352 problem
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Freshman User
Joined: Jun 2007
Posts: 33
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352 problem
I got a 67 F-100 with a 352, It pops and spits out of the carb, when it runs its only for a few seconds and its only at like 300 rpms. Timing is right, new carb, new points and two known good distributors. The only thing I didn't check is the timing chain backlash. The push rods don't look bent but I haven't taken them out to roll them. I don't know what to do next. Ive redone the timing a ton of times even though I know its right. The truck started and ran fine after I bought it last October. I put all the new stuff on it and fixed the exhaust gasket leaks. It ran good for a bit, after the work there was a flat spot off idle and hesitation with backfire/flame that got worse. It went all to hell after a few times around the block (less than 5 miles).I was thinking maybe it was the carb, but I don't know. Its a brand new Holley 1850, What about if the gas is bad, crap in the fuel tank/clogged fuel filter, would any of those cause this? The carb is getting fuel I checked. Any help would be appreciated
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
You need to check TDC and make sure the pointer on the damper is correct. It sounds like the either the timing chain has jumps, which throws off valve timing or the damper had slipped making your timing all wrong.
Thread Starter
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Freshman User
Joined: Jun 2007
Posts: 33
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Well I finally got the truck running a little bit better, I cant get it to idle for very long though. It runs if I keep the idle above 1200 or so rpms, it kind of misses and sputters slightly during this. When I let up off the gas the engine idles good for about 10 seconds and then dies. Turning the distributor has no effect. I took the distributor off my other truck that has Pertronix and its the same. It has a brand new Holley 4160 on it but we had the timing screwed up after it was installed and it backfired real bad a few times through the carb. Would this screw this up? I checked for vacuum leaks, and the carb is one of those "no adjustments needed". I was thinking maybe the gas was bad because its about 9 months old, there is very little sediment in the fuel filter canister. Any suggestions would be appreciated
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
Well I finally got the truck running a little bit better, I cant get it to idle for very long though. It runs if I keep the idle above 1200 or so rpms, it kind of misses and sputters slightly during this. When I let up off the gas the engine idles good for about 10 seconds and then dies. Turning the distributor has no effect. I took the distributor off my other truck that has Pertronix and its the same. It has a brand new Holley 4160 on it but we had the timing screwed up after it was installed and it backfired real bad a few times through the carb. Would this screw this up? I checked for vacuum leaks, and the carb is one of those "no adjustments needed". I was thinking maybe the gas was bad because its about 9 months old, there is very little sediment in the fuel filter canister. Any suggestions would be appreciated
Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
Just replace the power valve first. They aren't that expensive and it takes special test gear to properly test them.
Senior User
Joined: Feb 2006
Posts: 355
Likes: 1
Sounds like classic timing chain/nylon sprocket failure. They usually skip a tooth on startup after running fine. Then they go "fwop" through the carb when runnning.....and don't run worth a poop from then on. Make sure to discard the split washer behind the top sprocket - it'll be built into the replacement part.
