My 1979 300 quietly quit going down the road on me the other day. After pulling it home and looking it over, it appears as if the timing gears are gone (the rotor doesn't turn when the engine is cranked, also pulled the distributor and had someone turn it over as I looked in the hole and the camshaft didn't move). I've had experience rebuilding V-8's but this is my first 6 cyl. Any advice on replacing the timing gears would be greatly appreciated.

 

if you are familiar with the procedures on v-8 then there is nothing to it. the 300 is easy no chain just gear to gear. I would recamond buying a heavy duty steel gear but they are double the price. so it is your call. other than that i tis self explanitory.
the lifters are accesable via the plate on the driver side of the engine.

 

Thanks. Yeah, I've already purchased steel gears, they may be noisier but it will be a while if I ever have to replace them again.
My main concern is about installing the camshaft gear due to some posts I've read here that talk of instances when the gear was being installed and ended up pushing the camshaft back, possibly jamming up some lifters. Well, I'll see what damage I can do to it this weekend. Thanks for the info.

 

 

I rebuild my 300 a year ago and was suprised to learned that the cam gear has to be pressed on. crank gear is a tight slip on. may as well do a cam and lifter job while you at it. If you try to do it in the block you could seriously damage things.

f150 4x4 300/6 with 95 dual cast exhaust manifold, Unilite and mileage cam, I get about 20 mpg on the highway.

efstop22

 

I just went through the same thing on my 1990. 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 asuming your cam has the spacer and thrust plate behind the gear. 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 diffrent 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 towards 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 thighten 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 clearence 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 clearence and I realised 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.
Removing the gear was no picnic. The 90 gear is not metal and there was no place the gear puller could grab as it kept slipping off the phenolic gear, the book says simply pull it off. Yea right try it with one that has been in place for 10 years. I ended up removing the cam and bandsawing the gear off so I could get a puller on the steel hub in the gear and it took one hell of a puller to move the hub as soon as it went BANG and broke loose it came off easily. Hope this helps.
Bob / stractor

 

Hi just in case youhave to removed the cam, if it is a fibre gear you probably can't pull it , here is something I wrote for some one else.



Hi, relax you aren't in as deep as you think, but ( it is a big but )
you will probably end up removing the cam. I just went through the same thing as you are now. The cam gear on mine ( 1990 ) is fibre and you couldn't get a puller to move the gear for love or money.
You will have to do the following.

1. Remove the valve cover
2. loosten the rocker arms and remove the pushrods 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 acessed 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 You might be better off as yours is earlier.At this point you can devise some way of removing the gear. As mine was fibre , I sawed off most of the gear and took a hack saw and carefully spilt the steel hub of the fibre gear. Even with all this I had to use the largest gear puller I had and it didn't give up easily.
:-staun 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 pushrods. Check the web for a Melling cam kit and timing gears( yes it is the same Melling that used to sponser 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. Pushrods 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. When you replace the gear on the cam you can do it while the cam is out. It presses on using a bolt and a heavy washer ( get a grade 8 bolt and washer from Home Depot ) as the cam nose is internally threaded, don't forget the thrust plate first. The timing marks are dots on the crank and cam gear, all you do is align the dots. Also be very care full replacing the cam as you don't want to mark up the cam bearings. Use a torque wrench (and blue locktite), if you have one on the cam retaining bolts.

Thats the basics, look it up before you start.

Bob/stractor

 

Just for the rest of us, when do you recommend replacing the timing gears, I've got 201,000 miles on my 88 and things seem OK. I'm not eager to jump on this job, but I'd rather do it at home at a time I choose than get stuck somewhere. Also, seems like that would also be a good time to freshen up the head and check out the cam (reseat valves, springs, ....)

What do you think, am I on borrowed time?