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Old 10-09-2004, 10:48 PM   #3991
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Default Re: Centax

Quote:
Originally posted by HarKonnenD
How far do you guys tighten on the stock centax of the R40? I'm about 1-2mm down and my engine still revs while its off the ground. My MT12 is running really nice but the car goes no where. Meanwhile I'm gonna use some thread lock on the pinion gears since they keep coming loose. Hopefully tomorrow I'm gonna bash but the R40 aint ment for ball parks. It's gonna have a nice monday and wednesday afternoon all to itself though.
Pinion gears coming loose? I have not seen that one. The direction of rotation naturally "tightens" the gears if anything. I wouldnt use lock-tite if I were you. Just get a pair of large pliers and "hand-tighten" using a medium pair of pliers. You'll have to use another pair of pliers on the clutch bell too ( careful not to scar the metal too bad). HPI sells a tool just for this that I recently purchased but havent received yet.

As far as tightening the clutch (the M3x10mm) screw on page 36 of manual, I just hand-tighten it firmly using a good allen tool. Are you following directions exaclty as on pages 35,36?

You might try to post a picture to help us help you better.

1) Are the brakes dissengaging when throttle is applied?
2) Is the drive-train free to turn easily?
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Old 10-09-2004, 10:54 PM   #3992
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Quote:
Originally posted by rowveg36
need help w/ my clutch engagement . how come i can't get a good low end w/ it? how many shims are you guys using? does it affect it by adding more or less shims in it?
I am using exactly what the manual pg. 36 uses ..

Is your motors "low-end" adjusted properly ? When you say "..no low-end.." Does it bog down or does the engine "rev" too high?
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Old 10-10-2004, 10:56 PM   #3993
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i am using 2 gold and 1 silver too, just like what the manual said. engine sounded ok but not really sure if it's tuned exactly.
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Old 10-11-2004, 08:50 AM   #3994
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Guys, the engage point on a centex type clutch is controlled by a couple of different things. The number of shims and where you use them is only one of them. I'll paste some posts I lifted a few pages back on setting up the clutch. I think that the R40 manual tries to oversimplify the operation of the clutch.

Also, if your clutch bell is scraping the pins that hold the clutch shoes, remove the flywheel and tap the pins down gently with a hammer. This will allow the clutch bell/shoes and everything else to fit properly. I had to do this to 4 flywheels to make them fit.

Hope this helps.


I have found several things with the clutch.

1. You most likely need to put shims between the inside bearing and the sg nut to keep the bell from rubbing the shoe.

2.Clearance to the chassis cutout for the flywheel, on some of my engines I had to remove the big washer behind the collet other wise the outside of the bell will hit the chassis= slip
This can also happen if the motor is aligned too far to the gear side. I think this has been my problem all along, but in the process I learned the fine points of setting up a Centax.

3. The red clutch shoe as with most cars is better than the slip prone black stuff

If assembled right the clutch is supposed to be great; it's nearly identical to the Mugen's



I was starting to build the clutch last night....and I have to agree, the stock setting of the clutch (per manuel) is not even close to the GOOD setting of the centax..........

(1) I agree with OB42TC3's #1 idea....I ended up put a 0.1mm shim (from Serpent or NTC3 package) behind the SG nut and in front of the first bearing of the clutch housing in order to spin the house freely without rubbing the shoe.

(2) The 0.8mm shims behind the collet need to be increase to close to 1mm (I ended up adding 2 more 0.1mm from Serpent) in order for me to get to 0.3mm gap different....no matter how much or less shims I did in front of the threst bearing, it won't give me the clearence that I like....

Overall....that is the setting that I have on my RS 12 T5 S1 engine...does not necessary work for other engines, but the concept is like that.....at least 3 areas need to add or remove shims instead of only 1 (before the threst bearing like HPI said)

I still think the RED shoes is the one to use....the HPI one is almost like a solid black plasic block....



OB42TC3 already said it....it is the one from DELTA, you can see that on ebay, they are like $12 each. (keyword: Clutch shoe)...but I am sure the MUGEN one are as good...anything but the stock HPI black one....(if you have the chance to get a better shoe)...




the Mugen ones. They basically are made from the same material however, Rulon. The R40 one is absolutely ballistic it makes the car have incredible punch. You can email order them from Delta.

The Grey ones work nicely, but have less punch than the Red shoes, but to get it to slide on the pins properly you will need to ream the holes a bit. I posted a picture of this a few months ago.

If you are running your car at Brendale you should definately get the red ones, the cost me around AUD$15 from Delta. Most other local tracks will be fine with the grey shoes.




I posted this a while ago. Here is my latest clutch setup that has so much punch the car actually was jumping slightly on a low bite track:

Delta Red shoes
Kyosho Bronze colour spring - FW16
A heap of Mugen shims (or any other shims will work)

1. Assemble the clutch without the unner bearing. Pull the clutch housing away from the shoe. Measure the gap between the housing and the shoe. This is the clutch gap. You want it between 0.4-0.6mm in my setup.

2. Put the inner bearing back in place. Add shims between this bearing and the clutch nut until there is almost no float. 0.1mm or less.

3. Set the adjuster nut to 1.4mm.

This setup gives awesome clutch response, and also is far easier on the clutch bearings. I have posted previously that I had bearing failures, I have had no failures since I have been using this setup.





AMG, Thanks for the information, and that is exactly what I want to know...I was playing with SHIMS with the R40 centax, as much as they did a good car like R40, their centax is still not as good as a centax compare to Mugen or Serpent.

I have replaced most of the R40 centax parts with new one (new OEM parts)........I still feel the clutch housing is a little warble here and there..........my 4 years old Serpent centax does not have that kind of a feeling, still spin freely and smoothly.

But anyhow............I still want to work on the R40 centax cause that will fit the R40 the best (I hope), but I want to know, should I stick with the 0.8mm stock black shim behind the collet and add/remove shims in front..?

The old way of building centax is add/remove shim before collet, the newer way of setting centax is FIX shim at the collet and add/remove shim before clutch bearing and in front of the thrust bearing....

And last night, I have to do BOTH........collet shim ended up to 1mm and add a 0.4mm before bearing and 0.8mm before thrust bearing............STILL.........ended up 0.45mm gap different, which I don't really satisfried with, I want to shorted it to 0.25mm to 0.35mm range.....which is very easy to set on all of my Serpent Centax.

This is by far the longest time I have to spend on doing a Centax system.




quote:
Originally posted by Rookie Solara
Also, do you guys know that the thrust bearing from the R40 centax, both O-RING are having different inner diameter just like Serpent or Mugen Thrust bearing....? And the larger diameter one are suppose to go in first (toward flywheel) and the smaller diameter one are facing outside.


Thrust bearings ALWAYS have one ring with bigger inner diameter than the other and you always need to put the bigger inner diameter first towards the clutch shoes and then the smaller one further out.

quote:
Originally posted by Rookie Solara
I didn't see HPI manual mentioned that, don't know that matters or not, but on Serpent and Mugen's manuel, they both mentioned it and it must go in to the right direction.


If you did not happen to install the thrust bearing right, then HPI just gets richer selling blown out thrust bearing replacements.




quote:
Originally posted by Proteus
It's to adjust the roll center for the front upper arms. If you noticed that your kit came with two of those. They are to control the height of the rear portion of the front upper arm. Also, the kit came with two different rubber grommetts (sp?); the piece that fits into the bottom of the shock tower which holds the front upper arm hingepin. With the two different rubber pieces....you have three different positions where you can mount your arm, stock (low), center, and high. Use the corresponding rear pices to adjust the upper hingepin to keep the hingepin parallel to the lower hingepin. Hopefully that makes sense. And there you have it. I've tried raising the roll center by adding one rear shim plus using the other rubber piece. The car felt quite responsive but had no grip. I also tried angling the upper arm as I was using kickup on the lower arm. I ended up going back to the low roll center. That seemed to give me the most traction. I guess on high bite tracks where traction rolling is a problem, using a higher roll center up front would help. AND THERE YOU HAVE IT.



Now I can finally.......

Thanks bubba!!!!




OK I got serious last night and took TQ with my porky 1850g car. Then I broke the car in the first lap of the final. Oh well.

Anyway I learned a few things along the way..........

The clutch fix. The way to make the clutch awesome is as follows:

1. Get a Mugen grey shoe or a Red rulon shoe from Delta. This will eliminate most of the slipping. The stock black shoe I estimates slips around 10000 rpm at least. With the red or grey that drops to a few thousand. Very noticable punch increase.

2. I finally trialled the new spring. I am using the Kyosho hard black spring from the Evolution. A Mugen silver will work similarly. The main advantage is that these springs have less winds and you dont need to crank down on them so hard. They are around 1mm shorter. With the HPI spring you need to crank down on it so hard to get good high engagement you start to get spring bind (the loops touch each other) and the engagement sticks. A harder spring wont get the binding.

I also used a RB V12 motor, still running in. Man this thing was like having a turbocharger on the mid range. The low end was great, but mid range was phenominal!! Top end is less than a NS12, but I did not give up any car speed at all, and I was slightly undergeared as well. I should have my 2004 parts soon............
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Old 10-13-2004, 02:33 AM   #3995
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Default '04 spec kit for sale

Brand new '04 spec kit for sale in the for sale section.
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Old 10-13-2004, 03:54 PM   #3996
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thanks for the reply rapid roy. just ordered a mugen red clutch shoe, can't wait to get it.
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Old 10-13-2004, 08:57 PM   #3997
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How far did you guys crank down on the stock HPI spring in the R40? Last time I recall I followed the instructions shown on the page and had the wheels move after the engine revved a bit. I guess I should tighten it more. It was a nice run but darn that clutch. With my NEO centax, adjustments were a lot easier.
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Old 10-13-2004, 09:01 PM   #3998
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Default Re: '04 spec kit for sale

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Originally posted by kalani
Brand new '04 spec kit for sale in the for sale section.
How much and where is it coming from? Do you have pics?
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Old 10-14-2004, 02:11 AM   #3999
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Quote:
Originally posted by HarKonnenD
How far did you guys crank down on the stock HPI spring in the R40? Last time I recall I followed the instructions shown on the page and had the wheels move after the engine revved a bit. I guess I should tighten it more. It was a nice run but darn that clutch. With my NEO centax, adjustments were a lot easier.
With a higher HP motor, you really need to crank down in the nut. Thats why many are using stronger springs. When you crank down too far it make the engagement erratic and its difficult to adjust.
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Old 10-14-2004, 03:44 PM   #4000
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I've hade three different motors and did what the instructions said and have had no problems
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Old 10-15-2004, 09:41 PM   #4001
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I'm running the MT12 w/ SG crank slide carb. How far down should I crank it? Also, should I just bag a Mugen spring instead? I'd really like to drive the car again.
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Old 10-15-2004, 09:45 PM   #4002
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I just thought of something. I could try the spring and stuff from the NEO TNT. It runs a lot better and is very subtle to adjustments.
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Old 10-16-2004, 06:10 AM   #4003
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HarK, I sold the R40 for 150.00
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Old 10-16-2004, 02:40 PM   #4004
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has any of you guys tried using the mtx3 spider gear diff on their r40? cause it looks lighter. will it fit w/out a problem?
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Old 10-17-2004, 03:54 PM   #4005
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Just a note on the clutch setup. I ran my R40 on the weekend with a STS D3R motor and more or less Haras setup from the recent ROAR Nats. The car was on rails.

For the clutch setup I used the stock clutch and parts except I used a Kyosho spring (from the V1RR EVO) and the Delta clutchshoe. My settings were .5mm clutchshoe gap and I shimmed almost all the endfloat out. I used 1.7mm on the adjustment nut. The car has outstanding punch and I easily had the acceleration of any of the other cars I ran against, RRR and MTX3 as well as the G4.
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