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I am at my wits end. 1974 bone stock low compression 454. All cylinders have the same compression, valves look ok.
About three years ago my mechanical tach stopped working and I tried replacing the gear, but the insides were also stripped and ruined.
So, I bought a new one. It was a nightmare. After months of fiddling and fooling I finally got the car to run, sort of. Backfiring, spitting through carb. Terrible.
After checking, diagnosing and relacing the vacuum and trying different springs, I noticed that there was spark jumping all over the top of the distro.
Well, I tried to find a new cap, but to no avail. If you made it this far, bless you.
I just went ahead and bought another distro. Not wanting to throw more good money away, I decided to go discount, and after being assured this would work, I bought one.
I installed it today, and OMG, what a disaster. I put #1 at TDC, pointed the rotor at it, dropped in the distro and set the oil notch. Put in all the wires and new coil. 18436572 firing order. vacuum hooked up.
It is really bad. Wont even start, spits gas out of the carb, stumbles, bumbles and won't run.
Worse than the last distro. What can be happening here? I've done this simple job 100's of times!!!
I am still at a loss with this. The motor is at TDC. The line in the photo looks a little off, that is the camera angle. It is dead on. Compression on spark one detected with finger in spark hole, then hand rotated to TDC. Rotor pointed at 1, and set in oil pump. Car wont run. What have I boneheaded?
I am still at a loss with this. The motor is at TDC. The line in the photo looks a little off, that is the camera angle. It is dead on. Compression on spark one detected with finger in spark hole, then hand rotated to TDC. Rotor pointed at 1, and set in oil pump. Car wont run. What have I boneheaded?
"The rotor pointed at #1" could mean 2 things, but the only one that means anything is that the rotor is pointing at where the #1 spark plug wire is inserted into the distributor cap. It doesn't matter if the rotor is aimed at the physical location of the #1 cylinder. Both the #1 cap tower and the #1 cylinder could be in the same line with the rotor but that's not important.
Put the cap on the distributor and then place a marker/pointer somewhere nearby, indicating were you have the #1 wire connected to it. Remove the cap and align the rotor tip with the marker. Remember that you can make small adjustments with the alignment just like you would when moving the distributor to time the engine.
Are you getting spark at the plugs?
If you've still got your old distributor, you can get a new center shaft...
Last edited by barkingrats; Apr 21, 2026 at 09:17 PM.
^^^^THIS^^^
Another Paramount point or two:
When at TDC, that also means it must have piston #1 at TDC AND both Cyl #1 valves are closed (or quite nearly closed).
Camshaft always rotates at One-Half rate that crankshaft rotates; always.
Whenever crank is rotated 360 degrees, cam will rotate 180 degrees; always.
* many a mechanic/tuneup fellow has been completely befuddled when his harmonic damper's outer inertia ring has slipped and incorrectly placed his timing mark aka zero groove in the Wrong dang position. Old dampers fail and the groove shifts position relative to true TDC. There's no shortcut stupid fix for that; either have your damper rebuilt or purchase-install a new damper.
Last edited by Rebelyell; Apr 22, 2026 at 02:41 PM.
I want to thank all who responded to my dilemma. It is fixed now thanks to all the input. And running like a man possessed!!
To wrap up; I'm a septuagenarian and have been set in my ways for many decades. Well, I read on the internet (my first mistake) that all you had to do was line up the rotor and if the distro didn't drop in, just bump the engine until it did.
I went back to the old school PITA method of lining it all up, and turning the oil screw with a long screwdriver until it all fell into place. Thank you "Barking Rats" for setting me straight.
Car fired up instantly.....a little high on the idle and I still need to dial it in, but all is A-OK. Now I'm nervous about timing it. My wife bought me a new "digital" timing light. OMG
Which timing light do you have — the Innova 5568 by chance? I love mine, which replaced a c.1978 Sears Craftsman light and a Sears dwell & RPM meter, both that I bought new.
Which timing light do you have — the Innova 5568 by chance? I love mine, which replaced a c.1978 Sears Craftsman light and a Sears dwell & RPM meter, both that I bought new.
It is from Summit. Looks exactly like, and has the same instruction booklet, as an Innova my buddy has. I set it today and it took longer for the car to warm up than it did to time and set idle! I simply set it on 4 stroke, put the dgrees at 10, and lined up the timing mark. Set idle at 630. Got in car, put it in drive, and idles happy at 600. I forgot to disconnect the vacuum, so I may do it again tomorrw.
I had a request to post my "old school" method....so hear it is.
In the old days to insert and tune a distro you first bring the number one cylinder to TDC.
This is the same for all Chevy old school V8's. If you are sitting in the car, number one is the first one in front, on the left side near the radiator.
You remove the spark plug, put your finger in the hole and bump the engine until you feel pressure. You will notice it believe me!
At that point stop, and using a 3/4 socket hand crank the motor clockwise until you see the timing mark and line line it up with the mark on the damper. It helps to dab white paint on it.
Now, this is where it can get a little confusing. You align the rotor on the distro with the number one cylinder. This is NOT critical by any means. The primary reason for this is some Chevys have vacuum lines that get in the way of the vacuum can on the distro when advancing timing. So it kind of makes sense to leave room for adjustment. BUT, you can use any spark point on the distro
The CRITICAL alignment, is making sure the rotor lines up with a Spark plug on the distributor cap. Not in between, not before, not after, but directly in line. The rotor and the brass connector in the cap line up with the car at TDC.
Look at the bottom of the new distro, you have a bevel gear. That gear means the distro has be put in at an angle. What happens is, you drop it in to line it up, and the distro does not go in all the way nor does it line up. So you have to rotate the distro until it arches in line with spark plug connector on the cap. It still won't drop all the way in.
It doesn't drop in all the way because recessed at the bottom of the bevel gear is a Blade that fits in a fork on the oil pump to turn the distro. It is a little tricky and time consuming, but after you are confident you have the plug and rotor lined up with TDC, then you pull the distro back out. Take a long flat blade screwdriver and use it to drop into the hole in the manifold, go down to the oil pump, find that fork and use the screwdriver to turn it.
There will be a plastic sleeve around the fork to help guide the screwdriver in. Be careful, feel around until you find it, then let the screw driver slide down and then turn it. You don't have to turn it a lot. Then take the screw drive out, and note how the blade is oriented. You can then look under your new distro, note how the drive blade is oriented, and make a judgement call to line it all up. Remember, the oil drive fork and the blade on the distro will be line up every 180 degrees. So you don't have to rotate it far.
Once every thing is lined up, the distro will drop in like butter. The rotor will be sitting on a plug connector under the cap, the oil drive fork and distro blade will be engaged, and you can now time the car.
Set the distro hold down so it is firm, but you can still turn it. Make sure you replace the spark plugs.
Set your timing lite at 0, start the car and check to make sure the timing marks line up. You can now set your timing wherever you like. I set my 454 at +12. It likes it there. I like it there, So we are happy.
One simple thing I forgot to mention is that the wire designated as number 1 on your distro cap, is where you start installing the plug wires. Also, if you can see the little video of my car running above, at the end you will notice a piece of silver tape on my cap at about the 5 o'clock position. That is my number one plug. It helps to put tape on the cap and rotor where they line up.
LS 4, 454 timing issue
