Big block engine with 32dp gears?

[niggle]

As I understand it, the T-Maxx, RC10GT and some 1:10 touring cars use 32dp gears and many of the members here have successfully done big block engine transplants on these cars.

How do these gears stand up to the torque produced by a .21 engine?
Are the Robinson Racing hard alloy steel gears man enough for the job?
Will any old 32dp clutch bell fit on a .21 BB engine?

The pinion and spur gears used on 1:8 buggies are more like 24dp, but I have a "special" transmission project in mind and the only gears that I can get off the shelf are 32dp.

 

[Revo Rancher]

Hey, niggle, what does the "dp" stand for when you give your tooth count for th gear? I can't help you on this question, but maybe I can after we clear up what you mean.

 

[neobart]

I think the dp number stands for how many teeth there are per inch.

 

[niggle]

Hey, niggle, what does the "dp" stand for when you give your tooth count for th gear? I can't help you on this question, but maybe I can after we clear up what you mean.

"DP" stands for diametric pitch. 32dp means a gear with a particular tooth pitch, where pitch refers to the size and spacing of the individual teeth.

If I remember correctly (someone please correct me if I'm wrong) Diametric Pitch is actually the ratio of the number of teeth / the diameter of the gear wheel in inches, so a 32DP gear with 32 teeth would have a diameter of 1 inch. Electric touring cars use 48dp or 64dp gears and a 64dp pinion with 32 teeth would be only 1/2 inch in diameter.

Anyway, anyone out there running a big block engine conversion on their T-Maxx, RC10GT or other car with 32dp gears, I'd love to hear from you.

 

[neobart]

I think you're right. Just measured my 64dp 128 tooth spur for my TA04. Exactly 2 inches.

 

[olds97_lss]

What I found running the "stock" gears (whatever dp they are) for the cb/spur was that the clutch couldn't take the power of a big block very well.

I ran RRP steel in the trans for all gears with the RRP FOC. The only plastic gears remaining in the trans were the large two speed gears. I ran about 10 gallons or so through my trans with an OS 21 RG on my XTM converted maxx. During those 10 gallons, I chewed up the large two speed gears twice, 1 two speed one way and 1 two speed main shaft. After all that, the RRP gears still look like new. I also ran boca green seal bearings and an aluminum trans case to minimize case flex from trashing my investment in the RRP gears. They get pricey when you add them all up.

I had serious clutch problems throughout gallons 1-7. Running the stock type spur/cb I could only use the stock type clutch. I tried MIP shoes, integy aluminum shoes and stock shoes. We all know integy's aluminum sux and it sux bad for shoes. The MIP shoes lasted a gallon or so and so did stock.

Since I had an actual 21 conversion chassis, which is longer by about an inch between the trans and rear shock tower, I was able to run an 1/8 scale clutch system using an RCS spur. After installing the 1M pitch gear with an OFNA bell/savage flywheel/HPI teflon 3-shoe clutch, I never had a clutch problem throughout the last 3-4 gallons of the truck...

but... I did have a diff problem. But the diff problem went on and on throughout all 10 gallons. I think I rebuilt the diffs about once a gallon or so. I was using integy diff cases and maximizer diff cups with proper shims to keep the ring/pinion tight. But, the ring/pinion would shell out around a gallon or so anyway. Before going to this diff setup (running stock), they would only last 4-5 tanks before they would start clicking.

The RCS gear I'm talking about is RC-Solutions. Good gear, great idea. I'd suggest going that route before dumping a bunch of dough into a 1/10 clutch/spur setup.

If I had it to do all over again... I'd have started with a savage

 

[Monkey Wrench]

I tell ya, the man to ask is .21RC10GT! I know he put a BB in a RC10GT, used a stock T-Maxx CB and clutch, but upgraded the tranny with RR gears. I'm actually working on a similar project with my RC10GT, so if .21 reads this, hopefully my motor mount is on the way!!!

He has all the details on how and what you'll need, though!

 

[olds97_lss]

Keep in mind MW, a stadium truck is much lighter, more likely to spin the tires and 2 wheel drive. All of which make it much easier on the drive train regardless what it's made of.

Granted, a 21 in a stadium poses many problems... snapped axles, blown ball diffs, spinning the tires off the wheels...

With a maxx, it's hard on the gears and axles, but I found it to be most hard on the diffs and clutch.

 

[Monkey Wrench]

Granted, but he hasn't mentioned what rig he's doing this to, so I thought I'd offer what I know. Obviously, if he's doing this to a T-Maxx, he'll need to consider the axle and diff issue, I agree completely.

 

[olds97_lss]

Jeeeezzz.... I'm totally sorry about that MW!

I saw t-maxx in his first post and just started typing...

I'm not being sarcastic. I completely missed the fact that he wasn't talking about having a maxx, just that a maxx has a certain type of gear pitch.

 

[Monkey Wrench]

No worries, brother! Your points are right on! Niggle needs to keep that in mind if he is wrenching on a Maxx, or he may end up creating more problems down the line!

If you hadn't of brought it up, it may have gone completely overlooked, then he'd get mad, then dogs and cats living together, then Zandor becomes a priest then the world ends! See? You've potentially staved off world destruction!

 

[.21Rc10GT]

Yeah, i have the Collari .32 on my GT with the 32p gears, and they hold up just fine. I ran a Hyper 8 port .21 for about 2 gallons on it, and i didnt strip one spur gear (i must be good with the meshing of the gears). I have used almost all possible gear combinations with my GT, and they all hold up great, untill you stick an RRP steel spur on it. That thing chews up any clutchbell known to man, even the expensive hardend steel ones. The only thing i can think of being a flaw in the GT with the big block is the clutch setup. The hyper 8 port didnt have problems with the clutch, but the newer Collari is making it slip a little more (what can you expect from 3+hp?). I use the RRP tranny gears in my GT, and i havent broken a single one yet (except all the stock ones which didnt last too long).

MW: I'm sending a PM.

 

[niggle]

Thanks for the input guys. No, it's not a T-Maxx that I have in mind.

It's going to be a weird one-off project where I don't have room for a large spur gear so I need to obtain the correct reduction ratio by running a layshaft with some smaller gears (10/22) on it to couple the clutch bell to a 22T spur.

The RRP 32dp gears are the largest pitch that I can find off the shelf in steel. I could probably get 24dp in brass or nylon but I doubt that they would last long.

Thanks to .21RC10GT for the positive reports on the RRP pinions, I would be running something like a 16T clutch bell against a 22T RRP alloy steel pinion so I guess I might be eating clutch bells too!

 

[welchdennis63]

i can't get the link to open where did you get a 1.0 spur for a tmaxx and whats the tooth count on it?

What I found running the "stock" gears (whatever dp they are) for the cb/spur was that the clutch couldn't take the power of a big block very well.

I ran RRP steel in the trans for all gears with the RRP FOC. The only plastic gears remaining in the trans were the large two speed gears. I ran about 10 gallons or so through my trans with an OS 21 RG on my XTM converted maxx. During those 10 gallons, I chewed up the large two speed gears twice, 1 two speed one way and 1 two speed main shaft. After all that, the RRP gears still look like new. I also ran boca green seal bearings and an aluminum trans case to minimize case flex from trashing my investment in the RRP gears. They get pricey when you add them all up.

I had serious clutch problems throughout gallons 1-7. Running the stock type spur/cb I could only use the stock type clutch. I tried MIP shoes, integy aluminum shoes and stock shoes. We all know integy's aluminum sux and it sux bad for shoes. The MIP shoes lasted a gallon or so and so did stock.

Since I had an actual 21 conversion chassis, which is longer by about an inch between the trans and rear shock tower, I was able to run an 1/8 scale clutch system using an RCS spur. After installing the 1M pitch gear with an OFNA bell/savage flywheel/HPI teflon 3-shoe clutch, I never had a clutch problem throughout the last 3-4 gallons of the truck...

but... I did have a diff problem. But the diff problem went on and on throughout all 10 gallons. I think I rebuilt the diffs about once a gallon or so. I was using integy diff cases and maximizer diff cups with proper shims to keep the ring/pinion tight. But, the ring/pinion would shell out around a gallon or so anyway. Before going to this diff setup (running stock), they would only last 4-5 tanks before they would start clicking.

The RCS gear I'm talking about is RC-Solutions. Good gear, great idea. I'd suggest going that route before dumping a bunch of dough into a 1/10 clutch/spur setup.

If I had it to do all over again... I'd have started with a savage

 

[olds97_lss]

52T: http://r-cstore.com/store/product_info.php?cPath=26&products_id=92
54T: http://r-cstore.com/store/product_info.php?cPath=26&products_id=93

Found the 54T at horizon as well:
http://www.horizonhobby.com/Products/Default.aspx?ProdID=RC+066

Didn't see the 52T there.

For comparison, a 32P maxx 72T spur with a 20T bell gives you a 3.6:1 ratio (stock old school 2.5 T-Maxx gearing).
To get the same with a 1M 54T spur, you will need to run a 1M 15T CB.

Make sure to buy a hardened CB or it will fry it in a very short time. Trust me on that one!