Q Jet carb question

Mike Pearson · 09-26-2017, 08:25 AM

I tried to start my car on Sunday after I installed a fresh engine. The car had been sitting for about 6 months. The car would not start. I had fuel pressure. I checked the carb and the squirters were not pumping any fuel to the engine. I pulled the carb off and took the top off. It has a ball type valve instead of a standard needle and seat. I have never seen this type of valve in a Q jet before. The carb was originally built by Tony Critella from what I was told and it has been incredibly reliable over the years. Does anyone know what this type of valve is and where to buy them. I just cleaned and lubed the ball valve and put it back in and the car fired right up and worked flawlessly. Seems like a better deal than the needle and seat

Alan Nyhus · 09-26-2017, 08:55 AM

Mike, Tomco used to supply those in their QJet rebuild kits...did lots of those with no issues 'back in the day'. Not sure if they are still available. -Al

Hacksaw · 09-26-2017, 09:01 AM

I would like to try that ball type valve. Supplier?

Monte Howard · 09-26-2017, 09:06 AM

I just rebuilt a q-jet for a 85-86 Chevy truck and the kit had that type of needle and seat.

Lew Silverman · 09-26-2017, 01:29 PM

Tomco used to replace the needle-tip with a flat "disk" which was patented by the owner of the company. I haven't rebuilt a Q-jet in a while, but it's easy enough to check the kit at the auto parts store of your choice. I do seem to remember a "ball"-type, one-piece float valve for the 2-barrel Rochester's as well. The Viton-tipped needle-and-seat has always worked well for me, although there is another Q-jet post currently on the Forum which leads me to believe that a .047 orifice might be too large. I always thought "Bigger was Better"!

Hacksaw · 09-26-2017, 02:41 PM

Yeh Lew, I also thought bigger is better. Now I think a .135" non windowed needle and seat is the best way to go.

Mark Yacavone · 09-26-2017, 09:16 PM

Lew is correct. The Tomco deal is a disc thing.
Here is the original, I believe.
Called a Grose-Jet

https://www.google.com/search?q=Gros...w=1176&bih=590

Bob Mulry · 09-26-2017, 11:59 PM

Just a heads up........

The larger the diameter of the needle and seat orifice, the lower the fuel level should be

The larger area needs more pressure applied to the needle to seal it against the seat...

You apply more pressure by lowering the float level..

Just sayin'

Mike Pearson · 09-27-2017, 11:25 AM

Quote:

Originally Posted by Mark Yacavone

Lew is correct. The Tomco deal is a disc thing.
Here is the original, I believe.
Called a Grose-Jet

https://www.google.com/search?q=Gros...w=1176&bih=590

Mark, You are correct. My carb has the Grose Jet valve. Pretty cool piece.

SSDiv6 · 09-29-2017, 02:48 PM

The Grose Jet allows you to run a higher fuel pressure without flooding the carburetor.
Have used them for many years in all kinds of carburetors and they work great.

09-26-2017, 08:25 AM	#1
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,437 Likes: 611 Liked 1,904 Times in 571 Posts	Q Jet carb question I tried to start my car on Sunday after I installed a fresh engine. The car had been sitting for about 6 months. The car would not start. I had fuel pressure. I checked the carb and the squirters were not pumping any fuel to the engine. I pulled the carb off and took the top off. It has a ball type valve instead of a standard needle and seat. I have never seen this type of valve in a Q jet before. The carb was originally built by Tony Critella from what I was told and it has been incredibly reliable over the years. Does anyone know what this type of valve is and where to buy them. I just cleaned and lubed the ball valve and put it back in and the car fired right up and worked flawlessly. Seems like a better deal than the needle and seat __________________ Mike Pearson 2485 SS

09-26-2017, 08:55 AM	#2
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,180 Likes: 1,074 Liked 799 Times in 236 Posts	Re: Q Jet carb question Mike, Tomco used to supply those in their QJet rebuild kits...did lots of those with no issues 'back in the day'. Not sure if they are still available. -Al __________________ "That'll never work....."

09-26-2017, 09:01 AM	#3
Hacksaw Senior Member Join Date: Sep 2016 Posts: 880 Likes: 202 Liked 306 Times in 172 Posts	Re: Q Jet carb question I would like to try that ball type valve. Supplier?

09-26-2017, 09:06 AM	#4
Monte Howard Member Join Date: Nov 2002 Location: Potomac,IL Posts: 278 Likes: 1 Liked 65 Times in 22 Posts	Re: Q Jet carb question I just rebuilt a q-jet for a 85-86 Chevy truck and the kit had that type of needle and seat. __________________ Monte Howard 3209 STK, 3208 SS

09-26-2017, 01:29 PM	#5
Lew Silverman VIP Member Join Date: Mar 2010 Location: Newport News, VA Posts: 1,435 Likes: 371 Liked 129 Times in 59 Posts	Re: Q Jet carb question Tomco used to replace the needle-tip with a flat "disk" which was patented by the owner of the company. I haven't rebuilt a Q-jet in a while, but it's easy enough to check the kit at the auto parts store of your choice. I do seem to remember a "ball"-type, one-piece float valve for the 2-barrel Rochester's as well. The Viton-tipped needle-and-seat has always worked well for me, although there is another Q-jet post currently on the Forum which leads me to believe that a .047 orifice might be too large. I always thought "Bigger was Better"! __________________ Lew Silverman #2070 "The Wagon Master" N/SA

09-26-2017, 02:41 PM	#6
Hacksaw Senior Member Join Date: Sep 2016 Posts: 880 Likes: 202 Liked 306 Times in 172 Posts	Re: Q Jet carb question Yeh Lew, I also thought bigger is better. Now I think a .135" non windowed needle and seat is the best way to go.

09-26-2017, 09:16 PM	#7
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,792 Likes: 2,884 Liked 5,083 Times in 1,937 Posts	Re: Q Jet carb question Lew is correct. The Tomco deal is a disc thing. Here is the original, I believe. Called a Grose-Jet https://www.google.com/search?q=Gros...w=1176&bih=590 __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers

09-26-2017, 11:59 PM	#8
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	Re: Q Jet carb question Just a heads up........ The larger the diameter of the needle and seat orifice, the lower the fuel level should be The larger area needs more pressure applied to the needle to seal it against the seat... You apply more pressure by lowering the float level.. Just sayin' __________________ Bob Mulry 7516 STK A & M Motorsports

09-29-2017, 02:48 PM	#10
SSDiv6 VIP Member Join Date: Feb 2003 Location: Glendale, Arizona Posts: 3,036 Likes: 711 Liked 1,538 Times in 575 Posts	Re: Q Jet carb question The Grose Jet allows you to run a higher fuel pressure without flooding the carburetor. Have used them for many years in all kinds of carburetors and they work great.