Quote:
Originally Posted by AZKen
Fire trucks carry 1000 gal H20 @ 8.34= 8340 lbs. Yours may have had a larger tank than that!!! Maybe it's built special with heavy duty frame or something? 20K miles should run strong. Something big does seem to be wrong. Is it winding up OK? while climbing/hauling or is it bogging down? Ebrake stuck on?  Something goofy like that could be happening. Two speed rear end? 5 speed trans? I'm no expert on hauling with big trucks but do you keep it wound to highish RPM using proper gear changes? Could it be you? or are you experienced?
It is made to haul and it should do a good job.
I would absolutely check all brake shoes and parts at each wheel if you have never looked.
Been reading your past posts. BBV6 mentioned 5 deg BTDC, you said 10. I think 5 means 5. If it won't run there, find out why, don't use 10.
Snazzypig questioned your jets, gasket arrangement, vacuum, etc. I think you need a new stock carb. I think you have tinkered it into a mish mosh. Start over, do it right, don't screw with Mother Nature. These motors are not made to customize and tweek around on. They are designed by engineers who perfected it already. It ain't no SBC. Leave the jets alone. Assemble carb carefully, ALL NEW parts, setting level and drop as necessary. You are only 450 ft above sea level unless you are on some big mountain. So that should not be the problem.
I am not slamming you, just cutting to the chase. Hope you understand. Don't want to blog it to death, want to fix it. Making sure you are out of the past box and into brainstorming. You have added many new parts. Double check your work and your points gap. Tune it all TO SPEC, not someone's BS ideas. You can play with timing a little. It's not what it sounds like, it's what it runs like. I think you may have said it "pops" at 5 deg? Make sure that is Before TDC and not after. If it backfires at spec then it's vacuum leak....big time. Even an exhaust leak will do that. Analyze some more and see what you get. Please state if it's a carb backfire (pop) or a tail pipe backfire....at 5 BTDC. We'll get there...me, Snazzy, BBV6, TJ and anyone else who can try. |
Thank you Ken! Reading through that widdled everything down that I've been thinking about.
Let's see... this was a tanker truck so I'm sure it had at least 2000gal tank on it, I would figure. Has the boxed frame with the ladder-work on the inside.
Seems to wind up okay when you are on flat ground, sometimes a little hesitation at first.
Sometimes when winding up going up a hill or pulling a hill, I can keep putting my foot into it and there is no RPM/power change, then when getting close to the floor it will start to pick up some..
Negetory on the E-brake, no problems there.
Yep, 2 speed rear, 5 speed main, and a 3 speed brownie for OD. I keep the rear in HI now that I have the brownie. When pulling hills I keep my foot into it, not over speed the engine but to keep the momentum in order to change gears. If it's flat, 2nd, 3rd, 4th, 5th then OD. Hill or hauling, starting with the Brownie in Direct (2nd)... 2ndD, 3rdD, 3rdOD, 4thD, 5thD, 4thOD, 5thOD. The gap between 3-4 is pretty significant and I have a working 4th.
Front brakes have been done, rears I haven't but they don't drag... should still check 'em.
Sounds good, I'll have to set the timing back to 5 and see what happens.
As for the carb, if I can find another that would be great, if not, I'll have to see about ordering another kit and 2 new jets, because I messed with these ones...
Exhaust pop at 5. And that was before I did manifold gaskets and a few other things this year. Need to check that again.
YES! Less write up and more progress. I have to haul tractors to a show next weekend with it so with any luck I can delve into it before hand and give you-all an update.
Quote:
Originally Posted by TJ's GMC
Jake, did you ever get a chance to put those new intake gaskets on? Lightly buff the surfaces? Also did you reseal the valley pan?
351 power specs are: 180 hp @ 3400 and 312 pound ft @ 1800-2000 gross
351E power specs are: 220 hp @ 4000 and 320 pound ft @ 1600 gross
So not a Ton of power to begin with but plenty of torque to haul that thing at a decent speed. Specs are 4-6 degrees advanced so if you had to add an extra 5 degrees advance just to make it run decently I have to wonder if the timing jumped? The chains on these are not very tight so that could be a possibility. I haven't read of it happening yet, but there's always a first time.
Vacuum leak already mentioned.....check all gaskets and hoses.
When you did the carb rebuild did you check to see if the throttle shafts in the carb were all worn out? Vacuum leak through there will cause backfiring and power loss.
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Yep, that I did TJ. Beginning of the year took care of everything...
Throttle shafts are good and tight.
Timing chain has been on my mind for a while now. I did the whole metal rod in #1 cylinder at TDC thing, distributor was where it should be, of course that might not tell me if the chain is off.