Odd noises and no power on 651 ford

Sherrmann · Sep 15, 2008

I need some advice. I just fininshed rebuilding a 651. New pistons, sleeves, bearings and had the head redone (new valves seats, spring guides etc.) by a machine shop. It’s all back together and when I got it running there is a definite noise coming from the air cleaner. At low idle you can’t hear it, but at wide open throttle it’s almost as loud as the muffler. In addition there is no power under load. I ran it up a hill in high gear and the rpm’s just drop off. I set the timing with a timing light, right on the factory specs. I retorqued the head and adjusted the vales again. It has a new governor and when under load I can see it pull the carburetor wide open. The noise almost seems like some exhaust gases are coming through the carburetor. I was thinking that the intake manifold may have an internal crack in it allowing the gases to mix, but there is no external crack that I can see or hear. Has anyone ever seen or had this happen to them.
Thanks again, Steve

old · Sep 15, 2008

Sounds like it might be running lean and that will cause one to back fire into the carb. What happens if you choke it does it clear up and give you more power?? If it does open the main jet up some till you have adjusted it to the sweet spot
Hobby farm

Sherrmann · Sep 15, 2008

I'll try that, but I have made all kinds of adjustments to that carb. And it still makes that noise and lacks power.

twopop · Sep 15, 2008

I believe your 651 dist turns clockwise,but, you can check it by removing the dist cap and seeing which way the rotor turns.I think # 2 and 3 are crossed.make sure it is firing 1 2 4 3
it is amazing to me how well a ford will run on only two cylinders

Les Va. · Sep 15, 2008

Could be a lot of things but check to see if you have valve to tight.

glennster · Sep 15, 2008

if putting more fuel to it doesnt help, and your valve lash is good,(not too tight) i would start looking at ignition timing and valve timing after running a compression test. being a fresh motor and not having the rings seated yet, i would expect cylinder pressures to be anywhere from say 90 to 130 psi, all should be within 10-15% of each other. if that checks out, try resetting the timing by "ear", ie give it a little advance till you get a high idle and then back it off a tad, then see if you have a power increase. if so, look to the distributor/timing for a problem. last would be camshaft/valve timing. could be the gear is off a tooth or so. dont run too much advance on the timing, you could start preignition pinging (thats not good).

Odd noises and no power on 651 ford

Sherrmann

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old

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Sherrmann

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twopop

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Les Va.

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glennster

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