Gun Jam

I have a Comp Roller cam PN# 35-421-8 and some time ago it came to my attention that I need to run the correct gear with that cam. I think I have been running the wrong gear but all seems wellafter about a year daily driving.

I checked the distributor gear and cam gear a week or so ago. The cam gear looks fine it appears to have a nice wear pattern I see no cause for alarm. The Distributor gear is cast iron and is showing some signs of wear the wear pattern looks good but this cam gear has about 60 to 70k miles it ran on both the flat tappet cam and the new hydraulic roller cam over the last 8 to 10 years.

So I figured If im going to replace the gear I might as well get the right one. It appears that I should be running either the MSD bronze/nickel alloy gear or the steel gear (I gather this steel gear is an alloy that is softer than cast iron)

what are your guys thought on this???

Thanks

-Gun

67mustang302

Depends on the cam. Some of the newer gears can be run with iron or steel. Some cams come with iron gears to work with old distributors. You should get a hold of Comp and find out for sure.

Gun Jam

That was my thought but when I asked I said MSD has a gear (which I believe is steel) and said for use with OE style roller cams the tech said use the one that said its for OE style cams. I guess maybe I was hoping for a more elaborate response....

The gear on the cam appears to be machined from the same core (billet) so I can only assume its of the same hardness as the rest of the cam as it is one piece.

maybe I'll ask again

Thanks

-Gun

67mustang302

Don't assume that about gears. Many cams these days have gears that are separate from the rest of the cam material. I have a billet cam for instance, but with a standard steel gear.

Starfury

Also, just so we're on the same page, steel is harder than bronze or cast iron

Gun Jam

see thats what's beating me up.

I always thought steel was harder than cast iron but there are many forms of each.

for example mild steel vs high carbon steel or gray cast iron vs nodular/ductile iron.

So if they are worried about iron gears beating up the cam then I would gather the cast iron is a really hard form of iron and the steel is of a soft alloy.

-Gun

Gun Jam

well this is the gear that MSD tech recommended
A steel gear designed for hydraulic roller cams that is harder than cast iron.

http://www.summitracing.com/parts/msd-85833/overview/

I asked why steel and he was worried that the cast iron would wear too quickly and possibly introduce metal pieces into the oil..

Starfury

The steel used for billet camshafts is going to be harder and wear less than a high-nodular cast iron. That's the entire point of a billet cam: to have a hard bearing surface for the lifter rollers to ride on that won't wear out. The hardness comes from the alloyed components, like chromium and vanadium, as well as the relatively low carbon content that creates a specific lattice structure within the steel that resists deformation.

fastbackford351

Me being me I'd keep on trucking with your current setup.

I think you're dealing with a non-problem if it all looks good after flogging it daily for a year.

If it was going to go south I'd think it would have done it by now or show obvious signs of heading in that direction.

Gun Jam

The dizzy gear does need to be replaced so that is why im asking.

I thought I read that flat tappet cams were a harder alloy...Not true?