Over the winter I'm gonna install a 4.785 final drive in my JDM 2nd gen b16a. I read and studied the helms manual on disassembling the tranny, etc. I also purchased the "omniman dvd" <<< AWESOME DVD. Anyway, after reading and watching the dvd, i'm pretty confident on doing this. I've done a few engine swaps, cams, flywheel/clutches, etc. I have tools and I can't wait to do this. Theres only one thing i can't figure out and its not explained on the omniman dvd.

In the Helms book it says to reinstall the 80mm shim, install the tranny cover and check for clearances! I get all that, I know where to measure and what measurements to look for. But as far as the shims go i'm confused, in the helms book there is a list of different shim sizes. (clearence spec 0.00-0.010mm)
Ex.
Part # shim size
xxxxx 1.0mm
xxxxx 1.5mm
xxxxx 1.75mm

In the book it says if the clearances are not within specs, replace the 80 mm shim with one out if the list. Do the shims listed in the book replace the original 80mm shim, or do you add them on top of the 80 mm????<<<????

So lets say when i check the clearance and its more then what its suppose to be like 0.012mm, what math do i do to pick the right shim?

 

The thickness is usually printed on the shim in millimeters, but the print usually wears off.

I just measure the current shim with a micrometer, measure the thrust clearance, and that's all of the information you need to decide what shim to use.

 

So do you keep the 80 mm shim in place and add shims on top of that, or do the new shims completly replaced the original 80 mm one??

The math I don't understand is, lets say I put the tranny cover back on with the 80mm shim and when I go to measure it, and the clearance is not within spec like 0.012mm. How do I know what shim to put in there. If its 0.002 mm too much what shim do i use. the shim sizes start from 1.0mm!! 1.0mm seems too much if the clearance is off by only 0.002mm.

Sorry, if i sound confusing!! But this is the only think I don't understand. The correct clearance is 0.00-0.010mm. So if its off alittle, they should sell shims that are 0.011, 0.012, 0.013mm, etc.

 

You shouldn't ever need to stack shims. Even the two thinnest shims are probably more than the clearance needed.

If the clearance is .12mm with the current shim and the target clearance is .10mm, then subtract the two and add that number to the thickness of the current shim.

.12mm - .10mm = .02mm

If the current shim is 1.20mm, then by adding .02mm to 1.20mm, you get the approximate thickness of 1.22mm for the new shim.

Then you look up the part number that corresponds to that thickness in the service manual.

 

If I remember this correctly there is no shimming needed for a FD install. If you were to also change out the differential then you would need to shim it.

John

 

Usually, you don't have to, but it never hurts to check.

I've had to reshim a couple of stock differentials where I've only changed out the bearings.

On the other hand, I've installed a Quaife into a S4C tranny with new bearings before and it didn't need a different shim.

 

Thanks for the help guys. I get it know. I appreciate it!!!! Cool Cool Cool!!!

I have a JDM 2nd gen B16a, and i'll be using a GSR differential that i just bought off ebay, becusue you can't install a 4.785 final drive on a b16a differential. The GSR differential has tapered bearings on it, so i'm gonna order a set of 00 Type R differential bearings soon. So with all these new and different parts i'm pretty sure I will have to shim....


Thanks again!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IN VTEC &raquo;</TD></TR><TR><TD CLASS="quote">You shouldn't ever need to stack shims. Even the two thinnest shims are probably more than the clearance needed.

If the clearance is .12mm with the current shim and the target clearance is .10mm, then subtract the two and add that number to the thickness of the current shim.

.12mm - .10mm = .02mm

If the current shim is 1.20mm, then by adding .02mm to 1.20mm, you get the approximate thickness of 1.22mm for the new shim.


Then you look up the part number that corresponds to that thickness in the service manual.</TD></TR></TABLE>


WAIT, sorry I just reread it, another question. You wrote "current shim is 1.20mm" isn't the shim in there 80mm. SO would it be 80mm+.02mm????

 

yes in that case you will have to shim the diff since you are changing it out. By the way why not throw in a ITR LSD instead of the GSR one while you have it open?

John

 

80mm is the diameter of the shim, not the thickness. The 1.20mm is just an arbitrary, but realistically reasonable number I came up with in my head.

 

OOOOOHHHHHHHHHHHHHHHHHHHHH. Ok!!! ****. I'm done with the questions. thanks alot!!! Know everything make sense. I should have just started a thread asking what the 80mm standed for!!!! WOW, i'm happy now!!!!