and degrade at relatively low temperatures. Modern oils are tremendously more heat-tolerant than oils from the 1950s and 1960s.

Cheers!
Rob
Rob Edwards

Thanks. I see only one question here - Am I having a probelm?

I can overheat on the highway in traffic or in heavy traffic. My cooling system is pretty good, oversized rad with modern core and oversized oil cooler, electric fans
Frank Baker

How do you define overheating? Is it boiling over, or is it just registering higher on the gauge than you think it should?
Rob Edwards

The common history is that 1/ the european B's typically did not have oil coolers. 2/ the 3 main engines didn't have oil coolers. 3/ they started having some problems with lube failures with the early 5 main engines in the US and installed coolers for US cars 4/In 1974 they reduced the sump size, deleted the oil cooler, and put all kinds of smog stuff on the engine which made it run hotter.

The hot engine with no oil cooler, and less sump capacity typically had no problem with lubrication caused failures.

Oils have improved since 74. Unless you are on the track, you are - in my opinion - wasting your time and money messing with an oil cooler.

I've been off & on this board for nearly a decade and I don't recall anyone claiming his bottom end went because of lubrication failure related to overheated oil.

Barry

So it looks neat like a hi performance engine. Your engine inside is less neat because you cannot easily drain or clean the crap out of an oil cooler when you do your typical oil change.
Barry Parkinson

Overheating - on my gage it tells me it runs at 190 degrees (who knows what that really is). It stays there unless it is hot and the car is stressed, then it started to climb. At about 210, I stop and wait for it to come down. That is my "overheating". No boiling, no steam, no damage. It means 30 minutes and a diet coke at a gas station
Frank Baker

Barry-
I am well aware of the problems associated with overcooled petroleum-based oil. That's why I always recommend installing an oil thermostat. I suspect that the reason that British Leyland discontinued the installation of the oil cooler on the MGB had more to do with cutting cost rather than with any engineering reality. After all, they reduced the capacity of the oil sump just to save on the cost of putting oil in the cars at the factory, too. I am also aware that oil-related failures are exceedingly rare nowadays. I use Mobil 1 oil which keeps particulates in suspension so that the oil filter can remove them rather than having them settle into the bottom of the cooler. No sludge is ever formed by the stuff, and it remains the same consistency regardless of temperature, so the oil cooler on my particular engine is irrelevant in those terms. However, I feel that I should restate that the oil is what cools most of the moving parts, and maintaining running tolerances is easier with the cooler removing the heat that the oil absorbs. Hence, my oil cooler isn't present in order to prevent modern oil formulas from losing their outstanding lubricity, its there to prolong the engine's lifespan, just like an oil filter is. Yes, I do remove it and pour out the old oil whenever I do an oil change. Heck, I even tilt the car and let the engine drain overnight!
Steve S.

steve
I remember heading up a mile long 4% grade in my alfa romeo in 1963. I was winding it at 6000 rpm. 2/3 of the way up my oil pressure droped from 60 psi to 40 psi. I had 500 miles on the oil change, and 1,000 miles on a new set of main bearings.

Oil just wasn't as good then as it is now.

Barry
Barry Parkinson

The Moss fan shroud has realy helped my car hold it's temp. We got stuck in a lot of traffic which was going to Goodwood* when the SE centre event was next to it this month. It was a hot day and the gauge used to just keep heading north until my nerve broke, now it went from 170 to 190 and stayed there, the extra heat flow at the higher temp being enough to stabilise things. I still have the oil coler and it is still where Abingdon intended, I suppose some of that is memeory of how back in the 60s the B always held it's oil pressure no matter how far and fast you went and also it looks ,errr, cool.
I remember from my youth that there was an aftermarket oil cooler that actually went in the radiator bottom hose, this would not work for the B which seems to be a bit undercooled but you can see how an old square rigger could benifit and in fact one of the ads had some figures taken on something like a Hillman Minx cruising into a freezing headwind.
*behind a GTV in front of an Alvis and there was a run going the other way with a steam of classics one of which was a Porsche 550
Stan Best

FWIW, from Clausager(P79)
"An oil cooler, mounted in front of the radiator on all models with connecting pipes passing through the diaphragm panel to the right of the radiator, was fitted as standard on export MGBs from the start of production, but remained optional on the home market until the arrival of the five main bearing 18GB engine in 1964...The original oil cooler (ARH 181) was replaced by one of intercalary construction (ARH 186) in January 1964. Home market cars used ARH 186 when they were fitted with the oil cooler as standard in October 1964, but export cars received an improved 13-tube oil cooler (ARO 9809). This latter version was then fitted on home market cars from August 1965. Subsequently the oil cooler was changed again at the atart of Mark11 production in 1967 and on the 'rubber-bumper' cars in 1974. On North American cars, the oil cooler was discontinued in December 1974 (1975 model year)."
Regards
Roger
Roger T

>Overheating - on my gage it tells me it runs at 190 degrees (who knows what that really is). It stays there unless it is hot and the car is stressed, then it started to climb. At about 210, I stop and wait for it to come down. That is my "overheating". No boiling, no steam, no damage. It means 30 minutes and a diet coke at a gas station


Frank,
I consider 190ºF to be the MINIMUM acceptable operating temperature for my engine. I use a 195ºF thermostat year-round (and the typical NC summer afternoon is usually in the mid to upper 90s).

The late, great Smokey Yunick said (in his book "Power Secrets"):
Quote:
" It is easy to see how overheating can be a problem, but I think some racers overlook the fact that it is possible to 'overcool' the engine. Some guys go to great lengths to keep the engine temperature down to 180 degrees. And, though the engine doesn't overheat, they don't realize that they're putting energy (heat) into the cooling system that could be used to produce power at the crankshaft.
Running the engine at 180 degrees will drop the overall horsepower by 2%-3%. For max power the cooling temp should be at least 200 degrees...."

And Peter Burgess, in his book "How to Power Tune the MGB 4-Cylinder Engine" says "The ideal 'stat is 88 degrees Celcius (190F) ."

So I'd say the answer to your question, "Am I having a problem?" is "Probably not." It doesn't sound like it to me, anyway....

HTH!
Rob Edwards

Overheating is *only* loss of coolant or steaming. On the CNH gauges the 'normal' range is from just below the C to just below the H. That isn't to say that you don't stop and investigate if the gauges suddenly starts going significantly higher than usual. I've seen my V8 gauge in the red, and my roadster at the bottom of the H, with no loss of coolant or steaming from either. It is my belief that the oil cooler was fitted to reduce paranoia when seeing the pressure drop (but still be within the normal range) in long idles in hot weather. Made rather superfluous when they moved it below the panel and hence out of the cooling air flow, although it would rapidly cool it and regain pressure once underway again. As to why it was deleted from North American cars, probably a case of 'we can't afford it, let them be paranoid'. Don't know why it was kept in the UK, with its more temperate and certainly cooler temperatures. My 89 Celica has an oil cooler, just the other side of the radiator from the fan and so cooled by it (still drops to about 12psi after a hard run though).
Paul Hunt 2

My 67 GT has a 79 block with an alloy head. The engine was rebuilt at about 130,000 miles. I put a kit in the oil pump, new main and rod inserts in, but otherwise left the crank alone. The thermostat is 195f. The pressure cap is the '67 7lbs pressure.

Running either 10-40, or 15-40, after a 4000 rpm run in 4th up my "dyno" hill, (2 miles at 4 to 6 % grade at ambient temperatures over 100F degrees)I'm showing full oil pressure (60 lbs) at anything over 2,000 rpm. I'm not using an oil cooler.

In winter weather, a cooler that slows the heating of the oil can result in moisture not being evaporated from the oil, and harm to the engine.

Barry
Barry Parkinson

I have a large oil cooler slung underneath, although the presence of the box section means that it is impossible to bolt it up square or use the same mounting holes. Instead it is inclined at roughly the same angle as the valance. It's 19 rows tall though (as opposed to the standard 13) so I suspect a stock one wouldn't need such a bit tilt.

I have an oil stat on it which allows the oil to get to 80°C before forcing the oil through the cooler to avoid over-cooling of the oil.

All parts from http://www.thinkauto.com/

hth,
--
Olly
Oliver Stephenson

This thread was discussed between 26/08/2006 and 29/08/2006

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.