Clutch, Tickover Issues

[MattyBox]

Hi all,

Could do with a bit of advice!

Last week my engine cut 4 times in a 25 minute final. The first was on the line when the car was at idle.

I checked the car out after the race and the clutch was red hot (almost glowing lol) and the shoes were almost hanging out the side of the clutch bell.

So i thought this was the problem and replaced the clutch, flywheel, shoes, springs clutch bell all with brand new parts. Everything seems fine, clutch bell spins freely and about 1mm of play.

I put everything together and took it for a blast around the field and again it all seemed good until I re fuelled and the wheels were spinning on idle and then the car cut out.

I re tried a few times and still the same, It also seemed a bit 'boggy' at low revs.

Have I cocked up the clutch build? Again the car will idle for around 30 seconds but the wheels are turning and the engine cuts.

Any help would be greatly appreciated!

Matt.

['caster master]

You could have messed up the clutch build or if it is bogging the lsn could be too lean which would also cause the idle to speed up and make the clutch engage. It is quite hard to tell without actually seeing/hearing/driving the car, sorry i couldn't be of more help. You could take the engine out and check the clutch is ok, if it is then the lsn is just probably too lean and the idle also posibly too high.

[MattyBox]

You could have messed up the clutch build or if it is bogging the lsn could be too lean which would also cause the idle to speed up and make the clutch engage. It is quite hard to tell without actually seeing/hearing/driving the car, sorry i couldn't be of more help. You could take the engine out and check the clutch is ok, if it is then the lsn is just probably too lean and the idle also posibly too high.

Thanks for your help, I know it is difficult to describe and difficult to try to find a solution on a forum!

I will have a play with it again tomorrow.

Can the lsn just go lean on its own though? It was always fine and had good run times until last week when everything seemed to go wrong. I just thought it was down to the state of the clutch so thought replacing this would fix it.

Just a thought.... I always ran 16t clutch bell on the AE and ran this in the Intech last week, I have now switched to 13t since so maybe needs a retune anyway.

Thanks again for your help and advice mate.

['caster master]

No problem, always happy to help. Engines shouldn't just go lean on their own but they will need a little retune depending on the temperature, humidity etc as well as for a different track. Also you may need to retune a bit for different gearing and probably for a different clutch setup also, but no major adjustment.
Hope this helps.

[MALLET]

Check for end float on your clutch bell Mate

[MattyBox]

Check for end float on your clutch bell Mate

Hi mallett.

Sorry to sound like a spaz but I am still new to nitro and this is the first time I have messed with clutches!

What do you mean by end float?

[MALLET]

End float is the amount of movement that you have after shimming up the clutch bell. You need to be able to push your clutch bell in and out towards the engine for a minimum of 1mm.

What happens is with the amount of heat that is generated with the clutch and engine your bearings expand and get trapped against the bolt at the end of your crank so when you break you end up stopping your engine.

So when your engine is could on the first start up everything seams fine and then your problems start as it gets warmer.

Hope that helps.

Tim

[MattyBox]

End float is the amount of movement that you have after shimming up the clutch bell. You need to be able to push your clutch bell in and out towards the engine for a minimum of 1mm.

What happens is with the amount of heat that is generated with the clutch and engine your bearings expand and get trapped against the bolt at the end of your crank so when you break you end up stopping your engine.

So when your engine is could on the first start up everything seams fine and then your problems start as it gets warmer.

Hope that helps.

Tim

Thanks mate.

Will have a look later and let you know!

[MattyBox]

Had the clutch off and rebuilt (3 times) and still the same issue.

Plenty of play now, the initial problem was with the new clutch bell there wasnt hardly any movement so reverted the old one and seems good.

Well I thought so until I put everything back in the car and ran it. Its still the bloody same!

Tried richening bottom end, no good. Tried leaning the bottom end, no good. tried lowering tick over but cuts.

The only way I can make it run is to have it ticking over high but the wheels are spinning like crazy on the box, when I put the car down it seemed Ok but cant be doing it much good and cutting at random times, whether its when I brake (not always) or accelerate (again not always) it cuts.

The engine has been great up until now its a ninja and always sweet with 12 minute run times and bags of power and reliability and still loads of compression and holds its weight.

Losing my head with it now as I have a 2 day meeting at pembrey Saturday and Sunday.

May have to try a new engine, pipe, clutch and start again!

Stressed aint the word!

[Jaf]

Make sure the clutch nut is tight. If it is loose, the flywheel could move slightly and cause the clutch to lock up.

What type of clutch are you using and what springs are you using? You could maybe try a slightly harder spring if it is engaging too early.

Another to be aware of is that clutchbells do have different internal diameters and the shape of some clutchbells (taper on front edge) can also cause problems with some clutches. For example, the JVD/Ascendancy/Werks clutch requires a clutchbell with an internal diameter of between 26 and 26.8mm and an internal length of 10mm. If I remember correctly the MBX6 clutchbell is therefore not suitable.