QJet Pump...does this look right?

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Jul 13, 2006 | 11:29 PM

CheezMoe

Thread Starter

Melting Slicks

Joined: Mar 2006

Posts: 3,456

Likes: 102

From: Piedmont Va

St. Jude Donor '11-'12-'13,'19-'20

QJet Pump...does this look right?

Greetings,

I'm a novice with this Qjet thing, but after fighting through wrong gaskets and generic instructions from our friends at Edelbrock, I finally got this Qjet almost back together. Something does not seem right with the pump shaft...it seems to be too high. Check out the pics. Without the level attached, the plunger measures 1 1/8"above the top of the carb. In order to get the pump lever in position to insert the retaining pin, the pump shaft must be depressed about a 1/2". (Pic2)..

Is this right?

I used the new pump and spring assembly that came with the EBrock tuning kit, so the pump spring is long and stiff. With it all together and the pin inserted, it measure ~1/2". Is this right?

thanks in advance...I'm about ready to put this thing on the shelf and buy a Street Avenger...

Jul 14, 2006 | 01:00 AM

73, Dark Blue 454

Melting Slicks

Joined: Mar 2005

Posts: 2,838

Likes: 10

From: Austin TX

Yeah,..something is off in photo # 1. I have two q-jet cars,..both show about 3/4" exposed pump shaft.

Jul 14, 2006 | 08:29 AM

S489

Burning Brakes

Joined: Feb 2006

Posts: 1,024

Likes: 1

From: AL

That actually looks about right. You can do some tuning though. As the throttle is moved from idle to WOT, the accelerator linkage will travel a fixed distance. This motion is transferred to the accelerator lever tip which will also move a fixed distance along the axis of the accelerator plunger. This distance is all the travel available to work with (unless otherwise modified). Get a steel rule and measure this travel. Where the pump (seal) begins its travel is easily changed by filing or sanding the top of the accelerator plunger, just don't raise it too high (above slot) or squirt capacity is reduced. The lowest it should go is something like 3/64 (memory?) above the housing. The tip of the lever can also be bent (last) as part of getting the max squirt. There is a maximum typical plunger travel that one can obtain with a Q-jet, and a maximum (probably less) value that you can obtain with yours. Typing from memory, I've intentionally left out a lot trying to avoid too many errors. I'll come back and add numbers when I can get to them, unless someone else posts first.
PS, PM me first if you decide to get rid of it!

Jul 14, 2006 | 10:55 AM

BigBlockk

Drifting

Joined: Sep 2004

Posts: 1,959

Likes: 1

From: North Bend Ohio

The second photo is correct. You're doing a good job there boy. Keep it up.

By the way, what jets and rods are you going to start with?

BigBlockk

Later.....

Jul 14, 2006 | 11:42 AM

kdf1986

Safety Car

Joined: Jun 2004

Posts: 4,652

Likes: 80

From: Lakeland Florida

I noticed there are two holes in the pump lever. Is the rod that attaches to the lever in the right hole? If you moved it to the outside hole that would depress the plunger by about 1/4 inch, judged from looking at the photos.

kdf

Jul 14, 2006 | 11:46 AM

S489

Burning Brakes

Joined: Feb 2006

Posts: 1,024

Likes: 1

From: AL

it's in the correct hole for maximum travel

Jul 14, 2006 | 11:56 AM

CheezMoe

Thread Starter

Melting Slicks

Joined: Mar 2006

Posts: 3,456

Likes: 102

From: Piedmont Va

St. Jude Donor '11-'12-'13,'19-'20

Hi Guy's,

thanks for the replies. The rod is in the inside hole as stated in the instructions. When it's all together it feels right and seems to have proper pump action, so when I got home tonight I'm bolting her on.

BigBlockk, I'm starting with a 74/43 combo as you and Lars had originally suggested, with float at 3/8. I hope they are really close because taking the top on and off with this choke $uck$!

Thanks again..I'll let you know how it goes this evening...

Jul 14, 2006 | 12:06 PM

Bob Onit

Melting Slicks

Joined: Mar 2006

Posts: 3,342

Likes: 7

From: Connecticut

Quote:

Originally Posted by dosoctaves

I hope they are really close because taking the top on and off with this choke $uck$!

Its not that bad
Just dont hook up the choke until you get it right.
I installed studs I bought from Summit so I dont destroy the threads on my aluminum intake... makes it a 10 minute job to pull the air horn