Hey all. I'm in trouble here. In other posts, I mentioned about installing new timing gears on the truck. I got them installed yesterday and bolted up everything, went to start, no go. Posted last night, found that my dist. was not turning. Thinking that maybe busted my gear, I pulled the dizzy today, the gear, pins and rotor are fine. If spin by hand, the rotor spins. Looking down into the dizzy hole, had the wife crank the motor, and looked like the cam was not turning. So, tore everything loose, pulled the timing cover, and wholly crap, the brand new Comp Cams chain was snapped and hanging from the cam gear. The cam gear has no chipped teeth, nor does the crank gear. Some metal chunks are wedged between teeth on the crank gear. I am almost 100% positive that all marks lined up, before removing old gears, and I double checked the new gears once on. I did not do a manuel rotation once installed, I thought I was good. I don't think a brand new chain should have snapped, nor do I think that I was off on my marks. Even if I was, what would happed, maybe horrible running once started? It never did run yet since install, it did nothing more than turn over. What do I do next? Could the crank or cam be jamed up for some reason? It turned by hand fine when lining the marks yesterday. On the cam, the fuel eccentric is mounted using the same bolt thru the center to hold the cam gear. If that was to tight, would it have done something? I thought it would not matter. I really need help on this one. I thought I had followed the directions to a tee, and even called a guy who owns the machine shop here for a question. Seemed straight forward. What do you guys think? Blair

 

In your other post you mentioned that you used a rubber mallet and block of wood to tap the cam gear on. That might have been a big mistake. It's possible that you moved the cam back far enough to wedge it in place or jammed the distributor gear against the cam drive.

Here is what I would do. Take the broken chain and gear set back and claim defective unit. Install the new gear set with the dissy out. Try and move the cam forward a little by using gentle but firm pressure beind the gear. The chain should be perfectly level. Take out all the plugs and try and turn the engine over by hand. The engine should turn freely. If it truns freely then reassemble and giver a go. If it feels like its stuck then you got troubles.

There are a couple of different things that "might" have happened. One is that you "might" have wedged a lobe against a lifter and cocked it in the lifter bore. Or you "might" have jammed a valve into a piston (though I doubt this one very much). Or you might have jammed the fuel pump arm. You did have the pump arm under the pump lobe right?

Pull the intake off and check that all lifters are running on top of the lobes. Also look for bent push rods. If you find a bent rod it could very well be that you sent a valve into that piston. But don't have a pannic attack yet. Its very seldom that turning the engine over will do any damage other then to bend the rod.

So if you find a bent rod replace it, but remember that cylinder. After inspecting everything try turning the engine over again. If it wont turn over then you bent a valve, and it's probably the one you go the bent rod from. By now, if things aren't looking up, you might have guessed the next step, pull the heads and get new valves installed.

 

Before you take off the old cam gear, with a gloved hand, or an appropriate prying utensil, try turning the cam. Might answer some questions before you try and put everything back together. When you do get the old gear off, look and see how far the cam is shoved into the block. It shouldn't be too far in there. If it is, you might have some (more) problems.

Tony

'77 F250, 4X4 460 transplantee, "Flamer"
'74 F250. 460, "beater" now "1 dead ford"
'73 F250, "midnight auto" now a trailer for the flamer

 

All,
There is no excuse for breaking a new timing chain. When fastening the cam gear to the cam would pull the cam forward into position. If someone has hammered the gear on, then someone may have cracked the thrust plate and this could have driven the cam back far enough to cause lifter misalignment. This could seize a cam and break a chain, maybe. Can you imagine the forces required to break a timing chain! The cam must be ruined! The cam had to be free to align it for assembly. This would have meant that the gear was installed.
What if the fuel cam bolt is too long and protruding out the back of the gear and binding agianst the block?
I have read a post where an individual installed the wrong gear set and it bound against the thrust plate but it ground the thrust plate up.
If the crank is turning then a valve train interference would not stop the cam. The push rod would just bend.
Dissassemble and inspect.
My Way is the Highway,
KingFisher

 

[updated:LAST EDITED ON 28-May-02 AT 12:57 PM (EST)]Thanks so much for ideas. I will be looking into it today hopefully, if the new set gets here. I really don't want to have to take the intake off yet, that would be my first time, but I guess that should just be chalked up as a learning experience right? Thanks again, any more ideas, please throw them in. Thanks again, Blair


P.S. - I thought of this, should I have had a spacer, was the chain I installed not true as suggested? It looked like it was, neighbor suggested maybe off just a little, that would be enough to throw it. My old set didn't have a spacer. Also, if I did move the cam back, could I pull it forward somehow, what should be the proper measurement for such a thing? I persoally feel that the mallet and wood was not a good idea, I think I may have jammed the cam. How do you guys get the gear on? Thank you, Blair

 

>How do you guys get the gear on?

Useually very carefully!! Hehehe, no really, The cam gear in this case is "not" an interference fit. It should slide on with little to no grief. If it does require some positive motivation, aka BFH, then something is wrong. Get the hand file out and carefully file off any burs that are holding ya back. If you do wind up having to pull the intake manifold off, you might as well stuff a new camshaft and lifters in there. (more on that later) Now would be the perfect time to do so. You can get a cam and lifter set from PAW or summit for about $80. Just dont pick anything too big.


Side note. If the cam was pounded into the block, what are the chances of a cam bearing being nicked, or the freeze plug being damaged?

Tony

'77 F250, 4X4 460 transplantee, "Flamer"
'74 F250. 460, "beater" now "1 dead ford"
'73 F250, "midnight auto" now a trailer for the flamer

 

[updated:LAST EDITED ON 29-May-02 AT 03:19 AM (EST)]Just for the record, the crank gear dot points straight up at 12 oclock and the cam gear dot or mark is down at 6 oclock. Being off on this is significant and depending on the motor can try and put a valve through a piston. It doesn't sound like this is your problem though.

Maybe you should look closely at your fuel pump. Usually when you put the lever in on top of the eccentric it will snap the fuel pump lever off but in this case it might have been just right to wedge in there and break the timing chain.

As an afterthought, some double rollers will not clear the thrust plate. My Cloyes didn't. I had to grind off a small place on the thrust plate in one spot to keep the cam gear from hitting. Maybe this would be something good to check on.

 

Afternoon everyone. I think I may have found the cause or at least a contributing factor to the chain break. When looking at the truck last night, I noticed a few minor things. The cam "thrust plate" does not appear scorched or scarred or marked in any way. I can't find any marks or scrapes on the block from chain drag. I have about 1cm or a little less from back of cam gear (still on) to the block/intake. When inspecting the timing cover and water pump housing and what-not, I think I found something. Being a freshman here to say the least, I believe I may have over torqued a bolt that goes from waterpump housing to timing cover. It's one of the short ones, about 1 1/2 or 2 inchs long, the hole thru the timing cover has a "ant hill" that the bolt goes into. About a 1/4" or so is missing from this bolt hole where it protuded out. When I pulled the crank gear, there is a shiny brittle metal piece wedged between the two rows of teeth. Would that be enough to make the chain jump? I was guessing yep. Any thoughts? I am going to go home tonight, put on the old gears and chain, and see if the cam and crank will rotate freely. If they do, should I go with it and finish the job? I have a new timing set at home, wouldn't mind putting a new cam, but only if nesseccary, possible rebuilding motor next year, would rather wait. All thoughts welcome and really , really appreciated. :-X11 Thanks Blair

 

Anything that gets stuck in between the teeth could break the chain, and that sounds like what happened to you. 1 cm is very tight, and sounds a like it's (the gear) a little to close to the block. This is probably from the conversation you had with it and Mr. Rubber Mallet. When you install the new chain just be sure that the gears are in line with each other top to bottom and dot to dot. Try turning the engine over by hand BEFORE you put it all back together. If she cranks by hand I would say you're in luck, and should be ready to go.


Good Luck

 

I think the last statement by waynej sums it up pretty good. But one othre thought is if that bolt put a hole through the cover its to long and it may have jammed the cam gear also. If your sure its the right bolt put a few washers on it and apply silicone to the bolt so you dont get an oil leak out of it. Actually fixing the cover with some JB quik weld wouldnt hurt. Im thinking the chain would have ground up that peice of aluminum and that the bolt is really what jammed the gear.

Good Luck Andy

 

if you put too long of a bolt in the hole (you may have switched it with another) they will hit the timing set. that broken off piece got into the crank gear and then the chain ran over it. i am also thinking that you may have actually partially broken the chain if the bolt tightened up into it. hawkrod

 

Wanted to thank everyone for their help, havn't worked on truck lately. My oldest daughter is having surgery soon, the doctors appointments are keeping us busy. Thanks again, hope to have results about the truck to post soon. Or maybe more questions.............

 

I'm not a big fan of the timing chain. I'm going to be rebuilding my 351M and am thinking about ditching the chain and going with a gear drive system. I just have to find one for the 400 block. Pete Jackson has a set for the 429-460. Have you thought about switching over.

 

I think gear drive is too noisy.

Maybe in a HOT ROD it would be okay.


[font color=red]Dennis

Calgary,Alberta,Canada[/font]
[link:www.ford-trucks.com/guidelines.html|FTEModerator]

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Please Don't Ask Me Any Tough Questions,
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[font color=blue]78 F-150 429CJ,Silver,Explorer Pkg.
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I'm not to concerned about noise. It's a truck! I say let it be big let it be loud and let it get muddy. So is the noise the only negative thing with the gear drives?