Distributer gear for solid roller?

[Grandpa Ronsy]

Hi team this is my first post. I am running a solid roller in my 68 Camaro 406/richmond 5 speed and am concerned about the apparently short life of the bronze alloy drive gear. I have a comp cams polypropelene gear to try but am wondering if anyone has given these a go. My concern is that by the time I run an oil cooler and a big block oil pump it may load it too much. Running a full Msd and Pensoil 10/50 (oil spec from memory)

[speedster]

Hey Ronsy-
Welcome to the board. You may want to call Tom Nelson at Nelson Racing Engines. They use roller cams for everything and probably have some good info. Nobody ever answers the phone so just leave a message. 818-998-5593

[68sixspeed]

If you haven't bought your cam yet, you can get a cast iron gear on a solid roller billet cam. They also make cams with changeable gears.

I'm curious too on the polymer gear life; also Comp or crane just came out with a coated steel gear. -Dan

[Lowend]

I have heard some very good things about the poly-dist gears, basically that they last forever

[Norwoodx55]

I have had good luck with mine so far. Have never tried a bronze gear, so I guess I have no real comparison. They are a little pricey at about $100. It came highly recommended to me by several people, that is why I went with it.
Brett

[Grandpa Ronsy]

Thanks guys for the responses,

Norwood, can you tell me the loads and mileage on your gear please and your R.P.M. limit?

The cam that I'm running is a Reed I bought back in 1993.

I just bought a new Comp cam solid roller cca-12-700-8 268/268 .525" and I assumed by now cam companies were all running iron gears on their solid roller camshafts so they would be compatitable with stock distributor gears?? (Probably a dumb assumption, right? )

How could I tell if I have a steel gear or a iron gear? could I file the side of the gear and see if it was soft or hard.

Tell me I'm lazy and call the tech help-I can take criticism-It's character building.

I like the idea of the forum for quick real world answers.

[TD509EFI]

If you're running the cca-12-700-8 cam, these are specially treated cast cores. They normally run a stock iron gear. Check with Comp to be sure.

Having said that, I've read of problems with these cast street roller cams. Do not run high spring pressures with these cams, you will wear through the hardened surface and destroy the cam....or worse. Again, check with Comp on compatable springs.

John

[Norwoodx55]

Norwood, can you tell me the loads and mileage on your gear please and your R.P.M. limit?

The cam that I'm running is a Reed I bought back in 1993.

I just bought a new Comp cam solid roller cca-12-700-8 268/268 .525" and I assumed by now cam companies were all running iron gears on their solid roller camshafts so they would be compatitable with stock distributor gears?? (Probably a dumb assumption, right? )

How could I tell if I have a steel gear or a iron gear? could I file the side of the gear and see if it was soft or hard.

Ronsy,
As far as load goes, I am guessing you want to know what springs I am using. I don't remember the rates or the Comp part number for them. The cam I am using is a custom grind, although loosely based on an Extreme Energy with around 240*@.050 " and .570" lift. Cam core is billet with a pressed on iron gear. The springs are a little lighter than the recommended spring. The idea was to save the lifters. So far I haven't heard any float up to 66-6800 RPM. I only have a couple thousand miles on the combo. I have inspected the dist. gear recently and it looks untouched. Like I said, I have no experience with a bronze gear for comparison. I don't know if one would show signs of wear yet or not.
If you want to know for sure if you have an iron gear, I would call Comp. My cam has a different color than the very end/dist. drive section. I think the main part of the cam had a gold color to it between the lobes. The end gear section was grey.
Good Luck
Brett

[Blown353]

The Comp -8 cores are cast... which is a problem. I know this both from personal experience on my engine and several failures at a friend's shop with the -8 cores. They will shred the lobes with any decent amount of spring pressure. I wouldn't go over 350lbs max and even then they're a crapshoot. I've seen one lose 2 lobes during the first 5 minutes on the dyno and another friend lost a lobe after 26 miles of driving. The best option is to get the cam ground on a billet core with a pressed-on iron gear for the distributor but it's too late for that now unfortunately.

Also, if you run an MSD melonized distributor gear on a -8 core it's a guaranteed failure... I'm 2 for 2 in that department and know lots of people with the same experience. Comp blames MSD and MSD blames Comp, but it just boils down to the Comp -8 core and MSD gear don't play nice. About the only gear that lives when meshed with a -8 core is a genuine GM Melonized gear. If you have an MSD or aftermarket distributor with a larger shaft diameter you'll have to get the GM gear honed out to fit. I ran the GM gear on my 3rd -8 Comp cam and had no problems even after 8000 miles, although I recently junked that cam for the same exact grind on a billet core. Not going to play with cast core rollers anymore, they've cost me quite a bit of money.

And finally, my luck with the Comp polymer distributor gears has been hit and miss. They're great with dry-sump setups, seem to work decently with standard volume oil pumps unless you rev the snot out of the engine with cold oil which puts a lot of load on the gear and you can break the teeth, and finally I have seen several break the teeth off with HV oil pumps immediately after startup. I only use them on dry sump stuff now because of the spotty luck I've had with them on traditional setups with distributor-driven oil pumps.

Best bet for reliability and longevity in all departments is to get a billet core cam with a pressed-on iron gear and run a GM melonized gear on your distributor. I hate to say it, but I'd eat the cost of that cast core cam and have another one ground on a -9 core, which is a billet core with the pressed on iron gear.

Troy

[Grandpa Ronsy]

Thankyou for the great responses and real world experiences you guys have had. Troy I hear you loud and clear and don't want to take risks. This is exactly what I wanted to know and I'll put the cam aside for a sbc Vortec 350 4 bolt with smaller springs and stock oil pump and use the polly dist gear.(Or ebay it) Sure glad I posted the cam part#

You guys really rock because this is the sort of stuff that the product manufacturers will not pass on-for good reason. I understand some of their products end up outside their intended use parameters but the limitations would be a negative to sales so it's everyman for himself.

As an aside we have a local legend who has a drag car and builds V8 engines for a living. He runs flat tappet solid cams and decided to go full synthetic oil to reduce friction. He went faster but wiped out the cams on 2 of his engines and two of his customers engines. He challenged his oil rep and never got any satisfaction and so went back to his old oil spec-problem gone. He likes BPcoarse plus or Castrol GP 50. He and I could only suspect that the heavy load was wiping the oil film off the lobe. Roller followers were just coming at that stage. Probably boring you guys so i'll go now-thanks again.

[Norwoodx55]

Troy, do you have a part # for the melonized GM gear? Sounds like good insurance to me.
Thanks, Brett

[Blown353]

Troy, do you have a part # for the melonized GM gear? Sounds like good insurance to me.
Thanks, Brett

GM # is 10456413.

It comes out of the box bored to .491" to fit standard shaft GM distributors. If you run an aftermarket distributor with a .500" diameter shaft any machine shop with a sunnen rod hone can open it up for you in no time.

Troy

[Norwoodx55]

Thanx!

[ProTouring442]

How about Crane's roller hydraulic cams? I remember the instructions saying you could run a standard gear, but I was wondering if anyone had any experience with these. Mine is in a Big Block Chevy.

Shiny Side Up!
Bill

[Blown353]

How about Crane's roller hydraulic cams? I remember the instructions saying you could run a standard gear, but I was wondering if anyone had any experience with these. Mine is in a Big Block Chevy.

Shiny Side Up!
Bill

Crane does things correctly and uses billet cores with pressed on iron gears for their HR cams.

Comp uses a "specially treated cast core" (i.e. crap) for their HR grinds and some of thier "street" solid rollers-- unless you special order them on a billet core, which is the only way to go.

The GM gear is still better than the MSD gear. MSD actually sells the GM gear honed out to fit if you order their "Marine" gear...

[JTW]

Best bet for reliability and longevity in all departments is to get a billet core cam with a pressed-on iron gear and run a GM melonized gear on your distributor. I hate to say it, but I'd eat the cost of that cast core cam and have another one ground on a -9 core, which is a billet core with the pressed on iron gear.

Troy

Troy - you seem to have a wealth of knowledge in this area so I'd like to ask one more question...
After reading about all the problems with cast-core Comp HR cams I had mine ground on a billet core like you recommended. My engine builder handled this at my request, and when I saw the cam yesterday I learned they ground it on a smaller base circle for stroker clearance and used a pressed-on cast gear. This was a pleasant surprise since I was expecting the cam gear just to be machined into the billet core and I would have to use a bronze dist. gear as a result. I just ordered an MSD E-Curve distributor and I'm wondering if it's gear will play nicely with the Comp pressed-on cast gear? I understand the MSD gear with a cast core is bad news, but what about the MSD gear with a billet core? Is the GM melonized gear still a necessity with a billet core?

Thanks in advance for your help!

[Blown353]

My experience has been the MSD gear works well with "standard" cast core cams (i.e. flat tappet stuff.) A friend has one on his daily driver with a Comp hydraulic flat tappet cam and it still looks great after ~20K miles. Several other guys I know are running them with flat tappet stuff and no problems or unusual wear to report.

My feeling is that seeing how often they shred (at least on Comp's -8 cores) and because I've lost an engine to one myself I won't run anything other than a genuine GM gear now. It's just not worth the risk to play with the MSD gear.

It's $50 or so for the GM gear plus honing, so why not get it? Cheap piece of mind IMO.

Troy