The way I measure the grooves is with the Apex seal installed and a feeler gauge. Check out the FSM and report back to us. That will probably give you more of an understanding of the amount of gap. Because you're right, that little bit isn't much for concern, but I bet when you get the seal in place and THEN measure the gap, it'll make more sense.


I'll delete your previous post for you.

OK...well it appears I was onto the right idea first time I checked clearance. My first pics are of the feeler gauges on the corners. I put them in angled the top towards the middle as far as they would go. Like I was trying to slide them across the groove.

I checked out the FSM and I think I'll be referring to it more often. My Haynes has a handy page of tolerances but no description on how to go about getting those.

So I've got corner seals and plugs in, apex springs and seals in.

FD rotor on the bad corner
.011-.012-the tip of the feeler barely fits and can't go beyond where the damage is on the edge of the groove.

FD rotor same groove but on the good corner
.005-.006-gets about the same amount of contact...barely fits on the very tip

As far as sliding the feeler gauge all the way to the bottom of the groove. On the corners .002 is the only one that can do that.

I'm probably over thinking this again. But on the corners I can fit the feelers much easier. Probably because my old apex seals are OEM 3-piece. The top half can move a smidge.

With that in mind it seems the groove is within spec...except on the damage. Also the higher clearance is also only at the top where the damage is. The groove isn't uniform. The groove tapers out near the top cause of the damage. Max clearance according to FSM is .059.

Did you change units on us or miss an extra zero?
0.059?
0.059mm?
0.0059"?
:eek:


-Ted

That's what aI was wondering.....

:lol: Don't read what I wrote, read my mind and what I meant :lol:


FSM max clearance is .0059, but all the other numbers I posted are correct.

But again the thinest feeler gauge that I could slide was .002. That was the thinest feeler I own and moving it was difficult. Once the feeler got closer to the center of the groove it got hard to slide and was likely to tear.

What I noticed on all my rotors both good grooves and bad grooves is that on the corners it was much easier to get thicker feelers in the groove corner but was unable to slide them. Even on the good corners I could get between .005 and .006 into the groove to varying depths. On the damaged FD I just kept going higher and higher with feelers till I couldn't get anything wedged into the groove.

What I found is that the damaged groove isn't uniform. At the bottom of the groove it is consistent with the good grooves. But at the top I have more room as it tapers out due to the damage.

Me thinks my perfectionism has overcomplicated this whole process

No it hasn't. You've got twice the max allowed (per the FSM) clearance at the bad corner.... what does that tell you? It tells me that per the FSM, that rotor is junk.

There have been some great points brought up about reusing them, carbon buildup, reliability, etc etc etc. It's all personal preferance.

Personally.... I wouldn't use that rotor. but that's me. Others said that they have, and have with some degrees of sucess..... It's up to you.

You are forgetting a forth option though........ Get them milled out for 3mm seals.

^TTT

My concern regarding the clearance is the difference between the top where the damage is and the bottom where it's same measurement as my good grooves. I don't want to pay shipping back to the seller and have him tell me it's in spec because the bottom of the groove is in spec.

I'm not wanting to go 3mm. I don't live near any rotary shops or machine shops that have any experience with "das wankel" That means shipping two rotors out and back..along with labor costs for milling.

Update....seller inspected the returned rotor and has different one on it's way back to me.

Damaged Rotor Slots & Over Sized Apex Seals
 

Hello JustJeff,
Saw your post and photos about your concern with your rotor slots and read through most of the replies on the forum. Here are a few ideas for you and others that have been part of this conversation.

There is obvious damage, but as others have said, you can make it work as many have. However, that damage will contribute to you performing less than optimally.

Agreed, machining to 3mm and using thicker seals can be risky and expensive at best especially given your lack of proximity to machine shop, etc.

What if there were a way to add more material to your slots to fill in the gaps/wear/damage and get your rotors back to factory spec. clearance? That's not really practical, but if there were OVER SIZED APEX SEALS, that would essentially accomplish the same thing ... give you more material to work with.

That is the thinking behind a cost effective solution from Goopy Performance that is inexpensive and requires no special machinery or expertise. Here's how it works.

1. Goopy Performance OVER SIZED APEX SEALS ... for all of the RX-7 Apex Seals that we manufacture. We produce these seals with an additional few thousands of material. So in the example of your 2mm 13B seals instead of being factory stock .115, these seals are .118. By using these seals it is like we just put .003 of new material into your slots.

2. Goopy Performance ROTOR CLEANING KIT ... that includes a high quality flat file that fits into your rotor slots, a .0015 Feeler Gauge (= Factor Clearance), and two stainless steel wire brushes to clean your corner seal slots.

When you try to put the over sized apex seals into the slots they probably will NOT fit, but they will be close. So all that you need to do is CAREFULLY take a few passes with the file on the inside of the slot, keeping the file FLAT and TRUE against the inside walls of the slot and begin to remove some of the rough edges at the top of the slot on both sides.
Do NOT remove too much material at any one time before testing with your new oversized seals again. Probably still doesn't fit but getting closer. Continue to remove material from both sides of the slot and be sure to keep the file FLAT and TRUE against the sides of the slot as you proceed. Remove material along the sides to the full depth of the slot.
Retest and continue to remove old, damaged and excess material until the seals just fit into the slot. Pretty easy, correct?
Now you have another .0015 to go. That is NOT much material so proceed CAUTIOUSLY. Continue to remove material from both sides until you can just fit BOTH the oversized seal PLUS the FEELER GAUGE.
When they together fit perfectly into your slots you now have "FACTORY SPEC" ROTOR CLEARANCES!

No buying new rotors, no machining 3mm slots and hoping your rotors are not ruined, no 3mm seals, no running rotors and apex seals that are way out of spec and leaking compression like and old engine ... just your rotors back to spec!

JustJeff, there is more info. on our web site or feel free to call for assistance.
Reply if you would like contact info., pricing, etc.
Good luck and looking forward to being of help.

Goopy Performance