Slipping clutch

[AlvaSpeed]

Is it possible that my ESP mod/ported 27.2 engine has enough power to make the clutch slip?


I ask this because I feel that when the engine is properly warmed the acceleration from a standing start or coming out of a u turn is not that good.


I used the oem clutch, the installed a 8k spring, then a high response HPI clutch kit. The last one looked promising at the beggining but I fill that now it does not performs well. When the clutch is kind of cold (at the beggining of the run) works fine.


My friend just installed a Lauterbacher off road clutch on his Oneill ported 30.5 MT and his MT rips.


I know that this clutches are for 23cc stock and hopped up motors, but what happens if you install a race engine?


Do I need to get one of those Lauterbacher clutches?

 

[kryptonite]

the stock clutch is fine for all applications. im running an o'neill bros race ported/machined zenoah 27.2 with a 2mm stuffed crank, lightened flywheel and an 813. it doesn't slip at all and i run on blacktop. the clutch in my tt will sometimes slip, but it has to be pretty hot, and it doesn't slip that bad. im assuming the clutch is assemble properly with the thrust washer and spacer behind the sholder bolt? is the spring on the right way? if the spring "hooks" are facing out, it could bind on the clutch mount. but that is noticable during installation. im wondering how bad it slips. does it slip on the bottom, then grab. or does it slip on the top end? the clutch mount is only on the crank with pressure. if the center bolt backed out the clutch and clutch mount could just be slipping on the crank shaft.

 

[AlvaSpeed]

The clutch is assembled properly:


I thought about the whole clutch slipping on the crankshaft also. (ugly thought)


The thing is that when I start the car for the first time the HPI high response clutch seems to grab higher than the stock one. Good.


But after a while it seems that the clutch engages at lower rpms, bogging the engine and some times you hear the engine in a pitch similar to a boat. (like slipping)


I also installed 4 Hostile MX tires which grab more than the factory ones and that also maybe causing the clutch to slip.


A couple of weeks ago I was running on mud and after taking the whole car apart I found the clutch shoes "blue" from the heat.


I was just researching in some baja forums and a lot of guys were talking about clutch slippage on high output engines and swearing about the Lauterbacher clutch.


So I am going ahead and order it.


I hope it solves the problem.

 

[AlvaSpeed]

It is logical to think that if you (almost) double the hp the clutch will slip.


It happens in all of motorsports.


Also, having the clutch engage at lower rpms than the engine`s powerband is like dragracing without dumping the clutch.

 

[pup1970]

For a cheaper option to try, try flipping your shoes backwards and see if that helps. It will give alot of lock up but wont slip when hot

 

[kryptonite]

It is logical to think that if you (almost) double the hp the clutch will slip.
It happens in all of motorsports.


Also, having the clutch engage at lower rpms than the engine`s powerband is like dragracing without dumping the clutch.

i guess that may be a theory, but its just not very common. ive never had a clutch consistantly slip from torque unless its super hot. ive built alot of motors in a few diffrent rigs, and have yet to ever have a clutch issue. there are plenty of guys that are running race ported 30.5 reed kits with stock clutch's. are you running the vented clutch bell? the symptoms you have described are all related to the clutch getting hot. excess heat will losen the clutch spring and the "blue" clutch pad is from it slipping. you very well might have the need for an elcon or lought clutch with the MX'S. ive never ran them but could just imagine what kind of traction you might be getting with that set-up. if it was me, i would check to make sure the clutch bell is "true", make sure the bearings don't have any play in them, check the clutch mount on the crank for signs of it spinning. sand down the clutch pad and clutch bell. if it still happens durring hard driving then its time for a elcon/lought clutch system

 

[kryptonite]

For a cheaper option to try, try flipping your shoes backwards and see if that helps. It will give alot of lock up but wont slip when hot

pup, i cant really be sure of the "lock-up" theory. i was always under the impression that reversing the clutch simply allowed it to open sooner for a smoother engage from the rough high rpm start of the 8k spring

 

[roccos_van]

I can tell you from experience that the laturbaker is one hell of a clutch. I have one and yes it's true the stock clutch is fine but it made a massive difference in performance on my 30.5 ported 5T.

 

[emu67]

I second the opinion that it's not a clutch. One of my gear "squares" came loose enough to make it seem like the clutch was slipping so I tightened that up, replaced the gear and poof! everything worked like it should

 

[AlvaSpeed]

2 weeks ago I drag raced my car against a nitro. just for kicks.


With the clutch being new the car spun all 4 wheels easily (on asphalt).


The car was very fast:


I knew it was going to be a different story on grass/dirt and it was.


With so much money already put in the car a $100+ "investment" does not seem bad.


So I already ordered my Lauterbacher clutch.


Besides being adjustable, and having a larger contact area is also lighter than the one that comes with the car.

 

[AlvaSpeed]

I have the vented clutch bell already installed.


The squares are fine, the gears too.


If the engine overpowers the clutch is good news for me.


It means that it has good power.

 

[AlvaSpeed]

I took the clutch out.


One of the shoes was dark at the beginning and at the end, the middle of the shoe was not touching the bell.


The other shoe was shinny black.


The metal on the shoes looked fine this time.


I sanded the shoe´s pads and the clutch bell.


I am going to try it again before installing the Lauterbacher clutch.

 

[AlvaSpeed]

Well, I ran the car again on saturday and suddenly the car ran like it was direct drive, when you stopped the car the engine died. So I started the car in the air and throw it to the ground (nasty).


Anyway, when the car hit its powerband it was going like never before.


So I took the clutch out and found out that one of the bolts that hold the clutch broke and got jammed with the clutch shoes so there was no slippage.


I still believe thar this clutches slip on high performance engines.

 

[AlvaSpeed]

Yesterday I tried the Lauterbacher clutch.


It is lighter than the factory one.


When I started the engine I can hear the engine revving higher before the clutch engaged.


The car took off faster than before.


This is with the clutch`s factory settings.


At the end of the first tank, I could see that the engine was taking off at lower rpms so I guess the clutch loosened up somewhat.


I am going to readjust it so it grabs at higher rpms, higher than at the beggining of the test.


I was running 33T+27T gears.


I´ll keep you posted.

 

[kryptonite]

hey alva, check out this threaed with vid. i think im having the same issue as you. it starts out ok, but then it fades, but im not sure what fades, the clutch or the motor..


http://www.redcatrampageforum.com/showthread.php?t=1869

 

[AlvaSpeed]

That is the same situation I am talking about.


I believe that it has to do with the clutch/spring getting hot/soft.


When the car is kind of cold it will take off very well, the clutch engaging at a certain rpm, then after a while the clutch starts engaging at lower rpms. That is why you hear some bogging on the engine.


On a 2wd car like the Baja, when the rear tires spin, they release some of the pressure/work on the clutch.


On a 4wd car like ours the clutch has too much load.


The more power on the engine, the more load on the poor clutch.


I will try to retest my car with the 4 shoe clutch on thursday.


I opened a hole on the clutch case and 2 on the clutch bell so I don't have to take the clutch out to adjust it.


That way I will be able to re-adjust it and determine if it is the clutch or the engine.


I also cut the engine cover so the cylinder gets more airflow.


I bet a $100 it is the clutch.

 

[AlvaSpeed]

The clucth is working great:


At first I adjusted 2 turns in from factory.


Then went one turn out. After the clutch broke in.


Now, when I start the engine the clutch does not grab at all so I blip the throttle several times and it starts to move and by the time it gets hotter (about 30 seconds)it starts to grab and works fine from there on.


I will take half a turn out this weekend to see how it goes.


When hot it grabs at about the same rpms all the time (you get used to the engine pitch). I am going to have to install the Spektrum rpm sensor somewhere.


So when you are racing you do not have to worry about bogging out of a turn.


I like it a lot.


Regarding the engine shroud, I cut the front of the cylinder.


I believe that this parts where made for a stationary engine and not for an engine on the go.


Now the engine does not clog with grass as much as before.


Yesterday I was looking at some CC racing engines and If you look closely you will see that the flywheel fins were heavily machined.


I opened a hole on my TT ´s windshield a la nitro to increase the airflow.


So far so good.

 

[Sucram]

You mentioned something was blue? Thats a sign of overheating/slipping. I agree the hpi and ddm springs must heat up or something. When near cold it grabs well. Once hot its like my engine has a bog that wasnt there before. I wanted to experiment with some material removed off the clutch to engage later but when coldish its not a problem...

 

[kryptonite]

You mentioned something was blue? Thats a sign of overheating/slipping. I agree the hpi and ddm springs must heat up or something. When near cold it grabs well. Once hot its like my engine has a bog that wasnt there before. I wanted to experiment with some material removed off the clutch to engage later but when coldish its not a problem...

it seems like you have the same issue as us? what materail were you going to cut down on the stock clutch? there is a vid of what my truck did on this thread http://www.redcatrampageforum.com/showthread.php?t=1869


i changed out the spring and it workes better, but its not a permanent fix. need to get a good clutch system.

 

[AlvaSpeed]

Yesterday a friend of mine had his 8k spring on his TT broken.


I had a stock spring on hand.


So when the clutch was reassembled and the car restarted the car bogged all the time.


The stock spring makes the clutch to grab at very low rpms.


Install a Lauterbacher or any adjustable clutch.


You can make the car come out of turns on the powerband.


You don't have to wait till the car is at the middle of the straight to see it ripping!!!