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reason for it said 1500 has cooling [run to hot] problems?

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recordsj

Jedi Warrior
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Concerning the 1500 MG Midget, I hear talk that it hascooling problems (runs to hot) and people recommend using an oil cooler (to cool the oil and hold a better oil pressure). In connection with this I have seen it saidthat the design is poor which causes this issue of running hot.
I have never seen anyone say WHY the 1500 has coolingproblems. Does anyone have a good engineering/mechanical explanation ofwhy the 1500 has cooling problems?
My only thought is that ones with cooling problems havean old radiator that doesn't eject heat well (as opposed to a new/cleanradiator) and/or have tuning problems with timing and/or carb which isproducing to much heat at combustion.
Any thoughts or solid explanation on this?
 
I have never heard of or experienced issues with the 1500 running hot. Mind you, I did exactly what you mention - block boiled, rad rebuilt, new hoses. It runs solidly and always in a good temperature range. That said, what 1500's do tend to have issues with vapour lock. The design issue that it did have, was that the catalytic converter can was located right under the carburetor. This combined with the fact that the carb heat shield tended to deteriorate/ disappear over time and the reality that the gas of today is not what it used to be has caused the aforementioned vapour lock issues.

Now, all that being said, I am also of the opinion that vapour lock way over diagnosed. I regularly read about vapour lock issues when it is fuel filter, or mixture, or fuel pump, or dirty tank or ..... I don't believe it is a common (especially in 1500's) as people think.
 
Mine has never run hot. They say the Midget 1500 runs hot because of a smaller engine compartment and radiator compared to the Spitfire it came from. I have a cooler that came with a parts car that i haven't put it on yet. I don't know if I will.
 
I raced my Spridget with a 1500 for over 7 years. No problems overheating and never ran an oil cooler. Be sure block is flushed with clean 50/50 water-anti-freeze (too much anti-freeze can cause overheating). Be sure there is no air locks in cooling system; "burp" system by squeezing lower rad hose with cap off. Use a good thermostat (I like a 165F but a 180F is good too). If lower hose is old, check and/or replace. This hose is under suction and if it becomes soft with age, it will suck closed when engine is running at highway speeds.
 
Along the same line that the 1500 runs hot, why is it said that an oil cooler is needed for the 1500 because of the poor cooling design to deal with hot oil and low oil pressure?

I ask some of this since at startup i get 70 psi cold, 30-40 psi idle hot, 50-60 psi hot at 3000 rpm cruising down the road. At times though i get 15-20 psi hot idle especially on a hard drive.
 
My 1098 in Bugsy my '68 I just sold had the same issue. I attributed the rise in water temps to a weak lower radiator hose partially collapsing under high sustained RPM's. Oil pressure would drop from 70 to 55 lb as temps rose. A cool down coming off of the Expressway ramp would drop temps back to below N and oil pressure back up to 60-65 lbs. The fact that temps and pressures would change that quickly I attributed to partial copllapse of the hose. My thought was to put a copper elbow in there to make sure hose did not collapse under high suction. It's a very short hose but goes through a lot of gyrations to get connected from the radiator to the lower pipe.
 
Makes sense to me. I fully understand that as temps rise oil becomes thinner and oil pressure will drop.
My engine was rebuilt 2 years ago and don't think it is worn parts. I also have checked play in the crabk shaft to check for the thrust washer wear. I also have replaced radiator and hoses. In rhe rebuid i did go to a 9:1 compression pistons and head. With the higher compression producing more hp, maybe that is producing more heat.
 
Timing settings have a lot to do with heat production and cooling. Too far advanced = heat if I recall correctly. Retarding a gegree or two may improve cooling. Someone else I know will chime in here if I'm incorrect.
 
IIRC 76's are supposed to be set ATDC - though mine is BTDC. Also, the vacuum is Vacuum Retard not advance. Jeff (advanced distributers) suggested I disconnect the vacuum. I did and think it runs better - and cooler.
 
I thought what is shown in the manual for '76 to be set ATDC is for emission concerns (my emission components are removed). Why would other years for the 1500 be set at 10deg BTDC?
 
That's emissions BS, mine is set at 12 BTDC but I have 7.5 compression. I'd say 10 is a good starting point. If you want it to run like crap and have no power then set it ATDC.
 
JPSmit said:
IIRC 76's are supposed to be set ATDC - though mine is BTDC. Also, the vacuum is Vacuum Retard not advance. Jeff (advanced distributers) suggested I disconnect the vacuum. I did and think it runs better - and cooler.
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IIRC all 1500's are spec'd ATDC. You can find a vac advance diaphragm and convert yours. I did but I can't use it anymore because of the DCOE. I need to hook that thing back up.
 
recordsj said:
what is the front and what side is the back?
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The back is the part behind the front, which us just in front of the back. :jester: O.K, the round thing, right. The back part is the half that is on the distributor side. The front is the other side. It it plugs onto the front, it's advance; the rear, retard.
 
Greetings from the land of dysfunctional government ; Iā€™ve tried every conceivable thing to keep my 1500 cool , replaced all hoses , thermostat -with / without ,radiator replace , heater box (rebuilt) flow on / off valve , timing (10* BTDC) , rebuilt 25D distributor ($200.00) installed 3.5 differentials @ $1500.00 bucks , oil cooler , and finally my water pump (Triumph ) W/ a plastic multi blade fan ā€¦ā€¦. better but not great . The conventional old clutch fan is old / compromised ā€¦ā€¦ā€¦if you can freely move the fan than the ā€œclutchā€ is shot , itā€™s compromised , not fully engaging at low RPMā€˜S . On my 75ā€™ MG Midget doing 3500 RPMā€™s @ 66 mph on a warm day (80*) the temp starts to rise ā€¦ā€¦ā€¦..under 3300 rpmā€™s (60+) Iā€™m good but not thrilled . Today itā€™s 50ā€™s and it runs great (temp) but summer is coming .
ā€˜I dunno , I might just install my M/G (Moto Guzzi) engine in it and call it a day . God save the Queen !
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