cam gear? newbie needs help
 

Ok so I picked up a dirt cheap 1994 F-150 sport with a dead inline 6 300 (174k miles). I trust the guy I bought it from, he says the cam gear is shot.

While I know how to turn a wrench, this engine is new to me. I own a couple dodge/cummins and can do about anything I want on those. I just don't know how hard of a job it is to change a cam gear on this 300.

I would appreciate any help you guys can offer me. If its more work than its worth I might just drop in a 12 valve cummins I got sitting around for fun :D

I have never done this myself, but I am getting ready to.

If the cam gear is bad, you will need to change both the cam gear and the crank gear.
You have to pull the vibration dampener/pulleys off the crank. Then pull the timing cover. I believe the crank gear will slide off without too much effort. The cam gear, unfortunately, is pressed on. It can be really hard to pull it with the cam in the engine. Most people end up pulling the cam out. This is time consuming. You have to take off the valve cover and the lifter cover on the side of the block. You have to back off the rocker arms, pull the push rods, pull the lifters. The pushrods and lifters need to go back in the same spot they came out of, so keep track of their position (most critical for the lifters). You will have to pull the radiator and maybe the grill too to get the cam out. When taking the cam out and putting it back in, be careful not to ding the cam bearings. It is easy to let a lobe run into one and nick it or scratch it.

Once the cam is out, you may want to take it to a machine shop to have them pull the old gear and press the new one on.

Some people have reported that they were able to pull the gear at home. You have to be careful not to bend or scratch the thrust plate behind the gear. Some have reported that they were even able to pull the cam gear without removing the cam from the engine. It is not easy to get a puller on it, and often the puller just breaks off part of the edge of the gear rather than pulling the gear, and you can end up with broken pieces of gear down in your oil pan.

If you do a search for timing gears on the site, you will probably find more info.

Hope this helps.

Thank you! that is a big help. while the cam is out is it beneficial to replace it with an aftermarket cam of some sort?

LoL sorry I'm just not that good with engines that use spark plugs. My cummins made a pretty good gain with a max spool cam though :-jammin

Use caution when pulling the gear off the cam not to get the puller bahind the retainer. It's pretty hard steel and easy to break. It's even harder to find one after you break it.

And when those fiber timing gear goes, you'll find your oil pump pickup is jammed with the remains.

The gear usually starts chipping up little bits before it goes completely. My gear was still holding but had nearly clogged off the oil pick up already.

Boy, can I testify to that!!! I broke my thrust washer trying to get the cam gear off and it took me almost six hours to find someone online that carried it. It's cheap, but a bitch to find.

Thanks guys, I have been out on the road and haven't had a chance to even push the truck into my garage yet to get started. I ordered the new gears and they should be here Thursday and I should be home Friday to tear into it.

I will search for the write up, it would help a lot!

Yup. Me too. Just did this a few weeks ago and had to drive 45 min. each way to my parents to get one off my other engine there. I think it's cast steel, case hardened by the look of it. Wears good, but very brittle. I called around and the nearest one was at a dealer 3 states away. This on a Friday afternoon. I'd spent weeks collecting parts, getting machine work, etc and wanted to assemble over the weekend. It would be Tues. to get a new part. Wish I'd ordered if I'd had any idea how tight that thing was on there! Trashing the gear and the cam, I only wanted the plate and the key. What a lot of crap for one little part. Anyway, both of mine were on so tight I'd recommend pressing it off. I didn't have the luxury of a press(or a buddy with one), so I tried a puller, busted the fiber gear, couldn't get between hub and plate with jaws, so I figured the plate would be tough enough. Wrong! Be careful with this, so you don't end up with pieces!

Well I think today is the day that I am going to start this project of swapping out the cam gear.


I did a search but couldn't your write up ? I also tried to search to see if a piston and valve could meet when the gear goes.. but couldn't find anything on that either

The 300-6 is a non-interference engine so you're safe. You really should pull the pan and clean all the gunk out as well or you'll be back in there quite soon.

I don't think so, since the pistons do have a valve recess (not sure if it lines up now that I think about it), but the valves are way up inside the combustion chambers as well. I don't think they hang very far below the bottom of the head at all, unless you put in a big cam.

Read the following, it is a post I wrote some time back. The engine being described is a 1990.
1. Remove the valve cover
2. loosen the rocker arms and remove the push rods and number them.
3. remove the distributor--- line up the dist to number 0ne first and note where the timing mark is ( should be between 0 and 10 degrees on the timing plate ) try not to turn over the engine from now on.
4. remove the valve lifter cover behind the dist, the long and wide tin thing on the drivers side of the engine.
5. remove the lifters and mark them as to where they were, an egg carton makes a good container.
6. the cam is held in with two bolts behind the gear , they are assessed through holes in the cam. If you have to turn the engine to get the cam to move return it to where it set in step 3.
7. You should be able to remove the cam, be VERY CAREFUL not to tear up the cam bearings when you pull the cam. Pull it out slowly and lift it at the same time and you will be able to feel the cam bearings as the journals slide in and out of the bearings, there 6 or so cam bearings you have to clear.
On my truck I had to remove the radiator, ac condenser, and grill and drop the bumper to clear the way for the LONG cam. At this point you can devise some way of removing the gear. As mine was fiber , I sawed off most of the gear and took a hack saw and carefully split the steel hub of the fiber gear. Even with all this I had to use the largest gear puller I had and it didn't give up easily.
A word of caution, when you unbolt the cam from the engine you will be unbolting the cam thrust plate, This is a cast iron oval plate just under 1/4 inch thick and it is ground on both sides. DO NOT TRY TO PUT A PULLER ON THIS PLATE to pull the gear you will end up with a two part plate. In fact you may have to break this plate to get the jaws of a puller behind the gear and if you are careful in splitting the gear hub you might save the plate Don't loose the cam gear key you can't get them. While this is all in parts on the ground look at the cam and lifters.Now is a good time to replace the cam, lifters ,thrust plate and push rods. Check the web for a Melling cam kit and timing gears( yes it is the same Melling that used to sponsor Bill Elliot in Nascar). It's stock and the cam kit will go for around $80. with cam and new lifters in the kit. The gear set is about $35 and the thrust plate is $20 or so. Push rods are $1.50
each. Gasket kit for the side cover and the front cover( get the one that comes with the front seal ).
Before you run out and do all this get a good manual for Fords and read up on this. I have described what you would do for a 1990. Yours might be slightly different. Its not as hard as it sounds , it just pisses you off when you find the cam won't clear the front bumper as it is too long
As far as timing the cam , replace both gears . A good puller will remove the crank gear easily, I think Auto Zone has a loner gear puller for the crank gear.If you replace the crank gear and you should, make sure the DOT IS FACING OUT!!! It is also cheap enough for you to buy a puller, about $15. Getting the gear on is the easy part as long as you REMEMBER---to put the spacer and thrust plate back on first. I am assuming your cam has the spacer and thrust plate behind the gear, I think they all do. To replace the gear you get a grade 8 bolt from home depot to match the threads inside the cam nose, mine was 7/16 x 14 tpi. Yours may be different but the grade 8 bolt is for safety so you don't break it off in the cam while you are using it to pull the gear on. Any way you put the spacer on first with the bevel to wards the cam and then the thrust plate , if it is worn get a new one from ford for $8, then the key goes back in the cam, save the original key as they are no longer available from ford and they seem to be a hardened key. Start the gear on the cam and make sure it is going on straight , I made an aligner out of some scrap brass turned on a lathe so it fit inside the gear and had a hole through it of 7/16 to match the bolt. Start the gear by hand , it won't go far, find a heavy washer with the inside hole the size of your bolt and the outside larger than the hole in the gear.Thread the bolt in the cam nose and tighten away, a little oil is helpful, and you will pull the gear on the cam. Be careful of the following----- on my cam the nose of the cam stuck out of the gear about 1/32 of an inch when seated all the way, and there was very little clearance between the thrust plate and the cam gear. It should be .005 or something like that. Using the above method the cam will stop moving when the nose hits the washer. I noticed at this point that the trust plate
had a lot of clearance and I realized that the gear had to keep moving. I made a spacer about 1/4 inch thick to put between the
washer and the gear so the nose would pull through more, the inside diameter of the spacer was larger than the cam nose.