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74 midget oil pressure

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zimmy

zimmy

Jedi Knight
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i did an oil change using Castrol Syntech blend....
finally got car started for the first time....
oil pressure looked nice at around 45, 60 or so
when revved up.....then
i put some Marvel Mystery oil in to top off since
i was still low (is 3 qts about right?)
now my pressure want to go from 60 to 70+...
my idle is at 1200 which i know is high but
i cant rebuild my carbs till next week and they
really dont wanna go any lower......
to sum this up...could my high pressure be
from my lack of gas settings and high idle....or...
has the Marvels made something funky happen?
ive also considerd the oil pressure valve....
thaks lot guys and by the time im done im sure
il be a "midget jedi" /ubbthreads/images/graemlins/grin.gif ha..........zimmy
 
Maybe that's why it is called Marvel Mystery oil.

Would not worry till you get the idle down, your bypass valve might be stuck, give it a chance.
 
If marvel mystery oil is anything like STP, it's a sludge and that's the reason your pressure is jumping! I would never put STP in an engine, because it makes the viscosity absurdly high. However, it can work nicely in shocks for a stiffer feel ...

I have an oil cooler and take approximately 5 quarts. "Full" for a 1500, at least (without cooler) is around 4 quarts. I'd anticipate the A series engines would be the same.
 
7.8 US pints including oil filter.
 
Marvel mystery oil is about 20 weight or less. More like auto transmisson fluid and should not be the cause of increased oil pressure. MMO is for top end lubication (to be added to gas) and should not be used for your engines inner workings. Maybe it reacted to the syntech to cause it to be thicker by a chemical reaction?
 
MMO is kinda thin and my oil looks normal....
i only put 4 oz of MMO in anyhow....way below
the suggested on the bottle....
my car is missing the clutch pumps so i wont be
overheating etc on any long trips ; )
just getting her goin........
anymore suggestions? zimmy
 
First, a shy 4 qts is what goes in a 1275 with a new filter.
The MMO may have unstuck your oil pressure relief valve which may heave been gummed up.
80 psi cold should be the most you ever see on the oil gauge.
20 at an idle when hot should be the lowest.
So 70 in the winter at a fast idle is OK.
 
Marvel will work fine in the engine oil. It is a cleaner of sorts(read the label). 70 psi is good pressure on an A-series engine. The relief valve was likely an bit stuck in the bleed back position and the marvel may have freed it up. That is what marvel will do inside an engine. My engine idles a bit higher than that(race engine/stock pump) It will do about 80psi till warm. Then bout 60. Doesn't sound bad to me. And if it will make you feel better I put marvel in my oil too, maybe not quite that much though, bout half a quart. It is 10 wt oil and will not lose viscosity with heat.
 
finally flushed my radiator...(its COLD outside snow comin)
started her up reluctantly......
idle still high but oil pressure now back to 58-60...
i can live with that!
hopefuly everything will go well under load also...
(still need clutch and tires ;( )all in all the motor runs better than expected for its age ...86000 miles and most likely not rebuilt at all....ill do an audio to get you guys goin after i build my carbs to smooth things out ltr,z
 
Super duper, hope things continue to progress smoothly.
 
Have a 1976 MG Midget 1500, been driving it all summer long and oil pressure has been good. Last couple times out oil at start 60lbs then after only a few miles drops below 30lbs and at ideal next to nothing! Any thoughts?
 
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