kaamacat

Here are the symptoms:

1) engine a bit harder to crank (like way to advanced)
2) almost immediately backfires pushing fuel all over the place (thank god for flame arrestors)
3) IF engine starts, at low rpm sounds like a miss
4) at 2000+ just sounds rough w/miss
5) when turned off hear a sound almost like a pressure release


.......Is it possible its just the timing chain jumped and i'm getting the compression stroke pushing back up into the intake? Reason is, sounds similar to when i've been through this on autos...etc.

Whats the general vote on this?

rjcardinal

Another possibility is a flat cam lobe. If so probably the exhaust. Just a guess though.

Ron

Griff

More likely than the timing chain jump is a distributor gear thats worn out or has broken teeth.

kaamacat

Guys.........thanks for the reply. Its the old, engine ran great before putting it to sleep last year, but heck, now, when that backfire happens (almost immediately), I am talking lots of fuel being pushed back.

I will pull the distributor 1st. The piece about, when I turn it off, a pressure release you can hear........very strange.


Thanks........Bob

excaleagle42

kcat
you may want to pull the cap and rotor and look at the springs. it's possible one or both broke off and is advancing too early.

kaamacat

Checked the wires and order again (just because I did new stuff on both engines 1st thing this year), orders were ok.

Next:
1) Check points/springs...etc
2) Gonna watch the rotor rotation on start for continuity
3) Mark dist @ #1 on cap, then cranking engine to see if harmonic mark is same as when #1 on dist is there.
4) Pull distributor to check gear.

.....any other ideas.


Bob

rjcardinal

To check for a flat cam lobe you can cut the oil filter open and see if there is any silver metalic residue. Right after running the silver film should be on the dipstick also.

The thing that makes me think it is a cam lobe is the leaking down sound you are hearing and the back firing. If the exhaust valve wont open the engine will exhaust the combustion gases through the intake valve when it opens causing a backfire and spitting out any air fuel mixture in the manifold. Or with an exhaust valve stuck closed the burned gas cant escape and is recompressed and may make a leak down sound when shut down.

Maybe a broken valve spring also.

Just guesses again. I hope its just an ignition problem.

Ron

Blueman

Sounds like a chain or a gear. I think Griff hit it . Points?

kaamacat

Thanks again..........I've got it all on a checklist for Saturday.

mxz800

so what was the outcome of the checks??