1986 f250
4 speed 4.9 6cyl

cost me 1000$ but anyway the shifter broke and got stuck in first. After driving at about 9 for a while it shut off. Now its been sitting but i want to get it running. The engine will crank but the dist is not turning. I heard timning gears. If i pull the dist is that ok so i csn see if that gear is turning down there.

t

 

The dist has a gear that meshes with a gear on the camshaft. The camshaft is turned by a gear on the front of the engine and it's usually phenolic, and the teeth can strip out. There is also the slight possibility the oil pump locked up and that stripped the gear on the distributor, so yes you will see that right away if you pull the dist. The dist is what drives the oil pump.

 

ok thanks a ton. also i was told if i did strip the gears valve could be blown in the head and the timing could be off. Idont know much about this stuff so i need some help. Also do u have any instructions on how to reach those gears

 

My dad said he got his ram 1500 van swaped out the block for 900$ and found the block at junk yard so we might do that if is easier. Would doing that basically make it good to go. The trucks pretty beat but for an 86 not to bad

 

 

 

I'm going to give you the worst case scenario first. If your truck did what I think it did, then your cam stopped spinning and possibly left some valves hanging open. When this happens the piston can impact on the valves bending them. This will not only mess up the valves but will probably mess up the seats and potentially the piston.

The first thing you want to do is take off the timing chain cover and see if those gears have been stripped off. If so, then you'll be looking at a complete tear down to see how far the damage goes.

If the timing gears are still intact you'll want to look at the gear on the distributor. Is it thrashed or is it still good. Chances are if the timing gears are good either your distributor gear has had it or the gear on the cam has had it. The cam gear can be seen with a flashlight if you look down the hole.

None of these scenarios is cheap/easy to fix but can be done if you want to put the time and money into it. After you find the root cause let us know and I'm sure we can walk you through the rest of it.

 

As far as I know, the 300 six is not a interference engine.

There are two type of engines. A interference engine is one that when the cam stops turning, but the pistons are still moving or it's cranked over, the pistons can hit the valves and bend them.

A non-interference engine is one that when the cam stops turning, the pistons can still go up and down and not hit the valves. Most old school American engines are non-interference engines.

You do not know what this engine is like do you, you haven't driven it much. If you had driven it alot, and know it's on it's last leg,, then changing the whole thing out is a option to be considered. If this engine was in decent shape, I would fix it.

Since you do not know what condition it's in, I would go ahead and tear it apart and see what's actually wrong with it. I would at least get a cheap Haynes manual with a blown up diagram to help you along, I would do ahead and pull the distributor and see what you find.

 

to start with, pull the distributor out and take a look. for the distributor to not be turning, one of the following two things has to be at fault: 1) broken timing gear - camshaft not turning, or 2) broken/damaged distributor drive gear or roll pin that holds it to the distributor.

i've personally had the dizzy drive gear roll pin break on one engine, and cam timing gear stripped on 2 engines. in every case, the engine was ok after the broken piece was fixed.
the camshaft gear is fairly difficult for a beginner to replace, but a problem at the distributor itself is simple. with the distributor removed, use a flashlight to look in its hole, you'll see a gear in there. have a buddy crank the engine for a second - the gear will turn if the camshaft is turning. i suspect its not turning, which means broken timing gear.

here's a rough list of steps to replacing the the cam gear with the engine still in the truck
1) remove radiator, grill, fan, etc
2) remove crankshaft pulley and timing gear cover
3) remove side cover and valve cover from engine
4) remove rocker arms, pushrods, and lifters
5) disconnect left engine mount from frame perch, and raise the engine using a floor jack and block of wood under the oilpan. lift until the transmission touches the body.
6) remove the two bolts holding the camshaft retainer plate to the engine block. these can be accessed through the holes in the cam gear when turned to the correct position
7) carefully slide camshaft forward through the grill, removing it from the vehicle.
8) lower engine back onto its mounts for now
9) break the fiber gear off its hub, being very careful not to damage the retainer plate in the process
10) use a suitable puller to remove gear hub from camshaft. heat may be required.
11) clean the end of the camshaft where the gear sits and apply a thin layer of lube to ease the installation of the new gear
12) as per directions included with new gear, heat the gear in an oven, and maybe toss the shaft in the freezer for awhile. support the shaft securely near your oven
13) thread a piece of all-thread into the end of the camshaft. prepare a nut and suitable washers to aid in forcing the gear into place - time will be short once the gear is out of the oven.
14) make sure the retainer plate in in place on the camshaft
15) wearing welding gloves, remove gear from oven, place onto tip of camshaft, and quickly use the washers and nut you prepared to pull it to its proper position.
16) raise engine like it was before, lubricate and install camshaft, making sure to have the gears properly aligned - alignment is important, and details should be included with the new gearset
17) put it all back together properly, in opposite order of how it was removed.

if you're gonna do the job, i highly recommend using an all-metal gearset, not the fiber/pholenic stuff the factory used. both are readily available from most parts stores. the only real reason the factory used a fiber gear in the first place was to make the engine a tiny bit quieter. and while i would tend to condemn that choice of material, we must admit that it lasted 25 years, so it can't be that bad!

i don't know your ability, but now that you have a rough picture of whats involved, i'll let you be the judge of whether or not its within your ability.