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Supercharger Oil Leak?

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Supercharger Oil Leak?
#1
MG Cruiser Avatar
MG Cruiser Keith Delta4
Rockingham, WA, Australia   AUS
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1970 MG MGB "Moneypit"
I was working on the car today and wiped my hand under the supercharger to find an oil smear.
This is around the area of the bypass valve. Any ideas? Keith

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Re: Supercharger Oil Leak?
#2
hmac300 Avatar
hmac300 Harry M (RIP)
Troy, MI, USA   USA
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1980 MG MGB MkIV
check to see if it's coming from timing cover and being blown back on supercharger.

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Re: Supercharger Oil Leak?
#3
MG Cruiser Avatar
MG Cruiser Keith Delta4
Rockingham, WA, Australia   AUS
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1970 MG MGB "Moneypit"
Thanks for the reply Harry, never thought of that. Thinking of the worst at present! Keith

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Re: Supercharger Oil Leak?
#4
Be Coming Avatar
Be Coming Kelvin Dodd
So. Calif., USA   USA
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1957 MG MGA
1957 MG MGA Coupe
1958 MG Magnette
1958 MG Magnette ZB    & more
Keith.

What you found was fuel, not oil.
The supercharger oil is in the front gear case and there is only a small amount. There is no connection from the gear case to the bypass valve area for oil to seep. When the gears spin, the oil is atomized which keeps the bearings lubricated.
During cold start up, you may get some liquid fuel build up in the case, which may seep out of the bypass butterfly shaft and show up on the bottom of the case.

Kelvin.

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Re: Supercharger Oil Leak?
#5
gray Avatar
gray Graham Moore
CAMBRIDGE, CAMBRIDGE, UK   GBR
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1972 MG MGB GT
brown-green colour? leaking gasket between supercharger and manifold will produce such an oily film where they meet. stick your head under the car with torch illuminating the lower side and I would think the shape and distribution will indicate as Kelvin suggests or otherwise.

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Re: Supercharger Oil Leak?
#6
MG Cruiser Avatar
MG Cruiser Keith Delta4
Rockingham, WA, Australia   AUS
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1970 MG MGB "Moneypit"
The “oil” is a brownie green colour. Does the supercharger have to come off or is it a tighten up situation?

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Re: Supercharger Oil Leak?
#7
Denis Avatar
Denis Denis Hill
Bearii, Nth Victoria, Australia   AUS
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1968 MG MGB MkII
1973 MG MGB V8 Conversion
is the oil film under the bypass valve or the blow off valve. ? The blow off sometimes comes a bit loose and may want a tighten. not a problem.

Denis


68 B roadster, Daffodil yellow, supercharger, Burgess SC head, SC cam, Mikuni HSR 48 carburetor and engine built for supercharging.

73 BGT V8 conversion starting with a bare shell. Built the engine "3.9L Rover" early in 2016 with high comp pistons and a few other nice bits, plus a T5 ford trans. Started on the body late 2016 and complete late 2017, Did all the work myself, mechanical, body. paint etc.
Finished and going well, great to drive and quick. Now has a nice 3.23 LSD.

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Re: Supercharger Oil Leak?
#8
MG Cruiser Avatar
MG Cruiser Keith Delta4
Rockingham, WA, Australia   AUS
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1970 MG MGB "Moneypit"
I will now check the blow off valve as I had a couple of blow backs when starting up for the first time.

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Re: Supercharger Oil Leak?
#9
malski Avatar
malski Peter Malkin (RIP)
Bright, N.E.Victoria, Australia   AUS
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Hi Denis
I’m still running mine in and am experiencing the odd backfire thru the blow off valve as evidenced by a sooty residue - will give you a bell after Xmas.

Keith - apologies for thread hijack.


Peter Malkin
NE Victoria
Australia
MGBGTV8 (1977)
MGB Roadster (1967) Supercharged
Triumph TR3A (1959)
MGA 1500 (under restoration)

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Re: Supercharger Oil Leak?
#10
gray Avatar
gray Graham Moore
CAMBRIDGE, CAMBRIDGE, UK   GBR
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1972 MG MGB GT
just be careful not to overtighten the blow off. the thread is cut into alloy and the bolt is shanked. so when it feels pretty tight, it is. doesn't need lots of lbft!
but if it's coming from the blow off there would likely be signs just below it on it's vertical surface and not just underneath.

backfire thro blow off commonly too much throttle when cold and lean. if your blowoff gasket actually blows out (usually with a bang rather than a chuff), the best way I found to get it back was to put it in the freezer for a couple of hours to stiffen it up as it was pretty awkward to get it back in with everything in situ as it's thin and floppy. for situations like this an AFR sensor/gauge is very useful.

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  malski thanked gray for this post
Re: Supercharger Oil Leak?
#11
RAY 67 TOURER Avatar
RAY 67 TOURER Ray Marloff
Fort Bragg, CA, USA   USA
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1967 MG MGB "My Girl"
One minor issue with the supercharger kit is that you can easily blow out the gasket, between the supercharger and intake manifold, with a backfire. Running lean is the most common cause. You can make up a stronger gasket out of neopreme gasket material by removing the supercharger and using it as a pattern for making the new improved gasket. It's extremely difficult to tell if the gasket is ruptured with the supercharger in place on the engine. RAY

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about 5 months and 3 weeks later...
Re: Supercharger Oil Leak?
#12
Pattyracer99 Jeremy Patterson
Brownsburg, IN, USA   USA
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Hey guys. I just bought a supercharged MG BGT. Can anybody tell me the sizes of the backfire gaskets? I’d like to order a couple to have in hand. Or a Moss Motors part number. Any help is appreciated.

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about 2 years and 1 month later...
Re: Supercharger Oil Leak?
#13
jseal Avatar
jseal Jonathan Seal
Zurich, Schweiz, Switzerland   CHE
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1964 MG MGB
1969 MG MGB GT
2004 MG TF 135
I know this post is a few years old.
I do not have an oil leak from my supercharger. Mine runs fine and I have no issues. I would like to keep it that way.
I am wondering if the oil in the supercharger ever needs to be replaced or topped up? If so, when and how? I could not find any information regarding 'servicing' of the Eaton supercharger.

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Re: Supercharger Oil Leak?
#14
OldDuffer Avatar
OldDuffer Silver Member John S
Eugene, OR, USA   USA
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1970 MG MGB "Ella B (totaled And Parted)"
1971 MG MGB GT "Ashley"
1979 MG MGB "Mae B *SOLD*"
Not sure this applies but might be of some help.
https://superchargersonline.com/2022/05/16/oil-change-instructions-for-eaton-magnuson-with-standard-n-c-45-62-90-112-1900-2300/


I was addicted to the hokey pokey but I turned myself around.

The problem with doing nothing is not knowing when you’re finished.

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Re: Supercharger Oil Leak?
#15
Ralph Yingling Avatar
Ralph Yingling
Monroe, WA, USA   USA
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1973 MG MGB "Molly"
I know this post is old but it is worth replying to for others who may have this issue.

If it is a Moss kit.I probably have bad news for you. Post 5 and 11 are right,

The gasket between the supercharger and manifold in the Moss kit is a known failure point of of their product. I went through the exact same issue and finally came to believe it wsas the HIF carb float bowl bottom gasket leaking. It was not (LONG JOB to replace in situ).

After months of tracking down various possible leak points I was pointed to the thin,thin gasket between the supercharger and the manifold.

Once the supercharger and manifold was off again (NO FUN) and a new gasket made the problem was gone,


Ralph
'73, SUPERCHARGED! tubeless wire wheels, OD, Advaced Dist. recurved dist. w/Pertronix, de- smogged, ANSA

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