This is a FYI and I'm sure many , on this board, are aware of this. I've put a little over a thousand miles plus some just running time on the engine in my avatar. I've been aware that the bronze distributor gears wear faster than other choices, but when I built this engine the only choice I found to run with my solid roller cam was a bronze gear. Here are some pictures of the resulting wear. My guess is this should have been replaced after about 200 miles. I replaced the bronze gear with a melonite coated iron gear. I'll be pulling the distributor after about 100 miles to evaluate the wear. I bought a Comp gear.
I have many thousands of miles on my GMPP melonized gear in my coupe with no noticeable wear and nothing notable detected in the used oil analysis.
As you probably know the bronze material is used for billet steel roller cams (as opposed to IRON used on hydraulic and flat tappet cams) because an iron gear is not compatible with the steel roller cam material. The bronze is a sacrificial material, intended to wear and not wear out the steel camshaft. I am not aware of the melonite coated iron gear and its compatibility with steel roller cams. When you pull the distributor I would take a close look at the gear hobbed into the cam to be sure no wear is taking place there
That is good to know,Russco; Lunati says the Melonite gear is good for all applications. My motto is trust and verify.
That is good advice and I plan on checking in 100 miles.. if it's ok, then around 1000 mi. I knew it would wear faster, I now know how long faster is
Joel - The bronze material was chosen back before people were using "race" cams, read that solid roller cams... on the street. Not very often would a drag race combination go 200 miles..! Especially with being torn down very race / weekend / coupla months for repairing, or a change in parts. Things get inspected regularly. You may actually get decent mileage with a coated iron gear. I'd also call the cam manufacturer and ask them what the recommend on the street. Mike
I'm sure that's true and I have a high volume pump; I don't have a guess as to how much wear is due to the pump. When the engine is at operating temp, it carries 60 lbs oil pressure at 2000 rpm and 36/38 at idle.
I bought this cam in '68 from Chet Herbert himself and the people at Herbert cams didn't have any info about the alloy except that it was all the same billet probably , maybe 86xx.
In the FWIW dept, Crane has a 'special' iron gear for use with billet cams. IDK how it compares to the melonite coated part. I am putting a Crane piece in a 392 that I will be shipping to OZ and will cross my fingers... .
This should help answer some questions. https://www.onallcylinders.com/2020/07/01/ask-away-with-jeff-smith-solving-sbc-ignition-timing-
That's exactly what was going on in my case. If you recall, I removed the 3310 and installed an 1850 and it was okay for a short time, but the stumble came back. After I replaced the dist. gear I had to re-adjust the idle speed, idle mixture , and the clearance on the accel. pump lever slightly. Thanks, Bob. P.S. I think I'll put the 3310 back on.
howards cams ( competition products ) custom ground a cam for my sons off topic car and they pressed an iron gear onto the billet cam allowing use of the standard cam gear with minimal wear issues
i run a 350 buick in a fed with a blower. because the way buick built their oil system, we have had to modifiy things. every year it was replace rod bearings and dist/cam gear because we would run 7500rpm's and we had the 1/4 plate for more oil. the down side was wear on the cam and dist gear. now i run w/o the 1/4 plate, just shim the spring, and went to rem finish for the dist and cam gear along with some other things done to the gears. it is the only issue i have now, other than the driver lying to me on how many rpm. lol background of a retired r&d/exp machinist makes this the fun part of it all.
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