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MG Midget and Sprite Technical - 1275 Frog that never made it to Le Mans

OK the all knowledeable collective, a bit more on this saga.

Some background. The engine is an ex-racing 1275 bored to 1330 with a slightly hotter cam, Metro unleaded head. That is how it was when I bought it. I honed the bores, new rings, new shells and thrusts, new duplex and not a lot more.

From the first time it ran it always leaked oil, not a lot but persistant and a lot worse when given a bit of welly.

I'd decided to put a type 9 box in so after removing engine and box from car I thought I ought to check the oil-pump etc, so removed clutch, flywheel and back plate.

Attached is an image. The green and red arrows point to plugs in the block presumably fitted after work on the oil galleries. The area under the gasket near the plug identified by the green arrow was saturated with oil. So my question is, is it possible that oil is leaking past the plug? and if so, is there anything I can do about it? e.g. is there some sealant I can use to stop this?

Rob

Rob aka MG Moneypit

Ahh.... yes, try red thread lock

But id check that the threads are compatable with each other as well as not crossed

Something else to consider is the length of the allen head set screws maybe wrong...a common problem is they can be installed to LONG ... wierd I know

I want to say it was keith culver that wrote about this, so you will have to research this a bit, I know vizard covers this mod in his A series bible, but may not civer the flaw, and Im fairly certian ??? That danial stapleton covers this in one of his books....btw danial hangs out here on the boards regularly, so you might be able to just post a note asking for danial staplton

Maybe another option instead of red thread lock would be rtv sealer, silicone, hoylamar??? Or ptfe paste, (not the wrap)

Im not sure, but are those oil galley holes

Btw I think the lower end gasket set from payen comes with the press in caps like the 2 at the top of the block and you can eleminate those allen set screws

Personally I think the allen set screws are a modification for last resort, not the first idea

Something else I notices, all your holes have straight sharp edges...id at least sand/grind those edges down dull or best counter sink them

Sharp hard edges is where stress cracks begin

Prop
Prop and the Blackhole Midget

It also looks like your bango bolt to the oil feed tube on the side of the block is leaking... is it missing the copper crush washer

Prop
Prop and the Blackhole Midget

It has both washers but I think it does weep slightly. It's one I had in the garage but it wasn't quite compatible with the oil filter head because I had to bend it slightly to fit. It's still not a perfect fit but it will do for now.

Good point about the sharp edges, I will chamfer them slightly.

Also, I noticed a crack in the engine plate between the mounting hole just above the scroll to the oil-pump cover.

And, also, when I took the engine plate off all the mounting screws were quite loose. Tight enough to compress the lock washers but not tight enough for my liking.

Rob
Rob aka MG Moneypit

Rob,

I believe I used the PTFE plumber's paste that Prop mentioned.

Originally those oil galleys would have been plugged with a core plug. I pulled mine out to clean the oil galleys, and then I tapped the hole for a brass pipe plug so that I would not have to worry about the core plug blowing out. I believe this was recommended in Vizard's book.

The first time I fired it up there was a huge oil leak at the back of the engine. I had to pull the engine out again, and it turned out that I hadn't tightened them enough.

Charley
C R Huff

I've never had a bottom end gasket set that included the oil gallery plugs. Also, once the galleries have been threaded, you're unlikely to get a seal by fitting the original plugs.

There are a few thread seal compounds on the market that should stop the leaks - probably a 'Loctite' product will do the trick.

Presumably, the other end of the galleries are plugged in the same way?
Dave O'Neill 2

Thanks dave,

Some how i got several of those caps, I thought they came from payen, thanks for the correction

You have a cracked rear engine plate.... jez, that sucks, id call around for another one, it will just keep cracking until fail, sadly they cant be repaired ither... ive had a couple of pros try with no love, if you can try for an alumiunum back plate

Good luck

Prop
Prop and the Blackhole Midget

Rob
Have you removed the rear main bearing 'moustache' and failed to correctly align it with mandrel or feelers?
It is often wise to run a ring of sealant around the oil pump when fitting the gasket (both sides).
Alan
Alan Anstead

Alan

Do you mean the oil pump gasket, or the backplate gasket?
Dave O'Neill 2

Alan, no, never removed the moustache. Don't know whether the previous owner did but it doesn't look like it has ever been taken off.

I'll get some sealant when I get a new gasket. Presumably, you mean each side of the oil pump canister flange?

Rob
Rob aka MG Moneypit

Dave
Well picked up! The backplate gasket not the actual oil pump gasket as excess can block passages and give oil pressure problems.
Alan
Alan Anstead

I put a smear on both sides of the backplate gasket around the oil pump hole. Around the canister flange wont hurt either.
If people are new to Spridgets I think their expectations can be high. Where I lived, back int' 60's, what cars there were parked with two wheels on the pavement. More spots (of oil) than a Dalmation. Of course there is a difference between a few spots and the 'Torrey Canyon'.
Alan
Alan Anstead

On that mustache lip....

Get a piece of glass and a sheet of 400 wet dryand some wd40, spray wet dry sand paper place on glass sheet and take the moustache lip and sand on the glass/wet, dry sand paper in a figure 8 for about 10-20 minutes that will give you a flat finish which will.seal up nicely with the silicon ...if its worn and jaggy looking it just wont do.as well... im not sure how the get that way, but they sure do over time

Prop
Prop and the Blackhole Midget

Prop et al. I got some time in the garage again and had a good look at the oil gallery plugs and back of the crank.
There is no sign whatsoever of oil on the crank where it protrudes out of the scroll oil seal and no sign of oil on the back of the crank flange. So I think oil is coming passed the gallery plug near the pressure relief valve (the green arrowed location in the image in the first post). It must be under almost from pump pressure at that point when cold.
I have ordered some PTFE paste, as recommended, and will use it sparingly and see how it goes. I won't be able to do that until next week as this weekend is all booked up.

Rob
Rob aka MG Moneypit

Rob,

Thats one of those things your in a better postion to decide then any of us...just be confident in your decision making, study the problem until you fully belive in yourself then make the decision

I wish we could be there to see this in action, but we can only guess by what info you share with us.

But be assured, we will all keep guessing on your behalf. Some more exotic then others.

Prop
Prop and the Blackhole Midget

This thread was discussed between 28/07/2014 and 30/07/2014

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