NJFBOA - Home of New Jersey's Camaros and Firebirds - View Single Post - Getting my new 406 SBC installed, running, and driving

IROCZman15 · 01-24-2021, 07:26 PM

I thought they would be also, my old 3.73 richmond gears on my old 10 bolt were reverse thread. These were not though.

Today I got pretty far, and I think I am super close to being able to button up the housing and get it back under the car.

existing 3.55 gearset removal:

3.91 install:

Starting with the pinion's rotational drag, I have it set somewhere between the 14-18 inch pounds range. not break away torque, but rotational. this is what moser and US gears calls for.

see video (sorry, hard to film and turn at the same time) the photo below was not taken at desired/proper drag, but its the only photo I had that was not blurry. video is kinda better...
https://www.youtube.com/watch?v=54_jH_rWrfg

reused the pinion races and pinion bearings. Moser said i could and should do this since my 3.55 gearset was so new and only had 6,000 miles on it since March 2018. If something went wrong, I had new bearings to use, but all went well and the new bearings are in a box still. I used a 3shim combination to get a total of 0.0425" on top of the solid pinion spacer. I did put in a new pinion seal.

Used the existing carrier bearings and races also. Adjusted the sim packs on each side, and the carrier is SNUG in the housing. Can not be pulled out by hand, need a pry bar to gently coax it out. Main caps are torqued down, but not lock-tited yet just in case anyone sees something that I need to adjust.

Backlash is right around 0.0090 and 0.010. This is in spec, but the only thing I notice is a "knock/thunk" from the teeth contacting eachother. I am ASSUMING this is normal on a bone-dry set of new gears. You can hear the noise in the video. Is this normal for a dry gearset?
https://www.youtube.com/watch?v=oByzPG-Sb24

desired pattern chart:

current COAST tooth pattern:

current DRIVE tooth pattern:

It took me about 4 times taking the carrier out and re-shimming it to get the current backlash and contact pattern. Might have initially used too much yellow paste, as it got everywhere so I had to do a cleanup of stuff and re-try it.

So, thats where I am at. if the pattern is as good as it needs to be, GREAT. and, if that clunk noise while checking backlash is normal for a new set of unlubricated gears, then that is also good.

01-24-2021, 07:26 PM	#255
IROCZman15 10 Second Club / Meet Coordinator Join Date: Dec 2004 Location: Roxbury, NJ Posts: 2,101 iTrader: (8)	I thought they would be also, my old 3.73 richmond gears on my old 10 bolt were reverse thread. These were not though. Today I got pretty far, and I think I am super close to being able to button up the housing and get it back under the car. existing 3.55 gearset removal: 3.91 install: Starting with the pinion's rotational drag, I have it set somewhere between the 14-18 inch pounds range. not break away torque, but rotational. this is what moser and US gears calls for. see video (sorry, hard to film and turn at the same time) the photo below was not taken at desired/proper drag, but its the only photo I had that was not blurry. video is kinda better... https://www.youtube.com/watch?v=54_jH_rWrfg reused the pinion races and pinion bearings. Moser said i could and should do this since my 3.55 gearset was so new and only had 6,000 miles on it since March 2018. If something went wrong, I had new bearings to use, but all went well and the new bearings are in a box still. I used a 3shim combination to get a total of 0.0425" on top of the solid pinion spacer. I did put in a new pinion seal. Used the existing carrier bearings and races also. Adjusted the sim packs on each side, and the carrier is SNUG in the housing. Can not be pulled out by hand, need a pry bar to gently coax it out. Main caps are torqued down, but not lock-tited yet just in case anyone sees something that I need to adjust. Backlash is right around 0.0090 and 0.010. This is in spec, but the only thing I notice is a "knock/thunk" from the teeth contacting eachother. I am ASSUMING this is normal on a bone-dry set of new gears. You can hear the noise in the video. Is this normal for a dry gearset? https://www.youtube.com/watch?v=oByzPG-Sb24 desired pattern chart: current COAST tooth pattern: current DRIVE tooth pattern: It took me about 4 times taking the carrier out and re-shimming it to get the current backlash and contact pattern. Might have initially used too much yellow paste, as it got everywhere so I had to do a cleanup of stuff and re-try it. So, thats where I am at. if the pattern is as good as it needs to be, GREAT. and, if that clunk noise while checking backlash is normal for a new set of unlubricated gears, then that is also good. __________________ 1987 IROC-Z - modified Last edited by IROCZman15; 01-25-2021 at 08:27 PM.