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MG Midget and Sprite Technical - Problems with Grose needle and seats

Hi all
just had to replace my new "Grose" needle and seats with the old ones I took out because they weren't shutting off fuel flow adequately causing flooding especially on the front carby. Has anybody else had such problems? And yes the floats are OK and the height was set to factory.
Cheers
R W Bowers

a bit of googling reveals a lot of horror stories with Grose jets. The correct modern replacement needle valves use improved materials (Viton tips) and seem to be a lot better at curing any leakage problems.
David Smith

I found they don't do the job! I put one in and it leaked like a sieve. Then I Googled it and found that despite the Moss hype, lots of others thought they were rubbish too.
Replaced with the standard item and had no problems since.
G Williams

When originally introduced, Grose were a real improvement, but, IIRC, the originator sold it to some company, and those have never worked well since.

As David and G have pointed out, the modern replacement ones, Viton tipped, are simply better than the Grose are.



Norm
Norm Kerr

Same story here - not only did my Grose jet fail to seal, it caused sufficient flooding to contaminate my oil, cause the float chamber to overflow and fill my front charcoal canister with fuel, ruin my cat converter, and strand me miles from home.

Lesson learned!

-:G:-
Gryf Ketcherside

The idea of these looks good. Precision balls are readily available and machining a suitable seat wouldn't seem to be too arduous a manufacturing task. But even brand new mine didn't work. I wonder whether the cross sectional area of the sealing ball (under pressure from the pump) is too high and passes too much fuel whenever the float "jiggles" with the bumps (even without polybushes!).

I should have returned it really.
G Williams

Similar problems here about five years ago. I believe caused by E-10 fuel working on old deposits inside the original fuel tank, and system gumming up the ball seat of the Grose Jet. Went to the Viton tipped neddle valves, and no problems since, touch wood.

Larry C.
Larry C '69 Midget

Thanks lads, G williams I agree, probably seemed like a good idea at the time but too much surface area. She's running beautifully now, a real pleasure to drive.
Cheers
R W Bowers

This thread was discussed between 07/01/2013 and 08/01/2013

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