Hey i have a fresh 70 455 with hei and the timing light will only fire on the even side, ie 2 4 6 and 8? Anyone seen this before? Everything is new and have tried 2 dist with no change

 

There are a gazillion timing lights out there these days. Any chance the timing light is set to a 4 cylinder vehicle?

 

Have tried several and no change

 

Attempting to make a beneficial guess here. I have old school contact points and I use an old school standard inductive xenon tube timing light (strobe).

If you have a digital inductive timing light, there is a setting for measuring either a 2-cyle or a 4-cyle engine, I believe. Have you tried to evaluate that setting?

 

Have you tried attaching the clamp closer to the distributor?

 

Oh yeah, almost forgot. You also have to have the clamp oriented correctly on the plug wire - there is (should be) an arrow indicating the direction of the clamp. Ensure you're pointing the correct direction.

 

I don't see how the timing light cares which spark plug wire its attached to? If there is a spark it will flash.

 

You got me there, Eric. Curious if someone suggested changing which spark plug wire it was connected to?

 

Oh you mean, the timing light only picks up a signal on the 2, 4, 6, or 8 plug wires? Hmmmm.....that's interesting if that's what's going on.

 

It should work on any plug wire, although I can't say I have hooked to anything other than the #1 plug wire to set the timing.

 

I always read #1 plug wire, also. I can't say I've ever found any need to see if the timing light works on any other wire.

 

Works fine nice stable light on 2 4 6 8 and nil on odd cyls. Just bizarre. Swapped leads etc etc no change.

 

What is the manufacturer/model # of the timing light in case someone else happens to have the same issue w/ the same timing light?

 

And, just to ensure we're on the same page. The inductive clamp does have to reside on the cable with the arrow pointing (oriented) in the correct location. You can't simply cross over the intake manifold & clamp onto another plug wire with the clamp in the same orientation. You must reverse the inductive clamp so it is oriented correctly. So, if you just go ***** nilly from one side to the next you have to change clamp orientation.

 

3different lights, same issue. Yes all correctly oriented.

 

1843
6572

cylinder #1 and 6 fire at the same time, 8 and 5 are companion, 4 and 7, 3 and 2. For the life of me, I can’t think a reason why a timing light refuses to pick up a signal from a perfectly good ignition. Assuming the nine runs well, and 3 different timing lights behave the same, I’m stumped.

 

Yep its a possessed car, or maybe the southern hemisphere🤪 trying to find a points dist to eliminate that is impossible almost here in Aust. Nobody even knows what an Olds is here

 

OK I can't figure this out and it makes no sense to me. It should work from any wire I would think. Now, with that said, when I was a young man, I owned a TR3A (Triumph) and a couple friends owned foreign sports cars (Healy 3000, BMG and the like). I will say I do recall from 50 years ago there was one commonality to foreign sports car which I had to learn. And, that is (was) the timing light had to be hooked up backwards because they were of the opposite ground to American made cars. So, the white and black wires were reversed.

 

Yes talking with the guys who machined the block for me and with a combined 130 odd years on the tools we are at a loss too. This car has fought with me all the way. Going to put a new module in the mallory the car came with and try that next. Thnx for the input.

 

I can't figure how this would matter; but, the stranger an electrical problem seems the more likely it is ground related. Try running a temporary ground from the distributor body to the battery ground with the timing light ground.

Does it run well?

Will the non-blinking wires blink if the distributor is rotated as in adjusting the timing?

Had something like this on an mid 60's GM V-6. Someone put a DelcoRemy V-8 rotor under a Buick V-6 odd-fire cap on a twin engine boat. Both engines would only run on three cylinders at a time and which three changed when rotating the distributor. That took a while to find!

Try putting known good plugs into the wires that don't blink and watch for spark. The light doesn't know or care what wire it is on. Every wire will make the light blink or something is wrong.

I'd be replacing the cap and rotor with a known good one for test purposes.

Good luck!!!

 

Surely not. If the rotor arm is pointing at #1 in the cap then only #1 plug wire will see any voltage, and the same for any other position. Or have I misread your post?.

Roger.

 

Does it only run on 4 cylinders?. If you take off the odd number plug wires does it make a difference?. I'll be interested to see what the outcome of this problem is. I'm as baffled as anyone else by this one.

Roger.

 

You can time an engine on #1 or #6 as they are exactly 180* out. Like asked above are you saying its only running on the even cylinders?

 

Timing lights have nothing to do with the number of cylinders. There is one pickup that takes it's firing pulse from one plug wire, period. Doesn't matter if there is one cylinder or a dozen, the timing light still works exactly the same.

 

Why isn't it working then?

 

I have no idea, but if it works on any one spark plug the timing light is not the problem. The OP mentioned that orientation was correct, so I assume that means that the clamp-on timing light pickup has the arrow oriented towards the spark plug as required. If the engine is running on more than four cylinders, then the problem has got to be a weak spark or similar issue on that side. I've had situations where the spark was too weak to trigger the timing light, but that was on all cylinders, not just one side of the engine. I'd probably start with a spark tester and compare the spark from the right with that from the left, though I have no idea what could cause a side-to-side discrepancy.

 

Good point on the spark tester. I believe most of us agree this should work on every single plug wire as you mentioned. I asked and mentioned a gazillion timing lights merely to suggest in some cases I've seen some of these new digital timing lights selling for $10-$15 and the instructions (when you look at them) are the size of a Britannica Encyclopedia. And, I'm thinking to myself - why do you need that many controls and that many settings to test one single wire. I can't kill my 50 year old Craftsman.

It's oddly out of the ordinary when something works on only even numbered cylinder wires - that is bizarre.

 

Don't get me started. I still don't understand why coffeemakers need a microprocessor to boil water...

Well, if this were a Ford, it would be cylinders 1-2-3-4 that weren't working.

 

I would start looking at spark plug wire routing, starting at the distributor. There is something "common" to 1,3,5,7.

 

Electrically, there really isn't. The only commonality is that all are in one cylinder head (thus my Ford comment above). They aren't even every other firing pulse, since the firing order is 1-8-4-3-6-5-7-2, so the firing goes L-R-R-L-R-L-L-R. The contacts in the cap have nothing in common. As I said, the only thing I can figure is that there is some electrical issue that is causing weak spark on that side, such that the spark is too weak to trigger the light. There MIGHT be some weird thing that's happened to the plug wires on that side, or something, but apparently those cylinders are firing. Is there some non-stock wiring on the inner fender or that side of the block that is causing interference with the timing light?

 

you are exactly right!!! I was thinking of setting valves, and the companion cylinders. Doh!!!! This is what happens when I read this stuff before I’m fully awake.

 

Sounds like you were thinking of cars with lost spark ignition, like the Aurora. Four coils for eight cylinders.

 

Trying to understand the question but why would you put a timing light on anything but #1. OP doesn't say engine runs poorly, just light won't pick up spark.

 

I assume he was just trying it on other cylinders when he couldn't get it to work on #1.

 

Joe, Since they are on the same cylinder head (side), that is the commonality. Starting at the distributor (but not inside) and tracing each spark plug wire routing could be wires running paralell or near something thats energized and causing some kind of interference ? Bad spark plug wires on one side ? Not likely. Could the spark plug wire terminals (spark plug end) NOT be pushed into the boot far enough to have a mechanical connection ? Are the spark plugs firing on the side that timing light is being used ? Are the spark plug wires new ?
It could turn out to be something very simple.

 

Any time I've had trouble getting a timing light to work, there's been an ignition problem that caused it; and ignition problems are solvable.

FOULED PLUGS
Failed plug wires
Plug gap smashed shut

I suppose there could be a distributor cap problem, or faulty plugs beyond fouled or gap closed, but both of those seem very unlikely.

And if the timing light won't trigger on a cylinder, the affected cylinder(s) won't run properly, or at all. Nowhere in this thread does Garage28 confirm that all eight cylinders are actually running.

First Guess: He's finding that there's four dead cylinders.

 

I don't disagree with what you wrote, but I have to believe that if a "fresh 70 455" had four dead cylinders on one side, it wouldn't even be running and we'd be having a very different discussion about this motor.

 

However a loss of compression will not prevent a spark plug from firing.

 

Exactly. I've been trying to come up with credible failure modes that would account for all four spark leads on one bank not powering a timing light. Other than a coincidental failure of all four wires or plugs, or a really, really coincidental carbon track in the cap, the only other thing I can come up with is some sort of resisitve connection between the head and the block that prevents a good ground path to the plugs. Given the number of head bolts, intake bolts, and other fasteners, I have a hard time seeing this a a credible failure mode.

 

Back in the day I had a Mercury Comet with a 4 bbl v-8. Car would only run on one side. I could pull 4 spark plugs wires on side with no effect of engine running. I pulled one on the opposite side and engine died. Found the carb was only feeding half the engine. Replaced carb, and it ran fine. Just a suggestion. Bassinguy