Distributor Gear

[scott foxwell]

Having blown through a bronze gear (my fault and street) I’m a little more than casually interested in this topic.
Didn’t know there were the other choices in gear suppliers, thanks.
BTW here is a melonite process link because I can’t be the only one that had no idea what it was. If I keep hangin’ around here there’s no tellin’ what I might learn.
https://www.ibccoatings.com/melonite-qpq

I didn't know it was used on cam gears, but seems like a good idea. Melonite is a very effective coating for gun mechanisms that are prone to areas of high wear and corrosion. My apologies if I've caused a red flag to the FBI, CIA or NSA for mentioning "gun"

Melonite isn't really a coating, it's a thermochemical process called salt bath nitrocarburizing. More of a heat treat.
"QPQ" basically stands for Quench Polish Quench...

https://en.wikipedia.org/wiki/Ferritic_nitrocarburizing#Salt_bath_ferritic_nitrocarburizing

[blykins]

I haven't had any problems at all with them, but I use more of the Crane stuff than the others.

The largest engine re-manufacturer in North America (ATK) removes and replaces every MSD distributor gear they get. MSD used to use a US manufacturer for their gears @ ~24.00 ea. till they found out they can get them for ~2.00 ea. from China. The Crane (which is Comp) I'm sure, is also an offshore gear.

That's all fine and good, but still doesn't change my experiences.

LOL...OK, whatever. I'm just trying to share useful information for others. Do with it as you please.

I haven't built thousands of engines, but I literally have had ZERO steel distributor gear failures, from Crane/Comp/Mallory/MSD.  That includes engines I have built and swapped gears on and all the gears/cams I have sent out over the years.

Not sure what the difference is.   

Only times I have heard/seen issues is when guys run iron dist gears on steel cams (or vice versa) or have tried to push their luck with bronze or polymer gears.....or have installed gears incorrectly.

I had another engine builder (who really should have known better, because he specializes in Fords) send me a distributor to use with an engine and he had changed the gear on it.  I assumed that it was done correctly and didn't check it.  I clocked the balancer, stabbed the distributor in, locked it down and took it to the dyno. 

When we fired the engine, it spun the distributor......

[cjshaker]

Having blown through a bronze gear (my fault and street) I’m a little more than casually interested in this topic.
Didn’t know there were the other choices in gear suppliers, thanks.
BTW here is a melonite process link because I can’t be the only one that had no idea what it was. If I keep hangin’ around here there’s no tellin’ what I might learn.
https://www.ibccoatings.com/melonite-qpq

I didn't know it was used on cam gears, but seems like a good idea. Melonite is a very effective coating for gun mechanisms that are prone to areas of high wear and corrosion. My apologies if I've caused a red flag to the FBI, CIA or NSA for mentioning "gun"

Melonite isn't really a coating, it's a thermochemical process called salt bath nitrocarburizing. More of a heat treat.
"QPQ" basically stands for Quench Polish Quench...

https://en.wikipedia.org/wiki/Ferritic_nitrocarburizing#Salt_bath_ferritic_nitrocarburizing

Yes, I read the article. My sincerest apologies for using the wrong terminology.

[blykins]

Having blown through a bronze gear (my fault and street) I’m a little more than casually interested in this topic.
Didn’t know there were the other choices in gear suppliers, thanks.
BTW here is a melonite process link because I can’t be the only one that had no idea what it was. If I keep hangin’ around here there’s no tellin’ what I might learn.
https://www.ibccoatings.com/melonite-qpq

I didn't know it was used on cam gears, but seems like a good idea. Melonite is a very effective coating for gun mechanisms that are prone to areas of high wear and corrosion. My apologies if I've caused a red flag to the FBI, CIA or NSA for mentioning "gun"

Melonite isn't really a coating, it's a thermochemical process called salt bath nitrocarburizing. More of a heat treat.
"QPQ" basically stands for Quench Polish Quench...

https://en.wikipedia.org/wiki/Ferritic_nitrocarburizing#Salt_bath_ferritic_nitrocarburizing

Yes, I read the article. My sincerest apologies for using the wrong terminology.

Stall converter.

 

[scott foxwell]

I haven't had any problems at all with them, but I use more of the Crane stuff than the others.

The largest engine re-manufacturer in North America (ATK) removes and replaces every MSD distributor gear they get. MSD used to use a US manufacturer for their gears @ ~24.00 ea. till they found out they can get them for ~2.00 ea. from China. The Crane (which is Comp) I'm sure, is also an offshore gear.

That's all fine and good, but still doesn't change my experiences.

LOL...OK, whatever. I'm just trying to share useful information for others. Do with it as you please.

Not sure what the difference is.   

The difference is, YOU are not a consensus for everyone. You don't even register on the radar.
The difference is, this change has taken place only in the last few years. Before that, like I said, MSD used US made, high quality gears.
The difference is, this isn't about YOU...

[blykins]

For crying out loud dude.

Go take a Valium.

[Falcon67]

I should qualify my earlier remarks - I used a MSD steel gear on an MSD Billet distributor, installed per their distance specification: 3.996-4.005.  It got ate up along with the cam gear and the motor was full of steel filings.  I will be running bronze this time around and the gear is installed per the Ford Motorsports specification: 4.031-4.038.  This time I set the gear at a number, blued the bottom of the gear, installed the dist., shoved the shaft down hard and rotated the motor by hand to get a contact reading.  When I got a consistent contact pattern I pinned the gear.  4.032 was the number on this block.  I have a lot of mechanical inspection tools and used to be a front line mechanical inspector and later a QA program manager, so I'm pretty decent at getting a reading using calipers or a surface plate and height gauge.  This is in a drag only application.  I don't mind bronze - on the motors here I have to pull the distributor for an oil change so it gets looked at periodically anyway.

[feadam]

I have a crane roller cam and when I talked to crane they asked which oil pump I was using. Since I am using a high volume oil pump they said they only recommend bronze. I asked them about composite and steel and they said use bronze.

[blykins]

The difference in the MSD spec and the Ford spec is how you have the endplay.  MSD spec requires you push the gear towards the cap. 

[blykins]

I have a crane roller cam and when I talked to crane they asked which oil pump I was using. Since I am using a high volume oil pump they said they only recommend bronze. I asked them about composite and steel and they said use bronze.

The bronze just won't last long.  I've never had an issue with steel gears, high volume or no.

[machoneman]

Any idea as to why? Long ago, I did get a gear (forget now if ti was a BBC or SBF) that looked odd. Took a good look at the old one and it seemed the O.D. edge of each gear was quite wide.. Tried to just hand hold it into the cam's gear and it would
only engage not quite 1/2 way in! Don't know how they screwed it up. Maybe it was boxed wrong but.... 

Did you gear end up sharp-edged (filings) or just worn down (mainly dust) on the whole O/D?
 

I should qualify my earlier remarks - I used a MSD steel gear on an MSD Billet distributor, installed per their distance specification: 3.996-4.005.  It got ate up along with the cam gear and the motor was full of steel filings.  I will be running bronze this time around and the gear is installed per the Ford Motorsports specification: 4.031-4.038.  This time I set the gear at a number, blued the bottom of the gear, installed the dist., shoved the shaft down hard and rotated the motor by hand to get a contact reading.  When I got a consistent contact pattern I pinned the gear.  4.032 was the number on this block.  I have a lot of mechanical inspection tools and used to be a front line mechanical inspector and later a QA program manager, so I'm pretty decent at getting a reading using calipers or a surface plate and height gauge.  This is in a drag only application.  I don't mind bronze - on the motors here I have to pull the distributor for an oil change so it gets looked at periodically anyway.

[Falcon67]

I was under the impression that the end requirement was for the gear to ride gently on the bearing surface at the bottom of the hole. 

>Did you gear end up sharp-edged (filings) or just worn down (mainly dust) on the whole O/D?

Gear had abnormal wear, thinned teeth.  Same on the cam.  Just "mud", not any damage to bearing surfaces.  No, have no idea why.  We speculated about it on Brent's 351C forum - no conclusion.  It was set to the MSD spec and just got chewed.  Don't know other than maybe it wasn't heat treated correctly. 

[blykins]

MSD makes you push the gear towards the cap.

Ford spec makes you pull the gear away from the cap. 

[scott foxwell]

I was under the impression that the end requirement was for the gear to ride gently on the bearing surface at the bottom of the hole. 

>Did you gear end up sharp-edged (filings) or just worn down (mainly dust) on the whole O/D?

Gear had abnormal wear, thinned teeth.  Same on the cam.  Just "mud", not any damage to bearing surfaces.  No, have no idea why.  We speculated about it on Brent's 351C forum - no conclusion.  It was set to the MSD spec and just got chewed.  Don't know other than maybe it wasn't heat treated correctly.

Like I said above...the MSD gears, since they went to China for them, are failing at a regular rate. They're just junk gears.

[cjshaker]

Like I said above...the MDS gears, since they went to China for them, are failing at a regular rate. They're just junk gears.

Myelodysplastic Syndrome has nothing to do with distributor gears. Try to stay on subject.