Another thougth. Say that my cam gear did desintigrate. If the cam stopped rotating but the crank shaft was still spinning, wouldn't I need to be concerned about damage due to the pistons slapping the valves? Is the I6 and interference motor? I hope to god it isn't.

 

Don't know the answer to that for sure on this engine, but generally US manufacturers are smart enough to design engines so that they don't self-destruct in this way...

I have friend with a Honda whose oil pump just disintegrated. The oil pump is driven off the timing belt, and he was told by a Honda mechanic that it's done that way so that if the timing belt breaks, the oil pressure drops and the lifters collapse so that the pistons don't bend the valves. What a house of cards...

 

Hi,wanted to let you know that if you haven't done one of these before you are for a treat. The cam gear is pressed onto the camshaft so you will need a puller to press off the old gear. The fun begins when trying to install the new fiber gear on the camshaft as some cams don't have don't have threads to use a gear installer so some techs heat the gear to expand the metal so it will slip on or with very little persuasion it will go on the cam snout. You want to make sure you do not hit on the camshaft to hard or you damage the lifters or drive it out the back of the engine and that would be a mess. The other thing is not to let the parts store give you a steel gear in place of the fiber one unless you want it to sound like it has a gear drive in it. Hope this helps. STEVE

 

no the I6 is NOT an interference engine. most if not all the american trucks are like that. about half of the car engines are also not interference engines. i don';t know the exact engines that are interference engines but i do know a lot that aren't. so no piston and valve slapping. just a crank rotating pistons that aren't doing much of anything. when i replaced my timing gears on my engine when i rebuilt it, it was kinda a pain to take the gear off. just BE carefull when taking that gear off as to not break the cam gear holddown plate right behind it....i did and they are not stocked at the ford dealerships and i had to order it from michigan. its only like $20 but thats $20 you don't have to spend.

 

If the timing gear is broken, and not turning the cam shaft, the engine will have no compression. Compression depends on opening and closing valves. If they don't close, there can't be any compression. If the distributor is not turning, a compression test will be a waste of time. I broke a timing chain on a 302 many years ago, and the engine turned over very quickly. Much faster than any normal engine would go on a starter. This was because the starter was just rotating the crank and pistons, and not fighting compression to do it.
The 4.9 is know for a long life. It is not uncommon for the engine to go 200, 300, or 400,000 miles without problems. If your fiber timing gear is broken or worn out at less than 200,000, something else may be wrong. I would turn the cam by hand to make sure it moved without binding. Pull the valve cover and watch all the valves move as you rotate the cam. Everything should be smooth and take a continuous amount of torque to turn the cam. If you hit a real tite spot, going to have to find the reason before putting everything back together.
Good luck Frank

 

Ok, I returned home from my buisiness trip this evening and tried starting the truck again. I was wrong. The engine is turning over. Unfortunately after running ligths the other night to tow it home, the battery is pretty much dead. Thanks 89frankenford for the confirmation that the I6 is not an interference engine. One less thing to worry about.

Like fmr9 says, I too heard that the I6 was notorious for going 200 or 300 thousand miles without any trouble. My father or myself have owned the truck from day 1 and it was maticuliously maintained. We have been running synthetic oil in her ever since she turned over 10000 miles. For it to have a premature failure at 155 has me worried. I'll be sure to do as fmr9 suggest and check out the operation of the cam before reassembling the engine.

I won't know much until I get into it sometimee tomorrow. I'll let you all know what I find out. Thanks again everyone for your help!

 

Well I tore into this project Friday night and all day Saturday. A lot of time was wasted making trips to town to collect the necessary tools, parts, etc. I also ran out of LP for a bit making it rather uncomfortable working in the garage with an outside temp of 10.

Well all of your diagnosises were correct. It was the fiber cam timing gear that was the problem. After pulling the radiator, water pump, altinator, and timing cover it was immediatly obvious. I'd say approximatly 3/4 of the teeth were busted off. The fun began when trying to remove it. Using a two jaw gear puller, the fiber gear would must break apart behind the jaws. Eventually, the whole gear broke apart leaving only the steel press on gear center. I eventually was able to removed this by loseining the cam cover plate behind the gear and carefully using a two jaw puller on that to pull of the old gear center.

With the gear center on, I was able to turn the cam with some channel locks. It took a bit of torque to turn it, but it did turn with no noticable additional drag at any location along its radial path. Does it usually take some effort to turn the cam shaft? I would almost think so as it has to open and close the valves while turning. The distributer does rotate with the rotation of the cam, so good news there.

Also what is everyones thoughts about a replacement gear. I heard in this thread to replace it with a fiber gear, but I'm concerned about this happening again in another 100 thousand miles or so. What about the replacement alluminum gear. I would think it would still offer the failure protection if the cam was ever to lock but would have a lot longer wear life.

Now comes the fun part of removing my oil pan to clean it out and replace the oil pump and pick up screen. I've decided I'll do that to prevent premature a blocked screen or a pump failure as mentioned earlier. Any tips on removal. I see in other thread they talk about having to lift the engine to remove the pan. Is there any way to lift the engine with standard jacks or do I need an eninge hoist?

The fun never ends. Thanks to all you are saving me a ton of cash. I don't know why I've delayed become a supporter of this forum in the past. I've always meant too, but never have. I tell you what, I'm not delaying any longer.

 

I would go right back together with a fiber gear. Some reasons. Much quieter, most fiber gears last longer than the bodies on these trucks, should anything go wrong, the fiber gear will break as designed, much easier than any thing else.
I had to lift an engine once and was too cheap/ lazy to rent an engine hoist, so I laid a 4x4 nailed to another 4x4, between two roof truss. Used a comealong. With the hood off, I lifted the engine enough I could push the car away and then lowered it back down. Since you just want to go a few inches, I would think that would work real well.
Good Luck Frank

 

just loosen the motor and tranny mounts and jack that thing up with a floor jack. should have enough clearance then. its still tight but doable.

 

the best way to do it is lift it by the tranny specifically the front of the tranny and loosen the engine mounts and tranny mounts and jack it up about 5 inches so you can get the pan out. you do not need an engine hoist unless you have one readily available.

 

I borrowed an engine hoist from a friend and was able to jack the engine up without unbolting the transmission, just enough to squeeze out the oil pan. The problem has been getting the engine to drop back down onto the mounts. I was up until 1am the night before trying to mount it. I got the driver side lined up properly to slide over the mounting bolt, but the passenger side has been a pain in the @ss. I was out of town yesterday and part of today so I'll try again tonight. Maybe this time with a crowbar for persuasion.

 

Try just starting the nut on the motor mount stud on the driver's side, preventing the stud from popping out of the mounting hole but allowing you as much play as possible in order to get the other side in. Then you can do whatever you need to do to get the other side in without losing the driver's side...

 

That's where I am right now. I've got the nut started on the drivers side so it won't slip off while I man handle the engine to get the other side mounted. The problem is that i cannot get any leverage on the engine to slide it forward the necessary 1.5 inches so it'll drop down on the mounting bolt. If it weren't bolted to the transmission it'd be a lot easier, but at this point I really don't want to unbolt the tranny if I dont' have to. I'll try a pry bar tonight and see if I can get it to drop.

 

Wow - if the engine needs to come forward and 1.5"s on just one side, I'd almost think the tranny mount is already broken... the tail shaft of the tranny would have to be several inches to one side for the engine to be that crooked...

 

EXACTLY Herdsmans right!!!

Def dont do that its harder to line up the motor/tranny then it is to put a motor on the mounts. try loosening your tranny mount that should give you enough extra play to get that motor mounted. if you need to move the pass side of the motor forward push the rear end of the tranny towards the pass side the rotational force should move that side of the engine forward. just make sure when you bolt everything down your all straight and true.


oh and you'll def want to check and make sure theres still rubber in your tranny mount...sounds like its probably shot.