I've seen three other posts dealing with distributors and whether you need a new type of gear, but no one has a direct answer as to why. Is a brass gear stronger than the stock one. What's the difference and what happens if you use the wrong one?

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88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

 

Well, here's my take on it....the roller cam shaft gear are supposed to be harder..this is due to the gear holding a lot of the force in keeping the cam from walking...on a regular hydraulic lifter cam, the lobes are cut at a slight angle, and the lifters rounded...this pushes on the cam to hold it back.

I'm sure someone will come by and blow this theory out of the water....

 

well basically you ruin a distributor or your cam, or both if you don't use the harder distributor gear. the stock gear is soft, and only ment to take the forces applied by a lower lift (stock) cam. the brass gear how ever is much stronger and can handle the forces of the cam trying to walk on both roller and flat tappet cams. so in essence, you should really just put the harder gear on the distributor- you wouldnt want a 30 dolar part to ruin your motor would ya??

Steve

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86 Firebird, LG4, t-tops, 2.73 open rear, SLP 3 inch cat back exhaust, catco cat.

Gonna be sellin the 86 in the spring to hopefully get an 88-92 formula 350, and supercharge it!! (amoung some other sweet mods)

My Webpage- Battle of the birds, My own Thirdgen Page, still under construction, http://www.geocities.com/soares711/index.htm

88 Firebird Formula- deseased 2/9/99- 305 TPI, SLP 3 inch exhaust, SLP Intake runners, SLP cam, 3.45 BW disc brake posi, WS6, NOS, and all that good stuff, 13.8 on the motor, 12.89 on NOS and slicks! Hit by what else!?!? a FORD EXPLORER!!!!!!

 

Birmass, some roller cams are made of billet steel. The material is very hard and doesn't wear well against std cast iron dist gears. The two tend to eat each other, showering trash into the engine. They came up with the softer bronze gear so all the wear would take place on the dist gear and not the cam gear.

That said, you need to figure out what cam you have and talk to Crane. Find out which dist gear you need.

I highly doubt you need a bronze gear. I say this because it's my understanding that they require frequent replacement, not a good street car solution. Most street roller cams have a cast iron tail section that allows the use of a std iron dist gear.

With that in mind, there maybe another reason for your gear failure. Binding oil pump, binding dist shaft etc... Look very close at your cam gear, as it may be trashed too.

[This message has been edited by Brent (edited October 31, 2000).]

 

According to GMPP website, you need a "melonized" steel gear, p/n 10456413, when using a steel camshaft. I believe that's for HEI distributors, not sure about other factory units. But, your '88 should have had a roller cam from the factory, and therefore the correct distributor gear for a steel roller camshaft.

The basic principle is as Brent states. To add to that, hard against hard, or soft against soft, are not good "wear pairs". That's why you have a soft insert in your rod & main bearings running against your crankshaft. Roller lifter cams need to be harder to protect it against the contact line of the roller, but that leaves the distributor gear the odd man out. So, you need something different than what works for the old cast flat tappet lifter cams of days of yore.

The bronze gears are actually softer, and therefore weaker, than the steel gears they replace.

Brent's other advice to talk to your cam manufacturer is also sound.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Thanks guys, I really appreciate this. I have a much better understanding now.

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88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

 

you need a bronze gear with a billit aftermarket roller (solid) cam. if you have a factory or aftermarket hydrolic roller you don't need the bronze gear. it's always best to check with your cam grinder.

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