First real drive! Not tragic but not good. I think I need carb advice.

[legopnuematic]

Not necessarily, there are improvements with the later Q-jets that can make them more appealing if one was seeking a core to build for an engine.

External APT adjustment, hot air or electric choke (hot air can be converted easily to electric), I think there was some ‘circuit’ improvements to the later ones. Are the advantages.

Nothing crippling about the earlier carbs though.

 

[Matt69olds]

Rochester continually improved the Q-Jet design right up until it was discontinued.

The “best” cores are from the mid to late 70s. Better quality casting, externally APT, better chokes, and some of the big block cores were rated at 800cfm.

The reason the later cores get a bad reputation is because they unfortunately were calibrated to run on weezing, gasping emissions choked engines. Put the right parts in it so it’s tuned to the engine it will run great.

 

[Chris64]

OK - so as usual, nothing goes as planned.

I managed to get to all the plugs, which was insanely difficult and even more difficult to screw in the compression gauge. They all read about 135. Does that sound right? One read a little lower but I simply couldn't tighten the gauge properly so I'm assuming that's the problem.

Installed all new plugs. Gapped to .035 as suggested (they came .040).

Now the car won't start. I checked the spark. It was fine. The only thing I did other than the plugs and compression test was I did put a hose on the distributor advance and tried just sucking on it to see if anything would happen (I didn't see or hear anything, I probably have to take the cap off).

I'd like to install the new carb but I wanted to check the timing first. I'm trying to limit my changes to one thing at a time. It smells very gassy so it could be flooded. Any suggestions?

 

[Chris64]

Update (not that anyone was asking)...
Fuel seems to be the problem. I removed the fuel line going into the carb (still the quad, also the line was bone dry) and put the line into an empty clear bottle I could see while I was turning it over. Nothing came out.

I couldn't imagine I was out of gas already, but maybe. So I ran down and got 2 more gallons (biggest gas can I have). The gauge went up to a solid 1/4 now. Proceeded to crank it and I did get a few spurts of fuel. Maybe 1 16oz water bottle cap every 3 Mississippi's. Not what I was expecting. Maybe that's normal but seemed really light. I reconnected the fuel line an nothing still.

So I guess I need to investigate the fuel pump. This car will leave no stone unturned on my education.

 

[Grit dog]

16oz in 3 Mississippi’s, not that I’ve ever heard that metric used, lol, converts to about 60gph, at cranking rpm’s of like what, 300rpms?
Thats a lot of fuel. Thats not the problem.

 

[Chris64]

16oz in 3 Mississippi’s, not that I’ve ever heard that metric used, lol, converts to about 60gph, at cranking rpm’s of like what, 300rpms?
Thats a lot of fuel. Thats not the problem.

No

The lid of a small water bottle - like the little thimble amount of fuel. I'm seeing it should generally be 4-6psi but I'm not sure what that looks like in "flow."

 

[Chris64]

According to a random calculator I found online (that I'm probably using wrong), a 3/8 hose at 4psi between 3-6 feet in length would fill about 2.5 gallons per min.

Does that sound right? That sounds like a LOT of fuel.

 

[75gmck25]

AVS2 has a great reputation for excellent driveability. Seems to work better than the old 1406.

Does seem like a flaky fuel pump.

Is it a 3 port fuel pump, with one rubber line in, one rubber line to a fuel return, and a hard line running up to the carburetor? Most of the time the factory hard line has been cut near the valve cover, and a section of rubber line and a filter added up near the carburetor. 3 port pumps with a tank return work better in hot weather because fuel keeps circulating and that cools it down.

Just a heads up that your stock air cleaner probably won’t fit down over the Edelbrock because the fuel line fitting and choke interfere with the base. Edelbrock sells a plastic spacer ring to put on top of the carburetor and give the clearance needed. I think you can also solve the problem with the Edelbrock banjo fitting and dropped fuel line, but I’ve never tried it.

 

[Chris64]

AVS2 has a great reputation for excellent driveability. Seems to work better than the old 1406.

Does seem like a flaky fuel pump.

Is it a 3 port fuel pump, with one rubber line in, one rubber line to a fuel return, and a hard line running up to the carburetor? Most of the time the factory hard line has been cut near the valve cover, and a section of rubber line and a filter added up near the carburetor. 3 port pumps with a tank return work better in hot weather because fuel keeps circulating and that cools it down.

Just a heads up that your stock air cleaner probably won’t fit down over the Edelbrock because the fuel line fitting and choke interfere with the base. Edelbrock sells a plastic spacer ring to put on top of the carburetor and give the clearance needed. I think you can also solve the problem with the Edelbrock banjo fitting and dropped fuel line, but I’ve never tried it.

I believe the pump is a 2 port (I don't see a third).

I'm not sure if it's worth fixing (or fixable) or just replacing - the price range on the parts seem pretty huge. ($30-$200).

I got a new air cleaner just because the stock one looks a little beat and the filter, while clean, is old and needed replacing anyway. I figured I can slowly work on restoring the old carb and air cleaner off the car if I have something functional installed.

 

[Grit dog]

According to a random calculator I found online (that I'm probably using wrong), a 3/8 hose at 4psi between 3-6 feet in length would fill about 2.5 gallons per min.

Does that sound right? That sounds like a LOT of fuel.

That sounds about right, ish. If it’s only filling a water bottle cap in 3 seconds, either the fuel pump is shot or the suction line or filter sock in the tank ain’t letting fuel through.
Sorry thought you meant it was filling the whole bottle in say 5 seconds or less. You’re not pushing enough gas to the carb imo.
Been a long time since I redneck tested a mechanical fuel pump, but guessing it should spit out a couple ounces every cam rotation (1/2 the engine crankshaft rpm’s of course).

 

[Grit dog]

You can always diagnose the fuel pump output vs any blockage from the tank by connecting the pump inlet to a hose in a gas can and see if it makes more fuel like that. If it’s a lot more then it’s something back upstream like the fuel filter sock on the fuel pickup in the tank.
If it’s the same ish then it’s the pump (hopefully not a wiped cam lobe).

 

[Chris64]

You can always diagnose the fuel pump output vs any blockage from the tank by connecting the pump inlet to a hose in a gas can and see if it makes more fuel like that. If it’s a lot more then it’s something back upstream like the fuel filter sock on the fuel pickup in the tank.
If it’s the same ish then it’s the pump (hopefully not a wiped cam lobe).

I just picked up a new pump - so I have no doubt it will be the fuel sock on the pickup! I can't even imagine what that will take to fix - remove the bed? fun.

I will ignore the lobe comment entirely.

 

[75gmck25]

Two port fuel pump works fine, but might be a little more prone to vapor lock in really hot weather.

If you haven't replaced a fuel pump before, check out a few sites that explain how to hold the rod up while you insert the pump lever. Car sites will mention that some SBC blocks have a bolt you can tighten down to fix the rod in place, but it's never been on any block I've had. I usually use an old hacksaw blade bent at about 60 degrees because it's thin enough to hold the rod up and still have enough space to insert the pump arm into the cavity and under the rod end.

Dropping the tank is not really that hard if it's relatively empty (I've done it about 4 times for various reasons). However, once you get it unbolted it will not drop down very far before the fuel lines then hold it up. Plan to set it on something at that point so that you can remove the clamps on the sending unit. I usually use a wide board (2x8, etc.) and scissors jack under it. Also, don't forget to unscrew the fuel filler metal end from the bed, so it will also drop down with the tank.

If you do drop the tank, that will be the time to buy ethanol resistant fuel line to replace the old rubber line. Rubber deteriorates inside from the ethanol and chunks will block the line or it may leak. SAE J30R7 (50 psi) or SAE J30R9 (100 psi) EFI fuel line is a good choice to replace the old fuel line. I bought mine on Amazon because the by-the-foot price locally was really high.

 

[Chris64]

Good tips. I did watch videos on that holder bolt thing - which I think I do have. Which is of course behind the hard fuel line.

Before I even tried to find TDC, I unplugged the hose going into the fuel pump. It appears to be higher than my current gas level and nothing came out.

Since this had me a little curious I tried using the brake bleeding vacuum tool to pull gas out of the gas line but it wouldn't. I was thinking of the fuel filter, but I couldn't even get a vacuum at all. The vacuum had a little tapered tip that seemed to fit the gas line well.

I'm wondering if the fuel line has an air leak. I don't know. That's as far as I could get before dark.

You must be registered for see images attach

 

[Grit dog]

If you got a seal and pulled decent vacuum and it didn’t pull fuel then it’s plugged. If you got a good seal and didn’t pull vacuum then there’s an air leak. Although I’ve heard that 100 times but have never had it happen without also a fuel leak especially since it’s pulling a little fuel.