Plugs are fouling

[Ratbird]

OH!
One more thing. Can anyone tell me why having your "all in" timing start around 2500-2800 rpms improves performance? What is so bad about having it come in at 3500 rpm? Does it improve throttle response maybe?

Sorry again for my lack of knowledge and dumb questions.

Dave J

[cjshaker]

Having the most advance that you can get away with will give the ignited fuel mixture more time to expand before the piston travels over top-dead-center and starts on the downward power stroke. That in turn produces more push (or pressure) on the pistons downstroke, which produces the most power to the crankshaft and wheels. The result of more pressure/power on the piston is more horsepower and torque. So yes, throttle response is greatly increased due to the increased pressure, or power being produced. I hope that's clear enough to understand.

So it's a fine balance between getting the most power and not going too far on advance where the expanding combustion pressure is pushing back down on the piston BEFORE it gets to TDC and starts on the power stroke. Then you will lose power FAST as the piston is trying to push the crankshaft backwards against the other cylinders.

Generally, FE engines will handle "all in" at 3000rpm just fine, so you are producing the most power you can from 3000 on up to max rpms. Some engines can handle it a little earlier, some not so much. It depends on many factors (compression, heads, temp, rear gear, weight, altitude etc), but 3000 is considered the acceptable area of "all in". The only way to know where the limit is is to play with it and see what the engine can handle, but once maximum advance is determined and a loss of power occurs it needs to be backed off immediately. It doesn't take long to damage rod bearings because the extreme pressure will overcome the capacity of the oil to cushion the bearing and start to destroy it.....if it doesn't knock a hole in the piston, or try to push the piston through the side of the cylinder wall.

IMO, 2500 is pushing it. It's best to start at 3000 and go from there unless you have considerable experience with a particular combo. Aluminum heads and modern combustion chambers can also handle earlier timing....and less total, to make full power. So you can see, there are no hard set rules. Start at a generally safe level and see what the engine wants and can handle. And always err on the side of caution.

[428GT500]

When I installed the igniter II, Pertronix said that you should always install their coil. I bought both.

[Ratbird]

Thx gents. Yeah, I bought the ignitor back when I had the original 390 in the car. I only just bought the 40K flame thrower coil that goes with it - should help, definitely won't hurt.

I understand what you're saying about advance Doug. And that you don't want it to spark too soon as to push the piston backwards. What I don't really get is why you want the "all in" (38 degrees by timing light) to happen at 2500 rpm instead of gradually building up to "all in" at say 3500-4000. My "all in" wasn't happening until ~4000 rpm. So I pulled one of the distributor springs (there is one thicker one and one thinner one) and I stretched it just a little so it would come in a little sooner. Now it comes all in at around 3300 rpms. How does having the spark earlier supposed to help?  At some point in the lowest rpm range the early spark will do like you said and happen too soon and try to blow the piston backwards. It seems to me that you would want the earlier spark to advance gradually up through the RPM range. Does that make sense? (I don't convey in writing just exactly what I'm trying say.)

What's concerning to me is that since stretching the spring and getting "all in" to happen at around 3300 rpm I feel a vibration in the motor! That can't be good. Should I go back to say all in at around 4000 rpm? That seems way too late for what I read everywhere. And of course I can't "un-stretch" the spring so I'd have to find a new one.

thx, Dave     

[jayb]

I can't imagine how a change in timing would cause an engine vibration, unless it is detonation from too much advance.  Detonation usually doesn't feel like a vibration.  To be safe I'd get a replacement spring and go back to the original advance curve, and see if the vibration disappears.  If it doesn't, you may have picked up a new problem.  If it does go away, I think I'd leave the advance where it is...

[Ratbird]

thx Jay, yeah the motor revs and moves the car with the same power, and I imagine detonation wouldn't do that. I'll definitely get some new springs just to be safe. I'll get the big ones and little ones and try adjusting the curve with those as opposed to the crap shoot of stretching the springs. I wish I had a car buddy of some sort - being 55 years old, and only just now getting into the car scene means that EVERYTHING that I come across is new to me and I have no experience with any of the symptoms. But it's FUN! Always loved these cars when I was a kid, that's why I went with an old FE instead of a typical crate motor 302 or 351. Love that big block sound.

Any ideas on what the vibration could be with a 400 mile new motor? I've been careful with it and done everything as I should according to the builder.

thx again, Dave J 

[cjshaker]

I would start with Jays advice about replacing the spring. I can't see the timing causing the vibration either, but to be on the safe side and to eliminate it as the culprit. Vibrations can be tricky to isolate. First, have a look at your damper and make it looks ok visually. No looseness, wobble etc.

If it passes the visual test, you'll have to describe the vibration in as much detail as you can. It may be totally unrelated to the engine.

[Ratbird]

Hm, doesn't seem to upload or post anything. I'll try one picture at a time. Sorry for the excessive posting Gents.

[Ratbird]

Installed the new (and correct) Pertronix coil, Autolite 45 plugs, new vacuum advance canister, and Accel plug wires. Re-tuned and timed everything over and over to the point where it's running and staring real nice. Even stretched the large timing curve spring a little more as you can sort of see in this picture. Have you ever seen badging like this?

As for the vibration, I installed a new fan clutch, do you think this could cause a noticeable vibration? It even feel like it vibrates while idling but just barely. I just dropped it off at my local mechanic to have new tires put on the front and to get an alignment - hopefully that helps.

I found this car that I might make a project. It's a 63 Falcon (Sprint?) It has a running 6 cylinder and a 3 on the tree. Can anyone tell me if the Z-bar and clutch hardware will work it I put a 302 or 351 in it? Also, what does it take to go from a 3 lug wheels and axle to a 5 lug set up?

Hopefully these pix upload. This is my 2nd attempt.

[Ratbird]

next picture

[Ratbird]

Last one

[Heo]

Dont sure about the clutch parts but to go to
5 lug Wheels use the complete mustang V8
suspension its a bolt on if remember right

[machoneman]

[As for the vibration, I installed a new fan clutch, do you think this could cause a noticeable vibration? It even feel like it vibrates while idling but just barely. I just dropped it off at my local mechanic to have new tires put on the front and to get an alignment - hopefully that helps.]

Sure, it could be the fan or clutch, Heck, who knows the quality these days of what parts they put in those white boxes. To check, take off the fan & clutch and bolt the pulley back on (likely you'll need shorter bolts and a few washers). Amazing how long one can run the engine, especially if you're in a colder climate, before it gets hot. Run it around the block a few times while watching your temp gauge and see if the vibration disappears. If the fan itself is out of balance that's a harder one to detect. 

[Lenz]

Hope I didn't miss it but gotta ask, is the vibration most noticeable under load, at cruising speed or all the time?  That info could help sort this out.  As stated above, the more detailed description you can give the better.

[Ratbird]

Thx Bob, that fan idea is great, and easy.

Lenz, I forgot to give a better explanation.
It kind of feels like the engine is out of balance, the faster it revs the more it vibrates - whether sitting still or cruising down the road. The builder did the external balance by drilling out spots on the flywheel. I know nothing about how a motor would feel if it was out of balance so it's hard to say. Now that I have it all back together and tuned nicely it seems to be less noticeable. Maybe it's even gone and my imagination is just playing tricks on me. I'll see if I can get a second opinion tonight from my father in law. He's know cars a lot better than I do.