cvt motor-clutch adapter problems

[bajaBrothers]

Hi guys. So i switched my motor from a honda b16 stock to a crvtec (b20 block w/ b16 head that makes it vtec) the new motor has had some work on it:
type r intake
type r cams
adjustable fuel pressure regulator
310 cc rc injectors
balanced rotating assembly
adjustable cam gears (set at 0 still)
compression ratio is 10.4 or so
hondata cpu (thanks k-fab)
Ok so here is the problem. After changing the motor i sheared the clutch adapter clean off where the taper meets the clutch. Talked to neil @ atv racing and he says that has never happened that he is aware of so after a month or soo I get a new one from Neil. Fresh batch straight from heat treat. That one lasted a total of 25 mins. sheared it at the same spot.
Meanwhile i decided to find someone locally that I could work with to make a thicker adapter. I have 2 drive clutches a "comet 4pro" and a microbelmont 4 tower. so we took the comet and made the female part of the taper fatter and made a clutch adapter to match leaving as much meat at the base of the adapter. material is 4140. the first one of the locally made ones was not heat treated in any way and after driving it for 30 mins i decide to pull the clutch and check things out. well the clutch spun on the adapter and galled the crap out of the adapter and clutch, oops. So i went back and talked to the guy and he's like ok we'll harden the next one. 10 days later we put a "hardened" piece on. This one lasted aprox. 45 mins before the whole center of the adapter pulled out. The stub pulled from the baseplate w/ the bolt pattern leaving a "donut" on the end of my crank. Again back to the drawing board, the base plate of the original adapters is only 1/4" thick so we fattened that up 3/4" thick and made longer crank bolts. That piece lasted about 1 hour, this time the stub again pulled out the center but not all the way through, just about 1/4" deep. So I know that the pieces being made locally are not being "heattreated" per say but the guy is hardening it some how.
So about half way through this drama I contacted Gary at Micribelmont and explained my situation. He made me up 2 clutch adapters and modified the clutch to accept the new taper and thickened the base plate to 3/4" and sent it to be properly heat treated. I should be getting these pieces by mid week.
The purpose of this post is to see if anyone is having these problems or has some insight as to what is going on.
My clutches are offset perfectly, and paralellism looks on as well, I am going to check perpendicularity today.
I also ordered a harmonic dampner as well to see if that helps.
The tires are 31" mt's that have been "cut"
The RPM is running 8:1 gear ratio
One thing I have pops into my mind but I am not sure is that I am using a very thick oil in the RPM box, I think it is a 205wt. We were having problems with lighter oils turning into water and spewing out the breather line. This is the stuff that is being used in Trophy truck diferentials. Could that be creating too much resistance?

Any way what do you think?

[bazz]

Do you have any pics of the adaptors?

[standfast]

I would try to add a support bearing setup to the end of the clutch somehow. Pickup at least 3 seperate points off the motor to support the bearing.

[bajaBrothers]

I have one that supports the driven but not one on the drive clutch. i'll have to look into that. I know that they make a support bridge that spans the gap between the two clutches on the outboard side. I'll have to check and see if they make one that fits my center to center.
I don't have any photos of the original 2, sent one back to neil to check hardness and the other one to gary for template. I'll take some photos of the ones we made here.

[Philabuster]

If you do not mind, post some pictures of the failed clutch adapters. It sounds like you have a stress riser killing the part. If you still have a stress riser in your part, it will still fail even if you thicken up the mounting flange--it will just take a bit longer to fail. If your motor is out of balance, it will find weak spots in the rest of the drive train in a hurry.

My material preference for this part is 4340 heat treated to 38-42 HRc. The added nickel makes the material tougher than 4140. The famous 300m material is slightly modified 4340.

[bajaBrothers]

Interesting, what do you mean out of balance. We completely rebuilt this motor and balanced the rotating assembly. That being said it does have a strong vibration right before vtec engages at 4500rpms. Vtec engages at 5800. I am waiting on a harmonic dampner to see if that helps. I'll post up some pics later today.
Thanks for the suggestions.

[hauss]

I tend to agree....
probably a vibration/harmonic issue causing the problem.
There are lots of cars with ecotec's and cvt"s that are running 300+ hp with turbos, and They have some belt failure problems - but no clutch adapter failures.....

Oh yeah I Highly doubt that it has anything to do with your diff oil, the drag from the oil is Minimal compared with some of the other forces at work.

Good luck, and let us know what you figure out!)

[bajaBrothers]

ok here are a couple of photos of the ones we made here Mexico first the one that the clutch spun on the taper and the base of the third one were we thickened up the base plate.

[nutz4sand]

I may be way out in left field here with no fly ball to catch BUT being thats this does seem to be rare to see this and you keep shearing the part have you looked at the associated parts?

Does the drvien clutch spin perfectly true on its shaft? No wobble?

Same for the crank. If you put a dial guage on it and spin it or bolt the clutch on and put the dial gugae on it does it have a wobble?

[nutz4sand]

Also what FT/pounds are you torqueing the clutch bolt too?