ford 460 gasser

JackConrad · April 14, 2010, 06:19:54 AM

To verify timing is off, crank engine by hand till # 1 piston is at top dead center (TDC) on compression stroke. You may have to remove valve cover and watch valves to make sure the piston is on the compression stroke. With # 1 piston @ TDC, the rotor should be pointing at the #1 spark plug wire and the timing mark on the harmonic balancer should be pointing at the TDC mark on the engine front cover. Jack

luvrbus · April 14, 2010, 06:56:25 AM

If you have 2 fuel tanks on the RV it will have 3 fuel pumps and you are not going anywhere till you have the correct fuel pressure I have one same year model been there done that.

good luck

bowmaga · April 14, 2010, 09:48:22 AM

We have plans for the manual check for TDC and timing tonight. not sure how simple it will be to see all that behind the radiators and coolers, but were going to try.

Haven't tried the timing light while cranking, cause i didn't have one until this morning....and was told it probably wouldn't work unless the engine was actually running

checking the voltage at the ignition module has not been checked yet either, but will tonight.

only one big fuel tank, with fuel pump mounted outside the tank and inline filter on the frame rail.

the whole fuel pressure thing has me baffled also. I can't see how fuel pressure has anything to do with it actually starting. turning the key on, fuel pump operates and when you pump the gas pedel it squirts fuel into the carb....the thing should at least fire up, and then I can see where while running, the fuel pressure would have an effect, but not trying to start it. cause just turning the key on, doesn't make fuel start to dump into the carb...pumping the pedal does. the fuel pump should just be pressurizing the line. I think us dumping fuel directly into the carb and still not getting it to fire has eliminated that from the equation....I think.

changing the spark plugs last night i expected to see all 8 plugs to be soaked with gas, but i'd say only 4 were, 2 on each side. i found that a little strange for as many times as we've tried to start this thing with no luck....i assumed i'd have a half inch of gas in each cylinder sitting on top of the piston. its to the point when if fires....i'm kind of scared!!!

Chopper Scott · April 14, 2010, 10:49:01 AM

Coil? Generally they either work or not. Even if you had weak spark it works. Where did you get the new module and did you have the old one checked? (I know, I know.... I'm pig headed!!!!

) I replaced one once and the new one was bad. Sure hope it isn't the timing chain. I'll bet that's a bear to change in an rv. Bad enough in a pickup. Speaking of pickups. Distributor pickup?

luvrbus · April 14, 2010, 11:20:11 AM

You need to check the fuel pressure if that is truly a 89 model 460 it is a EFI engine and requires 32 to 40 lbs of pressure and the fuel pump is in the tank the one on the out side is the booster pump that is the same chassis as a F350 Ford truck or van and it will not spark without the correct fuel pressure

good luck

Chopper Scott · April 14, 2010, 05:17:06 PM

I think he has stated that it is a carb Cliff.

bowmaga · April 15, 2010, 07:38:17 AM

ok boys....we found the problem.....and it is..............the distributer. I stated early that we put a new cap and rotor on it and at that time I tried to spin the rotor by hand and couldn't. Well it seems I had a skirt on and just didn't put enough force into. Not ever having to do this, wasn't sure. But yesterday we dove into the TDC project and pulling off the dist. cap, I thought I might just try to spin it again. Feeling a little more frisky, grabbed it and sure thing, the rotor turned about a half inch.....then I spun it about 90 degrees and then I knew what the problem was. We found TDC, found the number nothces on the cam arm. and lined them up with the pointer, then pulled out the distibuter and there she was....a shattered shear pin. The distributer shaft still spun like a brand new one and the gear was tight enough on the shaft that when you cranked the engine it the gear still spun the shaft, spinning the rotor....still giving me spark. Just spark at the wrong time.

I feel a lot better. I just hope this is 100% of the problem and not 50% of the problem. I'll know in a few days. Having him order i new gear and pin. The gears pin holes were oblong and looked like the gear fins were worn slightly. for $40 or less i recommended replacing it. the distributer itself seems just fine.

hope this play by play will help some other people in the future - and if anyone wants to why this most likely happend - The owner/driver has a bad habit of using starting fluid to help get it started. I've warned him repeatedly that its not necessary with a gas engine...just need to be patient. He was impatient and coupled with a not fully charged battery - i believe sptayed her 3 to many times along with pumping a large amount of gas into her....I think when it finanlly fired and sent a 4' flame out of the carb, thats when the shear pin fractured. The small atomic explosion was to fast and to much. It didn't completely break, and it took about an hours worth of driving before it finally let go. That is my guess how this all played out. luckily AAA with the RV option payed off the tow at no charge to the owner and a lot of question asking and a few friends with ideas and a little knowledge - this didn't cost an owner thousands of dollars of mechanics fees.

thanks everyone for your help....I'll be hanging around.

Greg

kyle4501 · April 15, 2010, 09:07:54 AM

I don't think the starting fluid had anything to do with it. The flame was a result of excessive fuel still burning in the cylinder when the intake valve opened.
The camshaft turns that gear on the distributor shaft which, in turn, drives the oil pump. If there is something in the oil that caused the pump to hesitate, it will overload the shear pin.

I'd try the new gear & pin, but I'd get a few extra pins, so if it happens again, you don't have to wait for parts to arrive. . .

Also, if it happens again, you will need to investigate the oil pump. . . .

Good luck!

eddiepotts · April 15, 2010, 09:37:06 AM

I have had this happen to me on a 351 cleaveland. I installed a new pin and shaterd the gear. Then I was told to check the oil pump. And yes it was locked up. I took a 3/8 socket on an exstention and was able to turn it back and forth to break it loose. Installes a new gear cleaned out what I could of the old gear and the car is still running today. This was 15 years ago. CHECK OIL PUMP FIRST BEFORE YOU REINSTALL. You can prob put your distributer back in with out the gear and the rotor should turn freely. I was driving mine when it happend too.

bowmaga · April 15, 2010, 10:07:39 AM

interesting...i will for sure try to turn the shaft for the oil pump before reinstalling...great advice. thanks.

I'll repost my findings after we get her back together.

greg

rgrauto · April 15, 2010, 10:26:59 AM

Well I'm happy that you found the problem. Some things that might make that happen, is oil too thick (too much oil additive) over riving the engine when cold. The oil pump puts a lot torque on the roll pin and gear pushing thick, heavy oil. HTH_ Glen

Chopper Scott · April 15, 2010, 10:52:42 AM

Congrats on a simple fix. Sure beat the timing chain!! I had a buddy who had a 6 cylinder Ford pickup that sheared the pin every once in a while. Everytime it did it backfired and blew his muffler apart!! Kyle wins the award for the right guess!!

gus · April 15, 2010, 08:09:40 PM

I can easily see how starting fluid could cause that problem on a gasser.

A much better starter for gassers is spray carb cleaner, it isn't nearly as powerful but will do the job just as well.

bowmaga · April 19, 2010, 06:24:06 AM

The gasser is running, once we figured out that a previous owner did some adjusting somewhere, and that the yellow marks on the distubeter and cam arm really was TDC and correct rotor placement, she fired right up. That was a good feeling of success. The owner will now change oil and filter, and take her for a sping to make sure the distrubuter doesn't need anymore fine tunning. Oil pump spun freely with rathced and socket. I think she's good to got.

again, thanks everyone. All opinions helped the process of trial and error.

Greg

kyle4501 · April 19, 2010, 06:47:23 AM

Greg, glad to hear it is 'on the road again'!

Quote from: gus on April 15, 2010, 08:09:40 PM
I can easily see how starting fluid could cause that problem on a gasser.

A much better starter for gassers is spray carb cleaner, it isn't nearly as powerful but will do the job just as well.

Gus, please elaborate on how starting fluid can cause the failure of the distributor drive gear shear pin. I must be missing something as I'm at a loss to see the connection.

Starting fluid usually has 'upper cylinder lubricant' where carb cleaner usually removes oils & varnish. Seems that would cause more long term problems with ring sealing.