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TR4/4A GROSE-JET or Viton-tip for SU HS6 carbs?

Carlos

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After not driving my TR4A for four months I found both the Viton-tip float valve needles on the SU HS6 carbs to be firmly stuck shut. I had the same happen after a previous period of several months without strating the engine. I have been running -although I should know better- ethanol gas.

At this point I am going to replace the float chamber valves but as I have not seen much recently about the benefit -if any- of switching to Grose-Jet valves, I would appreciate any comments you all may want to make.
 
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Rut

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Carlos,
The Grose Jets seem to stick more often than the viton tipped variety and I just use carb spray to clean them. I pull the tops and spray until the valves free up with absolutely no sign of sticking.
Rut
 

sp53

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I have only used the early SU version of carbs. My experience with those is the Gross jets run richer and for that reason cause problems on the street. I have not had the Vinton seals stick, so not sure there. Perhaps there is another reason for the sticking on your car like the forks or something. Moreover, the Gross jets might not stick in your case because of the design with the little ball in the jet. The design looks clever and would not be prone to sticking, but I think it lets too much fuel come into the system.

steve
 
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Carlos

Carlos

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In view of y'all's feedback I am not going to trade a known problem for another potential different one. I am going to adopt Rut's approach, thoroughly clean my existing Viton-tip needles with carb cleaner, and not use ethanol gas in the future.

Thanks for your input guys.
 

dklawson

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+1 against Grose Jets. I have had them both stick closed and stick open. As mentioned above and elsewhere on the web, modern versions are often coated with a Cosmoline-like substance to protect the balls against corrosion while in storage. Anyone planning on using them should clean them thoroughly with acetone and/or carb cleaner before installation.

If the Viton tipped valves stick for you, there are two options I know of. The first is to carry a small dead blow hammer and tap the top of the float bowls before trying to start the engine. Sometimes it works, sometimes it doesn't. The second choice is harder to implement. On my Mini's HS2s I made a pair of "clips" out of music wire. They loosely connect the float valve body to the float arm so the falling float will pull the valve open. This is similar to what happens with Briggs & Stratton carbs.

The image below is for motorcycle carb float valves with similar clips to those I made.

41GedDAhjBL._SX450_.jpg
 

Joe Schlosser

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Have gone back and forth on Street car HS2s with Viton and Gross jets and have not found any difference. Gross jets are 20 plus years old and work well. I have an alternate cover set up (fancy AN braided lines) with Viton and no problem either.
I am told that the newer Gross jets have to be properly cleaned with carb cleaner before using as they have a "coating" on them.
 

trrdster2000

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Agree with Joe. They are shipped with a sticky lub and if you don't clean with carb cleaner, they will not work.
Any car that has sat for a period of time our cars do will have a problem with the float, Holly, SU or whatever.
I have them in the TR6 I got years ago, haven't seen them for sale for the Stromberg lately. Now they are a little more prone to sticking than the SU's ones. When used on a regular basics I have not problems with the Gross and think with unleaded, even high test, it leaves a film, so constant use washes it off.
Drive them if you have them.
 

Got_All_4

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When I went to Gross jets all my sticking jets went away. I think they have been in there for 20+ years now. According to our local former Triumph dealership service manager who I've befriended over the years talked me into using them. He said he put hundreds of them in over the years. He said why most people have problems is they don't thoroughly clean them before installing them. He told me not to use brake & parts cleaner like most people do. He said to soak them overnight in carb cleaner. I was shocked in the morning as to how many micro metal filings were in the bottom of the cap. I sprayed them down some more cleaner and made a tool to set the proper gap and never had a problem again.
This can be an explosive topic because of that love hate relationship!
 

Russ_S

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When I went to Gross jets all my sticking jets went away. I think they have been in there for 20+ years now. According to our local former Triumph dealership service manager who I've befriended over the years talked me into using them. He said he put hundreds of them in over the years. He said why most people have problems is they don't thoroughly clean them before installing them. He told me not to use brake & parts cleaner like most people do. He said to soak them overnight in carb cleaner. I was shocked in the morning as to how many micro metal filings were in the bottom of the cap. I sprayed them down some more cleaner and made a tool to set the proper gap and never had a problem again.
This can be an explosive topic because of that love hate relationship!
Some folks say the new grose jets aren't the same quality from years ago, any truth to this, and is why the ones from years ago seem to work fine?
 

glemon

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I have put Gros Jets on the 3-4 British cars I have owned in the last 20 years, never had a problem, the last set I bought was about 10 years ago on the TR4 Stromberg carbs on my TR250.

I don't know about the viton tipped, but back in the day had a lot of problems with stock float valves sticking open and overflowing. Would take them out and clean them (easier on SUs than Stromberg's) and they would work for a while then start sticking again.
 

Russ_S

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I have put Gros Jets on the 3-4 British cars I have owned in the last 20 years, never had a problem, the last set I bought was about 10 years ago on the TR4 Stromberg carbs on my TR250.

I don't know about the viton tipped, but back in the day had a lot of problems with stock float valves sticking open and overflowing. Would take them out and clean them (easier on SUs than Stromberg's) and they would work for a while then start sticking again.
I have the same repeated problem with sticking and overflowing, I guess I should try them, they couldn't be worse, and I could always switch back if it's not an improvement - thanks!
 

Got_All_4

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Just make sure you soak them in carb cleaner, acetone, MEK or anything stronger then brake cleaners. Then blow them out with air. I did mine I think 3 times. Don't forget to check and reset your float level adjustment. Should be 16 to 17 mm. If it runs a little rich readjust the float so it leans it out so not to flood the chamber. Also whenever possible purchase ethanol free gas.
 

martx-5

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I used the viton tipped jets when I restored my TR3 which was completed about 12 years ago. Never had them stick, and I use ethanol laced gas. Sometmes the car sits for a couple of months. I got my rebuild kits from Joe Curto.
 

Lotuswins

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I have gross jets on my Lotus with Stromberg carbs...no problems, work like a charm for 20 years now. I tried them on HS6 carbs on my healey, and the floats would overflow, sometimes, and carbs ran rich and idle was inconsistent. My theory is that the stromberg floats have a more positive force to close the needle/gross valve than the small SU float has, and the gross require much more force due to the area difference. I put vitons into the HS6's and it now behaves....just my 2 cents.

Jerry Rude
 
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