Just want to run this by you all. I bought a 79 f-150 with 351 C.
I went to pick it up and it started fine (really quick, barely turned over and was running) we idled it for a while and shut it off after it was warmed up. We went to start it again and it kept back firing into carb. After messing with it we backed dist off 1 tooth. It started up just fine ran well. The guy I bought it from has been working on it beacuse he went to start it up and it was doing the same thing. I'm not sure what he may have done but he started it up and was going to test drive it and it stalled out and backfired through the carb again. Could there be a timing problem, there are new timing gears and chain in it already.
He told me that he set the #1 to TDC on Exaust stroke isn't it supposed to be on compression stroke?
If it was 180deg out I doubt it would run fine for a bit and then start backfiring, it'd be doing it all the time. What happens if the motor is left to cool before being started?
If I remember correctly it starts fine when cold. (Truck is 100 miles from here)
So I agree about the 180 out. Only reason I mentioned it is because he said he set it to exaust stroke not compression stroke.
Could it be cracked dist cap or rotor problem?
When we worked on it a few weels ago we did have to take out dist and move it back 1 tooth then it ran fine.
Is it possibly a vaccum problem; does it even have vaccum advance?
Just an update...
The engine doesnt start at all. cold nor hot.
The timing seems to be off because he said that it pops and wants to fire but just wont; it fires back thru carb ect.
Sounds like it could in fact be out 180 now that I know its not running at all.
Just an update...
The engine doesnt start at all. cold nor hot.
The timing seems to be off because he said that it pops and wants to fire but just wont; it fires back thru carb ect.
Sounds like it could in fact be out 180 now that I know its not running at all.
Sounds like it's time to start from scratch , and make sure the leads are added in the correct rotation.
As suggested, start over. Someone may have installed the timing chain and gears out of time. FYI firing order 1975 and later 351- 1-3-7-2-6-5-4-8
dist. rotation-counterclockwise.
I talked to the previous owner today and he said that he could not find timing marks, and that he set #1 pist at TDC on exhaust stroke not compression. It is in fact 180 deg off. It ran really well a couple weeks ago (after new timing chain and gears were installed) The dist. is original to the engine. The dist was reinstalled too advanced and he has been trying to adjust it and had lost the timing by mistake. We are changing dist cap and rotor because it has been acting like there could be a moisture problem inside cap as well. No doubt could it use a bit of a tune up anyway.
I had a similar problem on a 302 a couple of years ago and the symptoms are the same. Turned out it was 180 deg off too. I finally got the help of my father in law to feel for the compression stroke, and it has run well ever since so I'm hoping for a similar outcome......
i'm not buying the whole deal. if it was 180 out, it'd be coughing, farting, gulping and throwing fireballs out the carb all at once, and it definately would not start and run. changing the distributor 1 tooth will not fix 180 out.
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