ford 460 gasser

[bowmaga]

I'm fairly certain it was gas....but it wasn't me driving.  I just re-asked the question.

I spent my lunch hour with the big gir,l and it appears to have good fuel pressure....pump is on and when you put the gas peddle down, she sprays in the 2 barrels real good.

The first spark plug a pulled, I effing broke.  Figures.  He's going to pick up 8 new plugs, a case of oil and some Lucas conditioner for gas and oil.  It appears that the 100 times she's been cranked to start, there seems to be quite a bit a fuel in the oil pan.  I hope this is just from being flooded and not from a hole in the piston or somthing stupid.  I picked up a compression tester and a spark tester from my mechanic at my construction shop, along with some pointers.  I hope to more tonight after i get off of work.  I'm leaning more towards the ignotion and no spark thing.  By the drivers explanation...it acts like it ran out of gas...or lost its spark.

I'll know tonight after work if i have spark and compression.

[JackConrad]

I had 2 vehicles that would try to start but wouldn't. They would spin over good and fire but not quite enough to run. Both times it was a timing chain/gears. Both were V8 gas engines. Only difference both failed when shut down. They ran fine when shut off but would not start. I think the "reverse load" when shut down made worn chain/gears jump time.  When checking everything else, you might want to also check the timing.  Jack

[kyle4501]

Yeah jack, I've seen that too. In my experience, if it jumps timing while running, it shuts down right then with some unpleasant fan fare. 

If it has jumped timing, the compression will be low.

On our ford van, the ignition switch would disconnect the power from the ignition module as it was moving from 'start position' to 'run position'. That was a difficult thing to catch - I was using a cheap analog volt meter to see what the voltage was as Dad was trying to start the engine. It would crank over & start firing, but die when the key was released.

Two short pieces of wire & a wirenut found on the ground put us back on the road. I got a new ignition switch a few days later & the problem was resolved. That van was rough on the ignition switches - would only last a year or two. We ended up keeping a new one in the van so we could replace on the spot instead of waiting for a tow.

I hope the solution is as painless as possible. 

[niles500]

Might try throwing a new rotor and cap on it (cheap fix) - FWIW

[Zeroclearance]

As Scott and I mentioned>>  From previous Ford owners..   Check for spark>>if you see no spark you have a "high" chance that it's the ignition module.    Timing chains in these engines are "common"   

[JackConrad]

Gas engines need 3 things to run-Spark, Fuel, & Compression (in the proper sequence).  Check the easiest first, is it getting a spark?, Is it getting fuel to the cylinders? (wet spark plugs after cranking, Does it have compression?  Jack

[Handyjim]

My 91 Southwind on a Ford F53 chassis, 460 engine, experienced similar symptoms.  Ford used an in-tank fuel pump that was notorious for problems.  They made several revisions on the pump.  I went with an external pump;  left the original in place.  I've got photos of how I did it.  But, my problem  happened when outside temp got high, and fuel in the tank (which cooled the fuel pump) got low.  No problems since the modification, maybe 4 years ago.

Having said that, I'm on this forum anticipating a change.  My wife said (I think) go for it, with 2 provisos:  the conversion must be in a timely fashion, and the bus must be in good shape. Oh, and I have to find the m on ey.

[gus]

My '77 Lincoln Continental with a 460/carb did just that exact thing after it had been sitting for a long time, drove it about 6 miles before it started losing power and then quit.

Turned out to be a stuck automatic choke. 

That could explain all the gas in the pan.

[Chopper Scott]

After reading more, it's the module. Unplug it and have it checked at a parts store. Even bad ones that still let the motor run didn't do things they were supposed to. If it checks out ok it could be a rotor or cap. Bad wires and plugs would make it run rough but not just quit running. Rotors will short out and make everything come to a standstill..... If it was the choke stuck it would have not been running so good before it quit.  It's the module.

[bowmaga]

Tonight I'm stopping by with a replacement ignition module.  Last night we checked for spark and had some, but I don't believe its a strong spark...or up to par for what it should be.  If its not that....then checking for compression.  I just can't imagine that he lost rings or a piston in a matter of seconds with out any smoke fan fare and major grumblings out of the engine followed up by fluid loss.  I would think it woiuld be tough to be running down the road 65 mph, have parts start to break and nothing come apart.  But Ford tough does say alot!!  This unit has an automatic choke... - but wouldn't that be the butterfly on the carb??  i can look right down on it and see that its not stuck.  Its turning over, just got not getting enough fire.....to fire.

[Busted Knuckle]

If it has spark & fuel, it sounds like timing to me.
But that said like others have said usually timing "CHAINS" jump on shut down, not rolling down the road.
However timing belts are notorious for breaking "on the fly" and trashing heads, valves, pistons, etc.

I too have had chains jump when shutting off! Once I backed a wrecked 1 ton in the shop that supposedly "had a fresh 350 Target crate motor in it" to pull the engine for my tow truck. After backing in I shut it off, but then decided to swap places with the tow truck and it.....yup you guessed it no start!
Good thing I found out it was junk before pulling it and installing it in the tow truck!
  BK 

[kyle4501]

Another thing that got us on that 460 in our van was something causing the safety pin securing the distributor drive gear to shear. Afterward, it would make spark - just not when it should since the gear was slipping on the shaft.

To check for this - remove the distributor cap & see if you can turn the rotor by hand.

Since the distributor drives the oil pump, I finally conceded to check the oil pump to see if it was causing the problem. It was, even tho it had great oil pressure.
I hope this ain't your problem.

I had heard that you should never remove the oil pan unless you want to learn something you didn't want to know. I found a piston skirt.   

[gus]

If you can see the butterfly open it can't be the choke. Also it ran too long for the choke to be the problem.

Mine ran very well with a stuck choke but for only about seven miles since it was cold and the choke wasn't completely closed. I just popped it open with my finger and it ran fine.

[bowmaga]

well....its not the ignition module.  Plugged in a brand new one, and no change.  purchased a new distributer cap and rotor.....no change.  replaced the spark plugs.....no change.  Went as far as to manualy pour gas into the carburator (trying to eliminate fuel pressure/pump problem)  no change.  The rotor does not turn by trying to manuly twist it....but it does turn when trying to start it.

I fear it is something to do with the timing now....or something worse.  To get to the timing gear and chain will take a major dismantel of the front of the RV and engine. 

Lets refresh:

new distributer cap and rotor
new spark plugs
It has spark
It has gas
It has compression - or at least i'm 99% it does.  We have a compression checker, just haven't done that yet.
it  turns over and is all but started.....

it ran for over an hour at cruising speed and without warning just gave up and died without fanfare....hero to zero.

She's definily being difficult

any way to check timing without tearing the rv apart?  anyway to know if it is for sure the timing.  I'd hate to recommend getting to the timing chain to find it chiny and clean and nothing worng.

[kyle4501]

Compression check will reveal if the timing chain has jumped.
If all cylinders are low - it has jumped.
If a cylinder is zero, not usually an easy thing to fix.

Check voltage to the ignition module while cranking the engine & as you release the key fron 'start' to 'run'.

Have you used a timing light as you are cranking it over?