I have read enough of Judge ITO's posts to know what clearances to give the side and apex seals to do a proper rebuild. But what I have not been able to find is HOW to clearance them.



They appear to be about 0.1" too long to even fit in the side seal groves.

How should I remove material from the ends of the side seals?

Do I just take some 800 ? 400 grit wet sandpaper and stand them on end and gently rub occasionally checking the clearance?



I have the Atkins 2 piece seals.

Do I lay the two pieces flat to measure them or should I try to glue them together?

Should I heat them up a bit and then measure them?

Do I remove material from the big piece? The little piece?

Do I use the same technique as the side seals?

 

you're supposed to sand the side seals with 600grit on a flat surface, i use a dremel with a sanding bit thats round and about the same size as the corner seal, you want there to be no leaks.



i'm not sure about the apex seals, i think you're gonna be grinding the big side



mike

 

I have spent about an hour and a half tonight fitting my side seals. At first I started with some 400 grit sandpaper. The seals appear to be about .1" too long. It was going to take forever to take that much material off with just 400 grit paper.



I experimented with some old broken seals on my bench grinder. I seemed to have good controll but I didn't want to risk it so I shelved that idea. I then got a small flat fine grain file and gently used it to take material off the end. Laying the file flat on my workbench and standing the seal on end seemed to work well. I discovered that it takes around 100 strokes to get it close then I finished up with 400 then 600 grit sandpaper. I took them down to 0.002 clearance to the corner seals.



With that amount of clearance the seals seemed to bind slightly at the ends when moved up and down. I discovered it did it on all three side seals I completed tonight, even with the corner seals removed. Is this nomal? BTW: it has .0015 clearance between the side seal and rotor groove all the way across.



Only 9 more seals to go! Then the real fun begins. I should have the motor finished and in the car by Tuesday morning, I can't wait!

 

I have the same question. i just fitted my side seals, but the apexes...They are just a hair longer than the rotor. I mean just barely. Should I trim them down or leave them as is?



Also if I trim them do I trim the big piece or the small piece?

 

Please correct me if I am wrong (I have only built one motor now). But the length of apex seals are supposed to be fitted to the width of the rotor housing and not the rotor itself. I fitted mine around .002" shorter than the width of the rotor housing. Because they were really close to start with I just used 400 then 600 grit sandpaper to take them down (on the big piece).



The hard part was measuring the length of the 2 piece apex seal. Nobody has been able to give me a good explination how to do this properly. I used a touch of super glue to hold the two pieces together. Then used my micormeters to measure the length of the apex seal.

 

well it shouldnt matter weather you measure it to the width of the housing or the rotor because just think about it for a sec, they should be the same, if not then the chambers would be open on the face part of the rotor to to speak. I mean imagive a grosly overexadurated case where the rotor housing is way bigger then the rotor. Just imagine it, see it now?

 

The rotors are slightly smaller than the rotor housing. The rotor itself is not what touches the side housing to create a seal. It relies on the corner and side seals. They are designed to stick out to the side (in effect making the rotor wider) to touch the side housings.

 

I see, thanks for clarifying that

 

not only is what KorovaKharne said above true, but also realize that the slightest change in the clearance will have a large effect on the compression of the chamber(s) associated with that seal, especially at low RPM.

 

Why are you having to clearance the Atkins seals? I thought they were clearanced as matched pairs by the manufacturer.



Clearancing apex seals can be very troublesome as doing it by hand leads to inaccuracies and you'll never get the angles exact wherever you take metal off. I have had to clearance corner pieces before by taking metal off the rubbing surface but only when re-using old seals (not by choice I might add!)



The 13B seals should be pretty much spot on 80.00mm long. Don't worry too much if there's a small difference between the housing width and apex seal width- the run-in process should sort it out.



I know some apex seals have to be clearanced, but are usually one-piece seals. The two pieces should be matched with no need to clearance.