Another Distributor Gear & Camshaft Drive Gear Scored

[wsa111]

Will is using the yella-terra 1.65 full roller rockers & has had no problems. I am also using the yella-terra full roller rockers.

I think possibly an oil pump pressure relief issue??? Plus other X factors.

I agree the oil dump at the front pedastal would supply more oil to the front of the engine, if you have the shaft oiling rockers.

I removed the distributor with the new gear & after 10 minuites of run time you can see slight score marks from the camshaft already showing on the distributor gear. When i had the distributor out i shortened the oil pump hex shaft by .020 cause it was shiny on the point of each end of the shaft.
I still think i am the victim of soft-unhardened distributor gears which contribute to the problem. Thanks again for any ideas, Bill

 

[simon]

Hardening, and coating of any form will just help for some time, it will not solve our problem.
We need to know all the factors which contribute to the gear failure.

- We highly presume an issue with material and hardness combination.
- We presume a slightly mismatched drive helix.
- we know drive helix width has been reduced by 1/3, compared to OEM camshafts

- there also might be an oil starvation problem at the cam/ dizzy gear contact area, which could be addressed with a hand-crafted spray bar/ nozzle.

 

[xctasy]

And fifth, the level of preload on the shaft, or Backlash. Its assumed the given distributor is able to sit on the helix of the cam. It may in fact be underloaded or overloaded due to maching issues.

According to 'Backlash', our resident Aussie mechanic, lots of problems happened around late 1985 when Ford Oz re-tooled its Geelong plant for subsequent new I6 engines. The was not a reliable 3 axis line boring machine, and plenty of XE to XF Falcons had problems with gears shearing with the new small pilot gears on the electronic ignition they used. I'd guess the Canadian Windsor factory that made the small I6's was more able to deal with issues like this.

Sixth, the shaft for a 250, and the placement of the oil pump without a gasket is imperative, as the register in the block of the whole shooting match sets the amount of preload the distributor gear faces.

If you just go back to simple differential rules of preload, backlash and helix angle, lapping and oiling, and then the problem will be isolated.

 

[wsa111]

I appreciate all the response on this problem, but let me go back to the beginning.
When i first did the engine it had a crane camshaft in it & a 68 distributor.
Wear appeared on the gear & camshaft. Also the rocker arms were stock adjustable type with the oil bleed on the front shaft pedastal.
When i installed the modified head with the direct mount 2 barrel carb i had a clay smith 264 camshaft in it & a duraspark distributor.
That also was damaged.
Then i installed the claysmith 274 camshaft & ran the shaft 1.6 roller rockers & then changed out to the present setup the 1.65 yella-terra, scored again, thats where we are now.
The only part that remained unchanged was the melling oil pump, which was not modified throughout this whole ordeal.
Got to blame the pump or the pump hex drive. I have since shortened the hex drive .020 cause the ends were worn shiney.
I have emailed crow cams about purchasing 2 of there DG2A gears, but have gotten no response.
I plan to replace the oil pump with a sealed power unit along with another new camshaft & the hardened gear from crow cams.
What do you think, Bill

 

[addo]

Can the pump's pressure relief be modified for greater volume? The way this problem was related to me by an old fellow, it was the "spikes" in RPM that gave the problems. So if the pressure relief could work almost like a BOV, it may be worthwhile.

I'd check clearances on the new pump, too.

 

[wallaka]

Can the pump's pressure relief be modified for greater volume?

Not on a positive displacement pump. The only way to increase volume is to spin it faster (impractical to impossible) or modify the internals for a greater pumping ratio. There isn't any way for the pressure relief to do this because the pressure is caused by forces external to the pump, not internal.

 

[wsa111]

Not on a positive displacement pump. The only way to increase volume is to spin it faster (impractical to impossible) or modify the internals for a greater pumping ratio. There isn't any way for the pressure relief to do this because the pressure is caused by forces external to the pump, not internal.

Adam, i am aware that you can enlarge the pumps bypass port, but this is a stock pump & i will just replace it with another manufacturer.

Am i the only guy on the block with this problem???

Looking at the aussi posts, this has been a problem for your side of the pond also.

From what i've read the crow cams hardened gear takes care of the problem.

 

[AzCoupe]

From what I've been told, an aftermarket company produced some cheap gears from some form of compressed pot metal and passed them off as steel gears. I guess they look similar so its hard to tell which is which, but the cheaper gears wear out prematuraly, especially if there are other issues at hand such as reduced oiling. This is why the problem is cropping up in several applications, not just Fords. It has nothing to do with the Camshaft. The easiest way to solve it may be to find an OEM gear off a used dizzy (from your local boneyard). I also ordered a dozen Crow gears so the guys having issues can try them out and see how they work. They're being air freighted so I should get them sometime next week.

 

[simon]

did you just say pot metal, Mike?

I suggest the magnetic or spark test.
Put a dremel fitted with a grinding stone to the surface someplace it won't hurt, somewhere on the collar above the gears. Sparks= iron alloy.
With cheap pot metal alloys, usually made from non-magnetic and non-sparking (?) aluminum, zinc, copper, lead and such, it is a miracle how those inferior gears will even survive break-in period, let alone sustained load conditions.

I'll have a go at nitriding my gears (bunch of stock OEM, off FoMoCo, Autolite and motorcraft distributors, and two SMP replacement units) some time in the next couple weeks. Already talked to one of the company's engineers; although they cannot get repeatable correct Rockwell hardness readings on an iron alloy of unknown composition (just approximate values), he was confident that my gears will benefit from any form of hardening...

...even if I'd put them in the fireplace until cherry red and toss them in a bucket of cold, used diesel oil (Of course, he actually didn't quite recommend this)

 

[62goldenrodvan]

Are you sure you want to harden the gear?
We ran a soft bronze gears on the roller cams we used in our drag motors
in the past with success. :idea:

Kevin.

 

[simon]

regular ductile iron as used for the stock distributor gears doesn't work well with the improved, harder iron alloys used for today's performance camshafts.

Since the stock gear gets eaten away by the new camshafts with chronic redundancy, they need to get surface hardened.

good quality bronze alloy gears are state-of-the-art for use with steel cams like Ford's 5.0 H.O. roller engine, which are actually softer than todays flat-tapped iron camshafts.

I remember an article where they said the first set of gears on a new (harder-than stock) camshaft will sacrifice itself during break-in, which will take a lot longer than the common 20-40 minutes, all depending on how well the drive helix was ground.
The driven gear grinds on the helix, as the helix grinds on the gear, until all is settled and fine.
That was the way on stock NOS parts, sadly on the new clay-smith (and other) cams, the gear will eventually wear out before your engine has reached a thousand miles. Add to this that the helix on the new camshafts has been narrowed in width and doesn't support/ mesh in with the driven gear like on the OEM camshaft, thus aggravating the wear.

Once the stock gear is worn, excessive play will also damage the camshaft drive helix due to shock loads.

So in conclusion, surface hardness of the dizzy gears needs to be improved and closer to (but not exceeding) the camshaft's hardness.

 

[wsa111]

Simon, you need a dizzy gear hardened to 39-42 on the rockwell C scale to match the new camshaft billets. Bill

 

[Bort62]

On SBC's, when switching to a roller cam, you use a soft bronze gear because the roller cam blank is softer than the flat tappet cams.

If you don't the factory hardened dist gear will chew the cam up.

 

[AzCoupe]

I've talked with Clay Smith and Comp Cams, both say not to use a hardened gear. Both recommend using a stock gear (Comp also recommended a bronze gear). If you use a hardened gear and its harder than the cam, you'll end up replacing the camshaft. However, if you use a stock or bronze gear, the dizzy gear may (or may not) wear out prematuraly depending on the various factors mentioned above. It's not a difficult task to periodically check the dizzy gear, or replace it, if and when it's required. It's certainly easier than replacing the camshaft.

I talked to Performance Distributors, which also uses stock OEM gears. Here's a few comments from them;

*Excessive distributor gear wear can be a problem with Ford engines. Most of the time, the problem is a result from the use of a high volume oil pump, which put a lot of stress on the distributor and cam gears. High volume oil pumps are not necessary on a street driven engine that turn less than 7000 rpms. Only extreme racing engines require a high volume pump.
*If your oil pump mounting bracket has elongated holes, make sure the distributor shaft and oil pump shaft are aligned so the distributor turns freely before tightening the mounting bracket bolts. Failure to do this will cause a binding situation, thus damaging the gear.
*Stock Ford hex oil pump drive shafts are known to vary in length. If too long they could cause a bottoming or binding situation which will damage the gears. Use distributor shims when needed.
*Brass distributor gears can be used to avoid damaging the cam gear. However brass gears are softer and can wear out quicker than cast gears, but they will not cause damage to the cam gear. If using a brass gear, check it occasionally for wear.

 

[wsa111]

Does ford still sell the stock replacement gear for our engines???

Who makes bronze gears for the six?????

Mike, did you ever get a response from crow cams on their gear as far as hardness? Thanks Bill

 

[AzCoupe]

AC Delco #F719

No response from Crow, but I do have a dozen gears being air freighted.

I'm looking into a supplier for bronze gears.

 

[simon]

what is the rockwell hardness of the clay-smith cams, actually?

 

[wsa111]

Guys, here is a good one.
I figured i needed to change something, since i have had dizzy gear wear since i built the engine.
The oil pump in the engine right now is a melling.
Several of our forum members & a cam manufacturer suggested changing brands of the oil pump.
Well purchased a sealed power pump & it has the same casting marks & on the side it had M65B, which is made by melling.
So since i'm back to square one, i shortened the pressure relief spring on a spare melling pump --.070.
I plan to drop the pan next week & install the modified pump.
After that i will install another driven dizzy gear from Mike at classic inclines when he receives the hardened gears from crow cams.
Will let you know, Bill

 

[66 E100 Pickup]

Well purchased a sealed power pump & it has the same casting marks & on the side it had M65, which is made by melling.

IIRC that group of companies is all the same. I found that out when shopping for pistons. Sealed Power = Federal Mogul = Speed Pro and I think Melling was in the mix too. It's a crazy world. And some of the cam guys get their cores from the same folks--Isky, Crane, Comp, etc. all from the same company. They just do different things with them.

John

 

[AzCoupe]

There are only two companies that make cam blanks in the US, and I believe only one of those makes one for an inline application. Hence, they all use the same billet. They just grind them to their own specs.

Federal Mogul is a huge conglomeration of companies. They own Sealed Power (pistons, rings, bearings, etc), Speed Pro (pistons, rings, valve train), Fel Pro (gaskets), Moog (steering), Wagner (brakes), Champion (plugs, filters), Carter (fuel piumps), Anco (wiper blades), Precison (u-joints, needle bearings), and others. I don't think they own Melling, but they may have their Sealed Power oil pumps made by them?