I am getting a vacuum gage to inspect my 51 V8, you folks are very kind.
Thank you.
Gw

 

Brian, Did you do what we suggested back in May? It looks like we are plowing over the same old ground again?

https://www.ford-trucks.com/forums/1...l#post17135006

 

I did not. I got it working after some fiddling, but I don't know how well it was seated on the rod. At the time I didn't think it was on there real good, but it was working! If it ain't broke don't fix it. Now it's broke. lol. It may have jumped off the end. I'll let you know, working it this weekend when i can.

I am thinking about an electric though, but I haven't researched if they are available for 6 volt. I do recall that plate you made, nice work! I'd do something similar if i switched to electric. I guess an electric also prevents vapor lock, so probably better all around.

 

firstrider, it's a fuel pump from LMC Truck. I bet they're all the same. Turns out it was off the rod, and the pump is working again.

 

Ok, so got the fuel pump fixed again. Looks like I did a bad job on install last time. The housing was a little loose and the basket was flipped over. This time, I definitely got the basket over the rod and it's tight. Working fine now. If it happens again I'll think about that in-line electric one.

I still have the hesitation, mainly under load. In fact, I thought it was running great until i took it around the block and the hesitation started again.

1. I used timing light to line up marks exactly.
2. I used vacuum gauge to check and set idle screws at max vacuum. It was only about 2 rotations from all the way in, and letting it out further did absolutely nothing. This is about where I had it set originally by ear.
3. Put the line back in the vaccuum advance and took it for a ride. Plugged the wiper vacuum port.

I'm getting 15.5 vacuum at idle, and it's steady. According to the chart above i may have poor rings or "oil" <-- not sure what poor oil means".

When i do a quick throttle, it goes to 2-3 or so and back up to 17, then back to 15.5. I didn't really notice the number it went back up to, but it definitely didn't go to 0 on throttle since I knew to look for that.

I did notice when i turned the distributor counter clockwise it ran a little "faster/better" and had a little better compression. I couldn't go far enough for it to run rough though because the vacuum advance was hitting the thermostat housing. Maybe I need to take distributor shaft out and make one turn and try timing it again?

I have the new power valve (5.5 for my altitude of 6800ft) and 0.049 jets. However, when this started I was at 7.5 and 0.051 and it was running VERY rich on spark plugs (lots of black soot). I haven't checked the spark plugs yet after having it running for 30 minutes working on timing.

The exhaust was not quite as smooth (I think). It was kind of popping a little maybe, but I never put my hand over it before it had this issue so it may be exactly the same.

Thoughts?

 

That's good vacuum for your elevation. You just can't get as much up high.

The way I was taught to set the idle mixture screws is to screw them in slowly until you get a stumble, then back out 1/4 turn.

 

Ok, that's good. Thanks Ross.

Speaking of altitude. I have the pointer on the mark for timing, which is what shop manual and owners manual says. Is that right? Does altitude affect that at all if it is right?

 

It's common around here (at 5300) to add 2 deg advance for altitude (thinner air). It makes a noticeable difference.

 

Van Pelt website says 2 deg BTDC timing for 1949-1951 V8. And Ross says 2 deg advance. I guess that's the same?

 

The "bump" on the crank pulley is at 3 deg., correct for trucks. I'm saying to add another 2 deg.

 

Numbers. Remember I'm at 6800ft altitude. All tests at operating temp.

1. I advanced the timing 2 degrees and it ran a little better, then 4 and it was even better. Should I keep going?
2. 3psi from fuel pump to carb all the time even at WOT
3. 1.5 psi vacuum advance at idle, drops to almost 0 at WOT
4. Possible bad news... 2 cylinders have 75 psi, the others are between 65 and 70.

Again, it was running awesome for a few weeks. And at times it seems to be running ok, until I drive and then it bogs down. I did fix the generator and the first startup after was when issues started. Ive unhooked generator and it does the same thing.

 

Reclock your distributor so it doesn't hit your thermostat housing. Hook up your vacuum gauge as before and advance your distributor until you get the highest vacuum then back off by 1" hg on vacuum gauge. I'm running 8 deg BTDC plus the 3 degrees initial that Ross noted in his previous post. Once again old school method.

 

Those are all good numbers (pressures and vacuum), although the compression numbers are a little low. The chart below shows the "service limits" per Ford.

No, don't keep adding advance. Pete, I'm surprised you aren't getting pinging with that much. You must be running rich.

 

You know, my 51 used to bog out around 40 45 mph. Turned out to be gas tank . I had cleaned that thing to no end with all kinds of carb cleaner and chemicals. Then took it and had it steam cleaned. You would think that would be good. Turns out it still had crap in there that would restrict the flow of gas above high idle. I finally broke down and bought a new tank. Solved the issue.

 

Ross, no pinging with such low compression at this altitude. The other method is to turn distributor until peak RPMs reached. That yields a bit too much advance for me. Got that from Daimler SP250 expert which uses an overhead cam version of the flattie.