Author Topic: 1975 k10, recent motor dropped in, sat, now wont run  (Read 4248 times)

Offline Hillbillydrums

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1975 k10, recent motor dropped in, sat, now wont run
« on: August 20, 2014, 05:15:42 pm »
Hey there. My truck.was running fine, actually just dropped the motor in a few months ago. It's never been running perfect yet, it back fires, and I havent wired up the elec. Choke yet. So I assumed that was carb stuff.
Anyways, we left to go to Hot August Nights with my 72 c10, and I returned to it not firing up. It cranks, and then it seemed like a cylinder or two would fire, but wouldn't start. And then it always smoked a bit out the exhaust. They are at least 15year old mufflers and the truck was parked for those years. But now it smokes a lot when floored and cranking. Then it'll stop smoking, (still cranking) and then it'll go boom and a ton of.smoke comes out. 
Any ideas? Plugs are brand.new, and all I've done to play with it is try my other old distributor.
Thanks in advance.
1972 C10 (Passed down since great granddad bought it new in '72)
1973 K5
1975 K10

Offline Captkaos

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #1 on: August 20, 2014, 08:14:52 pm »
Floored and Cranking, are you holding the gas down while trying to crank it?  By still cranking you mean holding the key to the start position?

Offline bake74

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #2 on: August 20, 2014, 08:27:11 pm »
     Your definition of fine and mine are a little different.  Since you installed it, it has always back fired ?
     Have you gone through the basics yet like timing ?
     Do you have any catalytic converters on the truck ?
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
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  74 k10, 77k10    Tom

Offline thefarmboy21

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #3 on: August 21, 2014, 06:45:14 am »
Are you sure your plug wires aren't crossed, distributor a cylinder off, or have a sloppy timing chain? Is it getting good fuel? Also GOOD fuel, not dirty/watery 87 octane or stale gas?
AMSOIL DEALER # 5583011
86 Chevy K20 Custom Deluxe-Grandpa bought it new 11/20/85
77 Chevy K10 Custom Deluxe-Dad's first truck
69 Chevy C30 flatbed-Grandpa's farm truck
1950 International L-112-Grandpa bought it new, parked in 1963

Offline Hillbillydrums

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #4 on: August 21, 2014, 06:23:49 pm »
Floored and Cranking, are you holding the gas down while trying to crank it?  By still cranking you mean holding the key to the start position?
   Floored- yes, held down. cranking as in holding the start.
1972 C10 (Passed down since great granddad bought it new in '72)
1973 K5
1975 K10

Offline Hillbillydrums

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #5 on: August 21, 2014, 06:28:14 pm »
     Your definition of fine and mine are a little different.  Since you installed it, it has always back fired ?
     Have you gone through the basics yet like timing ?
     Do you have any catalytic converters on the truck ?
I pulled it from another truck. Ran very good in it. All I did was add a edelbrock 600cfm carb from my k5, (carbs good, k5 needs a clutch so its non op)  And I think it has back fired a bit since i got it in. More or less when i play with the carb adjusments. Yes i timed it when it ran. I havent again since i just swapped distributors, but i did that after the problem.      And no cats, Just summit racing headers i had welded up to the existing exhaust. with whatever cheesy mufflers are on there.
1972 C10 (Passed down since great granddad bought it new in '72)
1973 K5
1975 K10

Offline Hillbillydrums

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #6 on: August 21, 2014, 06:31:17 pm »
Are you sure your plug wires aren't crossed, distributor a cylinder off, or have a sloppy timing chain? Is it getting good fuel? Also GOOD fuel, not dirty/watery 87 octane or stale gas?

Plug wires i re did when i swapped distributors. And the distributor couldnt have been off before i touched it anyways, it ran fine, then sat. Didnt change.    And the fuel looks good, not yellow or smelly. It was low (1gal or so), so i added another 5 gals of new 87 to it.
1972 C10 (Passed down since great granddad bought it new in '72)
1973 K5
1975 K10

Offline Captkaos

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #7 on: August 21, 2014, 07:55:37 pm »
Verify your on TDC, verify that the distributor is pointed to #1 plug,
Check for Fuel and Spark.

Offline Hillbillydrums

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Re: 1975 k10, recent motor dropped in, sat, now wont run
« Reply #8 on: September 01, 2014, 11:51:39 pm »
Ended up being ancient mufflers just plugged with like squirrel nesting. Who'd of guesed?
1972 C10 (Passed down since great granddad bought it new in '72)
1973 K5
1975 K10