Optimal Oil Temperatures

bunnspecial

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Just a little nugget of info- Just this afternoon, I took a longish interstate drive and at a sustained 4.5K-5K(80-90mph) the temp gauge settled at about halfway between "N" and "H." Slowing down to about 4K(a little over 70mph) would allow the temp to drop to "normal" operating position which I think is roughly 190º(thermostat rating). In any case, it was hot enough that apparently the radiator cap popped and let some coolant out into the overflow pipe. When I pulled into my garage, it was still dripping a bit, and after cool down the coolant level was low. This is not the first time I've seen it, and as far as I know it's not unusual since there's no expansion tank-I'm thinking I'll jerry rig one-I've seen a fair number of MGs with a milk jug or something a bit more elegant in front of the radiator with the hose from the radiator running into into it. The radiator hoses are tight and there are no other obvious where coolant would leak. I wish I'd been able to measure oil temps when the engine was that hot-I suspect they may have been over 180º but am not sure. The next time I measure, I may thread a thermocouple down the dipstick hole rather than just shooting parts with the IR thermometer. I was at about 55psi of oil pressure at that temperature, although it dropped to 50psi at 4K with the temp up(the 4K oil pressure went back up to 55 when the engine cooled). I've actually looked at some Glowshift products and at the expense of looking to "ricey" they do make some nice gauges along with a 3-gauge cluster that fits in the radio slot. I currently have a blanking plate there. My main interest is in an A/F meter(something that's actually useful on a carbureted engine), but have considered a voltmeter and oil temperature monitor to fill the other slots. They make a "sandwich" adapter that fits under the oil filter and allows you to screw in a thermistor.
 
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Originally Posted By: bunnspecial
I wish I'd been able to measure oil temps when the engine was that hot-I suspect they may have been over 180º but am not sure. The next time I measure, I may thread a thermocouple down the dipstick hole rather than just shooting parts with the IR thermometer. I was at about 55psi of oil pressure at that temperature, although it dropped to 50psi at 4K with the temp up(the 4K oil pressure went back up to 55 when the engine cooled).
Type K down the dipstick hole will scare you I think. My Caprice (with the supercharged 3.8 V-6) will run 95-105C pulling straight off the highway (1,800RPM). Hold it in "2", and it runs 4,000RPM at 65MPH, and I've seen 135C a couple of times, and 120-125 quite a few more...IR gun on the sump is 10-15C lower than that. Given that the oil you will be measuring is what has most recently been IN the bearings, it's probably more accurate than bulk oil temperatures for transient operation.
 
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Originally Posted By: bunnspecial
In any case, it was hot enough that apparently the radiator cap popped and let some coolant out into the overflow pipe. When I pulled into my garage, it was still dripping a bit, and after cool down the coolant level was low.
http://www.ebay.co.uk/itm/Classic-MG-Midget-Austin-Healey-Sprite-Brass-Expansion-Tank-Bottle-BMC-Morris-/232066982563?hash=item36084522a3:g:TgQAAOSw8oFXx44i I've got one in the shed...pm me if you would like it.
 
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Why does everything from BMC have to be labeled MG or Austin Healey ? They were just a small part of the badge engineering experts. That expansion tank was used on more Austin, Morris, Wolseley, Riley, and Vanden Plas than MG's. Here it is in an Austin 1800, the same engine as used in the MGB. I had a couple of 1800's...or 4 if you count the couple of donors I had in the back yard.
 
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Originally Posted By: Silk
Why does everything from BMC have to be labeled MG or Austin Healey ? They were just a small part of the badge engineering experts. That expansion tank was used on more Austin, Morris, Wolseley, Riley, and Vanden Plas than MG's.
Never said that it was an MG part, it's just the same as the one that I got on a parts car mini or moke.
 
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I wasn't directing it at your post, just the link. That tank was used on most BMC, and later BL vehicles for many years. In NZ the MG was a low volume product, because it came at a premium price, Austin and Morris were almost the most common vehicles on the road.
 

bunnspecial

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Shannow, I do really appreciate the offer but I'm afraid that shipping to the US would likely be more expensive than buying one locally. As for the association between BMC and MG-I think it comes down to the fact that, in the US, MG was by far and away the highest volume BMC brand that we saw, with a few Austins thrown in for good measure(I saw a Marina on the road not too long ago). Don't forget that roughly 90% of MGBs(~450,000 out of ~500,000) came to North America. The only other BL marques we saw in volume were Austin Healey(first the 3000, then several years later the badge engineered Sprite/Midget) and Triumph.
 
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I use to have a two position switch that I used to toggle between Oil temp and coolant temp using the same gauge and two different senders.
 
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Originally Posted By: SHOZ
I use to have a two position switch that I used to toggle between Oil temp and coolant temp using the same gauge and two different senders.
That what I have in my Caterham. Using the same VDO coolant gauge (that's calibrated in degrees - not just Cold-Hot), a ON/ON toggle switch and a second coolant sensor tapped into the drain plug.
 
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[quote=bunnspecialDon't forget that roughly 90% of MGBs(~450,000 out of ~500,000) came to North America. The only other BL marques we saw in volume were Austin Healey(first the 3000, then several years later the badge engineered Sprite/Midget) and Triumph. [/quote] Yes, you saw the low volume, and probably more profitable, versions of British marques, rather than their bread and butter models. So, MG's and not Morris Oxfords, Spitfires and not Triumph Heralds, TR's and not Vanguards, Sunbeam Alpine and Tigers, but not the Hillman Minx, E Types..but surely you got MkII's and the XJ6? In NZ, like the UK, we needed cars for transport, hauling people and trailers, a sports car was not an essential. We certainly got sports cars, there were plenty on the road at the time, but families had an Oxford or Minx.
 

bunnspecial

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Originally Posted By: Silk
Yes, you saw the low volume, and probably more profitable, versions of British marques, rather than their bread and butter models. So, MG's and not Morris Oxfords, Spitfires and not Triumph Heralds, TR's and not Vanguards, Sunbeam Alpine and Tigers, but not the Hillman Minx, E Types..but surely you got MkII's and the XJ6? In NZ, like the UK, we needed cars for transport, hauling people and trailers, a sports car was not an essential. We certainly got sports cars, there were plenty on the road at the time, but families had an Oxford or Minx.
I think you've hit on a big difference as well there. For a long time, we had a VERY strong preference for American cars for basic transportation...and let's also face it that the average "Big 3" car was a lot bigger and more in line with American tastes at the time than your average BL car. With the fuel crisis, we did start to turn to smaller cars, but again the preference stuck with the big 3(plus the scattered other domestic independents) and increasingly Japanese cars. BL tried a few times-with the Marina probably being the most notable example I can think of-but it didn't sell overly well. In the past few years, we've seen Fiat make a return to the US market, and from what I see on the roads the 500 has fairly strong sales. Alfa gearing up for a re-introduction. Jaguar(and yes we did pretty much get the full range) has waxed and waned over the years but has always maintained at least enough of a presence for it to be familiar. The current MG makes some interesting cars, and I'd love to see the brand return, although I don't know how well it would do.
 
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With my new pressure sender and taking the oil cooler off I have a better handle on the oil viscosity. But the oil has only risen to 205F so it's not even at it's rated temp. Currently using M1 5w30. Oil pressure is 30 at idle, 60 at 2000, and in the upper 70s when under load at higher rpms at 195F. The oil seems to lose 1 lb per 1F rise at 2000 rpm in temp when in the 190F-200F range.
 
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