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Old 01-09-2012, 09:17 PM   #1
brewerracing
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no low end. can't advance timing enough?

Thanks ya'll. I have a 79 custom deluxe, 350 w Th350. 2wd..think its stock other than being lowered. For reasons i believe to be the distributer. She's got no low end power whatsoever. I assumed the problem to be the timing.. Upon turning the dizzy and playing with the timing, thy more I advanced it the better it worked. But Still no low end. Now I cannot advance it anymore as the vacume advance is hitting intake. Could the weights and springs throw my timing off that much at low rpm? I believe the vac advance is good as I just changed it to see no difference at all. So now I'm left with a beautiful truck that my horse could take off the line. I'm going insane trying to figure it out and am about to park it and start building snowshoes for my horse!
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Old 01-09-2012, 09:23 PM   #2
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Re: no low end. can't advance timing enough?

Quote:
Originally Posted by brewerracing View Post
Now I cannot advance it anymore as the vacume advance is hitting intake.
It's easy to fix that. You can either rotate the plug wires around the distributor or go to the trouble to remove it and put it back in another position. But I doubt that's your problem.

Quote:
Could the weights and springs throw my timing off that much at low rpm?
It would take some *seriously* weak springs to have centrifugal timing advanced at idle. Besides, if that was the case you'd have TOO MUCH timing, but you're complaining about not enough.

Quote:
I believe the vac advance is good as I just changed it to see no difference at all.
Does the vacuum advance work or not? It should be easy to tell using a Mity-Vac or even just sucking on the vacuum tube with your mouth. If the linkage moves then you know it works. If you use a Mity-Vac you can tell exactly when it comes on. Assuming it's working it should be very easy to tell. Unplug the vacuum advance and the idle should drop - plug it in and the idle will go up (only if using manifold vacuum. Ported vacuum doesn't work at idle so there will be no change).

Have you actually set the timing with a timing light, or are you just twisting around the distributor and going by ear? You really need to properly time the thing, checking your initial and total timing and checking a few different points to get an idea of your advance curve. Just changing stuff without any reference point isn't going to make things better.
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Old 01-09-2012, 10:13 PM   #3
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Re: no low end. can't advance timing enough?

x2, unless your using a light and confirmed TDC, your shooting in the dark. FWIW, my 350 in my K-20 liked about 14 deg., any more, the starter started to "backlash".
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Old 01-09-2012, 11:15 PM   #4
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Re: no low end. can't advance timing enough?

x3, it sounds like you've got some other issue going on. If I was to take a guess, I'd say a vacuum leak.
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Old 01-09-2012, 11:26 PM   #5
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Re: no low end. can't advance timing enough?

If you have 273 gears it will kill low end. But it sounds like you have no acceleration set your initial timing with no vac advance at 10* btdc and when you plug in the vac advance it should idle up and be in 20*+ make sure the distributor is clocked proper. The vac advance should be pointing at cyl 4 abouts. Check and make sure your advance wights aren't stuck of have a crappy aftermarket advance kit. Those kits are only good for the springs
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Old 01-09-2012, 11:50 PM   #6
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Re: no low end. can't advance timing enough?

make sure they can move
mine were seized up tight
and the vac advance had almost rusted together ina spot(arrow)
I'm figuring this is the stock 305 one ,stuck back in the 350 soon to be replaced.....
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Old 01-10-2012, 03:28 PM   #7
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Re: no low end. can't advance timing enough?

I have nor used a timing light. I spend just about 24/7 on the ranch and don't get into the city much.. I figured something was off when I can crank the dizzy as far as it will advance and have her work better but not near par. My weights and springs are rusty but move freely. Vac advance is working properly. When I set timing to the where abouts it was when I got truck(truck was sitting for about a year) it will idle and lopes quite a lot. But no get up off the line.
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Old 01-11-2012, 12:33 AM   #8
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Re: no low end. can't advance timing enough?

Just took her to the store to pick up some chew, started fine. Idled fine.. Got to the main drag and she starting sputtering and stalled. Figured I was out of gas so I dumped some in tank and little in carb. Got her fired up and she's missing or spitting very bad. Made it to store barely. Stalled and coasted in haha. And no way would she start. Tryed everything till battery went dead. Thankfully a feller stoped and gave me a boost, after about 30 min. And she wirled a while but started and idled. Got on the road and the sputtering started. Limped her home. Popped hood and pass side manifold glowing red. WTF is going on?
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Old 01-11-2012, 11:11 PM   #9
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Re: no low end. can't advance timing enough?

do you have a working heat riser valve?
sticking it would do all that
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Old 01-11-2012, 11:20 PM   #10
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Re: no low end. can't advance timing enough?

Drastically out of time could do that. Like Motornut said check that the valve on your exaust is all the way open. Check your coolant of course.
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Old 01-12-2012, 10:29 AM   #11
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Re: no low end. can't advance timing enough?

Heat riser valve is the rusty pain in my a.. That's between manifold and exhaust? If that's the case its not there anyway.
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Old 01-12-2012, 02:56 PM   #12
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Re: no low end. can't advance timing enough?

is this when it's "cold"
what kind of choke do you have is it working ok?
wondering if it's pulling off ok
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Old 01-12-2012, 03:12 PM   #13
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Re: no low end. can't advance timing enough?

Warm and cold, same story. Choke is working fine. Stock quadrajet fresh rebuilt. If I pull dizzy and advance a tooth or two how many degrees will this be?
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Old 01-12-2012, 03:25 PM   #14
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Re: no low end. can't advance timing enough?

egr valve ok? hooked up
how bout stock air cleaner and it's sensors all ok?
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Old 01-12-2012, 03:48 PM   #15
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Re: no low end. can't advance timing enough?

egr removed and has a plate blocking spot on manifold. Some chrome holley filter. What other sensors should I check and how to check?
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Old 01-12-2012, 04:30 PM   #16
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Re: no low end. can't advance timing enough?

i was wondering about the snorkel dampener working
there is a sensor in the snorkel,
you can throw a cold wet rag over to see if the dampener opens ok

but dosn't sound like you got that

may wana check fuel filter/and line....
remove the line from the pump to the carb,drain and clean it out
change filter ,maybe pump too....
pump/lines you can check if you have a vac gauge
checking the gas line for leaks.....do you smell gas at all?
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Old 01-12-2012, 09:05 PM   #17
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Re: no low end. can't advance timing enough?

No gas smell. Other than when she decides not to start, so I don't think there's a fuel issue. I've sprayed every little spot possible to look for vacume leaks to no avail. When I got her home the plug wires were a mess, and not in right order so I think someones been playing with dizzy for whatever reason. Also came with another distributer, stock by the looks but is cleaner than current one. Ill try swapping them
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Old 01-12-2012, 10:33 PM   #18
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Re: no low end. can't advance timing enough?

that was the next question
if the dizzy had been out....then check TDC
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