How to set spur gear mesh?

[sgra2951]

I have torn about 7spur gears out of my savage 4.6.. I set the mesh with a paper between, set it, checked it, and then i get about 30 minutes of play and then, with no bumps or wrecks it tears out again. I cleaned the plate where the motor mounts to the engine, and replaced all the bolts. When I install the new spur the mesh is horrible. I use loctite and everything. 47 tooth spur and 16 tooth bell housing.. please help me.. I'm so frustrated!!

 

[Childresshunt]

Paper trick is trash IMO. Put the motor on and get the mesh so tight its not smooth at all to spin the spur. loosen your mount bolts a little to where you have to hit the motor your hand to move it. It should move ever so slightly. Hit it spin the spur do this until it spins nicely. Also be sure the spur and bell are parallel to each other and that the motor isnt cocked one way or the other. that will eat a spur everytime after just a few runs.

 

[Zdragon71]

I firmly believe in the paper trick but only as a test after the mesh is set to feel. If it pulls the paper thru and has good groves and NO tears in paper then its good. If you dont have good sharp grooves in paper then its too loose. I do not use the paper to mesh gears only use it to turn spur gear and feed paper thru to check mesh. There is a difference. It has never failed me yet and i been running the same spur gear for over a gallon of fuel with many engine removals for other repairs and adjustments.

---------- Post added at 1:02 PM ---------- Previous post was at 1:01 PM ----------

Also make sure your bearings are good and not binding or wobbly and worn out. Any awkward offset movement under rpm will eat a spur gear.

 

[Childresshunt]

[/color]also make sure your bearings are good and not binding or wobbly and worn out. Any awkward offset movement under rpm will eat a spur gear.

+1 on that

 

[Childresshunt]

And zdragon i agree it is a good way to check mesh after installation but knot for instal

 

[sgra2951]

I'm thinking maybe the motor is crooked.. I have been using the paper every time, maybe when I'm pushing its making the engine crooked.. I'm so pissed. I have got to figure this out .

 

[2revo1maxx]

Maybe something's broken and flexing.

 

[TaterX]

Check your screws. Make sure theres none missing or loose. I'm with 2revo1Maxx, Your flexing somewhere. Going through 7 spurs. You would have got the mesh close enough at least once.

 

[sgra2951]

Guys, thanks for all the help, came home last night ands looked at it again.. screws were loose.. got her back on the road! Hopingbtodayvi don't tear it up again. Ran a couple high speed runs and it DoD good

 

[olds97_lss]

I had an issue like that once, was a cracked engine mount. I didn't know it was cracked but kept chewing up spurs for no reason.

 

[sgra2951]

Team.. I threw the truck to the side for awhile.. finally brought it back out today and bam! Two spurs back to back. I'm so pissed I'm about to cry.. I got hundreds of dollars in new shocks, servos, tuned pipe, tires ans wheels.. and the whole time, I've still got spur problems.I put venter bell housing, took it to mechanic and had them set mesh, its all bad.. is there anyone near Hamilton Ohio, or surrounding areas that can help me out. Ill come to you. I'm frustrated, my buddy has same truck and never an issue..thanks again for the help.m

---------- Post added at 7:29 AM ---------- Previous post was at 7:28 AM ----------

BTW, as unsaid earlier in post that it was loose screws, that didn't fix it.

 

[Alexander_0_1]

Go for a hardened steel spur (HPI makes a bunch), a 10mm engine plate (optionalnHPI product), and check your bearings in the transmission something might be giving you resistance though out your drivetrain

Take the engine out get eyes level with you spur gear, give it a spin see if you can tell if the driveshaft is bent

 

[sgra2951]

Driveshaft is the? Part that connects to the bell housing?

 

[Snook Man]

The driveshaft he is refering to is the transmission input/slipper shaft. Its the only shaft (other than the crankshaft)that if bent would cause a stripped spur.
A bent engine crankshaft (cluthbell attaches to it) would cause a lot bigger issues.

Evidently something is not right with your rig, mesh/something loose/broken/bent, etc. I only run plastic spurs and have used the same one for approx 4 gallons running 18/49 cb/sg and 2 of those gallons were with a pretty stout Nova .28. No signs of wear at all to the spur and no problems with the slipper. (the plastic spur easily outlasts the center drive cups).

 

[sgra2951]

Ok, ill look into it. I am having wear quite quickly, and am thinking that this could be a definate possibility.. I have upgraded the tires to monster ones, and have already burnt up a servo. I am running 47/17 sg/bh and am thinking that I need to change to 49/16.. I hope that I do have a bent shaft, I'm so sick and tired of the probelms..

 

[Alexander_0_1]

What size are those tires the extra weight could be the issue, when using stock/plastic spur gears one has to change the SG/CB ratio so your not putting too much strain on the stock parts, if the tires are bigger then you've just found where the adjustment needs to be made!. People usually gear for torque when the tires get bigger, when I have my jumbo kongs on I go 52SG/14CB, although I'm still using steel SG/CB

 

[sgra2951]

I looked for the bent shaft, if there is any bend at all, its so slight that I can't notice. I inspected the spur more and noticed that it seems that my mesh isn't tight. The gears are flat but only slightly. I am going to order the Robinson metal spur, I'm going to go to 16/49 and try. Are those mesh gears compatible? Also, with the metal spur do I need to use the stock slipper or go with the ceramic pad?

 

[Alexander_0_1]

I would go with the HPI steel spurs, I've run more than my fair share of Robinson racing spurs. Reasons: A. They are weaker metal then HPI, B. HPI spurs are made for your truck by the people that make your truck C.theres no bearings to worry about D. Less expensive

For sure you can use the ceramic pads, they will not generate as much heat as the stock pads, and they last longer

---------- Post added at 10:32 PM ---------- Previous post was at 10:29 PM ----------

As for compatibly, if you got an extra engine mounting plate you can make the grooves longer towards the inside, I've don't this before I started adding to my SG/CB collection.

 

[sgra2951]

Ok, I'm going to look into metal hpi spurs.. really hope it works..

 

[SchrodeMode]

Go for a hardened steel spur (HPI makes a bunch), a 10mm engine plate (optionalnHPI product), and check your bearings in the transmission something might be giving you resistance though out your drivetrain

Take the engine out get eyes level with you spur gear, give it a spin see if you can tell if the driveshaft is bent

Ok, I'm going to look into metal hpi spurs.. really hope it works..

It'll work....for a while. If you're going through plastic spurs that fast, you have a problem that will only be temporarily fixed. In the end, metal gears will still wear out....the only difference will be the cost of repairs and maybe a little longer run time. Plenty of guys on here have either larger engines or modified engines and get gallons of use on stock plastic gears. When I first had my Rustler, I was pretty bad at setting my mesh, now I've had the same gear on it for 3 different engines. I think you should do a complete tear down and really inspect every part of the truck, if it all looks good, it may be time to dig into the transmission.