Greetings gentlemen,
Have a mystery and wanted to get any opinions as to the cause. Have a 400 that died and will not start. Engine was running well but missed a couple of times and then died (while driving hwy at 70 MPH). No noises or funny smells. Will not start now and backfires (loud).
It has 3 month old Accel dist. and is getting fuel (not sure about fire yet-haven't tested). My guess was some sort of timing issue and I intend to check the dist. shaft and rotor movement (dist is not loose). Also wondering if ignition module could cause this? I was going to get a module (only $20) tonight as a start.

Am I on the right track?


Thanks

gas_hogg

 

I'd start with the ign. module. Could be a timing chain. How many miles? Some stores will check the module for you.

 

You could have sheered the dist. gear roll pin. Sometimes a piece of stem seal can get into the pump and cause this. Usualy it'll cause abig back fire though.

 

I'm hoping just the module and not a chain or broken dist. shaft.
The engine was rebuilt about 8K ago and has been running like a clock.
Heading for Advance to get a module and starter solenoid relay (seperate issue) right after work. The backfire was loudest thing I ever heard after trying to start it cold (cranked about 5 secs then BOOOM!) Seems like some sort of incorrect fire somewhere.

Thanks.



gas_hog

 

Hogg,
If it backfired on a cold start, then the distributor is turning. This rules out the ditributopr gear and roll pin.
You''ve described a classic timing chain failure.
We need to run though a few more test first.
Do you have consistent spark. Pull the coil wire off the cap and check for spark. if you've got spark this means the ignition module, and coil are working. This leaves timing. Rotate the crank to TDC and pull the distributor cap. is the rotor pointed to #1 firing position? If not, you've probably got a bad timing chain.
Good Luck,
KingFisher

 

Actually I'd take a good look at the dizzy shear pin. The gear fits tight and if the pin goes the shaft will slip a little every time you get it running. Try a timing light. If it's way off you have a chain or dizzy problem. If it jumps around it may be the module.

 

Thanks for the replies guys-appreciate it. It WAS a sheared pin at the distributor gear-gad. I pulled the distributor and the gear was laying down sideways in the base of the hole-not what I wanted to find...
The whole area looked suspiciously dry so I pulled a valve cover and it was dry there too-so it looks like I had an oil circulation issue. The oil pressure gauge was always flaky so I never saw any warning the pressure might be gone. But, looks like it had been running dry for a while. It turns over and there's no noise but I'm worried it needs to be replaced.
Time for a coupe of beers now...





thanks again,

gas_hogg

 

Better drop that pan and check that pump. That pin didn't sheer for no reason.

 

Going to pull the pan this weekend and see what I find. If I find just a blocked pick-up tube or pump issue I don't think I'll feel comfortable just swapping the cam (teeth have a few chips) and then trying to run it. After having no oil circulation I'm thinking of just swapping it completly. (just what I wanted to do this summer)




gas_hogg

 

The pin probably sheared on account of the engine backfiring. If it is the factory chain and gear's FORD and other's used a phenolic (plastic) camshaft gear and that could have been the cause of your backfire

 

I'd like to think the backfire sheared the pin, nothing seems to be binding so that may be the cause. I'm going to pull the pan and try to see why the oil isn't puping and then if I can fix that. If I can, I then have to decide what to do next. The cam has some chips so I don't feel comfortable dropping in the distributor again unless I replace the cam. Since it hasn't been pumping oil I'm thinking I may just need to yank the engine and put in a new one. Do you think it's worth replacing the cam (if I can determine/correct the cause of the oiling issue) and then trying again to get it started? It's doesn't seem to be binding or making noise but I have no idea how long the oil wasn't flowing.

Garage near my house has a rebuilt 351 with 3K on it of $600, but I haven't looked into what I'd need to change (like mounts, exhaust) to get that in.

A rebuilt long block is $1100 and then about $350 to drop it in if I have the garage do it. Not sure which of the 3 is the best option at this point.



sigh


gas_hogg

 

If it is a 351M it will bolt right in with nothing needing to be changed, if it is a 351W don't waste your money. Check your carb, probavle cause of the backfire and definetly change the cam, while you are that far I would put a chain and gear's in it as well. If it ran good b4 just fix the current motor. Not alot of dough to get it back up and running.

 

Thanks. I'm all for saving money so-I'll see whay I find tomorrow and see if I can save it.



gas_hogg

 

Greetings all,
As you may remember a few weeks ago my engine just died while driving on the hwy and would not restart. Engine is a rebuilt 400 with about 20K tops on the rebuild. A backfire broke the dizzy pin at some point while I was trying to get it started again.
Since then I replaced the distributor pin and then reset the timing to try and get it started again. Now here is what I got:
I get pretty strong backfiring through the carb and it still doesn't want to catch. Changing the timing never seems to get rid of all the carb belching fire and smoke.
I put in fresh plugs as there was some mild wet fouling, rechecked all the timing, wires and vacuum-but no change. Tonight I pulled both valve covers to see if I might have a busted valve spring or stuck valve but all the springs are good and all the valves seem to be sliding fine. I also have oil pumping.
There is no mechanical noise from the engine when cranking either.
To me it almost seems like a bad gas problem except for the carb belching. I'm thinking of getting a buddy over to look at the timing to see if I'm missing something there but other than that I'm pretty stumped.
What else might cause hard backfire out the carb? Any suggestions on this one are very welcome.


Crankin' in NC ;(

gas_hogg

 

could you have reinstalled the distributor 180 degrees out?