In my racing engine experience a front bearing that will not seal will not run properly ..... if the bearing has oil coming out its got air/dirt sucking in . Ive worked on thousands of engines ;)

As for plugs ... c6tgc is a cooler plug and will be a slight bit more difficult to tune in cold weather .... c5tgc is a hotter plug for cooler weather

Any opinons on the .21 ISON novarossi engine for top end power?
any first hand experience

Letting it idle is no good alone. Heat cycle it while doing figure eights is about the most easy way of breaking in a engine.

Hello Team Novarossi,

I currently use a stock Novarossi GT5/17. It was originally a 2016 spec which i upgrades by changing the piston, rod and sleeve. It a very good and fast engine.

My track is very technically(tight,hairpin corners, asphalt parking lot) and that is about 3/4 of the track(Accelerate and brake). The other 1/4 is a straight away which is about 120-150 ft. To paint a better picture the average time on the track for GT is 18 sec and the straight last no more than 2-3 secs.

The guys i am racing against are using off road engines such as OS 21XZ-B VII and OS 21 VZB. They are very very quick in the technical section. i believe due to the extra torque and the low rpm starting range.Their cars launch very quickly. On the straight i can pull a gap or maintain the gap (depending on how quickly i get on the power) but i lose it all in the technically section and have to get defensive until i reset on the straight. no matter how well i THINK i have set up my serpent gt 3.1 clutch i cant get that launch or acceleration like my competitors.

i have tried xhard, hard and medium springs, carbon and yellow shoe, steel and alu clutch bell, and different gear ratios and engine tuning. i am using Nov 41032 manifold and tesla 2139 pipe(i tried Nov 51010 pipe as well). The best operating temperature for me is 280-300 degrees. and once it stops its the hardest thing to re start. The bottom needle is a bit lean in order to be competitive in the technical section. i am getting good smoke and the engine revs come all the way down when i come in to pit after about 9-10 mins.

Someone told me if i use Nov41031 manifold i should get more torque/bottom end, is this true?

Also, if anyone can provide any solution i am happy to take notes.

my current serpent set up is:

spur:63/58 pinion:19/24
2 carbon shoe w/ medium springs
2 yellow shoe w/ hard springs
nov41032 w/ tesla pipe 2139
#8 plug (i live in a tropical country...HOT)

Hello houston,

Regarding bad/spoiled Front Bearing in Off Road engines, I also believe that this can cause erratic tune..

But how about the Steel Bearing in an On Road engines? The type of shield/seal on the Steel Bearing is a non contact type.. Will it able to properly seal the crankcase negative pressure while the throttle is open?

Cheers.. :)

The bearing does not provide the crankcase seal. No bearing is sealed to begin with. They are shields only and only intended to keep debris from getting in. Many engines in the past never came with any seals or shields to at all!

The crankcase is sealed through an oil film between the crankshaft and crankcase. If the bearing is loose, the crankshaft can wobble. This wobble can/will wear the crankcase if it’s a tight tolerance engine. This whole process will upset the crankcase seal causing erratic behavior. If an otherwise predictable engine starts running wonky all of the sudden - check the rear bearing. Usually if a bearing is going South, glow plugs will pop more often too.

on road rpm's usually stay in the upper rpm range where the crankcase pressures do not vary near as much and the fling/film seal between crank and block stays constant . offroad varies immensely in rpm range in comparison .... also gearing in offroad 8th scale has 1 speed .... engine gets a big load pulled on the low and an extreme rev situation at high

soooooo ... question ..... when an offroad engine has a leaking front bearing and will not run properly what do you attribute that too?

The leaking bearing (assume oil leaking out) where it didn’t leak before is probably due to one or both bearings being out of spec (too loose). That is the only time I’ve ever had an engine leak from the front excessively and suddenly.

However even with a loose bearing, the engine will still run. It just won’t tune worth a damn. Even a minuscule amount of play can wreak havoc.

They are good engines. Too bad I am selling mine, but I just don't do the GP class any longer. QUOTE=NitroB810;15141576]Any opinons on the .21 ISON novarossi engine for top end power?
any first hand experience[/QUOTE]

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..

its also a 14.5mm crank, most novas are 14mm

Placing it in a crankcase with a center mounted carb will give too much distance from the normal timings. Although I have seen the most weirdest timings I do not think the engine will run well.

Thanks fellas

were you thinking about trying one in your mantra? i think the only other crank that would work is the 15013 and its really basic with a tiny center bore

I buy a new engine novarossi legend 28-8, what pipe and manifold is the best for this engine to truggy to buy? I have on old engines two pipes, sh 2075 and jammin jp-4.

41032 header and 9886 pipe.

Need some help here, I am not a racer by any means, jut local weekend track having fun type. This is for a Serpent Cobra buggy

Need a new engine soon, www.absolutehobbyz.com

Novarossi Rex Paloma 21 Off Road 7 Port Engine Extra Long Stroke (Steel Bearings)

Novarossi KARMA 3.5cc Buggy Off Road Engine (4 Port) Limited Edition

Any suggestions from the two listed above? Open to other suggestions as well. Do not want to go over $200 if possible.

Thanks,

Novarossi Paloma 7

Ended up buying a Paloma with some extra long stroke shims for break-in. Got a Novarossi 2096 EFRA and 41021 manifold to go with it. Cannot wait till it gets here.

This has already probably been covered earlier somewhere in this thread but could anyone tell me if there's a cheaper alternative or another Nova bearing that fits the rear main of the Virtus? If so what size bearing is it?

Thankyou in advance.... ��

Modify the crankcase:
https://www.rctech.net/forum/onroad-...gs-virtus.html

Is anyone having issues with there Rolling engines and how are you liking them in truggy?

Look what got delivered.


https://cimg8.ibsrv.net/gimg/www.rct...078aa2a64.jpeg

Did you buy that from absolute? If They are using the good head and block on the extra long stroke paloma im getting one.

yes absolute has them 2018 version with updated o ring head button as well