Ring and Pinion Coating

[FSA1673]

Time for a new set of gears for my 12 bolt. I have pushed my luck for too long with the regular steel street gears. Time for an update

Is there any one in the Northeast or Canada that sells 12 bolt coated pro gears? What is the best REM, Mikronite, or MicroBlue?

Thanks, Scott

[Myron Piatek]

8 3/4" Mopar gears have a reputation of being a weak link and need to be watched/checked. But I've gotten more life out of them with REM finishing and cryo treatment at Evans Performance near Atlanta, GA. They do both and I believe they have a dry film coating that can be used on ring & pinions as well. You'll have to do some shipping no matter where you buy from, but apparently they can buy parts as well. You can do some cost crunching to see what would work best.
http://www.evansperformance.com/home2.html


With the REM finish, my differential guy sets them up before treatment because the highly polished surface makes it difficult to get a clear pattern.

[D. Hake 4459]

Originally Posted by Myron Piatek

8 3/4" Mopar gears have a reputation of being a weak link and need to be watched/checked. But I've gotten more life out of them with REM finishing and cryo treatment at Evans Performance near Atlanta, GA. They do both and I believe they have a dry film coating that can be used on ring & pinions as well. You'll have to do some shipping no matter where you buy from, but apparently they can buy parts as well. You can do some cost crunching to see what would work best.
http://www.evansperformance.com/home2.html


With the REM finish, my differential guy sets them up before treatment because the highly polished surface makes it difficult to get a clear pattern.

I run an 8 3/4" also, and I get about 50-60 runs before they break. How many more runs do you get from your gears after rem and cryo compared to before and how much does it cost? Thanks

[Myron Piatek]

Derek,
I try to keep records, but I can't be 100% sure I didn't miss noting a gear change. The last one I have noted was at the start of the 2010 season. I can't swear that I hadn't changed them since then, but even if I did, I'm sure it wasn't more than once. I easily do over 100 runs per season and I have gone at least 2-3 seasons without a problem. Last set was changed due to wear rather than cracks. I need to check the current set before next season. Most runs are 1/8 mile, IHRA allows the Mopar aluminum centers and I run Amsoil synthetic lube. Car weighs 3,530+ or 3,700+, 1.47 - 1.52 60' times footbraking with a 360. 11.20's to 11.50's. But even with OEM centers and untreated gears, I've gotten at least couple of seasons out of them. Have you tried anyone else for gear set-ups? Your car is probably heavier, which doesn't help. But I honestly can't remember if or when I may have wiped the whole gear. A while back I had a howling rear and found 3 teeth gone and 3-4 chipped and/or cracked. That was before I started getting them treated.

[Myron Piatek]

Here is a thought......despite the pulses being dampened by the torque converter, does a 2-step have enough affect on the drivetrain to shorten ring & pinion life? I would imagine that leaving at a higher rpm than what is possible footbraking could as well.

If I had a choice starting from scratch, I'd probably go with a Dana 60. But I'd treat the gears in it as well. I just accumulated too much 8 3/4" stuff over the years and experimenting with ratios was easy.

[Mike Pearson]

Originally Posted by Myron Piatek

Here is a thought......despite the pulses being dampened by the torque converter, does a 2-step have enough affect on the drivetrain to shorten ring & pinion life? I would imagine that leaving at a higher rpm than what is possible footbraking could as well.

If I had a choice starting from scratch, I'd probably go with a Dana 60. But I'd treat the gears in it as well. I just accumulated too much 8 3/4" stuff over the years and experimenting with ratios was easy.

Myron,

If you ever get a chance to change to a Dana 60 you would never have to buy another gear. The only issue with the Dana is the limited number of gear ratios that is available now. The last gear in my car was in for 10 - 12 seasons and it looked perfect when I changed ratios. That would be about 1000 - 1200 runs, I use synthetic lube.

[FSA1673]

Myron,

Did you see any performance advantage from them being coated? Not looking for much but some would be nice. Good tip on getting them set up before being coated. I have not had any issues with my gears yet, but I thought since I am buying new pro gears might as well try coating as well. I found a place in Southington, Connecticut that performs REM polishing.

Thanks for the replies.

Scott Underhill

[Jim Bailey]

If you're located on the West Coast, contact Terry Earp @ Earp Machine in Safford, AZ. - 928-651-4567. - JB-

[Myron Piatek]

Scott,
Unfortunately I did not do a back-to-back, controlled comparison. But everything I heard from other racers and in advertising for these processes did indicate a small performance gain. I believe Michael Beard is one who did see a measurable gain. But it just makes sense that a smoother surface, whether it be against another smooth surface or through the oil, will reduce friction and free up HP. I wouldn't have spent the money if I wasn't convinced it would help performance and durability.

You're lucky because you have a cover you can pull for inspection. 8 3/4" rears have a removable pumpkin. But on my current project, I have a large filler cap near the top of the housing which can also serve as an inspection window.

Mike,
I agree. The Dana 60 in my bracket Challenger lasted about 9+ years before I replaced a gear and broke axles, and this was already used. (The 35 spline axles are the same as an 8 3/4", just different lengths.) I was bracket racing 2-3 times per week averaging a few hundred runs per year! It's that initial purchase price that makes it tough to change. But selling the 8 3/4" stuff would help.

[D. Hake 4459]

I am just trying to figure out if the Rem and cryo is worth the expense. If it makes the gear set last twice as long or there is a decent improvement in et it might be worth the price. If not I might have to bite the bullet and go the Dana route. In I/SA the minimum weight is 3770. May run some in H/SA a little this coming year and that will be at 3620. As soon as I can figure out how to get the car to leave good off the 2 step I'll start doing that, until then I'm a footbraker. I think the air door is messing with me on the 2 step. Thanks for all your input.