making a short story long...
 

Truck is a '72 350/350 with HEI, newer Holley 4 barrel, stock. It's been running rich so finally got some time and decided to explore prior to putting it to bed for the winter. All the signs of running rich, fouled plugs, smell of gas etc. Started running poorly in the fall, stumbled on accceleration, poor mileage etc so I assumed carb issues and/or timing as well. Must note that I'm no mechanic.
So far I've changed out the in-line fuel filter, Checked the compression (between 120-135), sprayed around and checked lines for vacuum leaks, new plugs gapped at .045, tested plug wires for arcing and double checked firing order.
While doing this I gave the distributor a twist and it was very loose. Now I've shifted it and I'm assuming screwed up the timing. It's getting gas, two streams squirt into the primaries when I stroke the throttle, but won't start.
Cranks and almost wants to go but won't start. Any advice on next steps would be appreciated.

Re: making a short story long...
 

If it ran before you moved the distributor have somebody crank it while you turn it slowly and it should fire. Snug it down once you get it close and get the timing checked or buy a light and learn from YouTube!

Re: making a short story long...
 

Ok...(always) start with the timing, not the carb.

Any chance of putting the distributor back to the position from whence it came?....it was running there?

If not, then:

You need to get the firing set up correctly so you need to pull the #1 cylinder spark plug so you can check the cylinder position.
Then you need to crank or turn the engine over to where the #1 piston is at top dead center (TDC).
You can tell this several ways...looking at the timing mark on the flywheel is part of it and it should be aligned crank to timing pointer. Also check in through the spark plug hole if the piston is there at tdc...you can use something medium soft to check this.
As well, when cranking...you should feel or hear the air coming OUT of the spark plug hole while the piston heads up to its TDC position.
With that established, trace the #1 spark plug wire back to the distributor cap and mark on the lower metal body where it plugs into the cap.
Remove the cap and see if the rotor is at that position or very close.....ie: would spark be achieved from the rotor to the cap if you reinstalled the cap.
This should also immediately tell you which way (rotational) that you have to adjust the distributor to get the rotor lined up with the cap and the #1 wire to get the engine to fire.

Ok, I'll leave off there for the moment.

Coley

Re: making a short story long...
 

Another note on finding TDC:
Be aware that since this is a 4 cycle engine, the crank spins twice for every rotation of the camshaft and rotor. The #1 piston comes to the top and timing mark lines up to 0 twice for every 1 time the rotor lines up to the #1 position. If the rotor looks to be 180* out, spin the crank around again.

Once you get the rotor pointing to #1, make a mark in the intake straight out from where the rotor is pointing. Reinstall the cap and see if this is near #1. You want the #1 terminal on the cap to be at or slightly before the rotor position. I prefer to make a mark on the intake, so I can spin the distributor and line it up if it is not aligned correctly.

It is always best to figure out timing first before messing with the carb. With a timing light, you can KNOW where the timing is at. You don't want to tune your carb to cover up incorrect timing.

If it was running rich in the summer, it should be running better in the winter. The air is colder and more dense, which causes a leaner air fuel ratio.

Re: making a short story long...
 

Thanks for the fast responses - much appreciated. I love tinkering with the truck and use the search function here a lot but, again, I'm no mechanic. I have turned the distributor back to where it was (close) but working alone I haven't be able to crank while turning. I'll have help this weekend.
Secondly I did pull #1 plug and bumped it until it blew my finger off the hole. At that point the rotor appeared to be pretty close to the #1 terminal. Now, here's where I'm confused, at that point I've found TDC correct? Now I need to find the timing mark on the balancer and rotate it so it lines up with the timing tab, correct?

Re: making a short story long...
 

All good advice above. As long as you didn't remove the distributor (i.e. you just rotated it), the worst you could have done is to mess up the initial timing setting - cam and crank relationship is intact as well as the distributor being installed correctly into the cam gear - so you should not need to find TDC. Projectking's method would be preferred if you have a helper, and Coley's distrib body mark is the way I do it also if doing it by myself. So in a nutshell for me (if working solo), I remove the distrib cap, rotate the crank (by the balancer bolt) until the balancer timing mark is at approx 4-6 deg BTDC AND the rotor is pointing approx to the left headlight quadrant of the truck (may take more than one trip past TDC mark as mentioned above). Twist the distrib body (if required) such that the leading edge of the rotor tip is approx directly above the mark on the distirb body you made), tighten the distrib clamp, reinstall cap, start it up and set initial timing with a timing light. Then worry about the fuel system :)

Re: making a short story long...
 

Ok I am sure some people will really hate this idea, but it certainly is the easiest.

1) pull a spark plug or 2 from each side of the motor

2) hook up a timing light

3) have a buddy crank it (it will crank faster missing some plugs)

4) set the timing like you would with the car running.

It isn’t perfect but it will get you close enough to run. Then set it right.

My buddy and I do this as an added insurance policy with new motors to help make sure we don’t get a carb backfire or something on first start up.

Re: making a short story long...
 

No hatin' here. That sounds like a great idea!

Re: making a short story long...
 

Once you get the timing done if it still acts up or for preventive maintenance if the original quadrajet is still on the truck get it rebuilt..

Re: making a short story long...
 

[QUOTE=projectking;8405232]If it ran before you moved the distributor have somebody crank it while you turn it slowly and it should fire. Snug it down once you get it close and get the timing checked or buy a light and learn from YouTube![/QUOTE
Thanks projectking. I do have help this weekend, and your suggestion sounds simplest, so I'll start here.

Re: making a short story long...
 

Thanks Jocko, didn't remove or lift the distributor - just rotated it. Just for my education when you refer to the 'left' headlight do you mean looking into the engine bay or from the driver's seat.

Re: making a short story long...
 

sorry about that - I should've just said driver's side - same as if pointing at #1 cylinder. And right taillight is passenger side.

Re: making a short story long...
 

Just an update for all who provided much-needed input. Had some help on the weekend so tried cranking while turning the distributor but still wouldn't start. Sooo close, she wants to fire but just won't go. Anyway, probably shouldn't have started messing with it so close to Xmas - too many things going on. I do have a couple of questions though....
1) while turning the distributor how much precision is involved. Would it not start in one spot and then start if moved 1/4", 1/2" etc?
2) I know I have gas so want to check spark again. What's the best/easiest way to check?

Re: making a short story long...
 

Hook your timing light up to any plug wire, crank it over and if the light flashes you know you have spark.
Some motors don’t like to start unless the timing is spot on.

Re: making a short story long...
 

At this point I suggest going through and verifying that all of the spark plug wires are hooked up correctly and that you have 12 volts present at the HEI when cranking the starter.
As far as turning the distributor, 1/4" at the vacuum advance at a time will get you there. If you are in the ball park you shouldn't go more than 3/4" at the most. And if things still are not working throw the old plugs back in and see what happens.
Many years ago I installed a set of new Champion plugs and could not get the engine to start. Hours later in desperation I put the old ones back in. The engine jumped to life at the first touch of the starter. Last set of Champions I ever bought.
Good luck.

Re: making a short story long...
 

Yes, 1/2" of arc swing matters (1/4" should ALMOST be close enough for government work though). As mentioned above, it will generally only start in a somewhat narrow part of the overall swing arc of the distrib body - and that sweet spot is "about" where your #1 cylinder distrib tower is pointing at the #1 cylinder (front driver's side of the car). So,technique-wise, I'd start with it about there.. then rotate slowly thru about 5 deg of arc/distrib swing in either direction, then back 10 deg the other direction (increasing the outer limit by about 5 deg of swing each time is the idea). If you get more than 15 deg or so of swing from pointing at #1 cylinder, quit, it's either something else or it's flooded. Just to be clear, when I say "pointing" I mean a line drawn from the distrib cap coil wire tower (center) thru the #1 cylinder tower, if that makes sense. Remind me - did this truck run fine before you bumped the distributor when it was loose?

If it was almost starting - it's quite possible you were about in the right spot but had flooded it. If you think this may be the case, pull a spark plug and check it out.

Also a great suggestion above to confirm wired correctly for firing order. I bought a car once that I wasted a week of troubleshooting on only to finally figure out it was cross-wired on 2 cylinders (it did start still somehow though!). Worth checking.

Re: making a short story long...
 

Thanks Geezer - that sounds so easy. I tend to over-think a problem and miss the simple stuff. Appreciate the help.

Re: making a short story long...
 

It seemed close and I suspect it was flooded. I'm going to pull and change the plugs and then try again after I follow Geezer's suggestion on confirming spark.

Re: making a short story long...
 

also...when I cranked it over to find TDC the rotor was pointing to the passenger side headlight. I re-attached the distributor cap with the #1 cap over rotor and then re-confirmed the firing order. Does it really matter where the rotor points as long as it's at the #1 cap and the firing order is accurate?

Re: making a short story long...
 

Sounds like the distributor is off a tooth. Should be fine as long as the rotor points to the right wire at the right time.

Re: making a short story long...
 

If you were building an engine from scratch or were installing a new cam, etc - then you would need to find TDC. Since your engine was running fine, albeit a little rich as you noted, there is no need to 'find' TDC - you've found it when the line on the balancer aligns with the 0 on the timing tab (as noted though, that is only 1 of 2 possible TDCs for the 4-stroke engine). My point is that you don't need to re-find it if all you did was twist the distributor (without pulling it up/out) to the point that it won't start.

Can you describe what you mean by "re-attached" the cap so that the #1 spark plug wire tower is aligned over the rotor tip at the point where you think it's over TDC? (specifically the "re-attach" part). A Distributor cap only fits how it fits, it can't just be rotated while disconnected from the distrib body and then re-attached where convenient. Or, are you really trying to say that you re-wired the cap so that the #1 spark plug wire is now in the cap tower that is over the rotor tip at the point where you determined is at TDC?

What rpmerf is describing (correct me if I'm wrong rpmerf) is that IF your distrib is off by a tooth-ish (relative to the cam gear), you 'can' twist the distributor (with cap attached and all - and still installed, just as if you were setting initial timing on the engine) enough to compensate and set timing for it to run - or, if off by more than a tooth or so, you can re-wire the distrib cap so that #1 wire is over the rotor at TDC for cyl #1. I believe that is what he's referring to - but that is not what you've described because you mention re-attaching the cap in a new spot, which doesn't sound right to me (unless you really meant you re-wired the distirb cap and then reinstalled it).

So please clarify when you get a chance so maybe we can help ;) a little more.

The bottom line is that if it was running and all you did was rotate the distributor one direction or another, without lifting it out, the only thing you need to do to correct that issue is to rotate it back to where it was. Since you don't know where it was, that's why we recommend rotating it through a range in the area we mentioned - the direction anything is pointing and that whole discussion was to help you cross-check stuff - but it's really irrelevant since this was a running engine before this happened - so the ONLY thing you need to do to correct what happened to the distributor is to rotate it back to where it was. At a minimum, the way the wires lay and twist when you rotate it should give a rough idea where it "was" - i.e. if 1,3,5,7 are all stretched and 2,4,6,8 are all slack, it probably needs to be rotated clockwise, etc. You should not need to re-attach the distrib cap some other way (if that's even possible) or re-wire the cap - only rotate. If that doesn't fix it, it's something else in this situation - i.e. flooded, etc.

The safest (or maybe "most productive") way to troubleshoot is to change only 1 variable at a time - now that you've re-attached the cap differently somehow (or re-wired the cap), you've induced more variables when the whole reason it wasn't starting when you did the rotation method may have just been that it's flooded. The scenario now is that if you change plugs - and it still doesn't start, you won't know whether you fixed a flooding issue but induced a timing issue because of whatever you did with the cap. I'd put the cap back like it was, clean the plugs, and re-try the dizzy twist while cranking method to try to get it to start. Sorry, wish this was working out better for you! We'll get her goin, don't worry!

Re: making a short story long...
 

yes, rotate it til it lines up. The cap should have slots that it fits into so it only fits one way. On the caps that have the L shaped arms you rotate under the distributor, you MIGHT be able to install it at a different angle, but that would be a hack and a good way to have it not start next time you take the cap off.

Re: making a short story long...
 

It sure sounds like a worn / slack timing chain to me .Here's a quick 5 minute check to see whats really going on .:chevy:

https://www.youtube.com/watch?v=Aso_RXTHEB4

Re: making a short story long...
 

why do you suspect a slack timing chain? op stated he rotated the distributor without removing it and is trying to get it back to the right spot for initial timing. it was running before that.

Re: making a short story long...
 

Just wanted to do a quick update and to thank everyone for their time/advice. Had family staying over Christmas (daughter from Ireland that I only see once a year) so didn't have any garage time.
I set the distributor as close as I could to it's former position using some photos I'd taken years ago. Didn't give it any gas and it started on the first crank. Didn't run well at all but it started. Seemed starved of gas as I really had to rev it to keep it running. I suspect I really had it flooded before. Had the timing light hooked up but then noticed a leaky lower rad hose. So, need to swap that out and then I'll get back to the starting issue. Big thanks for the help so far.