Bronze gear wear

Hi, i have about 600 miles on my Mopar 499 cui with a Howard custom grind hydraulic roller cam, end play 0.008". I checked the intermediat shaft today and noticed some excessive wear, see added pictures, i also noticed some wear marks on top of the bushing to, see pic. The cam gear looks fine but the bronze gear have wear alot. What causes this? The bronze gear is a 440 source. I ordered a milodon bronze gear now and a new pioneer bushing.

More pics

I read in an Motortrend article that the first bronze gear on a new cam may wear faster due to it massage/deburr the cam gear. See added pic.

This topic pops up monthly !! Do a search, you'll find the reason they wear and how to prevent it. And the brand of gear and bushing have nothing to do with it!

hi ,

roller cams in a street motor ae plain STUPID !

my street hemi has a hyd. roller cam , i did not build it , same issue .

you can buy a melonized treated metal gear about 200.00 i jut got one an have not intalled it yet .

wish it was just a flat tappet cam no hassels with correct oils .


how many records are u gona set on the street anyway !

The only issue i can see is just the bronze gear and that have been an issue for quite long time. Its amazing that this issue havent been sorted out yet, like a composite gear for Mopar, or a steel gear like for Ford. Its the melonized that is a alternative for Mopar but they say not to used with high volyme pump and not on used cam.

Hydraulic rollers on the street are AWESOME!

Zero issues when used with a melonized gear. 7,000 miles and lots of dragstrip passes.

Much better than having the issues with cams going flat (which led me down this path) like so many are having issues with!

Hey don't expect the Milodon to be any better. I had a 440 source in mine that was getting chewed pretty bad. I replaced it with a Milodon in the spring and just pulled it to inspect after 75 passes...

Doing the same thing.... I also have a problem with getting the Milodon to drop in the right spot when I am timing it. It will go in some spots and others you cant get it to go....

Mine is wearing high on the gear due to the fact that the bushing surface is getting worn down I think. Always had this problem with this engine too.

Almost like the distributor is forcing it down when it is tightened, but I have play in the distributor shaft so don't know how that could happen.

I have lots of street miles on bronze gears. I have worn some out but never destroyed one. I always try to run as thin of an oil as I can and still have good idle oil pressure and I know that helps keep the load off of the gear. My current motor will hot idle at 25-30PSI on 5W30 and runs down the road at 60PSI.

I think the gear in my car has 2-3 drag weeks on it combined with any other street driving I do. I haven't inspected it since 2019 but will probably do so before drag week this year.

Had the same issues till someone suggested the Crane gear which has the hardest Rockwell (sp) hardness and now my timing is even rock steady from idle on up.....

There is a simple law of physics that causes the bronze to fail - its the fact that the two parts in contact are both bronze - similar metals. Putting a "dissimilar" metal between them eliminates the problem. It's the same reason they don't use a steel intermediate gear with a steel billet roller cam. They solved that problem using the bronze gear but apparently didn't consider the bushing it would be in contact with. Maybe they didn't count on rollers ever being used in high milage street use, who knows !!

As to the OP's question, you want a .030" thick Torrington washer. Obviously with a large enough hole for the shaft to fit through. You won't find the exact size because the shaft is an oddball .486 dia. but a washer with a 1/2" hole will work just fine. On some gears I've turned the underside down the thickness of the washer but I don't bother anymore.

Just keep in mind this fix only applies to the wear between the gear and bushing. If the gear teeth are chewed to crap you have other issues.

Thanks for your answer!I wouldnt say Shewed up to crap but for sure it is some wear. What problem would that be? Cam end play is 0.008", i have a collar on the distributor shaft set to 0.010" to prevent up and down movement, all lifter wheels go on exact centers of the cam lobes, the intermediate shaft through the bushing have allmost no marks at at all and holding correct clearance, the cam thunnel was checked for straightness and honed to correct size and roundness and all bearings have 0.0023" clearance, so what else can you do? What would the other problem be? My intermediate shaft gear i have with my flat tappet before the roller for 4 year looks same new and also the gear of the cam, so its not any odd things with the engine block. Correct spring pressures for the cam and so on. Everything is within specs, its just this stupid bronze gear that seems to wear fast. Its my first gear so things maybe be better i dont know. I will looking for a torringon washer. And the melonized gear i dont know if its worth a shot, you can not drive high volyme pump, you can not use on a used cam and so on. The engine is really great its just this [censored] bronze gear.

This, I forgot to add that I split up the 3-piece Torrington bearing deal I ran before and just ran 1 stainless washer between the two and problem solved...

I like the stainless washer idea!

I forgot to add I drilled as small as a hole as I possible could in the galley plug so it squirts directly onto the gear. I can't remember the size but it was as small of a bit as I could use without fear of breaking it in with my rock steady precision hand drill mill/rickety vice setup.

I do not know if that mod is possible on a big block.

Says you, I loved my last one (solid roller lifter) a lot, never beaten on the street, no one would race me that was a 400 stroker (505 C.I.) pump gas motor that made 727 HP at 6800 RPM on Oregon pump swill the last time I had that motor on a engine dyno
AKA, it ran great and was easy to maintain by using all good parts in it to start with

Sounds great! I really like it to, responsive and make great power. Good parts you say, what distribution gear should i use? The engine is great all over and everything in spec, it just surpriced me that the bronze gear weared out so quickly, a 440source gear. I ordered a milodon gear now together with a new pioneer bushing to try with and planning to have a washer/shim between those two and see how that workes out.

hi ,

yep mine runs fine on pump gas also , but you did hot say ho many miles you actualy drove it and i have also made passes at the track which i drive 43 miles 1 way race and drive home .


app 3500 miles per bronze i gear is not a trouble free street motor .

if the melonised gear does not cure this prob next winter that cam w[ll go in the trash and get replaced with a flat tappet ! 511 hemi

I was told to burnish the cam gear with a wire wheel prior to installation. The teeth are pretty sharp on some pf the cores and need to be dressed. If I was going to make an intermediate gear it would be either dlc/pvd coated or REM polished and cut out of 9310 steel.

What I think gets lost in these 'discussions' is how do the Magnums get away with the roller camshafts? I don't know of anything special with the distributor drive gears in them?

I dove into this for awhile, maybe 12 years ago.
The earliest 3.9s ate distributor gears and timing chains.

Before leaving the big blue m in 2013 I never had access to the development info...as that was
well above my pay grade and it happened several years in the past... but in the field the failures were often believed to be due to harmonics because of the firing order,
since they started off as the same parts as a 318/lifespan was generally good in a 318..

After a certain model year, the intermediate shaft part number for the 3.9 mysteriously changed.

I requested a print pull for the newer gear, and the spec was on the print. It had to have been a fix for the previous failures.
The fix was melonized gear which I believe then carried over to 5.2-5.9, and also the famous timing chain tensioner was added/subject of another debate.

Many of the aftermarket 5.2Magnum roller cams were ground on Crane cores which had a cast gear pressed on to a billet steel front.
The MP 380HP 360 and variants that used the same 501/513 lift cam had this arrangement.
Both the melonized gear and a regular gear could be used on those, but I believe the crate engine was the melonized part sourced from the
5.9L OE parts bin, as it would be the least expensive/best supply during that time period (which now feels like 100 years ago instead of 12).

Thank you, thank you. Clears up a lot of confusion in my mind.

cast roller cams don't need bronze gears.

Okay, fair enough. Is there a mild, streetable, cast aftermarket roller camshaft available?

Going only by what I recall having read over the years, cast aftermarket roller cams got either a bad rep -- or a bum rap -- for durability issues with the higher-than-stock spring loads performance cams generally require. They were less expensive and didn't require anything special for a distributor gear, but people tried to use them in applications that really needed billet cores and had problems.

They were (are?) common for SBC and SBF; may have been available for some SBMs, too. I don't remember any cast roller cores for BBM.

yes any hydro roller from howards, for a magnum.

The first Isky roller cam that I installed (1971/1972) in a built 383 streetcar was a cast core solid roller 505 T grind, it lasted for ever, (probably less than 5000 miles total) the guy hardly ever drove the car. He had a Super Bird also that he preferred to drive for fun and attention

Thanks! I learned something new today.

How about the Comp hydraulic roller Magnum 360 cams ? I'm building a 408 stroker from a crate 360 Magnum and the owner bought a Comp hydraulic roller for it. I still have the factory intermediate shaft and it looks really good.
Probably should just get a bronze gear for it

Gus

What does the cam core look like? Or, if you have the cam card, the type of core should be identified in the part number. No point in using a bronze gear unless you have to.

Maybe we should start a new post of "how many people have ruined a bronze gear on a cast cam?" Their big block hydro rollers take the stock gear also.

This discussion reminds me of the "cam material" info I saved in my "Auto Library" some time back as I was trying to figure out what my 2nd hand hydraulic roller cam is actually made of.

So here is the info from CompCams:



Further on, following a multi-email exchange with a CompCams Tech (who genuinely seemed like he knew what he was talking about and had no problems answering yet another email from this guy here - LOL), here is what he shared:



Finally, here is a link to a good EngineLabs article on Roller Cam Cores

For me, I did get the bronze gear at first, then ended up picking up a Melonized gear from Hughes and eventually just tossed my old MP setup because that is already mated to a hardened shaft and I am running a HV oil pump. We'll see how that turns out, but based on all of the above I should be fine.

Well I looked at the cam and it's not billet, it looks like a cast unit. So I'm going to re-use the low mileage shaft that was in the engine.

Gus

Bronze gear on 20w50 with a standard pump:

Mopar 493, you stated that you have .010 end play on the distributor, could it possibly be too tight? The reason I ask is because I work in a engine machine shop and the guy who assembles the engines took a sbc/bbc aluminum distributor housing and measured it at room temperature and then put it in the oven and heated it to around 225 degrees and the overall length of the aluminum housing grew around .015" if I remember correctly, so I am wondering if when the engine gets hot there might not be any endplay left on the distributor shaft? I know that the sbc/bbc distributor setup is a little different from the mopar setup but it might be something to check. I would take and bolt the distributor in the engine and measure the end play cold and then measure the end play after the engine is hot to see if you still have end play if not then you could possibly be forcing the distributor gear down against the bushing in the block and causing problems that way. Just a thought.

what time frame/use/passes did that gear have ?
my thoughts are, where do the gear particles cause the most damage to the rest of the internals ?

Holy gear wear batman.....Mine never look like that....I will get a pic of the one I replaced this year after about 200 passes and post it but its not near as bad as that.....

Here's mine after 5 years 20w50 high volume pump

Here is an answer i get from Howard cams when i asked them some time ago, the core is 8660, its a custom grind cam. Im going with the melonized now, it feels like an more reliable option

Thats a thought. The 0.010" came from Hughes that was selling me the collar. Im going with the melonized gear now, it feels like a more reliable option.

2.5 years, six passes and roughly 3k miles. Cold oil pressure would run 80 PSI. After the change from 20w50 to 10w40 cold pressure is something like 65 and hot idle is 25. Been checking the gear every Spring since and it looks like it's wearing OK. Don't drive the car too much anymore though.

No idea what the clearances are in the motor. Would have to find the paperwork from the shop.

An update to this thread i start. I changed the gear and bushing, i changed to Hughes "melonized" gear and i have drive it for about 800 miles more now and checked it, it has no visible wear at all now on both intermediate shaft gear or the gear on the cam and i drive this engine with a Milodon high volume/high pressure pump, external oiling and Valvoline vr1 20w-50. Hot engine just over 20 psi idle, 2000 rpm just over 40 psi, 3000 rpm 60 psi and so on. Main clearance 0.0033" rods 0.0028" and pushrod oiling aswell as oiling from number 4 cambearing through the rocker shaft. Its running great.

To me the cam looks to be extremely worn in the are area indicated. I've never seen a tooth profile like this. The profile of the cam teeth should match those on the intermediate gear which has a "V" pattern

Looks nice to me as well.

The teeth have a bevel so it looks like wear.

Look at the lowest tooth to the right, down low.

if it "ain't" making metal (in the oil and oil filter) your probably good: luck:
Keep us in the loop please
I bought several of those gears for both BB and SB earlier this year and hope to use one on a BB soon

In that case the cam gear was worn out as new. The gear looks the same when i installed the cam new. See the added pic with the cam installed with a bronze gear, its the same.

No metal in oil, but it sure was with the bronze "sacrificial" gear

An update again about the melonized gear, i have drive it for another 1200 miles and the melonized gear looks same as new, no visible marks at all, same with the cam gear and nothing in oil or oil filter. So about 2000 miles with the melonized gear so far and no wear at all. I drive the milodon high volyme pump with external oiling and Valvoline vr1 20w-50.

Good news, thanks for the update.

I just installed one in mine and fired it yesterday with a new roller cam install.

Will drive a couple of times then pull it to check.

Im sure it will be just fine. They are so incredible much better than the bronze gear, no signs of wear after 2000 miles, the bronze was toasted after 600 miles.

I like what I’m seeing here!!

I have been running the Hughes Melonized gear for about 6k miles, I checked it at about 5k & it was like new

I probably go through 1 bronze gear every two years on a 493, HV oil pump, NSS car. My machinist suggested the melonized gear, but when I contacted Hughes, they said it would wear the cam (custom solid roller), so I elected to just stock up on the bronze gears.

Same bronze gear in my racecar since 2013. Over 800 passes. High volume pump. Springs are 310/805.
Doug

Same here... cuz I swapped the dyno-only bronze gear for a Hughes/Crane melonized piece before the engine went back in

An update about the melonized drive gear after one season and about 3000 more miles it still looks great. It only has a nice wear pattern. Same with the cam gear.

I posted about my wear issues I had awhile back in this thread and I may have found my issue over the winter. I had cam walk from timing cover flex. Welded a support on the cover to stiffen it up so I think that will fix the cam walk. Be interesting to see if the gear wear goes away. I suspect it will.