I have a 1983 Chevrolet C10 Silverado that I am slowly restoring. I recently had to change nylon timing gear and chain. It ran ok but now will only crank but not start.I am getting gas to the carb and I tried a couple of shots of starting fluid. It didn’t try to start at all. I pulled some of the plug wires and I am getting spark. The plug wires look good. Any suggestions? I am starting to get a little stumped.
You need to do a compression test if the timing gear/chain failed.
Believe it or not, the valves may be bent.
I know it can happen on a Ford 302!
Tester
It ran good after the timing chain and gear were replace. It never jumped time but the timing chain had a lot of slop in it. Today when I was driving it was hesitating a lot during acceleration. My next project was going to be rebuilding the carb.
Hmmm?
I thought you stated you couldn’t get the engine to start.
Tester
Are you sure it didn’t jump time? A new timing gear and chain should not have a lot of slop. It should have just a touch of looseness. If it refused to start with starter fluid, your problem is probably spark timing, not fuel related. Rebuilding the carb will not fix this. Recheck your igniton timing at the distributor, and remember, the camshaft drives the distributor. If spark timing is off, the timing gear could also be off. With it being the last thing touched, it could be the problem.
Presuming OP still has this problem, one idea, remove the spark plugs and hand-turn the engine so the number-one cylinder at tdc on the compression stroke and pressurize the cylinder and see if it holds pressure. That’d prove the rings are probably good enough to at least start the engine and the valves are timed correctly & doing their thing. At the same time make sure the ignition rotor is pointing at the number one spark plug. Then you could do a compression test to verify the other cylinders.
If you feel lucky, maybe you don’t have to go through all that. An engine that won’t start but seems to be getting gas and spark might just be flooded. Try holding the accelerator all the way to the floor and crank it a few times. It might just catch and run. Flooded Detroit steel, ask my how I know about that problem … lol …
OP, your story is not consistent. "Today when I was driving it " and yet you said you could not start it.
Could you restate your problem? thanks.
There was about a day and a half that I drove the truck without too much problem after the timing chain and gear was put in. The truck started easy during thst time but had a little hesitation which I thought was from the carb needing to be rebuilt. Yesterday on my way to work it started running rough and finally died and it wouldn’t restart. I had this problem before I replaced the the timing chain and gear. I thought I had things fixed but I now see I don’t.
There could be several causes. I’d check fuel flow. Have you replaced the fuel filter???
It requires four elements for an internal combustion engine to run.
These are air, fuel, spark, and compression.
If any of these are missing, the engine won’t start.
Since you say there’s fuel to the carb, there’s spark, and we know there’s air, the only thing left is compression.
Tester
Pull a spark plug (or three) and see what the tips look like. Wet? Dry? Brown/black/white?
It could just be the carb. And have nothing to do with the timing chain. Don’t entirely discount the carb idea. I’ve been working some carb problems of my own the last few months on my 70’s Ford truck. So an engine alternating from running and starting fine to impossible to start and running terribly are a recent memory, mostly due to various carb troubles. If you think about it, with the size of the passages involved, it’s a wonder a carb ever works … lol …
If it were a carb problem, then why didn’t the starting fluid get the engine to at least try to fire?
Tester
The engine could be flooded. Adding starting fluid might just make it worse.
George.
When we use to flood engines with carbs in the winter, the first thing that was added to the intake was starting fluid.
Tester
I didn’t realize that starting fluid could cure a totally flooded engine. Good to know, thanks.
I got to wondering about this, since learning starting fluid – that’s just ether right? – can cure a badly flooded engine straight away, a short squirt of ether and even though it wouldn’t pop at all, it starts right up. At least briefly, there could still be other problems, but at least it will start and run for a bit.
But what is it about ether that makes that work? And more basically, why won’t an engine with too much gasoline in it pop & start in the first place? I mean – now I’m not recommending this, very dangerous - but I can pour a little gasoline on the driveway, that area where the gasoline is poured remains soaked with wet gasoline, toss a match on it, and it burns w/no problem at all. Not even a whit of delay before it burns. So for the excess gasoline in the engine, is the stubborn start problem b/c the excess gasoline vapors are displacing the available air? In other words, no air, no start? If that’s the reason, how does the ether help? Does ether burn without needing air?
George,
Why don’t you try using your search engine?
Tester
From what I can see by using my search engine, the combustion of di-ethyl ether requires considerable oxygen, here’s the chemical eqn
C4H10O + 6O2 —> 4CO2 + 5H2O
Thanks for all the ideas. The compression and the fuel both checked out good. I took the distributor cap off and found the coil looked good but tested bad. I replaced the cap, rotor, coil, and checked the plugs and wires. It runs good now.