Holley carb rebuild help [Archive] - Team Camaro Tech

: Holley carb rebuild help


Jdawg
Jul 11th, 03, 04:01 PM
OK, I am past the point of no return on my Holley 4150 4346 rebuild. It's disassembled and all parts are now clean. The documentation that came with the Holley Renew kit is, in my opinion, not that great. The exploded diagram for the 4150 doesn't even seem to match my carb. Anyway, I have a couple questions...

1. How can I tell which of the several replacement float valve & needle assemblies that came in the kit are for my carb? I don't see any markings on the installed ones.

2. I only found a single needle inside the pump discharge nozzle...not a check ball or check ball weight as diagram shows. Did I lose something or is this correct for the carb?

3. What is the proper dry float setting? I see 3 potential techniques in the instructions.

4. The air vent valve - should that be completely closed at idle and then open as you hit the throttle.

Obviously, I am not an expert at this...but I will prevail. Heck, I did it in high school 20 years ago and I don't remember it being this hard. Are there any other common pitfalls I should watch out for in re-assembly and tuning?

Thanks,

Jay
69 Z/28

dnult
Jul 11th, 03, 07:59 PM
Those holleys were reved a few times and there are some differences between units.

As for the needle and seat arrangment...use the one that looks like what you took out. If you supsect it is wrong, you'll find out during the foat adjustment.

I belive you're correct in that some accellerator pumps used a needle that installed under the accellerator nozzle. Is there a captive ball on the bowl assembly where the pump diaphram mounts?

Float should be set level. Hold the bowl upside down and adjust the float level until its level. This gets you close. The final adjustment will come when the unit is installed and wet. You'll adjust the level until fuel just runs out of the inspection holes on the side of the bowls.

The air vent valve...I'm not sure about that one, since my carb doesn't have it. I don't think it's a critical adjustment though so if it hasn't been bent, it will probably install and operate as designed.

-dnult

DjD
Jul 11th, 03, 08:57 PM
Only one revision of that 4346 that I know... It's the same carb from the '60s and still manufactured today.

The holley renew kit is "37-1539"
Trick kit is "37-933"
Pri and sec needle and seat is "6-504"
Pri jets are "68"
Sec jets are "76"
Pri discharge nozzle is .025"
Power valves are 8.5 (both)

The vent valve is open at idle and the clearence from the float bowl to the rubber is .060" and should close when the throttle is opened...

All this is available on the Holley web site if you look for it. Download and save this http://www.holley.com/HiOctn/ProdLine/CarbList.pdf
And go here http://www.holley.com/HiOctn/TechServ/TechInfo/FMCTech.html and download and save the Carburetor Rebuild and Adjustment Manual. Get the .doc not the html one. It shows how to dry adjust the floats and a ton of other adjustments as well as making sure you have the right gaskets...

Some of the others, dnult and myself have posted volumes on carb tuning and adjustments. Just for starters do a search in the Performance forum for "holley" and put in my member number (186) and you'll find plenty. Here's an example with some more good holley links.. http://www.camaros.net/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=4;t=007097

Take your time and you'll have great results...

Oh, here's a little bonus info!! http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=4;t=015939

Jdawg
Jul 12th, 03, 06:07 AM
Thanks guys. That was helpful but this Renew Kit (and it is the right one) is still driving me CRAZY. First off, it doesn't even come with any 8.5 power valves. Only 6.5, 5.0 and 3.5's which are stamped clearly and are not 8.5. Should I just go with the 6.5's?

Secondly, the six needle and seat packages (each with two assemblies) do not bear any marking that resembles the "6-504" listed on the Holley Carb Num List. Two of the packages look like my primary and the other four look like my secondary. The assemblies themselves each have a single digit letter code...but my installed ones don't.

This was a $80 kit...not exactly cheap. Aside from the confusion above, it didn't even come with new springs, filters, plastic parts or screws other than ones I believe are throttle plate screws but appear to be too long. Plus I have to pick through the smorgasborg of tiny gaskets they gave me to find the right ones. I hate to complain but this is frustrating. (OK, deep breath) I will take my time, call Holley and get a Holley book to get this right, but if you have any more advice...I am all ears.

Also, my primary jets are currently 71 instead of 68. Is that worth changing?

And I did have a check ball in the bottom of the float assembly which presumably substitutes for the lack of one in the pump discharge nozzle.

DjD
Jul 12th, 03, 08:08 AM
Sounds like what you got is a universal kit made for many different 4150 carbs. You paid for a lot of extra parts you'll never use. i've never gotten a kit with an assortment of needle and seats or power valves. I didn't find an exact kit for the 4346 but one for a 3310-1 or the DZ 4053 should have the right parts except for the power valves.

As for the power valves use ones that are at least rated 2 below your in gear idle vacuum for higher performance applications and as much as half the idle vacuum for less performance applications. You shouldn't have a big issue running 6.5's if you are pulling 10 or more inches. If you've never run the carb on your engine I'd go to stock jetting for setting a baseline but if it ran good with whats there stay with it for now.

Just a thought, the needle and seats in kit you have - do they have bit tall adjustment nuts or thin low profile nuts?

Jdawg
Jul 12th, 03, 08:35 AM
The kit that is listed on the Holley sheet and the one Summit recommended, definitely seems like a waste.

The adjustment nuts are thin...maybe 2 millimeters or so.

I should have mentioned that the carb was running on the motor originally, but it was not running great and I was having trouble tuning it. I thought perhaps the power valves were shot.

The motor is a stock DZ.

DjD
Jul 12th, 03, 08:44 AM
I've got to get going but reference the List 4053 on the .pdf carb list I linked to above. It's what came on the DZ mill. It's setup a little different (pv's and jetting I think) and doesn't have the vent on the pri bowl. also reference the '69 chassis service manual under carbs in the back of the book. The sec throttle is adjusted 1/2 turn not 1/4 like holley says. Do everything else as shown in the word doc (found in link above and you should be there) I can call my buddy if needed to see what jetting he ended up with but run the factory recomended for starters... I'll check back later..