On your C4, what broke on them? Was it stock parts failing, or upgraded parts failing? I'm pretty confident this trans should hold up on my motor, I won't be pushing it to it's limit according to PA.

 

Stock parts. I somehow sheared the input shaft once, and later sploded all the synchros.
I was pushing around 400 to the wheels with only some valve body mods and upgraded clutch packs.

 

Gotcha. Well I hope this one doesn't break, cause it's ORDERED!!!!!!

3,900 for the trans and converter. Time to go fast!

 

Good work patsmx5 a C4 will be a very tuff setup

 

I wish I could remember my converter specs.
I had been a high stall converter in my C4 and daily'd it for years.
It never bothered me, but I was much younger then.

 

I can't wait, it should be what I need and hold up to the power.


Good to hear. I watched some videos online and there's people driving cars with high stalls on the street no problem. I am hoping I can do the same without much issue. I can tolerate the RPMs for the reliability and performance gains.

 

Oh yeah, trans is supposed to be here tomorrow!!!

 

I don't know why I wasn't subbed to this thread, but now I am. Good luck!

 

Thanks!

So.....

This showed up today!

 

I forgot the Auto was a bolt on bellhousing. Thats awesome.

Someone should try it out with an adapter plate for a manual, with a hydraulic release bearing.

 

perfect size for the tunnel it doesn't even look any taller than stock auto bell housing to input shaft length will be the issue

 

Yeap.

I've bounced around a lot about how to fix that. I bought a ford bellhousing that will bolt to the C4, and the area where it bolts to the engine is withing 1/4" or so of the mazda part in that same area.

For now I think I'm going to lathe a part that bolts to the crankshaft, and slips over the output shaft of the pump. That will center the crank and trans, keeping them concentric and parallel. Set it the correct spacing for the converter and all.

Then measure and cut both bellhousings in half.

Bolt mazda housing to motor, C4 housing to trans, install coupler, and weld housing to each other. Done. Then custom converter and the hard part is done.

 

is the miata bellhousing too short or too long?

 

Too long.

 

Damn. short is easy to fix. Long is harder.

I have the same idea for an adapter that goes crank to bellhousing to hold the transmission in the correct location.

Good luck.

 

Do you have access to a bellhousing off the early miata n4a-hl (4n71b based) transmission to try? That may be more easily adapted than the later bh.

 

I don't have one, but didn't even think to look before! Just did a google search and it looks like it could be an option. Didn't find a cheap bellhousing in a quick search, or any good pics.

For now I'm going to try and make the bellhousing I have work. The one I ordered for the C4 has shipped, should arrive on Wednesday.

Plan to buy some material to fab the crankshaft-to-trans-oilpump centering piece locally. Need some 3" or so steel round bar. If can't get a deal, I'll buy online.

After that it's wait for the torque converter and c4 bellhousing. Do preliminary measurments for crank to trans oilpump adapter.

Once I have parts, finalize design of crank to trans oilpump adapter and machine it. Install it and make sure it works as intended.

Mark and cut both bellhousings. Bolt them to motor and trans. Install adapter and put housings next to each other. Support block and trans, check that it spins freely. Prep surfaces, tach it up, weld it out.

 

Got the flex plate and bolts for it off ebay. Got the worlds lightest 1.8L crank from shuiend! Thanks again for the crank, I really appreciate it!

Got those parts bolted together. Will be using those for mock up and for sending to the guy building my torque converter so they can get the bolt spacing/bolt pattern and crankshaft pilot bearing diameter and depth all setup correct for the new converter to work with the BP.

 

bellhousing arrived 2 days early, thanks FEDEX!!!! That would never happen with any other carrier.

picked up 2 feet of 3.5" round bar from a local steel place. At this point waiting on the converter to take some measurements. Going to do some measuring and design that I can do for now. Also still working to get access to a lathe/mill/TIG.

Any ideas on a good way to clean really really old/dirty cast aluminum bellhousing clean enough to weld to it?