AP1Touge

Hello All,
This is my first post on S2KI, so forgive me if I am posting this in the wrong place. I have gotten by pretty well until now searching the forum and internet for answers but can not seem to find what I need to know this time.


THE QUESTION:
I am installing a set of the Mazdaspeed 4.44 gears (pn: M054-27-110A) in my differential and wanted to know where I could find the backlash specifications. I understand the OEM spec (0.0035"-0.0043") might not be correct since these are not the OEM gears. Does anyone here with these gears know the backlash spec?

Thanks in advance.


***Answer found***
Answer: 0.0020"-0.0040" is acceptable

Edit: Answer

AP1Touge

Here is some info that I can find:

http://www.rx7club.com/1st-generatio...torial-711712/
^^^4th post has a paragraph saying that the backlash spec is the same as a standard s2000 (0.0035"-0.0043")

Racing Beat lists the part number as a 79-85 rx7 so that I why I looked there.

What concerns me is on Rob Robinetts page(https://robrobinette.com/S2000Differential.htm) it shows his 4.44 gears being set to 0.0028"-0.0033" by, the master, s2kpuddydad.

Perhaps they are not Mazda gears? I am not allowed to PM yet so hopefully someone with the right info will see this.

***Answer found***
Answer: 0.0020"-0.0040" is acceptable


Edit: Add answer

AP1Touge

Anyone?

baileyman11

I got nothing man. not sure many people are running these gears in the s2k. you might be able to get an answer posting on an rx7 forum? idk worth a shot. good luck.

Slowcrash_101

The rx8 also used 4.44 gears. Anyway part of the reason for the backlash is not just to compensate for metal heat expansion, but also because otherwise you cannot have the correct contact pattern. That's part of the art of building diffs us mere mortals don't really experience.

AP1Touge

Yes, I am aware that the backlash is crucial in obtaining a correct gear contact pattern. That is why I am asking this question.

The RX8 uses a different ring and pinion than the one I purchased.

Hopefully S2kPuddyDad, Billman, Rob Robinette, or anyone that has used these can chime in.

Billman250

If it were my dif, I'd follow s2kpuddydads specs.

AP1Touge

Totally agreed. I just wish I knew what those specs were.

Do you think all 4.44 gears that fit our diffs have would have the same backlash or would it be specific to the actual gearset?

AP1Touge

Would anyone be so kind as to ask S2Kpuddydad to check out this post? I would do it myself but I'm not allowed to PM yet. Thanks!

SpitfireS

Are there any numbers engraved on the set?
That's how Richmond tells you what backlash and pinion depth to use.
IOW: It's not just about backlash.
If you do not know what pinion depth is... maybe you should not try to install your final drive.
They both have to be right to get a good contact pattern.
They both have to be right to make your final drive as quiet as possible an live long.
That.. and good oil (so basically 3 things are needed)



edit: typo