UnkleLumpY

Ok, ever since I modded my engine, this things has crazy power and unbelievable low end, but now I'm blowing clutch Bell bearings left and right. I use the standard bearings that come with the bell. I get an hour or so on them and the just explode, i use a washer and a small bit of locktite. Is there an aftermarket bearing I should be using? Is it possible that the torque is too much for the bearings that come with bells?
When I say this thing screams I mean it, this buggy will keep with and even pass most electric trucks on track (not all but most), but now I have this bell bearing issue that is getting old fast. Hoping somebody on here can help

1QwkSport2.5r

What did you do to the engine to "mod" it, and what brand and size of bearings are you using? Are you shimming your clutchbell?

Not shimming a clutchbell properly will cause bearings to fail quickly. Not oiling them every so often will cause them to fail quicker.

I run a modified Picco .28 in a 1/8 monster truck and I get about a half gallon to a set (3 - $1 AvidRC bearings) of clutch bearings if running hard. Engine break-in took about 1.25-1.5 gallons of fuel and the first set of bearings went poof at the 1gal mark, and I just changed them a few weeks ago at the 1.5gal mark. I oil the bearings every 2-3 tanks of fuel. I shim the bell for about .001-.0015" endplay and because my bell has two pinion gears on it, I can run a 3rd bearing with a special Ofna shim kit.

UnkleLumpY

I fluted the ports, switched to a turbo head and reshaped it to a more aggressive angle, removed most of the head shims and put a 3/8 riser on the carb (similar to what you would see on prostock dragsters)
I use ofna racing 5x10x4 with the standard washer/shims the engine calls for

1QwkSport2.5r

Fluting the ports is bad karma. I wouldn't recommend doing that anymore. The turbo head button is a good addition, but I'd like to know what exactly you did to the head and where you got the info about the modification.

As to the clutch shims - how much end play does the bell have?

UnkleLumpY

This is a learning engine for me, so I'm playing round with it, a Rossi is in the near future, as for the head I carefully dremmeled a sharper angle into the rounded angle on the bottom of the button. I didn't get the information from anywhere, I just applied my knowledge from motorcycle and automotive mechanics, my theory was if I could more directly control the expansion and combustion I could generate a more efficient combustion process, it appears to have worked. As for the clutch Bell I haven't measured, just using the recommended washers from the engine diagram

TimJ

Double check your gear backlash as well.

controlliner

Modding an engine is fun but if you do not have a dyno, you will never have comparisons or figures to see what worked or not. Hearing is not always an accurate way to judge your mods.

1QwkSport2.5r

A GPS and a Tachometer will tell you if what you did made a difference of not. If the modifications are done to change the powerband (usually moving it higher in the rev range), you probably will be able to hear the difference too. The Picco .28 I modified had a notably higher top rpm that you could hear. This engine probably picked up 2000-4000rpm on the top end without sacking the low end punch. At least in the truck I put it in anyway. But overall, I agree that it's hard to quantify your results without some sort of scientific way to measure it. Changing the manifold and pipe can change the exhaust note and make it sound more powerful, but it could just be that - a different sound.

With these engines, the manifold can have a more significant influence than the pipe or even the fuel (more nitro or less oil).

UnkleLumpY

I agree a dyno is the only way to truly know, but it sounds better and side by side comparisons is how I judged if it did anything, I concluded it did in fact help, how much it helped specs wise I can only speculate

UnkleLumpY

Well all those mode mean nothing now! Just bought the Rossi rex legend 28-8 paired with a Argus TB-1 race pipe and header

Put almost $300 into an engine and pipe combo, better be worth it!!!!!