mismatched tooth pattern on new cam

Simon, great link, especially the rockwell C scale hardness numbers.

Maybe someone will come up with the fix.

I may go to our local college & see if they can do some testing on the gear collection i have.

I had this course in college but never worked in a heat treating or a testing facility. All my experience is in automotive technician status or automotive service management.

But that link gives me a place to start on the witch-hunt, Thanks Bill
 
wsa11 for the most part you are dead on the grinders sell anything to anybody with their girlfriend's credit card however when talking about a few extra horses even the guy at the local station talk cam. they do not know a cam from a crank. if the gears are cut etc... right they could make them out of lead and get longer service than some guys say they are getting. start referring people that have an idea what they are talking about ie the right questions to ask these problems woul almost disappear. or mabe cam and dist. gear packages with warrantees... now we're talking.
 
Has anybody tested the cam helix and distributor gear to mesh correctly?

My block is currently out for a bore'n hone job, so I can't rig them up myself.
 
update: I've sent out a trashed gear for metallurgical analysis.
Depending on how fast they work, we'll get to know the composition of the iron alloy, and the possible treatments to gain some points on the rockwell scale.

Still, I am unable to check for correct angle of the drive helix' teeth. Maybe someone else can jump in here.

Class? Anyone?

Anyone?

Bueller??
 
The metallurgist called me today. the gears are made from high carbon steel (also some silicium and traces of molybdenum)

He was amazed to learn that the gears I sent him were actually OEM (distributors were all original and date coded from C4 to D3) and that all came from running cars, because the alloy appears to be completely untreated.

Other than the teeth cut, they are merely cast blanks, and highly inapplicable for use with anything but the original camshaft Ford put in the engines back in the day.

We now have valid proof that stock gears from Ford dizzys will inevitably fail when used with any camshaft of better quality than the OEM cams.

Heat treating is strongly recommended, but a propane torch and a bucket of used motor oil sure won't do the trick.
 
Simon, i conversed with a heat treating shop the other day & he said since nitriding is only .007" deep that the rockwell C test may give a false reading.

What he suggested was hardning some gears & then run a file test.
What he ment was he has a number of files for say 40 rockwell-50-60.
Each file will only file the material if it is hardened for. For instence if you run a 50 file on a 60 surface the file will slide like its going over glass, or you run a 50 file over 40 hardness it will remove material.

When i get some more gears i am going to send him some for nitriding & testing, then after that have the gears melonized by another vendor. Bill
 
First, I think that saying a stock OEM gear will fail on an aftermarket cam is totally incorrect. In fact, there are literally hundreds of aftermarket cams out there running with OEM dizzy gears, with no problems what-so-ever. Explain that?

There are many other reasons for gear failure that I haven't been addressed.

What oil viscosity are you using?
What type of oil are you using?
What is your oil pressure @5000rpm's?
What is your camshaft end-float?
What is your dizzy end-play?
What does the wear pattern look like on the bad gear?
Have you check oil supply to the gears?
What steps were taken when installing the gear?
How long before you noticed the wear?
How was the surface finish when installed?
Was the gear new or used?
What method was used to lap the gears and when was it done?
If lapped, what were the results?
What method was used to check the pitch and mesh?
What is the Rockwell hardness of the OEM gear?

simon":2gd7tynu said:
When fitted dry, there is some binding between the camshaft and the distributor gear. I've double checked with both used and NOS dizzy gears, and with both the old FoMoCo camshaft and the new ClaySmith grind. It only binds with the new cam.
Click to expand...
How was this checked? In the motor, or on a workbench?
simon":2gd7tynu said:
I finally found the time to dig up my old 250 Ford cam and compare it to the clay smith grind. The drive helix on the ford camshaft is much wider and supports the driven gear of the distributor way better. Consequently, the load is applied unevenly, which leads to uneven wear.
Click to expand...
Again, how was this checked? And is the Clay Smith cam new, or used?
What method was used to reach your conclusions? Or are they assumptions?
 
The casting for aftermarket cam and OEM cams are the same. When I was working at crane cam gears were one things on a cam that fine as long as things like the endplay on the dist were checked and a stock oil pump was used.
At Crane only the lobes were different from stock specs on a cam unless it was all out race part like the nascar stuff is.
It sounds like its not the gear cutting but the facing of the gear teeth that may have caused the issue.
 
I'm definitely not trying to poodle on your business or your opinion, Mike, but the stock gears just are what they are, and they are inadequate when used with a new camshaft of a significantly higher surface hardness.
If they were suitable, we wouldn't have to discuss this topic, now would we...?

"Binding" was checked for in the old motor with a sealed power oil pump and TRW pump drive in place before it was taken to a shop for a bore`n hone job. So I can't recheck until in a couple weeks (or months).
Sure wasn't severe binding, but didn't really feel comfortable either.
A workbench check is pretty useless.

@80broncoman:

incorrect gear tooth facing sounds possible, but I have no solution to this problem. No sensible shop will rig up their machines to re-shape a handful of gears or camshafts.

Are you sure the casting technologies and alloy composition used for the cam cores haven't changed in 40 years?
 
I have looked but could not even find wheather this is a small six or a big six.
But I just went out side and measured the gear cut into the cam on a big six. The cam is whatever brand of cam Jasper installs on thier rebiuilds. It had no abnormal wear at all on the gear but the lobes did show wear.
The gear teeth facing cut the gear to .525 height. (measured front to rear on the cam)
I'd be very surprised if othe ford sixes had a different size.

If you put the engine together and ran it with its "slight binding" then I really would not be surprised by any parts that don't last. I would not expect parts would self clearence without wearing.
 
simon":3camqqxk said:
I'm definitely not trying to poodle on your business or your opinion, Mike, but the stock gears just are what they are, and they are inadequate when used with a new camshaft of a significantly higher surface hardness.
If they were suitable, we wouldn't have to discuss this topic, now would we...?

"Binding" was checked for in the old motor with a sealed power oil pump and TRW pump drive in place before it was taken to a shop for a bore`n hone job. So I can't recheck until in a couple weeks (or months).
Sure wasn't severe binding, but didn't really feel comfortable either.
A workbench check is pretty useless.

@80broncoman:

incorrect gear tooth facing sounds possible, but I have no solution to this problem. No sensible shop will rig up their machines to re-shape a handful of gears or camshafts.

Are you sure the casting technologies and alloy composition used for the cam cores haven't changed in 40 years?
Click to expand...

I've beat on stock gears harder than anyone else here on the forum and in 10 years I've never had a problem.

Thats with stock cams, Clifford cams & Clay Smith cams.

Making a blanket statement like that,

but the stock gears just are what they are, and they are inadequate when used with a new camshaft of a significantly higher surface hardness.
Click to expand...

Is just misleading.

Hundreds of people on the forum have used Clifford, Isky, Crane & Clay Smith cams with absolutely no problem whatsoever.

How many inch pounds on your torque wrench did it take before the cam moved?

Did you make sure that you had the right length bolts in the pickup tube? The wrong length bolt in one of the holes will cause binding of the pump.

My motor manual shows how much it takes to move the assembled crank but I never looked to see what the specs were to move the assembled cam/oil pump/distro.

I'll take a look in my manuals today and see if it lists it.

I'd say more research on your part is in order. :) And I'm not saying that in a "mean" way either :wink:

Later,

Doug
 
Mustang_Geezer":2ddlubp5 said:
And I'm not saying that in a "mean" way
Click to expand...

didn't consider that as an affront either.

I have evaluated the whole topic and came to one conclusion:
since I can not present any technically sound results now or in the near future, the thread should as well be closed, especially since only a very small percentage seems to have encountered gear problems of unknown origin, if at all. Also, don't need to alarm other board members on an issue as such. Sorry if I should have caused any inconvenience.
 
simon":3fe3f8of said:
Mustang_Geezer":3fe3f8of said:
And I'm not saying that in a "mean" way
Click to expand...

didn't consider that as an affront either.

I have evaluated the whole topic and came to one conclusion:
since I can not present any technically sound results now or in the near future, the thread should as well be closed, especially since only a very small percentage seems to have encountered gear problems of unknown origin, if at all. Also, don't need to alarm other board members on an issue as such. Sorry if I should have caused any inconvenience.
Click to expand...

8) i am not sure the thread should be closed yet. as long as the information is put out in a civilized manner, there is no problem. it also gives us things to think about when installing new parts and combining them with used ones. keep it civil, and perhaps it will eventually even become a sticky posting. one good result of this thread is that mike is prepared an excellent article on this very subject, and it will be a good read when he is done with it.
 
Edit!!! I don't doubt the engine building skills of anyone on the forum.

What oil viscosity are you using? *
What type of oil are you using? *
What is your oil pressure @5000rpm's? *
What is your oil pressure at idle?*
What is your camshaft end-float? *
What is your dizzy end-play? *
What does the wear pattern look like on the bad gear?
Have you check oil supply to the gears? *
What steps were taken when installing the gear? *
How long before you noticed the wear?
How was the surface finish when installed? *
Was the gear new or used? *
If new, what brand and material? *
What method was used to lap the gears and when was it done?
If lapped, what were the results?
What method was used to check the pitch and mesh?
What is the Rockwell hardness of the OEM gear?
Did you use camshaft breakin lube on the gears? *

Lets get back to a scientific approach and try to find similarities, or a pattern.
I have seen lots of different results over the years.
I don't feel like we will find a single smoking gun, however, I do feel that we can find a workable solution.
This solution might be a combination of things.
Whenever I build an engine, I always rework the oil passages in the block. I disassemble the pump and clean it up inside. Sometimes I try to increase oil to the dizzy gear. I tend to run tight bearing clearences and low viscosity oils. I have seen how much horse power can be robbed by thick oil. I would imagine it would take more power to drive the pump.
I have seen problems from excess end play on cams and dizzzys. The cam on the sixes is controlled by the plate on the front of the block, so it shouldn't be an issue.
The dizzy is another story. It appears to let the gear set on the pad inside the block and would possibly bind if the dizzy were setting too low in the block. It appears that the correct way to set end play in the dizzy would be to bolt it in the block and measure the up and down play with an indicator and shim it (on top of the gear) accordingly. Then when you pull the dizzy out, it might have more end play than it has while installed.

Edit!!! I don't doubt the engine building skills of anyone on the forum. I feel the problem is a combination of things.
The changes in cam cores/material. The added strain of a performance engine RPMs/ faster revs/ the pulsing of a radical cam at low RPMs.

I feel the solution will be a combination of countermeasures. Minimise load on oil pump with low viscosity oil/ reworking oil passages. Possibly even creating an external bypass on the pump.
Increasing oil to the gears thru whatever method possible.
Creating a workable method of checking end play and gear mesh.
 
8) perhaps the best thing is to install a new gear when installing a new cam. also check the clearances before final assembly so that you can make needed adjustments. maybe even soak the new dist gear in something like Z-max and heat the gear, then install it after it cools.
 
simon":3di2s28u said:
Mustang_Geezer":3di2s28u said:
And I'm not saying that in a "mean" way
Click to expand...

didn't consider that as an affront either.

I have evaluated the whole topic and came to one conclusion:
since I can not present any technically sound results now or in the near future, the thread should as well be closed, especially since only a very small percentage seems to have encountered gear problems of unknown origin, if at all. Also, don't need to alarm other board members on an issue as such. Sorry if I should have caused any inconvenience.
Click to expand...

No, you havent caused any inconvenience IMO....I'm curious as to why its binding and if its the cam/distro gear and how you came to that conclusion?

Did you look to see if there was excessive wear on the cam thrust plate? I was talking to someone the other day and we were talking about the plate. I'm sure that everyone is using the stock 30+ year old item.

Could it be causing some alingment issues if its badly worn? I dont even know if they are available new or not.

When you get your engine back from the machinist maybe you could get some of that stuff they coat rearend gears (forgot the name of that stuff :roll: ) with to check the pattern and spin it a few times & post some pictures?

I would think you could shim the distro to get a good gear pattern.

What did Clay Smith have to say?


Later,

Doug
 
Definately keep this topic open.

I have spoken with Mike, & he is going to LA to get some dizzy gears tested for hardness, this includes oem gears, other gears he has & the 2 AC Delco F719 gears i sent him, plus testing hardness of several makes of camshafts.

I believe George at clay smith cams is going to parkerize some of these gears.

I ordered several F719's & am going to get them checked for hardness & possible nitriding them to a higher rockwell.

Gary, on my engine i just shortened the oil relief spring .070", that brought my hot oil pressure from the high 50's to 47-48 area psi, using 10W-30 oil. This was a stock melling oil pump.

The pump & the block are the only common items from my original buildup, now the pump has been taken out of the equation.

I also have another idea howto increase oil to the hole in the lifter galley which is right over the camshaft.

I am also going to get a quote on melonizing the hardened dizzy gears when i do get them back from the heat treater.

GM uses the melonizing process on the replacement gear in their performance parts book for the chevys.

Crane also markets a gear for the small block ford which has a hard face surface coating on their gears.

A lot of good things are going to surface on this subject in the near future, Bill
 
I agree, keep it open. I've done a ton of research over the past two weeks, in fact it's about all I've done. I learned a lot about gear failures and why they happen by talking to people in the industry, searching the web, and reading books and articles. Unfortunately no one put all the info together in one place, so I spent the time writing a Tech Article, which will be posted on the website. This is a good thing, and we can all learn from it. Trust me, I did. :)

I know you don't mean to spill the apple cart, but do think your quick to make an assumption, and have not addressed all the possible issues. You seem fixated on hardness and gear mesh, but there are a lot of other reasons for gear failure.

Did you know that new gears and cams must be broke in, and that the gears will set to one another. They are just like the lobes of a cam and the lifters. You never use old lifters on a new cam, or change the order of the lifters, the same holds true for dizzy gears. A new gear, or a new cam may cause binding until they are broke in properly (1500-2000rpm for 20 minutes). This is a must and failure to do so can result in gear failure. You can also lap out high spots. Its best to lap the gears before hardning, but it can be done afterwards. How many check cam end-float and dizzy end-play, which determines proper alignment? I doubt many, if any. The list goes on........ read the article.

Tech Article http://classicinlines.com/dizzygear.asp
 
Mike, great tech article.
The factory service manual states the gear location be 2.510-2.515' from the mounting flange. The shaft end play should be .022-.033"
All the gears i have used show contact with the block which is the thrust surface for the gear. Stubby made a very valid point, that is make sure the gear rests on the block thrust surface & is not in a bind, in other words when a dizzy is installed the shaft should move somewhere within the end play designed in the dizzy.
I feel personnally snake bitten with this problem. Even with the first camshaft i installed & with the stock rocker arm shaft with the oiling pedistal i have always seen gear wear. The only thing i havn't changed is the block.
The reduced oil pressure with the AC Delco F719 gear even with the scored camshaft gear have seemed to stop 85% of the wear compared to before.
The small block ford 302-351 also has a gear wear problem.
I have a fix for the lack of oil to the gear even when using the full roller rocker arm design on our six's. When proven i will let everyone know what the fix is.
Mike, keep up the great work, & let us know what the hardness tests reveal on your trip to LA. I will do the same on my end. V/R Bill
 
We also need the info from those who don't have any problems. This will give some good comparisons. Maybe help narrow the focus.

Another good source for gear info would be a large gear manufacturer like Martin. I would suspect that most of the aftermarket gears are being bought from a company like Martin.
 
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