grose jets or not? anyone else

[Richard_Brown]

I did a search here and on the net and could not find any info to help decide if this is a good thing to do to a pair of Strombergs on my TR4A or not?

 

[71tr]

Re: gross jets or not?

I put grose jets in a pair of ZS carbs rebuilt about five years ago. I think they are far superior to the original friction needle valve design. So much so I'm putting them in my SU carbs currently being rebuilt.

 

[dklawson]

Re: gross jets or not?

Reading past posts you may have come across my comments... but I'll repeat them here. When they work, Gross jets are great. I installed one that leaked (never completely shut off) and it had to be replaced. Hopefully that was just an anomaly.

 

[Andrew Mace]

Re: gross jets or not?

Just so there's a balance of opinions here.... /ubbthreads/images/graemlins/grin.gif

I've heard and seen little or nothing to recommend Grose jets over the originals!

 

[Geo Hahn]

Re: gross jets or not?

I discovered that my SUs had grose jets when one of them stuck closed after a bit of time off the road. Cleaned it up and no further issues but to me they look like a solution for a problem that doesn't exist.

 

[dklawson]

Re: gross jets or not?

I shared Geo's experience recently with the Gross jets in my GT6 after is had been sitting for nearly a year (wife's car... it's her fault it sat that long!). I dropped the bowls, flushed the jets with carb cleaner and they were operational again. I suspect that regular rubber/nylon tipped valves would not have fared as well.

 

[Richard_Brown]

Re: gross jets or not?

Not many chimed in on these, I guess that must mean not many people have installed them and I guess thats a sign.

 

[71tr]

Re: gross jets or not?

Richard,
I may seem to be backing away from my previous post but here is a quote from the guy rebuilding my SU's.

"I dont use the Gross float valves since they will sometimes oscilate with the engine harmonics and cause the fuel level to become unstable. I use original SU float valves just like the engineers intended."

 

[dklawson]

Re: gross jets or not?

Interesting comment from the rebuilder. I'm curious where he got this information. The contacts who directed me toward using Gross jets were/are racers. If vibration is a problem affecting the jet performance I would expect racers would experience this before it would be seen on a street car.

I'm not making light of the rebuilder's comments, but "like the engineer's intended" is a comment that could have limited our cars to mechanical band brakes, manual spark advance, and hand cranked windshield wipers... if someone didn't invent new ways of doing these things.

 

[TR_Jim]

Re: gross jets or not?

I put gross jets in my GT6 carbs when I rebuilt them. Almost evey day for a week I was getting gas flowing from one or the other carb. Checked the float level several times but I had the same problem. I gave up and put the old needle valves back in. That was 4 years ago...haven't seen any gas leaking yet.

 

[SkinnedKnuckles]

Re: gross jets or not?

I put in a set of Grose jets during a carb rebuild 12-13 years ago and never had a problem with them. Shortly after the install the jets became "unavailable" ... I don't know the history.

When I went to a triple ZS set-up a std needle valve was used in the third carb. It and a replacement leaked through when the gas tank was full.

Grose jets were then available again from 1 of the big 3. I got 2, one for a spare, I thought. The newer ones look slightly different than the original, but are functionally the same. The first one had a problem right out of the package - the big ball lodged in the retainer and finger pressure wouldn't get it to release! It would have stuck open if installed. A good rap on a table freed it up, but it only lodged again when inverted. Seems the retainer hole was just a bit too large - the ball almost fell out, but jammed instead. That one got sent back. The other has worked perfectly.

A big advantage of grose jets is that if you do get some crap in them and they won't close, they can usually be cleaned with a dental pick & compressed air. Then good as new.

BB

 

[dklawson]

Re: gross jets or not?

The two posts above echo what I said earlier that if you get "good ones" the Gross jets are good. Like BB and Jim, of the four I've installed, one was DOA (or leaky on arrival). The replacement and remaining three have worked for years without issue. I've never had a dead "stock" valve right out of the box but I have had their little sealing tips stop working over time.

 

[71tr]

Re: gross jets or not?

I think that is a good point and indicative of many issues with out cars, replacement parts quality!

 

[Rick O.]

A Grose Jet float bowl valve seals better and keeps the fuel level more precise. A viton-tipped needle valve allows the level to vary up to 1/4 inch and is slowly destroyed by gasoline additives. The Grose Jet has 2 stainless steel balls that cope with higher inlet pressures, eject dirt particles, improve high speed running, and don't stick or dribble. The balls rotate in the flow stream so wear patterns are minimized. I have had Grose Jets in both my ZS carbs for several years with no issues.