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Old 05-17-2004, 09:13 PM   #10681
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Default Re: gears

Quote:
Originally posted by roadrage
what is a good gear combination for a high speed big track for the 710?
How long is your straight? Usually the stock gearing 17/22 pinion and 60/56T spurs is plenty enough for most tracks. The tallest 2nd gearing is 23T pinion and 55T spur which has an FDR of 4.48.
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Old 05-17-2004, 09:15 PM   #10682
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Default track

the track is a 280-300 ft straight but wat is the tallest gear o get so i can have top end?
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Old 05-17-2004, 09:17 PM   #10683
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tallest gears to get? sorry for spelling
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Old 05-17-2004, 09:27 PM   #10684
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Default Re: track

Quote:
Originally posted by roadrage
the track is a 280-300 ft straight but wat is the tallest gear o get so i can have top end?
The tallest 2nd gearing is 23T pinion and 55T spur which has an FDR of 4.48.
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Old 05-17-2004, 09:39 PM   #10685
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Originally posted by markp27
Thanks bro! This motor is a gonna - just check the prices for the spares I need - cost more than the engine itself

Something went big style in the gearbox/engine deparment after the hit yesterday - the clutch shoes shows signs of wear just in one spot I think I'm going to replace the clutch bell, gears and bearings of the centax whilst I'm about it - oh man is this going to be expensive
Avoid to blip the engine in full throttle too much/ too long on the starter box.
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Old 05-17-2004, 10:09 PM   #10686
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Quote:
Originally posted by GoldFinger
Avoid to blip the engine in full throttle too much/ too long on the starter box.
What I usually do is not rev the engine for the first 30 seconds of starting or so on the starter box. I let it idle and then slowly start to rev the engine.
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Old 05-17-2004, 10:20 PM   #10687
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Originally posted by InitialD
Take off the whole engine and give it a thorough wash with a nitro cleaner. If possible, take off the bearings too. Use a heating plate. Check and see if they are gritty as a result from that incident.
I'll check, but I would be afraid to replace the major components and then find that the crankcase is also damaged, resulting in all the new parts being damaged.

Quote:
If they are, then you need to replace them as well. I don't know how much you can get the individual spare parts and how much they can add up too. Perhaps since NovaMega engines are difficult to find, you could try the Novarossi route or the JP FX engine. You can try HK online shops. They may be cheaper.

Sad to have to read through this early in the morning...
As I've got a JP FX on its way, I'll replace it with another JP . It seems the JP is actually based on the Novarossi/Novamega design - I wonder if it uses the same conrod?
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Old 05-17-2004, 10:23 PM   #10688
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Quote:
Originally posted by InitialD
That was what I was thinking too... The clutch / crankshaft must have take a hit. I knew something was wrong when both bearing broke. I had the same thing happen to me but turn out the crankshaft was bent !

When the engine internals are moving pretty fast, a slight tap to misalign it can cause a lot of things.

Mark, can you see if there are scratches as a result from the conrod on the engine backplate?
I think the crankshaft must have been damaged, but when I put it in the engine and spun it, I could see no deflection at the end of the crankshaft But it may have been a very small deflection. This is borne out by the fact that the engine seemed to work "fine" for 5 tanks and then blew on the 6th

Yep, there are scratches on the backplate - which weren't there yesterday.
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Old 05-17-2004, 10:24 PM   #10689
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Quote:
Originally posted by InitialD
Yup. It is a nice engine indeed. I had a bad incident on my NovaMega 2104TMS 5 port engine too. The circular clips that holds the crankpin on top of the piston jumped out and made a deep scar on the piston and liner !
And the liner is where a lot of technology/research is invested - which is reflected in it's price!
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Old 05-17-2004, 10:30 PM   #10690
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Quote:
Originally posted by markp27
I'll check, but I would be afraid to replace the major components and then find that the crankcase is also damaged, resulting in all the new parts being damaged.
Crankcase damage? That would almost be impossible. I think you meant crankshaft...

Yeah, you're right in saying that. If a major damage like this happens, usually better to get a new engine.

Perhaps can you take a pic of the piston / liner condition after cleaning it? There is a chance that they can still be used.

Quote:
Originally posted by markp27
As I've got a JP FX on its way, I'll replace it with another JP . It seems the JP is actually based on the Novarossi/Novamega design - I wonder if it uses the same conrod?
If you got the FX engine, I would not know if they have the same internals having same dimensions as the Novarossi / NovaMega. Hope Schrijver99 or someone else can shed some light on this.

JP came out with their own line of FX engines but had Novarossi make them to their own specs. I know in the previous times, what JP does is get Novarossi engines and do their own "mods" on them and sign them off as modded JP engines.
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Old 05-17-2004, 10:30 PM   #10691
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Quote:
Originally posted by InitialD
You can check if the clutch bell is warped. Spin in on the crankshaft with a new set of bearing in to see if it wobbles.

I'm surprise to hear that the crankshaft is straight after the incident.
I checked the bell, too. I mounted it as normal, so it was pretty near the clutch and span it - it seemed to spin smooth and straight and still does But when I have a look at the metal shielded bearing nearest the engine end - it has been rubbing the clutch bell, as around its circumference there are three "rub" stripes, i.e. it has been rubbing the inside of the clutch bell - that should never happen. I think the hit bent the clutchbell or crankshaft to such a small degree that it is impossible/very difficult to see the resulting damage, but at +35,000 revs, the forces generated by the wobble caused the bearings to slowly disintegrate.
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Old 05-17-2004, 10:35 PM   #10692
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Quote:
Originally posted by markp27
This is borne out by the fact that the engine seemed to work "fine" for 5 tanks and then blew on the 6th
Could be. But most of the time, the crankshaft is bent where the Centax clutch is installed. The part inside the engine is pretty think and not like to bend. A bent crankshaft would usually result in the spurs / pinions stripping out of no where. Engine also has excessive vibrations when you rev it. And these vibrations are no good to the front and internal bearing as well.

I guess the bushing was also waiting to disintegrate as a result of the accident.

Quote:
Originally posted by markp27
Yep, there are scratches on the backplate - which weren't there yesterday.
Ummm, so the crankshaft was somewhat pushed to the other side which hit the backplate and dislogded the conrod in the process...
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Old 05-17-2004, 10:46 PM   #10693
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Quote:
Originally posted by InitialD
Could be. But most of the time, the crankshaft is bent where the Centax clutch is installed. The part inside the engine is pretty think and not like to bend. A bent crankshaft would usually result in the spurs / pinions stripping out of no where. Engine also has excessive vibrations when you rev it. And these vibrations are no good to the front and internal bearing as well.

I guess the bushing was also waiting to disintegrate as a result of the accident.



Ummm, so the crankshaft was somewhat pushed to the other side which hit the backplate and dislogded the conrod in the process...
The conrod bushing(big end) blew up first then anything goes wrong.
Should be no problem with centax assembly. Just my observation.
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Old 05-17-2004, 10:56 PM   #10694
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Quote:
Originally posted by InitialD
You could use a motor spray or a dedicated nitro cleaner to blast off the dirt from the bearings. Serpent has a bearing oil. Part number is 1682.
Kawada SK-18 Bearing Cleaner Case for about USD8
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Old 05-17-2004, 10:57 PM   #10695
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Quote:
Originally posted by InitialD
Crankcase damage? That would almost be impossible. I think you meant crankshaft...
The crankcase is damaged in the area where the conrod mates to the crankshaft - as the bearing disintigrated, the conrod came away from the crankshaft and damaged the crankcase.

Quote:
Yeah, you're right in saying that. If a major damage like this happens, usually better to get a new engine.

Perhaps can you take a pic of the piston / liner condition after cleaning it? There is a chance that they can still be used.
I see a lot of micro-scratches in the liner and on the piston head - I'll try and post some pictures.

Quote:
If you got the FX engine, I would not know if they have the same internals having same dimensions as the Novarossi / NovaMega. Hope Schrijver99 or someone else can shed some light on this.

JP came out with their own line of FX engines but had Novarossi make them to their own specs. I know in the previous times, what JP does is get Novarossi engines and do their own "mods" on them and sign them off as modded JP engines.
Certainly the JP website shows that the engine has the same dimension as the Nova series - then probably the parts are exchangable. My suspicion was that they have made a lot of work in the liner deparment - the conrod seems to be the same anyway in all the 12 series engines, so it doesn't seem to play any part in performance. I'll let you know when I find out, though
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