Car turns over but won't start sometimes, but will pop start.

[Granite CB7]

Could you please explain more?

The spark plug tube seals are exactly that. A seal for the spark plug tube. If the seals leak and let oil into the spark plug tube, then it can travel through the threads and leak into the cylinder. I've had my spark plug tubes overflow with oil once and have had to deal with this issue multiple times. There was obvious evidence of oil being burnt in the cylinder on the spark plug itself.

How would the oil get into the combustion chamber and foul the spark plug?

My main focus is the crush/sealing washer on the spark plugs, when installed properly the washer really should seal all compression in and all oil out. I suppose a tiny tiny bit of oil could bleed down into the combustion chamber but would it really be enough to foul plugs? Plus, if it were leaking that bad, wouldn't compression be leaking out of the motor? If the plugs were really that fouled I'm leaning towards worn valve guides or piston rings. I guess a good experiment would be to see how well a spark plug would seal out water on my spare cyl head, may have to try that. My reasoning obviously doesn't cover unconventional problems such as a cracked cyl head or completely stripped spark plug threads in the head. Just kinda thinking out loud here, if you have some good info on this please share

[oni_cb7]

I would just want to add that with the spark plugs installed properly, leaking lower tube seals will NEVER let oil into the combustion chamber. Lets say you don't "siphon" the oil out before unscrewing the spark plug, when you unscrew it then the oil goes in the chamber. The spark plug is essentially a pipe plug really, it will stop all fluids from entering the chamber as long as they are tight/snug and not loose. I would for the moment clean most of the oil up so you have good connections @ the wires to spark plugs and continue with your diagnosis. With spark, fuel and compression she'll run.

Could you please explain more?

The spark plug tube seals are exactly that. A seal for the spark plug tube. If the seals leak and let oil into the spark plug tube, then it can travel through the threads and leak into the cylinder. I've had my spark plug tubes overflow with oil once and have had to deal with this issue multiple times. There was obvious evidence of oil being burnt in the cylinder on the spark plug itself.

How would the oil get into the combustion chamber and foul the spark plug?

[Granite CB7]

I would just want to add that with the spark plugs installed properly, leaking lower tube seals will NEVER let oil into the combustion chamber. Lets say you don't "siphon" the oil out before unscrewing the spark plug, when you unscrew it then the oil goes in the chamber. The spark plug is essentially a pipe plug really, it will stop all fluids from entering the chamber as long as they are tight/snug and not loose. I would for the moment clean most of the oil up so you have good connections @ the wires to spark plugs and continue with your diagnosis. With spark, fuel and compression she'll run.

[lbus9168]

Sniff.

Advocating for petrol sniffing???

Well I never!

[joey_crandall]

Cap and rotor are fine, I'll order some grommets, plugs and wires when I get paid friday. The car does run great and no smoke out the tailpipe, so I'm assuming the oil hasn't leaked past the plugs yet.

[oni_cb7]

Repair the leaking spark plug tubes. Any oil getting into the cylinder will foul the spark plugs and cause starting/running issues.

Why haven't you taken off the cap for the distributor and actually look at the internals? It is really (REALLY) easy to just pull it off to see the health of the distributor. Super easy.

[deevergote]

If there's a substantial amount of oil that is actually entering your combustion chambers, it's very likely. Depending on the amount of liquid, it could also cause severe engine damage (essentially, hydrolock... bent valves, bent connecting rods, maybe even a brand new central air system for your block!)

[joey_crandall]

Crank the engine. Pull a spark plug. Sniff. If it smells like fuel, the engine is getting fuel.

Thanks for the tip, I'll check that when I get hoelme,

One more thing, could bad spark plug tube grommets cause this?, I noticed cylinders 1 and 3 have a good bit of oil in them

[deevergote]

Crank the engine. Pull a spark plug. Sniff. If it smells like fuel, the engine is getting fuel.

[joey_crandall]

You could always determine what it's not getting (spark or fuel) before randomly replacing parts...

Yeah I'll check that when no get, would I be able to find a walk through for checking for fuel on thus website. I can't remember how to check for fuel

[deevergote]

You could always determine what it's not getting (spark or fuel) before randomly replacing parts...

[joey_crandall]

When it doesnt start, does it just crank? Or does it fire up but once the key is let go it dies? Either way, id check for continuity from the ignition switch to where it plugs in by the fuse box. This would happen to me on cold mornings. It would just crank then eventually would turn over, after a few months it would turn over fine but die immediately. Or maybe the igniter is bad? Have you changed the distributor?

I haven't looked at the distributor, the car will turn over all day with the key just won't fire up, it runs fine all day when nit starts, it's been doing it more latley, mainly when the car is wares up... so on gonna go with replacing the main relay first

[Dabsfordaze]

When it doesnt start, does it just crank? Or does it fire up but once the key is let go it dies? Either way, id check for continuity from the ignition switch to where it plugs in by the fuse box. This would happen to me on cold mornings. It would just crank then eventually would turn over, after a few months it would turn over fine but die immediately. Or maybe the igniter is bad? Have you changed the distributor?

[joey_crandall]

Hmm. Look new doesn't mean anything really, man. I've had remanded starters fail on startup. It sounds to me like the starter might be sticking if it did start though. You can always hit it with a wrench

The starter spins the motor no problem so no wrench snaking necessary

[F22Chris]

Hmm. Look new doesn't mean anything really, man. I've had remanded starters fail on startup. It sounds to me like the starter might be sticking if it did start though. You can always hit it with a wrench