A few questions

[Jesse 67 c-10]

1. I've been driving my truck to university every one in a while lately and I'm noticing that it will bog down quite a bit before it gets going when you step on it. goes good once it gets going but its hard to drive at low rpms. above 2500 it's ok. All new stuff, carb ignition. I have to run regular gas, (bulk farm tank) any tips on setting up my advance curves to improve this without causing pinging etc.? was running a bit better before. Another thing, my idle speed seems to change regularly, sometimes it doesn't want to go below 1100 and others its just running at 500, was thinking sticking advance? springs? new accel dist but who knows? probably related to above problem too. also accompanied by only bad gas milage, well that could be me too!

2. my truck has recently developed an annoying buzz under acceleration seems to be coming from about where the dome light is but holding it still doesn't stop the sound, any ideas or experience? things that could be causing this? seems to kind of resonate up in the cab

3. when I go around a corner, it sounds like there is something that slides from side to side in my fuel tank. fuel guage still works. Sounds like it goes from one side right to the other. nothing under my seat, something come disconnected?

4. recently noticed slight oil leak around pinion on rear end. not nearly a drip but wondering, can I change the pinion seal without having to re-set the gears? or am I going to be looking at a re-build in a bit anyways if this is leaking?

Probably simple solutions, I hope, any tips, personal experience or ideas would be greatly appreciated! Thanks for any help!
Jesse

[67shortie]

I will give it a shot.
1. Could be a choke problem. If the engine is bogging down and the idle varies that much, the first place I would be is the choke for a mis-adjusted curb idle screw or/and a electric pod if your carb is an electric choke setup. If the electric pod is out of whack, the choke plate at the top of the carb will close off partial incoming air that the engine needs. OR you have a big vacuum leak. Recheck everything you did, and make sure you hooked up all hoses and used new gaskets. And you should have a vacuum advance unit on the side of the distributor, check to make sure the line is correctly hooked up. One side will go into the fitting on the pod, and the other will attatch to the carb either on the side or on the bottom near the idle adjustment screws. And you said you have a new distributor? You sure the timing is set right? Backed off timing will do some of the things you desribe, recheck it and set it at 6-8 degrees advanced.

2. Resonation in the cab will rattle allot of things, don't know.

3.Not sure, maybe you or someone dropped something in the tank?

4.Pinion seal is a toughy. You CAN replace this, but if you are rebuilding the rear soon, I would wait. But if you are not doing that soon, pulling the pinion nut off of the pinion requires carefull attention on re-assembley. What you are doing is releasing the bearing and crush sleeve preload, this controls the pinion depth, bearing pre load and effects the backlash settings on the ring and pinion. I have seen and heard people peening or carefully marking the pinion and nut where they started from and opon reassembley put it back in the SAME thread and position, no exceptions. A pro would be better suited for this job I am afraid to say.
Hope this helps, and someone else I am sure will pop on in here and suggest more that I missed

[mikep]

Ditto on that last point. There is nothing more important to a rear end than the pinion depth and if you release the tension on that crush sleeve or compress it more than it had been before you are asking for a rear end full of sludge. I'd say unless you are absolutely driven crazy by the drip to leave it alone unless you want to do an overhaul. If you do want to do an overhaul it just takes some careful measuring of the existing pinion depth and a new crush sleeve and seal kit. I could walk you through it.

[Jesse 67 c-10]

Thanks for the help, I'll definatly check out the choke, I kind of have a feeling it is something ignition though. I'd like to set the timing with a vacume guage as I'm pretty sure that my balancer is a newer style, with the mark straight up at tdc, and my timing tab is a mr gasket bolt on for older motors. balancer is in good shape, shouldn't have slipped, anyone know a good way to find exact tdc so I could put a mark on my balancer @ 0 or some timing tape? or anyone know the proper way to set it with a vacume guage? other things, I have the advance hooked to full manifold vac, I might adjust on that too, accel adjustable adv. with regular gas I should probably use the heavier advance springs in the mechanical adv right?

Ya I'll just forget about that pinion seal I guess, don't want to go through all that till I have to.
Thanks!
Jesse

[Lippyp]

1. can't help you

2. Bee's nesting in your headliner for the winter? LOL!

3. I wouldn't have thought you'd hear anything move in the gas tank as the fuel would cushion whatever it was and quieten it down. It's more likely just to be something rolling around the floor possibly behind or under the tank, irritating and can be a pain to find, you may have to yank the seats and carpet out, may be a stupid suggestion but have you made sure you have nothing rolling around in the front of the bed that you could be hearing through the cab. Otherwise turn the stereo up!

4. Can't help you

[chewed 71'er]

Just to comment on something 'shifting' in the fuel tank when cornering. My 71 C10 does the same thing, but only when tank is 3/4 to full. Sounds like a heavy 'thud'. Makes me wonder if there's a loose baffle inside, don't know construction of fuel tank. Gas gauge works fine at all times. Nothing rolling under the seat, fuel tank is secure to frame. Strange.

[68ChevC10]

Can't help on the others, but on the first question, My 68 was doing the same thing. It was a combination of an old distributor, a vacuum leak and a stuck choke.

Took my a while to find everything that was wrong, but it was simple to fix. I still have to put a new choke cable so I can get better control of it, but the Beast loves her new distributor. My points weren't firing right due to the ramps (I think that's the term) being worn. The advance was an unknown number of years old, too and wasn't working properly.

Hope it helps.

68ChevC10

[Jesse 67 c-10]

I'll definatly check all those possibilities, thanks for the tips! My dist is a new accel hei but I'm still going to check the advance out, I'll probably pull the plugs to check things out too, and I'll wash my truck and polish the bumper and clean out the interior, maybe I'll change the oil in the rear end and tranny to, a little extra tlc should help right? no if only I can find time for this, midterms are coming up right away!
Thanks
Jesse