Carb

[Gypcmechanic]

Need some advice on running. I was driving my truck today after installation of new heads fuel pump radiator. After driving for awhile, it started pinging if I tried to accelerate past 60. Didn't matter if it was fast or slow. I had the timing set at about 10 degrees. I backed it off to six took it out and it had no power as I accelerated up a hill. I stopped to adjust the time and noticed the paint around the exhaust ports was discolored. It also stumbles if you really get in the gas going thru the gears. It also backfires thru the carb while accelerating under a load and the water temp increases. I'm thinking the carb is too lean or maybe not the correct one. I'm thinking of buying a new one. Also the whole ignition is brand new. It also idles great and around town it is fine

 

[DNFXDLI]

What do the plugs look like?

 

[Gypcmechanic]

They look good almost too good. They are very clean. Again another sign of a lean mixture

 

[Gypcmechanic]

There is no brown or gray on them

 

[Gypcmechanic]

What plugs should it have? I believe they are auto lite 45

 

[DNFXDLI]

You've probably said it in another post...but what engine?

 

[Gypcmechanic]

360 with rebuilt 390 heads

 

[Gypcmechanic]

I'm really leaning to carb especially after the backfiring. The power valve is probably shot.

 

[DNFXDLI]

Plugs sound right.

 

[Gypcmechanic]

Also just to make sure it's right, I have the advance plugged into the RH side of the carb and the retard plugged into the tee in the #4 I take runner. Any help is appreciated. I don't want to fry the damn thing after all this work plus I need it for a road trip in a couple of weeks.

 

[DNFXDLI]

I might be way off here, but doesn't the retard need some kind of a vacuum valve?

 

[blacksnapon]

I might be way off here, but doesn't the retard need some kind of a vacuum valve?

Dennis????????????????????

 

[DNFXDLI]

Dennis????????????????????

What??

lol

 

[Gypcmechanic]

Valve? Like an orifice? I'm not familiar with fords at all this is my first. It was a basket case when I got it. Also the egr valve was removed. There is a temperature actuated valve in the front of the manifold but nothing is hooked to it. It's a dog at 6 degrees so I have the initial timing set at 12.

 

[Gypcmechanic]

I ran it without the retard hooked up as well. Also I found some junk in the fuel pump when I changed it because it had sat for over a year. I put a filter in before the pump. I wonder if it has crap in it. I ran it before I found the bad pump. I really want it fixed. Other than the running issue, the engine runs so quietly good oil pressure etc. I spent a lot of time fixing everything else.

 

[Gypcmechanic]

You know up until today I had 100 octane AVgas in it. I put 10 gallons of 85 octane in today but it was still hesitating and the carb had a couple of flat spots with the AVgas.

 

[DNFXDLI]

That could be part of your problem...the 360 was quite low compression and using too high of an octane will result in less power.
There is a misunderstanding that using a higher octane fuel than required will result in more power...the fuel burns slower and unless you have the compression ratio to use that higher octane you can lose power and driveabilty.

 

[Gypcmechanic]

Yes and no. Lower octane fuel has more BTU's but you lose power due to detonation. It ran good with the 100 it's the 85 that's part of the issue now. I think it has the wrong carb on it. It has been wired for an electric choke. This year should have a hot air only. The Venturi size it different between a 302 and a 360/390. I'm going to order a new one tomorrow. It was so lean at low timing levels it was torching the paint of of the heads. I think it may have been the issue when I bought it. The number 8 exhaust valve was almost burnt off.

 

[Gypcmechanic]

It also doesn't help that I live at 4000 feet

 

[DNFXDLI]

That altitude isn't too bad. On the octane...yes, but with the low cr, you shouldn't have detonation unless your timing is too far advanced.
I don't see how it could have run better with the 100.