The Stovebolt Site Forums The Shop Area Engine Shop Carb install problems

'bolters,

I'm having trouble with what should be an easy install of an edelbrock 1406 performer on my 1954 chevy. The truck has been converted to a 327 and the previous Rochester Carb (#7028821) was flooding, leaking, etc.

I have posted pics of the intake manifold to see if anyone can ID and ensure that the 1406 works on it (i think it does). The numbers I was able to find on the manifold were: GM 5, E 90, and either 9746829 or 3746829.
http://homepage.mac.com/spider/truck/PhotoAlbum23.html

Anyway, the carb is bolted in. I have the HEI Distributor vacuum line plugged to the timed port on the passenger side. I have the full time port plugged. The Front PCV port is plugged for now as I have breathable oil caps on the valve covers (pcv is next after the carb is working). The fuel line is correctly plugged in with a new filter. The rear vacuum port on the carb is plugged to the powerbrakes. Throttle Linkage plugs right in as does the return spring. I wired the electric choke to a switched connection and grounded it correctly.

Problem:
The carb overrevs the engine at idle and I can not get the RPMs down no matter what I do.

I've started the truck with no linkage but with the reutrn spring attached and idle screw set all the way down and still, the truck is revving pretty high.

I've tried the PCV plugged to the powerbrakes and the rear port plugged.

I've tried switching the vacuum line to the full time rather than ported.

I suspect that there's a vacuum leak, but the engine is revving so loud I can't identify if that truly is the issue.

Any other hints that I can look at?

thanks!

Is it a new carb or used carb?

is the float stuck??? It's got to be pumping fuel into the engine to make it run away..

It's a brand new carb so it may not be that the float is stuck. good suggestion though. I'll look at that tomorrow after work and see if that could be it.

the manifold looks like an early one to me I,d say the carb you are installing on it will not work,,not sealing at base...doc

oh. crud.

doc41 may be right. Anyone know of an adapter for an early style manifold?

Seems like a lot of work to replace a really good carburetor with something else, but if you really want to do this, an adapter should not be necessary. Here is the method (assuming that the bolt pattern, and throttle bores of the eclone exactly match those in the intake manifold):

(A) A trip to the local auto parts house
(B) Ask for the black, rubberized gasket paper (would suggest Armstrong N-8090, but there are probably other brands)
(C) Set a piece of the gasket material over the manifold
(D) Using the "peen" of a ballpeen hammer, GENTLY strike the gasket material all around the fuel holes, and bolt holes, making a pattern impression on the underside.
(E) Cut out the gasket to have 8 holes only, the 4 for the air/fuel, and the 4 mounting holes. Your wife or girlfriend"s (not both!) fingernail sissors are good to cut circles.
(F) Install gasket and e-clone.
(G) Begin the adjustment procedure.

If the holes in the e-clone do not exactly match those in the manifold, acquire a 3/8 spacer from the local speed shop. Use the gasket you cut above between the manifold and the spacer, and use the gasket supplied with the e-clone between the spacer and the e-clone.

A better (MOO) suggestion: sell the e-clone to some 16 year-old, and rebuild the original Rochester.

Jon.

Jon,

thanks for the info. I'll try this tonight after getting the gaskets from the parts store.

I'll also check to see if the throttle bores match.

if this doesn't work, then I will sell the edelbrock and rebuild the old carb -assuming that I can find the rebuild kit. The auto stores I hit (Napa and Kragen/Checkers) couldn't find the right rebuild kit for the number rochester I listed. Oh well.

thanks again!

The Rochester number which you posted is not a valid carburetor identification number. It is probably a raised casting number. Should you need to go this route (and the carburetor tag is missing), send me emails (1 picture per email) with the following shots:

(A) a shot of the throttle arm
(B) a shot of the side of the carburetor showing the choke housing
(C) a shot of the bottom of the carburetor with dimensions of the throttle bores
(D) a shot of the accelerator pump with the overall length
(E) a measurement of the inside diameter of the accelerator pump well (inside the carb) taken in the lower third (the non-tapered area) of the well.

Then call during normal business hours.

Jon.

Great. thanks for the help! I'll keep you posted on progress.

volcan96,
I was in the same situation. I wanted to replace the old rochester carb with an Edelbrock 1404. Then I realized for the carb to work right/better/as inteded, etc, that I would have to replace the manifold. So I purchased the Edelbrock 2701 manifold. I took the new manifold in to my local parts store and we plugged all the vacuum and extra temp sensor holes with the correct fittings. Carb bolts right up and looks really nice. The only thing I have to do now put in the correct jets, since I live at 7000 ft. elevation. BTW, the manifold was $129.00 at Autozone.

-anthony

You can make that carb work by sealing those heat rizer holes & useing the right gasket but I would do like AJC says & get a aluminun manifold. If you don,t want to spend the bucks for the aftermarket manifold the factory had aluminum manifolds on early to mid 80s GM cars with 305s. They are cheap in the salvage lots or swap meets.

The factory aluminum manifolds for 305s (Monte Carlo SS for example) are for spreadbore carbs...CCC Quadrajets, in particular. Their secondary openings are too wide for an AFB-type carb (squarebore) and will require an adapter, just as a cast-iron manifold would.

If you DO go to an aluminum manifold, whether it's a GM or aftermarket, I strongly suggest some sort of heat insulator between the carb abd manifold. A wood, composite or phenolic 1/2 inch spacer will work great and makes a world of difference in preventing percolation.

A couple of other things I've run into regarding intake manifolds: if you're going to go with an Edelbrock (which is what many of the FLAPS carry) the Performer (2101) manifold is basically a stock replacement manifold. It flows about the same as a factory 4-barrel intake. The Performer RPM manifold (7101) is more of a performance oriented manifold with decent street performance. If you don't plan to run your motor over 4500 rpm or so, the 2101 manifold is fine.

Let us know how it turns out.

ray,
dont want to hijack this thread, but what are the signs of percolation?
thanks,
-anthony

Quick Update:

I'm trying the spacer approach as suggested by carbking. I tried the first approach he suggested and that almost worked except the holes on the carb are too big for the manifold.

I have a spacer on order from the parts store, but if that doesn't work, I'm rebuilding the dang thing. My "easy" project went to being very difficult, very quickly.

more to come.

are the butterflys being blocked from closing all the way

Folks,

Well, this has been a true PITA. Anyway, I think the best long term route will be to replace the manifold with the 2101 or 2701 as recommended above and then use the 1406 on that.

however, I have an immediate short term need for the truck and need to get it running sooner rather than later. Carbking, I'm PM'ing you some info to get the rebuild kit.

my learnings: For future reference for anyone in a similar spot, the early style rochester 4-jet ported manifolds will not work without fabricating a spacer/adapter for it. contrary to what transdapt and edelbrock say, their adapters will not work. Transdapt recommended 2304 and that was the same thing as the edelbrok 2696. None of the holes line up to the 1406 thus not allowing the butterflies to open fully. On top of that, there is not a good seal to the manifold.

UPDATE
Thanks to the great Carbking, I was able to get the carb identified and then get a rebuild kit for it. His guidance was invaluable and his service was excellent. No way do i get the truck working without him.

After posting some pics on my website, I then sent the accelerator pump off to confirm the ID of the rochester 4 Jet as a 1959-1961 283 carburetor. Check out http://homepage.mac.com/spider/truck/carb/carb.html for pics.

Anyway, I got the rebuild kit a couple of weeks ago after a very quick turnaround from carbking (use his services folks; he's great) and after reading up on the rebuild (thanks to a couple of books from amazon), I did it this past weekend.

The truck started after the 2nd turn of the key and needed no initial adjustment! It idles great, the leaks around the intake manifold are gone as are the nasty fumes inside the cab of the truck. Just as important, the truck has no signs of hesitation it displayed previously and has picked up a lot of power. Amazing.

So, almost 1 year to the day that I bought it, the truck is running great. It has received full tune up, gotten installed an HEI distr on the V8, gotten installed power disk brakes up front, gotten an 700R4 tranny, been rewired electrical while adding saftey feature like turnsignals and backup lights, been rebuilt rear brake cylinders, gotten custom dual exhaust, recieved a rebuilt carb and a bunch of other small things.

It's been a great learning experience.