Kai! Awesome work man, hope you get your transmission problems sorted. We'll have to go boost cruising one day after were both done with the builds

 

Thanks bud, I hope things get sorted out soon because I am just exhausted with everything. But yea, I'm down for that cruise for sure!

 

Hey everyone, looking for some advice, help or opinions, I'm absolutely stumped at this point... If you've been following my build, you'd know that I recently got my 350z transmission conversion running. However, it is making some really strange and nasty noises. I am running a CC twin disc s2000 clutch set with 350z friction discs and have the bell housings milled and welded to place the input shaft splines at just the right dept in the clutch. The noise isn't what I would associate with a twin disc clutch. There is some clutch noise at idle and upon take off and coasting. The noises I'm concerned with come on at very light throttle and when letting off the throttle under load. It almost sounds like loose gears or even marbles rolling inside the transmission. I initially though it was the bearings inside the transmission so I bought another trans. from a wrecked G35 with less than 100K. Swapped the internals and put it up in the car and still make the same noises! I'm literally pissed beyond logic right now and can't seem to come up with any ideas about this, so I'm turning to my S2k community for help. Thanks in advance for any help you can give me.

 

when u pulled the tranny down did u inspect the clutch? or hydraulic bearing? can u get the car on a lift and have someone start the car and put it in gear?

 

Yes, I checked the clutch and hydraulic bearing, everything looked normal. Everything was new when I put the setup together. I made sure the hydraulic bearing had enough clearance from the clutch fingers while at the same time, not being too far. At this point, the only thing I've come up with is the drive shaft. It is a custom piece that I had to cut and re-weld because I had ordered the wrong u-joints with it. Laying under the car with it free spinning in first, I could see that the u-joint flange is off-center by about .015" as the shaft spins. I didn't think that would be enough to cause such horrendous vibrations and noises, so I disregarded it as a potential fault. Is there anything else I should be looking out for while under the car, Phil?

 

Are you sure the input shaft is no in a small bind with that custom bell? Also are you sure it's not to tight well the pilot goes into the pilot bearing maybe the pilot is a little bit too long and is pushing the input shaft into the transmission a little bit

Only reason I ask that is gforce mentioned that are some of the things that could happen if I tried to do my bell housing myself that's why I sent it to them

The drive shaft is a good start tho my buddy stand about 1800 dollars on his rear end before he found out it was just the drive shaft out of balance
Sent from my VS870 4G using Tapatalk 2

 

^ Thanks Bobby! The pilot bearing I'm using is almost an exact fit on the input shaft pilot. It might actually be a bit too tight now that you mentioned it. As for the custom bell housing, I assembled the transmission on top of a spare block with the clutch set bolted to the crank. I had both bell housings milled to ensure flatness so that when I put the input shaft into the clutch, everything would be centered on the clutch. I guess I'll take the trans off 1 more time and see if I can do something about the pilot bearing and see if that helps... If not then I will definitely be getting another drive shaft made -_- this build is quickly adding up and I'm not even boosted yet. I just want to be able to enjoy my car!

 

Listen to some youtube videos of single flywheel disc 350z transmissions. They ALL sound like a cement truck when you go to single mass flywheel. Even the stock ones will make the same sound, just much quieter. Nissan went to a dual mass flywheel to combat this problem. You're using their transmission so it stands to reason you're going to encounter similar issues. Textbook symptoms are if the sound is present at a stop in neutral and goes away when the clutch is depressed. It's a well documented phenomenon with the z33 crowd.

I think the lightest single that will minimize the gravel sound is around 23 lbs.

BTW I have a stock z33 and I can still hear it at idle if I listen for it.

 

Brutha, I think you may have just found my problem. Now to figure out a solution... Damn I wish I would have known about this before buying that second tranny

 

How heavy is your flywheel? Easiest solution I think would be to make your assembly close to the stock 350z flywheel weight. Honestly, most of the Z guys don't worry about it. It's a quality of life issue as opposed to something actually going wrong. Many have gone tens of thousands of miles with a single FW without an issue. That being said, when I get around to installing my TT kit, clutch, etc, I think I'm staying dual mass and I have an ACT single FW sitting around too.