12a Rebuild: Opinions on rotor assembly
08-10-14, 06:46 PM
#1
12a Rebuild: Opinions on rotor assembly
I'm at the point of assembling the 12a.
Between Hayns, Atkins, Mazdatrix, Youtube, and the FSM there seems to be more than one method of assembling the rotors+housings.
Petroleum jelly to glue all the rotor pieces in place then slide into place inside the housing.
Or oil only and install the apex seals and springs as a unit (superglue the apex end seals to the apex seals first).
Or lay the assembled rotor on the iron and position the housing over (this appears to require the "assist pieces" on the apex seals).
For those of you who have traveled the path I'm about to take, what might be your preference?
If it is a matter of "What works best for you." I'll go with that.
Thought I would ask to avoid mistakes.
Between Hayns, Atkins, Mazdatrix, Youtube, and the FSM there seems to be more than one method of assembling the rotors+housings.
Petroleum jelly to glue all the rotor pieces in place then slide into place inside the housing.
Or oil only and install the apex seals and springs as a unit (superglue the apex end seals to the apex seals first).
Or lay the assembled rotor on the iron and position the housing over (this appears to require the "assist pieces" on the apex seals).
For those of you who have traveled the path I'm about to take, what might be your preference?
If it is a matter of "What works best for you." I'll go with that.
Thought I would ask to avoid mistakes.
08-10-14, 08:06 PM
#2
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there is a lot of flexibility here.
you do want something to hold the seals in as you assemble it, i find you only need a dab on each corner/end, the less you use, the less it smokes on startup. vaseline works great for this, i ran out like 15 years ago, and just use grease.
the faces of the irons, trochoid surface, and the gears, get a light coat of engine oil, as i'm assembling. so before i put the rotor housing on, i wipe a little oil on it.
the dowel pins, bearings and gears get a coat of grease/assembly lube.
everyone read the RB catalog and loves hylomar on the legs of the rotor housings, but the factory uses silicon.
i put the, rotor housing on the iron, and then put the rotor in, with the apex seals in but without the spring. pull the apex seal out out, put the spring in, and put the end piece in with a little dab of grease. then i pop in the corner seals, and put the next iron on.
the trick with the apex seal, is that sometimes the bottom corner seal turns, which will block the seal, and cause colourful words to come out of your mouth.
if you're worried, try a dry run without water seals, and see how it is
you do want something to hold the seals in as you assemble it, i find you only need a dab on each corner/end, the less you use, the less it smokes on startup. vaseline works great for this, i ran out like 15 years ago, and just use grease.
the faces of the irons, trochoid surface, and the gears, get a light coat of engine oil, as i'm assembling. so before i put the rotor housing on, i wipe a little oil on it.
the dowel pins, bearings and gears get a coat of grease/assembly lube.
everyone read the RB catalog and loves hylomar on the legs of the rotor housings, but the factory uses silicon.
i put the, rotor housing on the iron, and then put the rotor in, with the apex seals in but without the spring. pull the apex seal out out, put the spring in, and put the end piece in with a little dab of grease. then i pop in the corner seals, and put the next iron on.
the trick with the apex seal, is that sometimes the bottom corner seal turns, which will block the seal, and cause colourful words to come out of your mouth.
if you're worried, try a dry run without water seals, and see how it is
08-10-14, 08:20 PM
#3
there is a lot of flexibility here.
you do want something to hold the seals in as you assemble it, i find you only need a dab on each corner/end, the less you use, the less it smokes on startup. vaseline works great for this, i ran out like 15 years ago, and just use grease.
the faces of the irons, trochoid surface, and the gears, get a light coat of engine oil, as i'm assembling. so before i put the rotor housing on, i wipe a little oil on it.
the dowel pins, bearings and gears get a coat of grease/assembly lube.
everyone read the RB catalog and loves hylomar on the legs of the rotor housings, but the factory uses silicon.
i put the, rotor housing on the iron, and then put the rotor in, with the apex seals in but without the spring. pull the apex seal out out, put the spring in, and put the end piece in with a little dab of grease. then i pop in the corner seals, and put the next iron on.
the trick with the apex seal, is that sometimes the bottom corner seal turns, which will block the seal, and cause colourful words to come out of your mouth.
if you're worried, try a dry run without water seals, and see how it is
you do want something to hold the seals in as you assemble it, i find you only need a dab on each corner/end, the less you use, the less it smokes on startup. vaseline works great for this, i ran out like 15 years ago, and just use grease.
the faces of the irons, trochoid surface, and the gears, get a light coat of engine oil, as i'm assembling. so before i put the rotor housing on, i wipe a little oil on it.
the dowel pins, bearings and gears get a coat of grease/assembly lube.
everyone read the RB catalog and loves hylomar on the legs of the rotor housings, but the factory uses silicon.
i put the, rotor housing on the iron, and then put the rotor in, with the apex seals in but without the spring. pull the apex seal out out, put the spring in, and put the end piece in with a little dab of grease. then i pop in the corner seals, and put the next iron on.
the trick with the apex seal, is that sometimes the bottom corner seal turns, which will block the seal, and cause colourful words to come out of your mouth.
if you're worried, try a dry run without water seals, and see how it is
Off to the garage to get things started.
Thank you for the info.
08-10-14, 08:28 PM
#4
i have done each of the methods you described. for now, i prefer to glue the apex seals together and i glue one end of the spring to it. i place the rotor in the chamber and then slide the apex seals into their slots.
just a note that may seem a bit like a commercial
, but it is my experience ... use actual Krazy Glue. it makes a huge difference.
EDIT (because J9fd3s' response was not there when i started typing)
i use copious amounts of gear oil, motor oil and petroleum jelly on various parts. i've recently seen Jeff20B and J9 admonish this practice and it got me thinking about cutting down on some of it. i'm also giving some thought to using actual assembly lube in my next engine. that said, i honestly have never experienced ridiculous amounts of smoking either. they smoke for a minute, yes, and might even smoke a tad on the second start up, but that's about it.
i've never bought Hylomar in my life. petroleum jelly has always held the water seals in place for me. i've also never put silicone between the housings of any 12A i've built thus far.
just a note that may seem a bit like a commercial
, but it is my experience ... use actual Krazy Glue. it makes a huge difference.EDIT (because J9fd3s' response was not there when i started typing
)i use copious amounts of gear oil, motor oil and petroleum jelly on various parts. i've recently seen Jeff20B and J9 admonish this practice
and it got me thinking about cutting down on some of it. i'm also giving some thought to using actual assembly lube in my next engine. that said, i honestly have never experienced ridiculous amounts of smoking either. they smoke for a minute, yes, and might even smoke a tad on the second start up, but that's about it. i've never bought Hylomar in my life. petroleum jelly has always held the water seals in place for me. i've also never put silicone between the housings of any 12A i've built thus far.
Last edited by diabolical1; 08-10-14 at 08:41 PM.
08-11-14, 12:19 AM
#5
I only use a little grease to hold in the coolant seals and some of the corner seals (facing down). Then I use engine oil as assembly lube on bearings and irons. I don't worry about the rotor housings as the oil from the irons gets on them after assembly. I put RTV on the legs. I tried hylomar on the first couple of builds and didn't like it.
This method leads to no spilled oil on your shoes and a low-smoke first startup. They start up easily and fast.
Some would say that's not enough oil for a first startup. To that I say ever clean oil off fouled spark plugs over and over? It's not fun.
Judge Ito once used no assembly lube on a 12A to see what it would do. It started up super fast and ran fine.
This method leads to no spilled oil on your shoes and a low-smoke first startup. They start up easily and fast.
Some would say that's not enough oil for a first startup. To that I say ever clean oil off fouled spark plugs over and over? It's not fun.
Judge Ito once used no assembly lube on a 12A to see what it would do. It started up super fast and ran fine.
08-11-14, 09:51 AM
#6
+1 RTV on the legs.
+1 on superglued glued side pieces. Done right, you can hear them 'ping' free when you torque the stack.
+1 on rotor w/seals minus apex springs, then housing, then pull apexes & install springs.
+ on oil for all oiled surfaces
I use Hylomar (Smurf snot) to retain the water seals & o-rings. It doesn't swell them like Vaseline does. Never had a leak.
+1 on superglued glued side pieces. Done right, you can hear them 'ping' free when you torque the stack.
+1 on rotor w/seals minus apex springs, then housing, then pull apexes & install springs.
+ on oil for all oiled surfaces
I use Hylomar (Smurf snot) to retain the water seals & o-rings. It doesn't swell them like Vaseline does. Never had a leak.
08-11-14, 10:06 AM
#7
What if you don't get all 6 pings? What if the glued apex seal is just too short to ping, but still longer than the rotor housing? It will put pressure on the irons and drag causing hard spots while hand cranking. Not good. So I glue them slightly shorter than the rotor housing. That's 69.94mm or similar.
After my first glued build that had hard spots and only a couple of pings, I started gluing them shorter and it works great with no worry of damage to apex seals or irons.
The glue breaks the first time it starts.
After my first glued build that had hard spots and only a couple of pings, I started gluing them shorter and it works great with no worry of damage to apex seals or irons.
The glue breaks the first time it starts.
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08-11-14, 07:04 PM
#10
Follow-up question....
As I have limited time, usually between 9:30-11:00pm, is there an issue with assembling in stages over the next 4-5 evenings?
Hylomar for the water seals & O-rings
RTV for the legs
I'll only apply the Hylomar and RTV to the pieces assembled during that session.
As I have limited time, usually between 9:30-11:00pm, is there an issue with assembling in stages over the next 4-5 evenings?
Hylomar for the water seals & O-rings
RTV for the legs
I'll only apply the Hylomar and RTV to the pieces assembled during that session.
08-11-14, 11:15 PM
#11
Hylomar doesn't harden, but needs time to tack up as the solvent dries. RTV obviously starts to cure once it leaves the tube but you have some working time.
I get everything ready to assemble. Then I do the RTV on the legs and the stack process begins. Takes about 23 to 25 minutes on average. Some builders take longer and some work quicker, but my speed works for me and the RTV on the front iron doesn't fully cure by the time I'm done torquing the tension bolts, so it seals well and can still squeeze out as it should without being an incompressible mass.
I get everything ready to assemble. Then I do the RTV on the legs and the stack process begins. Takes about 23 to 25 minutes on average. Some builders take longer and some work quicker, but my speed works for me and the RTV on the front iron doesn't fully cure by the time I'm done torquing the tension bolts, so it seals well and can still squeeze out as it should without being an incompressible mass.
08-11-14, 11:26 PM
#12
You might find the black outer coolant seals to be a little short out of the package. I give them a gentle stretch and check them in the rotor housing groove. This is something to be aware of. Don't count on hylomar to do the job of keeping them in. They can fall out and get pinched. Make sure they are the same length as the groove before applying your sticky stuff.
08-12-14, 03:58 AM
#13
I was worried that the crazy-glued apex side/tips would remain "glued" and affect compression for the initial start. I did this anyway too. Discussions with Bob Golden at Pineappleracing.com (longtime West coast rotary shop) led him to suggest that if the tips haven't "popped" for a starter-motor fire-up, that a tow-start might free them up for you. Or alternately, after assembly, use a hot-air gun (the kind used to melt electrical shrink-wrap) aimed into the intake or exh ports could also release the glue (obv this is done with no manifolds attached…)
Stu Aull
80GS
Alaska
Stu Aull
80GS
Alaska
08-12-14, 09:28 AM
#14
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Follow-up question....
As I have limited time, usually between 9:30-11:00pm, is there an issue with assembling in stages over the next 4-5 evenings?
Hylomar for the water seals & O-rings
RTV for the legs
I'll only apply the Hylomar and RTV to the pieces assembled during that session.
As I have limited time, usually between 9:30-11:00pm, is there an issue with assembling in stages over the next 4-5 evenings?
Hylomar for the water seals & O-rings
RTV for the legs
I'll only apply the Hylomar and RTV to the pieces assembled during that session.
i have built engines where the front rotor got built like a week before the rear and it was ok, although its probably not ideal
08-12-14, 04:25 PM
#16
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have fun! it is neat in there, isn't it?
08-12-14, 07:58 PM
#18
In addition to rehearsing, here are some build videos:
Notice the differences on how much and what kind of assembly lubes and sealants are used.
From the Mazda factory:
Some of their tools make the job a little easier.
One thing I noticed was that the other builders put the rotor on the iron first, then the dowels, and then the rotor housing over them. Sometimes they have to do a little wiggling to get the housing down on the iron. The Mazda workers insert the dowels in the housing, put them on the iron, and then the rotor in.
Notice the differences on how much and what kind of assembly lubes and sealants are used.
From the Mazda factory:
Some of their tools make the job a little easier.
One thing I noticed was that the other builders put the rotor on the iron first, then the dowels, and then the rotor housing over them. Sometimes they have to do a little wiggling to get the housing down on the iron. The Mazda workers insert the dowels in the housing, put them on the iron, and then the rotor in.
08-13-14, 01:34 AM
#19
I put the rotor on the front iron, then put the shaft in which aligns the rotor, then raise the shaft 35mm, then the housing and then the dowel pins, then apex seals. Intermediate plate is installed and the shaft is lowered. Rear rotor same as front. Make sure the oil singers are aligned 180. I do. Is it important?
08-13-14, 09:13 AM
#20
If there's any tricky bit at all, it's getting the mid iron situated without scraping anything sensitive or messing up your sealant. If you don't have an assistant to hold the e-shaft in position from below, then you'll want to rig up a support for it that pushes it up at the proper height & lets you lower it as the iron comes down.
I use a couple of pieces of wood that work like a foot pedal, pivoting on the bottom of the engine stand. Step on it, e-shaft goes up. Ease off, it goes down.
Not "hard," just takes a bit of finesse. Easier with practice. Or competent assistance.
I use a couple of pieces of wood that work like a foot pedal, pivoting on the bottom of the engine stand. Step on it, e-shaft goes up. Ease off, it goes down.
Not "hard," just takes a bit of finesse. Easier with practice. Or competent assistance.
08-13-14, 09:53 AM
#21
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i use the jack from the car, it works really nicely as you can position things pretty exactly
08-15-14, 06:57 PM
#24
Thank you one and all.
As you can see from the attached image, I was successful, but not without 2 restarts. Both due to black water seals (front facing) popping out just ever so slightly.
Next to get the big flywheel nut torqued and then off to the front end.
(Harbor Freight does have an $80 50-300 ft-lb torque wrench, 3/4 drive & Sears has 54mm 3/4 drive sockets.)
As you can see from the attached image, I was successful, but not without 2 restarts. Both due to black water seals (front facing) popping out just ever so slightly.
Next to get the big flywheel nut torqued and then off to the front end.
(Harbor Freight does have an $80 50-300 ft-lb torque wrench, 3/4 drive & Sears has 54mm 3/4 drive sockets.)