Flex plate R&R 710 Wagon

[ggzilla]

That flex plate in the photos is bad. It may have been rebuilt, but since then the gears have been ground down.

 

Find a good one. The ring gears are not reversible.

[datzenmike]

The ring gears are not reversible.

 

There's a front and back side to them??

[ggzilla]

Yes

[datsunaholic]

That's interesting, because the manual makes no mention of a direction of install for the ring gear- in fact, it doesn't even say how to replace it other than to install at 180-220 degrees C.   At least the Haynes manual tells you how to get the dang thing off (the factory manual doesn't).   I've had a new one- I could see no difference front to back of the ring gear itself, but all my USED ones of course have a slight bevel due to wear.  And usually 2 spots with more wear than others.

[datzenmike]

Same here. FSM... Put flywheel in freezer over night, heat ring to 400F and quickly tap into place. If there is a front or back it's not mentioned.

[74datsun710]

So here's a minor update and a question to all.  First I had bought a flex plate thinking it was in better shape than the one i currently have only to find out that the teeth were worse.  I decided to grind off the existing gear ring, flip it and weld it back onto the "good" side.  We will see once I R & R the flex plate, how it goes.  

Secondly before I remove the Trans. cross member does anyone know where I can find the replacement bushings? 

[Eagle_Adam]

you wont be able to find them, i replaced them with large thick washers and thick rubber grommets 

 

check my 710 build for pics 

 

Edit: seems like i dont have any pics.... 

[datzenmike]

So here's a minor update and a question to all.  First I had bought a flex plate thinking it was in better shape than the one i currently have only to find out that the teeth were worse.  I decided to grind off the existing gear ring, flip it and weld it back onto the "good" side.  We will see once I R & R the flex plate, how it goes.  

.

I've been told it won't work because the front starter side is ground different. Myself, I don't think Nissan went to that much bother. I think it will work.

[Busta Nut]

It'll work........but might make one hell of a racket....

[Eagle_Adam]

this ^^^ 

[74datsun710]

you wont be able to find them, i replaced them with large thick washers and thick rubber grommets 

 

check my 710 build for pics 

 

Edit: seems like i dont have any pics.... 

 

Where did you end up finding the rubber grommets? 

[74datsun710]

It'll work........but might make one hell of a racket....

 

Mine currently makes a ton of racket as is but at least I will be able to find out if this method will or won't work out for future knowledge.  

[Eagle_Adam]

Where did you end up finding the rubber grommets? 

 

local hardware store 

[datzenmike]

Mine currently makes a ton of racket as is but at least I will be able to find out if this method will or won't work out for future knowledge.

I think the cut of the ring gear is just straight across and makes no difference which way round it goes on. If this is the case it won't make any noise unless the starter star gear (pinion?) is already ground up.

 

edit: Well with some digging I found a reference to the front (starter side?) of the teeth being chamfered. Best to get an angle grinder and take the leading edge off each front side of the teeth. That's not the top of the tooth, but the forward facing edges. Use your own best judgment.

[74datsun710]

I have a bran new starter with a perfect gear, so this will be the deciding factor to weather or not it will work.

[datzenmike]

Well if it clashes and there's lots of gear noise. Pull the starter and use a dremel on the starter ring.

[74datsun710]

So after looking at a couple different gromet / bushing options I found a perfect solution. I bought these rubber furniture foot pads that are thick enough and the right diamater to replace the transmission cross bar brace bushings. I also purchased washers that fit perfectly in the already grooved out hole. All I had to do was slightly grind off a flat spot for it to work in the crossmember bracket. I took a 3/4" wood drill to make the holes for the bolts and they fit very snugly. The black bushing in the top of the photo are the old ones.

[74datsun710]

So one thing I didn't take into consideration is that the flex plate might be balanced? After welding on the ring gear, (and putting a slight camber on the face of the ring) I am now thinking that the plate might not be balanced. Will this really matter?

[Eagle_Adam]

I do seem to remember what seemed to be balancing weights welded on.....

 

Maybe a local driveshaft / machine ship would do it cheap

[74datsun710]

So here's an update to this project. I pulled the transmission and removed the flex plate. I  grounded off the ring gear on the flex plate flipped it and re welded it back on and also took my angle grinder and notched the leading edge of the tooth like the factory did.  Put it back in and the problem still remained. (The grinding and not fully engaging of the starter to the ring gear) So once again I took it all apart, ground some more on the spots where the starter made hit marks, and put it back together. Just as you would guess it still was making the same sound.  After a few kind works and some kicking of my tools, I regrouped drank a beer and thought about it some more.  I ended up pulling just the starter and after looking at the front leading edge of the pinion gear i found it to be slightly mushroomed.  I took a Dremel tool and ground a sharper front edge to the gear teeth.  After re installing the starter low and behold it worked!  So long story short, when in doubt drink a beer and save yourself hours of frustration....

[ggzilla]

Great work!