Well, my old faithful truck (1966 F-100, 240-6) left me on the side of I-55 on Thanksgiving. The truck had a fiber timing gear set that finally died. Needless to say, I replaced the fiber gears with a steel gear set from NAPA. I have read several posts on here concerning the whining steel timing gears make verses the fiber version. I must say, I was very surprised when I fired the engine with the steel gears installed. I was not prepared for that much noise. I took the engine down again to check everything—gear faces flush, no play, oiling, no rubbing, etc.—everything was great. I have been driving the truck daily for about a week now with no problems—other than the noticeable whining. I spoke with a friend of mine who’s a mechanic about the whining; he says that the whining is due to the gears (teeth) being a straight cut. I also discussed with him if he thought additional oiling would help alleviate the noise; he indicated that it would not. (I run an oil cooler on my engine and thought about breaking off a Ľ” return line from the oil cooler into the timing gear cover to supply additional oil to the gears.) For those of you that have been running steel gears, will the whining noise decrease as the gears wear? Also, has anyone tried supplying additional oil to the gears to relieve the whining? Any comments or thoughts you have on the subject would be appreciated.

 

Sounds like a good idea, though never tried it...

But then again, it makes your truck sound like it has straight-cut gears on a big nasty V8. Kewl.

 

I know Ford used to make a helical cut gears set, as a matter of fact at one time they
made two pitches. I preferred the course cut set as they are stronger. Those were
not noisey if you bought the set. Try and sneak by using the steel crank gear from
a fiber steel combo and then putting on a steel cam along with it and you would get
noise as the cut wasn't the same.

 

Thanks for your comments. I did replace both gears. I am beginning to wonder if i got a mismatched set or simply a bad set. The truck sounds like I'm running a blower on the engine.

 

Straight cut gears will always be noisy, that's just the nature of the beast. The only reason we have helical gears is because they are quieter.

As far as the course tooth gears being stronger, that's debatable. One tooth against one tooth they would be, but with the fine tooth gears you will always have about twice as many teeth in mesh. If there is any difference at all it shouldn't be the deciding factor of which set to buy.

 

You should have purchased the Crane gears with the aluminum cam gear. The best of both worlds.

 

With the helical gear cut you always have load being carried by more than one tooth. Offenhause/Meyer- Drake went from fine teeth to course because ot the failure
of the fine pitch in the racing engine. That tells me something as that engine was always stressed to the limits. As far as aluminum against steel, I know we have come a long way in alloys but it seems to me to be out of place.

 

Ford has used aluminum against steel in lots of OE applications. The pedestal rockers in mid 70's big blocks used aluminum pedestals without problems and those are under a lot more stress than the timing gears. The Comp Cams sets are mixed metals as well and they offer a course and fine tooth design. The fine tooth is about $70 from Summit.

 

Did you ever look at the underside of those pedestals, they worn like the devil. Amc used
them as well as some others, if it hadn't been for the lifters taking up the wear they would not have lasted so long. Sorry I'm not convinced a gear set is the place for
aluminum.

 

I am of the opinion that helical gears are stronger as well as quieter than straight cuts. They are stronger because there is more surface area to distribute load along as well as multiple teeth always in contact at any time.

Glenn

 

I've never heard of a straight cut gear set for a 300. All the ones I've ever seen were helical. I have heard some 300's with significant gear whine however. I am running a fine tooth set in mine and there is no hint of noise. I think you are much better off with a finer tooth gear as it will tend to have more than one set of teeth in contact at once. These were usually found in the heavy duty industrial engines. If you go to a parts supplier they should show a listing or option for the fine tooth set. Make sure you are buying a good quality set and not some offshore knockoffs either.

Steve

 

All steel gears whine without oil lubrication. There's a way to lubricate the gears better by inserting a roll pin into the oil galley above the cam gear. Insert a 1/8" diameter by 1/2" long roll pin into the oil galley, allow 1/8" clearance from the tip of the roll pin to the outside teeth of the cam gear.

 

The aluminum pedestals do wear out faster than iron, but they last plenty long. Aluminum has no place in any application that requires direct sliding contact. A perfectly designed and made gear set will have no sliding contact at all, although perfection can never be achieved. They do have very little sliding contact and it is for a very short period of time, so gears should be OK with aluminum. Especially on the big gear.

Helical gears would be stronger than straight cut if they only had to deal with force in one direction, but they don't. Helical gears generate a thrust force due to their angle that the tooth must also stand up to. The angle also increases the temperature that the gear runs at. The thrust force is also transmitted to the thrust bearing on the crank and the cam thrust bearing and retainer.

 

And plastic definitely is not! IMO, its an upgrade either way.

 

he idea behind the aluminum or fiber gear is to give some flex to the system needed for best performance.