1970 Carburetor removal & installation help

[Joe W.]

[James G.]

Re: 1970 Carburetor removal & installation help

Joe, I would suggest that you get a service manual for your car if you don,t already have one . Torque specs and procedures are all listed in there. I have replaced many carbs over the years , it is a fairly simple job. Taking the time to set up the new one is critical so be patient when making adjustments. Hope this helps, good luck!

[Patrick H.]

Re: 1970 Carburetor removal & installation help

Joe,

First of all, do not even think of installing that filter. It is not correct for your car. You need a paper filter with a spring behind it like this one (though I think yours will be a bit shorter):



The date code is 1957 or the 195th day of a year ending in 7 (77, 87).

To remove and install you will need not only the flare wrenches but also a very large open end wrench or adjustable wrench to hold onto the fitting that goes into the carb (the one next to the incorrect filter in your first pic). The flare wrench will only work for the fuel line's own fitting.

To remove, use the large wrench on the large fitting, and then loosen the fuel line using the flare wrench. Once that is loose you can remove the 2 long bolts and 2 others that hold the carb down as well as the other attachments.

To install, before you attach anything to the carb (and assuming you've installed the correct paper filter and spring) install the large fitting into the carb "as hand tight as possible" and then thread the fuel line into the large fitting. There are times when the carb and the fuel line don't quite line up, and if you don't connect them ahead of time you'll be sorry.

Do not overtighten the large fitting where it goes into the carb. If you mess up those thin threads, you'll be sorry.

Hold onto the large wrench very tightly and be sure the carb is tightened to the intake before any final tightening of the fuel line.

Getting it dialed in is a whole 'nother article...

Patrick

[Clem Z.]

Re: 1970 Carburetor removal & installation help

in your throttle side picture there is a problem,the accelerator pump shaft is not extended upward to touch the pump arm. this could because the pump plunger is stuck or the re builder forgot to install the return spring under the pump plunger

[Patrick H.]

Re: 1970 Carburetor removal & installation help

in your throttle side picture there is a problem,the accelerator pump shaft is not extended upward to touch the pump arm. this could because the pump plunger is stuck or the re builder forgot to install the return spring under the pump plunger

Good catch, Clem.
Also looks like he used the Eastwood fake carb paint on it?

Also missing the stud to attach the throttle cable.

[Stuart F.]

Re: 1970 Carburetor removal & installation help

Yes, that carb is definetely painted, and not too well either I might add. In general, I'm sorry to say, from the carbs appearance I'd hesitate to install it on any car of mine. Sorry, hate me for it if you will, but I would want to have it checked over completely first by a good carb man - assuming as you say you don't know much about it yourself. There are a lot of things that just don't look right. The exterior condition may well indicate what the inside looks like.

You have good advice on the filter installation, but just remember with any type filter you want the open end to face the incoming fuel flow (same as the bronze filter you show in your photo). Beyond that, make sure you have all the vacuum hoses connected right. There are not too many on a 70 so it is pretty straight forward. You didn't say if you have automatic transmission or manual, but with automatics you have a procedure you must follow to get the cable linkage set right. I recall on a 72, there was a plastic type linkage clip that you released, then with linkage connected, you opened the throttle full and snapped the clip closed. Better check a service manual about yours.

As for the idle mixture screws, probably dry set out 1-1/2 turns each then adjust (with the engine running and a vacuum gauge connected to a manifold vacuum source) for highest vaccum reading (turn in to lean CW until gauge needle starts to drop then back out until it is steady).

You really need a Service Manual to refer to. It's not rocket science. Most of us are self taught backyardagains anyway and we've all made mistakes in the process. Trick is to make SMALL and correctible mistakes.

Stu Fox

[Terry M.]

Re: 1970 Carburetor removal & installation help

Stew,
The cable linkage you are referring to is for a TH350. 1968-1972 Corvettes have a TH400, which doesn't use a cable. It has an electrically actuated passing gear. The switch is on the accelerator linkage, inside the cabin. Ordinarily one can change the carburetor without affecting this switch.

[Stuart F.]

Re: 1970 Carburetor removal & installation help

Thanks for the clarification Terry. I wouldn't want to be responsible for messing up Joe's mind anymore than I have already, I guess. I even learned something about C-3's this way. I just assumed all small blocks had the TH350 and the TH400 was for the big blocks.

Stu Fox

[Terry M.]

Re: 1970 Carburetor removal & installation help

Stu,
You are thinking the original A-body -- Chevelle, Cutlass, and so on. That is the way those cars were. I think full size Chevrolet were that way too. Proibably some other model lines too. Corvettes were/are different.

[Stuart F.]

Re: 1970 Carburetor removal & installation help

Terry;

You are probably so right. I just have trouble associating any Corvette with an automatic transmission, and my last "fun" Chevy w/ a N.S. V8 was a 72 SS Nova. Even at that, I foolishly bought an automatic as I thought my wife would drive it, Ha!

At any rate, I hope Joe has an idea on how to proceed with has carb change. I recommend he jump right in there and learn the process as so many of us have done. You don't have to be a "Duke", "Joel", or "Michael" automotive expert (oh yes, John H. and many others on the board) to tackle this accessory stuff. Use basic good ol American Common Sense and read a little. You'll do fine.

Stu Fox

[Clem Z.]

Re: 1970 Carburetor removal & installation help

the thing that concerns me is that it looks like a "spay can" rebuild

[Joe W.]

Re: 1970 Carburetor removal & installation help

Gentlemen,
Thank you for the input.
I realize the spray job done by the re-builder was a last minute deal.
He offered to do it and I said ok, so it's my own fault. Obviously,
I have not looked at a lot of carburetors and really didn't know
if it looked as bad as you all think it looks like.

I know his intentions were good.
In terms of the re-build, I'm going to give him the benefit of the doubt.
Other than the fuel filter, does the carburetor have all of it's external parts?

Thanks.

Joe

[Stuart F.]

Re: 1970 Carburetor removal & installation help

Joe;

I believe it was Patrick that interpreted your date code as a 195th day of either 1977 or 1987. If your Vette is a 1970, perhaps you have a replacement carb anyway, right? Also, the main point that was noted about the accelerator pump lever not engaging the pump plunger end is very important. This should be clarified before you attempt to put it on your car. Check with your rebuilder as it may require that it be opened up again if he left out the return spring.

As far as the linkages go, look at what you now have on your engine; you may have to transfer the throttle linkage connector from the arm on the other carb to yours. Also, make sure all the vacuum ports are available for hose connections. Some look like they are plugged and they may need to be open on your application. The loose linkage rod on the right (passenger) side should connect to the divorced choke. Make sure that is still on your intake manifold and is available (correct).

Stu Fox

[Patrick H.]

Re: 1970 Carburetor removal & installation help

As far as the linkages go, look at what you now have on your engine; you may have to transfer the throttle linkage connector from the arm on the other carb to yours.

Stu Fox

I'm pretty sure that the carb he has now arrived at his house with the linkage connector already in place.

[Joe W.]

Re: 1970 Carburetor removal & installation help

Hello,
After your input as to the parts missing on my rebuilt carburetor and
after looking at the loaner (current) setup on my car I noticed that I own
the throttle bracket, return spring and accelerator linkage - it was taken off
my other carburetor setup. So all I need is the spring for the fuel filter.

Does anyone have an extra one they would like to sell?

Thanks.

Joe