every single bearing has a certain amount of clearance built in and rated as such .... they all have a certain amount of "slop" .... i have noticed front bearings in the offroad race engine side of things having problems from either fuel with very low oil content and/or too rich lsn creating an excessive amount of oil in crankcase then when the case is pressurized upon high rpm throttling the oil pushes out through the front bearing (path of least resistance) . just my real world experience. i personally get as much as 10 gallons of use out of 17011 front bearings as i keep my lsn very lean .... i have seen them go out in less than a gallon when guys leave lsn blubbering rich and compensate by leaning the piss out of the high speed needle


anyways ....

happy motorin'

Are you plugging the little pulse port behind the front bearing in your engines? I’ve only seen this port in car engines and I remember Neal saying it’s best to plug that port, but the side effect is you get more leakage from the front bearing.

I do not plug this port in my engines and I find many engines will weep a little bit of oil when running at higher rpm - I see a very little bit slung off onto the chassis. I’ve seen it happen on several engines - Novarossi, Picco, SH, and even some junky Traxxas Engines. I’ve only had a few Novas, but I have the same expectations from them that I do with any other engine. With a properly tuned engine, I expect a tiny bit of leakage from the front bearing, but that’s it. If I see excessive visible wetness around the front of the engine, I tear the engine down and check the bearings. Most of the time, the rear bearing is visibly and audibly loose. There should be no discernible radial play in a bearing when installed. If there is, the bearing is toast. Treatment of the engine will obviously play a large role in how long bearings will last among other things.

I’m not trying to argue or prove anything right or wrong - just sharing my experience. I am curious to see what you have to say about that port behind the front bearing.

hijacking the novarossi thread ..... we are goin to he!! now .... :lol:

it all changes with the offroad engines as they vary rpm's much greater than onroad which is where most of the design efforts have been placed at novarossi through the years . with a constant rpm or smaller range of RPM you can design a certain aspect of the engine to working within those certain rpm parameters and they do exactly as intended , deviate from the range of rpm your specific design was intended to work and results are all over the map . the "vacuum port" is designed to pull lubrication through the rotating components of the front bearing , it works , offroad engines have required some design changes from the original designs that the engines were built on . it is fairly easy to discern an air leak from improper tune on these supercool lil micro motors but it takes some experience :nod:

anyway .... im probably babbling

happy motorin

Experience speaks volumes. It’s nice to pick the brains of other experienced guys that see a different side of the hobby than I do. I work all over the map from cars to boats to planes. The big design efforts are definitely visible in car and boat engines; airplane engines haven’t seen much innovation over the last 20 years with the exception of Novarossi and the old Rossi line. It’s interesting to see Novarossi car engines are incredibly affordable while the boat engines are priced quite high and aircraft engines are between car and boat engines.

Novarossi does make one heck of an engine though. I absolutely love my Legend 28-8 even though it’s one of the “budget” mills. The power is insane.

POSSIBLE BENT CRANK
 

Fellas what could/would be some symptoms of a bent crank? I have a nova mantra n I think the crank is bent, this is the 2nd front bearing that has had a front shield get a lil ovaled out n basically fall off after 1race day:flaming: Now sounds like the rear bearing is toast.....have any of you experienced a bent crank?

Ive seen it in an airplane engine, yes. Car/buggy engine - no. A bent crank would be fairly easy to see when running - the clutchbell and flywheel would wobble a little bit. It would likely be visible if it’s bqd enough to make the front bearing shield to oval out and come out. I would be removing both bearings and checking them over carefully and take your crank to someone that can chuck it up and run a dial indicator across it to determine if it has any runout. Maybe it’s not the crank - maybe it was the rear bearing the whole time? Is the engine under warranty?

Thanks. I doubt it's under any kind of warranty , I have a new rear bearing but I was hesitant to install if crank was bent, this time I was going to try a front bearing with a metal shield n the new rear bearing n see what happens .......

hows the block inside the crank bore? any signs of rubbing?
my guess would be to somehow check if the bearing seats on the block are true.

I'll try n check

This is sorta what I was talking about a few posts back. If the rear bearing goes south, the crank can wobble in the case and ding up the inside of the crank bore within the case. I would be inspecting the crank bore in crankcase and removing the rear bearing and checking it for looseness. If there is any notable play in the rear bearing, you’ll have at least part of your answer.

ive never seen a "bent crank" from the factory after a few thousand of them .... Rick Brake of RB mods has tooling to straighten cranks as well as a full shop to help u out if you do suspect a bent crank. Rick is a great guy

if you wanna send it in i can take a look at it and get ya fixed up ... lmk

Thanks Monty. I might just send it

I have to get new bearing for my bonito and was lookimg at avid and the nova bearings. Has anyone ever used the avid ceramic engine bearings. I know the nova front bearing is double shielded and the avid says 2 rubber seals. Is this the same?

Fellas quick question, Can a mito 4 crank be used in other novas? Or are they specific to the offset motor case?

it's an extra long strong engine, so using it in a regular engine will upset the timing slightly, and may not work, but also make it slightly bigger than a .21 engine..