MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Grose Jet

Hi All. Curious how HS2 Grose Jet users are feeling about them. I've read about quality issues with older jets, but my first set were less than 2 years old. I can't seem to stop a random overflow issue. I've changed the jets (another new pair of Grose), and the float gap is set at 5/32". It should be shutting off in plenty of time, and 'usually' does. BTW, the nylon floats are tight... no leaking. The floats also pivot freely. The issue comes and goes. Thanks!
Sheldon
SS Schwartz

Could be small bits of crud coming through the fuel line and temporarily making the valves not shut off before being washed through. Have you tried an in line fuel filter to see if that helps at all?

Mark
M Adams

Great thought... but yup... clean carbs, clean lines, and clean filter. As a side note my carbs don't have a "Lid plate baffle" like is see in the catalog schematics. The exploded diagrams don't do a great job of showing it as installed. But maybe my issue is related to engine vibration and this baffle is the solution. I have a second '74 HS2 set... no baffle there either, so I may just be grasping as straws.
Baffled.
SS Schwartz

I remember reading lots of criticisms of Grose Jets in here

I always advocate getting the Rover style viton tipped needle valves. They were original equipment on Rover Metros and I didn't get any problems with them at the roadside

I have just nicked the following off the SU Carburettors website re; Viton

Note the last sentence...

"Needle valves come in various types, the main differences being size of orifice and tip material.

The most popular had a brass body with a spring loaded, stainless steel tip, mounted in a nylon needle and would withstand a pump pressure of about 6psi. Now are all fitted with a VITON tip.

Newer carburetters are often fitted with a VITON tipped brass needle in a brass body and will withstand a pressure of about 10psi.

All of our needle valves are air tested and are far superior to the steel ball type which are cheap but make lots of money for suppliers. !

Bill1

Thanks for the note Bill.
Anybody interested in 4 very slightly used Grose jets??... lol. The bummer is that the viton jets were doing just fine and I could not tell you why I thought GROSE jets were the way to go. I’ll make the swap back and post the results. My wife loves the smell of gas on me. Not.
Sheldon
SS Schwartz

Sheldon -

My experience was very much like yours. I saw Grose Jets advertised in one of my parts catalogs, and the adverts made it sound as if they were something special. So I ordered one for my single ZS carb, and had intermittent overflowing shortly thereafter. I was stranded once until I noticed fuel dripping from the front charcoal canister in my '78, undid the bottom vapor hose, and let out about a quart of fuel. Then the car started and ran again. I went back to the original spec needle valve, and haven't had a single instance of overflowing since.

By the way, I was chatting with a gent who had a TR-6 shortly after that incident, and he reported ZS overflowing too. I asked him what sort of float valves he had fitted, and he answered "Grose Jets."

That's all I need to know. They may work for some, but they sure didn't for me.

Cheers,

-:G:-
Gryf Ketcherside

Thanks all. I went back to the Viton tipped needle jets yesterday, and what do you know... There was nothing I could do to induce any sign of overflow. As a side note. I think the Grose Jets we're causing more subtle fuel level issues the whole time. The car instantly sounded better, and unlike in the past two years, I was very easily able to dial in a very accurate carb tune. That thing is purring.
SS Schwartz

This thread was discussed between 24/05/2012 and 30/05/2012

MG Midget and Sprite Technical index

This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now