Chet, with as cold as it is up there now, the 6 plug was going to be hard to tune. Plus you run your motors too fat(the excessive oil is why the front seal blew off your bearing) The hotter plug burned off more of the residual fuel and oil and gave the impression that it fixed your issue. If you started out by leaning the motor out, to get away from all the extra oil and fuel running through the engine, you might have been able to get the 6 to work.

There is a reason I always start tuning your engines by leaning them out. You are relying on fat tuning to keep power in check, but you should tune them with a clutch or venturi instead.

Motors hate to be run extremely rich, just as much(sometimes more) than being run lean.

Mini me is always trying to hook you up. You should let him sometime. The kid can tune a motor.....

You right Marc , but this one was not rich, unless it dropped its nuts after the main at CVR. I Came off the track at 250°

Need some pointer on p5xlt I got it used(I know) in a package deal and this is my first nitro in a decade. It has good compression fairly clean mounted in a tki3. Got a kyosho starter started up fine I let its idle for about half a tank. It's about 40 degrees here gave it a few full throttle punches while on the box it dies and it was stuck tdc, pulled the motor out mounted it to vise to get it unstuckand now it has a very hard punch at tdc. I don't have the tools right not to take it apart and I don't what to strip any screws spins very smooth till it get to the top then it's pinch-free-pinch then on the down stroke. Temp was at 210 when it died. It's to late right now to try to start it up again

That engine is not fully broke in yet. Every time you get that piston stuck, is hurting that engine. Be best to warm that engine to 220-240 or higher, you will get longer lasting engine. Your low end needle seems close enough for now because of good idle. Don't full punch it. "If you need a vise to un-stick it" its too tight. "New" And seems to set on the rich side "good thing" and is loading up to much for "full punches". I would "heat cycle" that engine a few more tanks if it was mine. Then start to lean it out a little at a time. Never full punch a tight engine.

Thanks for the reply!! It was no where near this tight when I got it that why I thought it was already broken in/warn out. Hitting the track today so try letting it idle in the pits today while running ebuggy

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]