I just replaced the distributor for my 1978 F250 460. This is the first time I have done this with any vehicle and I had no problems getting the first piston to TDC, etc. I bought a timing gun to make the timing precise. The specs state 12 degrees BTC. Right now, it is about 10 degrees ATC. My problem is that the distributor has already been moved as far to the left as it can go. Is it possible to reassign the plug wires on the cap in order to move the vacuum line fitting to point more toward the front of the truck?

Thanks,
Matt

 

Engine question ? Not 73-79 truck specific

Yes the wires can get to the next position of the firing order provided you pull the dizzy and set it first.
Did you mark a spot with the rotor to make sure it went back in the way it came out ?

If the timing is that far gone I would suggest that the gears/chain are almost worn out and will need to be replaced soon.

*****NOTE: Remember though the gears and chain have to be in exact position when setting the dizzy,they should be in a slop position.

As any slop in the chain & gears will throw the timing off.

This is probably what you are already experiencing.

Do a timing chain/gears slop test before you do anything.

 

When you installed the distributor, you probably got it out of time by one or 2 teeth relative to the camshaft drive gear. You need to pull the distributor out slowly until you just feel the drive gear disengage from the cam. Then, turn the rotor so that you feel it turn past one tooth on the drive gear. ( I think you need to rotate the rotor one tooth in the opposite direction of the way the distributor needs to go. ) Then, drop the distributor back in and retime the motor.

 

First of all, no- do not reassign plug wires. It sounds like you've got the distr. one tooth off. First, puul the spark plug out of the no. one cylinder, rotate the engine by hand (battery diconnected, socket on crank bolt) until pressure from cylinder wants to blow finger off hole. Rotate slowly until timing marks on harmonic balancer is at O*. Loosen and raise distributor straight up and rotate rotor until it is pointing at where the no. 1 plug wire would be if your cap was on, then lower dist. back down. You may have to pick it up and actually go on by a little bit, because when you lower the dist., it twists a little. Now snug it up and set your timing.

 

Set the harmonic balancer (crankshaft damper) to Top Dead Center (TDC or zero degree). Pop off distributor cap and notice where the rotor is pointing, it should be pointing reasonably close to the number one spark plug wire. Sometimes when the harmonic balancer is set to TDC the rotor could be off 180 degrees and the rotor will be pointing 180 degrees off. Then the crankshaft will need to be rotated 360 degrees to set the rotor in the correct orientation in pointing to the number one spark plug wire. Take note where the number one spark plug wire is oriented on the distributor housing. Remove the distributor housing from the engine and reset the distributor shaft and rotor to the proper orientation as discussed. If the distributor housing does not set down on engine, have an assistant crank the engine will you hold the distributor housing in place an gently apply downward pressure. This should set the distributor housing in place. Re time you engine with a timing light and tighten down the distributor housing set bolt.

Note: Be carefull when pulling out the distributor housing, sometimes the hexagon shaped rod which rotate from the oil pump to the the distibutor housing will stick to the distributor shaft and could fall down into the oil pan. Just be aware that this can happen.

-----buck-----

 

Thanks for the advice - I forgot to add that I have started the truck, and it runs Ok. It is just not at 12 degrees BTC.

 

You forgot to answer the questions that were asked of you too

 

Mil1ion,

You asked te question:

"Did you mark a spot with the rotor to make sure it went back in the way it came out ?"

Answer:

I did not mark the rotor, as the old rotor was returned for the core charge. This was my mistake; however, I did find out to manually turn the motor over until spark plug #1 was at TDC. I installed the new distributor with the rotor pointing to plug #1 on the cap. Doing this was difficult as the vacuum advance is now moved to the left of center almost as far as it can go (relative to looking at the enigine, the VA is left). I went out and bought a timing light and checked the timing. The truck is at 10 degrees ATC, and it does not appear that I can move the distributor any more to the left.

Your question is the only one I see at this time on this thread, and, I have no idea what a "timing chain/gears slop test" is or how it is performed.

Thanks,
Matt

 

When he mentioned the "slop test", he was referring to the slack in the timing chain and gears that occurs due to chain stretch and gear wear. To check this, simply remove the distributor cap, and manually rotate the engine like before, noting how much you can turn the crank before the rotor starts to move.... hence the "slop".

 

Mestrell, I believe that when Mil1on asked if you marked where the rotor came out, he was stating that even with a new rotor and distributer, the rotor would still point the same direction as where the old one came out. Now that you have started it, it probably doesn't matter as obviously the position would have changed. If anyone has an easy way to get back on track, Mil1on would be the guy to help you out. Sounds like the answer to his question would be, "oops, no".
You will need to find TDC (compression stroke like stated by others) and point the rotor toward the #1 wire position in relation to where the cap sits (as the others have indicated), by re-stabbing the distributer to end up in that position. As stated, the rotor will rotate to this position while inserting the dizzy so you will have to compensate for this prior to stabbing her in. This will get you started.
You may need to take a couple of stabs at it to get her in correctly but be patient. You sure don't want to drop that shaft as 75Ford warned of.
Good Luck. Feel free to ask for more help if you get into trouble.

 

What I meant with the rotor was to *Site In* and mark with chalk somethiung that you realign the rotor to pont to when re-installing the distributor so it goes back in....the way it came out.

The engine CANNOT be touched with the distribuor out unless you want to start from scratch to set it up again.

This is why you mark a reference point spot.

The pistons in one complete cycle goes to TDC Twice.

Once just before the POWER stroke
and Once at the end of the Exhaust stroke.

The slop test is when you Manually turn the crankshaft ONE direction with a breaker bar and socket on the crankshaft bolt while watching for the rotor in the dizzy to move.....then STOP........now...turn the crankshaft the opposite direction slowly and make note how many degrees of a circle until the rotor STARTS to move the other direction.

Do this test and post the results.

If there is more than about 3-5 degrees difference you have a problem houston

 

Mil1ion,

The truck passed the slop test, not much play there, none that I can see.

Below is a link to a web page where I have placed photos of the distrib. along with a picture of the damper. Maybe this will be a better explanation.

http://home.twcny.rr.com/mattandamie/

Thanks,
Matt

 

Ah Pics
The pic of the dist cap looks like the number one position has a wire going to the wrong side of the engine.

Number one cylinder is the front passenger side spot.

It looks like there is a #1 imprint on the cap as well.

Looking at the engine from the front, the number one cap spot should appear in the 1:00 o'clock position.



When timing an engine the vacuum line to the dizzy HAS to be removed and Plugged.

The timing rpm should be at 650 rpm.

You can find you specs on this page ..

http://mil1ion.clubfte.com/78Calibra...e-upSpecs.html

Yours are the 2nd last numbers at the bottom of the page.

Calibration 8-97-R0

 

The #1 wire is correct, look at the expanded view picture on the web page below:

http://home.twcny.rr.com/mattandamie/

My concern is with how far to the left the VA is relative to the engine. I do not have a way to check the RPM... Thanks for the specs, I have those already.

Matt

 

The pictures tell the story, I believe. Your VA should be real close to pointing straight forward, hence the thought that your distributor is not oriented correctly with the cam. Like we said before, remove the dist. hold-down bracket, slowly lift up (about an inch or so) and turn the dizzy counter-clockwise until you can engage the cam gear one (maybe two) teeth over. This should orient your VA more toward the 6 o'clock position. Now, set your timing with the engine warm, idled down, VA disconnected and the hose plugged with a golf tee or screw to spec. I know this has all been said before, but from the picture, that's the way it looks to me.