Another Home Rebuild Thread :)

[SmbFD3S]

As mentioned in my strip down thread (in members section sorry) this is on other non-rotary sites so explanations may seem a bit basic but not everyone knows about the rotary please point out any errors if you spot them lol.....
 
I\'ve now received all the parts for a fresh rebuild bar the rotors and housings and thanks to Tim at RX Motors for sorting me out :D
 
ROTORS BUILD

So the thing we have to do is to build the rotors back up. This means we have to clearance the side seals, all 12 of them to match the grooves and the corner seals.
As standard from the factory the side seals come over length, which means you have to “lap” them in order for them to fit in the groove. A fine stone and patience is required for this.

Firstly we install the corner seal springs into the corner seal holes and then the corner seals (this is not a final fit) and then we install the side seal springs (again not a final fit). The side seal springs must be installed with the “ends” of the spring facing up to give the ends of the seal the tension. You will not have a good seal if you get this wrong.

Pic below shows 2 corner seals. You can just see that the faces are slightly different. The shiny face (seal on the left) faces the housing as it’s the “finished” side.



Pic shows, corner seal spring, side seal spring and side seal. And pic below it shows the spring end.




Ok, one end of the side seal is the “finished” end and one isn’t, which is the one you machine/grind/lap, whatever you want to call it. This has a specific angle that must be maintained in order to get a good seal.

It’s essential not to get carried away with the lapping otherwise the clearance will be too great and cause a poor seal. The standard clearance for a road motor is 0.05mm.

What you’ll need:-



Keep checking the angle as often as you want and make sure it’s correct and seats nicely against the corner seal to ensure a good seal. It don’t matter if you have to stone a bit more off but you can’t put it back, remember that !!!!!

When you have checked and checked and checked lol, you should feel the 0.05mm feeler gauge slightly drag and this is the clearance you want as it will wear over time obviously.



If you plan to final fit these, you should now Vaseline the grooves and re-insert the springs and side seals. The Vaseline is there just to stop them falling out while you rebuild the motor and is actually mentioned in the Mazda Factory Manual, I’ve not made that up lol

However I don’t want to fit these yet cos I want to do a final clean of everything first, so I did the following. Mazda have a box in which to place all the side seals in order when compared to the rotors. Each rotor face has a number next to the side seal i.e. 1,3,5 and 2,4,6 like this:-



But I decided to make my own box cos it’s cheaper

So here we have all the side seals in order and corresponding to each rotor in their very own special box:-



So after this, I decided to put the oil control rings in which go in the centre of the rotor, and there are 2 per face, inner and outer and associated springs.

Now there are 2 types of spring aswell as the inner and outer. There are “cream” painted and “blue” painted springs. The BLUE marked springs fit the rotor face which faces the REAR of the engine and CREAM ones fit the rotor face that face the FRONT of the engine.




New O rings are installed into or around the oil control rings and coated with oil first.

The springs go in a certain way (forgot to take photos sorry) but basically there is a dimple in each groove and the end of the spring fit’s into this. There are also dimples on the oil control rings and these line up to the springs. Once lined up, the oil control ring can be pushed down into place. This Is repeated for all 8 of the rings.

I will take some photos of the Oil Control Rings installed before I carry on so you know what I’m on about, but that will prob be tomorrow as it’s now silly O clock and I’m going bed lol :D

Thanks for reading will post more soon

[Kieron]

Good luck mate Few more of theese threads will be poping up soon :Giggle ada is going to do his and I might do mine before it propper kills its self.

Looking forward to more pics.

[SmbFD3S]

ENGINE

Just before we get to this, these were the rotors cleaned up




You’ll notice that I’ve written an “F” on it. Basically this means “front face” in other words the face of the rotor faces the front of the engine/car. On the rear funnily enough it says “R” for rear lol… This is just an aid. The other rotor will have the same only the geared face will say R and the non geared face will say F. This is due to the oil control ring springs having to face certain directions as explained above with the colours. You would also nominate a rotor to be rotor 1 and the other to be rotor 2 so you can keep track.

Anyways, for the FD model it don’t matter which rotor is 1 and which is 2 as they are identical, however older 12A engines have specific front and rear rotors, and they are not interchangeable.

Ok, so now we’ve installed the side seals by the process I wrote earlier and the oil control rings in the specific face of the groove and facing the right way. The oil control rings complete with o rings now fit in the grooves around the centre of the rotor. Remember to oil the rings before installing. You do this to both sides of the rotor and the rotor should then look like this

When you’ve done this, run an Apex seal along it’s groove to align the corner seals.



Ok so now we move onto the block. I don’t have an engine stand so I made do with a workmate bench which is fine :D
The front plate faces down so you can build then engine up if you get me. No idea why I put the Eccentric shaft in here but hey lol…

So, what you do first is Vaseline up the water seals and gas seals (outer and inner respectively) This is to ensure the remain in place and also to give a better seal apparently. Also helps if it\'s at room temperature too



You do this to all 3 plates, in which the centre plate will have them on both sides. You can then place/press the seals into the grooves.



NOTE: THE GAS SEAL HAS A JOIN. This MUST be placed near to the cold section of the plate. This being near the inlet port and should be placed just above it near to the bolt hole. It can only go one way so you can’t get this wrong and as long as you remember the join you’ll be ok. If you have the Pinapple racing seals they are O Rings and dont have a join so that bit\'s irrelavant.

ALSO, the outer seal has 2 white edges. These NEED to be placed so they face the groove sides. In other words you should see the black side of the ring and this faces up towards the housing. Again if you have the Pinapple racing seals this dont matter either.



You can now install the first housing. You will notice 2 dowel pins also, which will line the housing to the plate. The one on the bottom left of the pic also has an o ring that goes around it on each side of the housing.



OH, and while we have the above pic up, you can see the stationary gear. I have installed a new bearing sleeve for this and should really be done if renewing the engine parts as these have the most wear. Rotor bearing sleeves, (if no copper is showing through should be re-usable)

Now place the rotor into the housing gear face down so it sits in the teeth of the stationary gear. You should ideally have a corner of the rotor facing either the sides or the length. I.e. like a compass, imagine N, E, S, W when looking at the housing from above and make sure the teeth are meshed together.



You can now, “carefully” place the eccentric shaft into the rotor and through to go through the stationary gear.



At this point you want to remove the corner seals, carefully, from the rotor and place them near to their respective slot so you don’t mix them up. Be careful the spring doesn’t get lost as these might stick to the rotor or the corner seal due to the Vaseline used.

We remove these as it makes the installation of the Apex seals a whole load easier.

Put some oil down the grooves of each corner seal/apex seal slot so it makes it easier for the apex seals to slide down and also provides lubrication.

This is 1 new 2-piece apex seal together with it’s small and large springs. You can see there is a join. On the original Mazda seals, when the car was built, there were 3 pieces. The large piece would be split in half down it’s length. Mazda R&D came up with the fact that 2-pieces were more stable some years later and is what is commonly used today.

Anyway, the apex seal is installed with the Solid (uncut) piece facing down, you’ll see in the photo. The corner piece is actually glued on for installation from the factory and will break off when you tighten the engine, but more on that later. So the fidly bit !!!!! You have to slide the apex seal in, with the small spring first making sure it catches the recess. When you have this half way you have to slide the larger spring over the top. Hard to explain so here’s a pic



When you’ve got to this stage you can push the whole thing down until it stops. If it don’t go all the way down then a corner seal has moved and the apex seal is not slotting into it, which means you have to remove the eccentric shaft and rotor and align the corner seals again.

You can now place the corner seal that you removed previously into it’s groove and you should have something that looks like this.



When you’ve done all 3, it will look like this.



You can now install the centre plate. Now for this you may need some help. In order for the centre plate to get over the eccentric shaft journals you need to lift the shaft up about an inch or so, so get someone to lift it slightly from the bottom while you put the plate over. Don’t lift it up any more than an inch or so otherwise the shaft will come out the stationary gear !!!! CAREFULLY manouver the plate over the shaft making sure you don’t hit or scrape the journals and it will sit on the housing.



Once the plate is in you can insert the other 2 dowels into the grooves as before.

Then place the next rotor housing on ensuring you’ve installed the o rings into the grooves on housing as before (with a little Hylomar) OH and forgot to mentioned the bottom portions of the housings should also have some sealant on to stop oil leaks, sorry, bound to miss a few bits out……

Anyway, so you install the housing, the rotor which can now only go one way as it’s impossible to be out of sync with the other rotor, as it will sit on the journal.of the shaft.

Install the apex seals as before but a bit more carefully this time. IF YOU DROP A SPRING YOU’LL HAVE TI STRIP THE ENGINE BACK DOWN TO GET TO IT !!!!!!



Before putting on the rear plate which is the last part of the sandwich, put a new oil seal over so it slots in the groove and put some Vaseline around it to stop it pinching. Install into the rear housing lining up the pin (sorry no photo) you’ll have to rubber/plastic mallet it into place as it’s quite tight. Install the six bolts and torque up.

REAR STATIONARY GEAR


Install the plate on the block

[gmogle]

A superb write up mate !!!

[matt p]

+1!

Very good explaination there, just book marked it for when i do mine.

What sort of ports are those?

Regards

Matt

[shaunwil]

Excellent write up, should be a sticky !

Shaun

[karl_tate]

yeh nice one mate

[SmbFD3S]

Thanks for all the nice comments guys, i know some of it may seem obvious but it was written with the intention that anyone could follow it, be it they know about the rotary or not
 
Matt, the ports are standard mate, i have a spare set of plates and will most likely be bridgeporting these to build a second engine

[SmbFD3S]

Ok so carrying on then
 
I didn’t take a photo so using an old one, but you put the new washers (supplied in the water seal kit) onto the engine bolts, lube the bolts and threads with fresh oil and then install in sequence.
Tighten them in stages, torque setting is 30ft lbs, so tighten them in stages of 10ft pounds at a time always in sequence.

Once this is done you can place the flywheel on the shaft, not forgetting the keyway.

Now this is the difficult bit.  The flywheel nut is tightened to 300ft lbs torque!! For this you WILL need a ¾” breaker bar and a lever to get to this. Most people are not gonna have a torque wrnch that will go this high.  Firstly, coat the threads with threadlock and put some sealant on the back of the 54mm nut.  Now tighten the nut.  It’s suggested that you use a 4 ft lever and tighten until you start to struggle/strain and then it will be tight enough lol….
To hold the flywheel and stop it moving put a clutch bolt in and use a chain connected to another bolt on the top of the rear plate as I’ve shown.  You will somehow need to anchor the engine also, I have eyebolt in the floor of the garage that I anchored it to
Next you can install the front part of the engine temporarily as we have to measure the end play in the shaft. This being the counterweight, timing gear/oil chain and front hub and bolt

Keep the chain on the flywheel to prevent the whole lot turning again.  Make sure the thrust bearings on the front are positioned correctly (behind the counterweight).  Tighten the bolt to 80ft lbs and check the end play with a dial gauge like this.  Pull on the flywheel to make sure it’s set at one end and then zero the dial.

Now move the shaft in and out and measure/record the amount play.  Mazda Spec is 0.04mm to 0.07mm.
These were my results.


As you can see there is about 0.045mm of play here which is absolutely fantastic
If you had less than this you would need to measure the thickness of the thrust bearing you used (available in thickness’s letters A to E) and subtract the necessary amount onto it to get the correct end play and order the relevant thrust bearing.  If you had more than specs you would need to do the opposite and decrease the thickness of the thrust washer.
Next, you can remove the bolt you just put in, remove counterweight and the timing gear and install the oil pump.


Now install the keyway and re-install the counterweight and timing gear/oil chain and make sure you line up and install the keyways on the pump and shaft.



Install the washer and nut on the pump.  The washer has a “tang” on it that fits into the groove to stop it rotating.  Tighten the nut and then bend over the washer to lock it in place. (sorry no pic of this, was getting carried away lol)
Next install a new front cover gasket with a bit of Hylomar and place the front cover on.  Tighten the bolts to spec’d torque.

The oil lines you see are from the oil metering pump which is what supplies oil to the rotor tips. A lot of engine failures are due to these pipes cracking or splitting due to heat so make sure you check them first or replace them with braided hoses you can now get!!!!
You should have also removed the oil metering pump (bottom left of the front cover) and placed a new O-ring in the groove.
You can now install the front bolt.  Put threadlock on the bolt and sealant on the rear of the head washer and install.  Tighten this to 200ft lbs.  When you’ve done this, re-check the end play and make sure it’s not changed !!!
Ok that’s it for now, we’re getting on the external parts of the engine and will require a lot of explaning lol so I’ll do that at a later date when I’ve thought about it again.
For now that’s the main block complete :D:D

[karl_tate]

that excellent mate. did you get all the info off the dvd\'s??

this has to be made a sticky :god

[SmbFD3S]

Got a lot from the DVD\'s yeah but knew the majority to be honest by just reading the manual. The manual is in fact very good it just helps to see it if you get me. Also the Pineapple racing rebuild videos that are online are good also as some of the info on the dvd\'s is a little lacking, but depends how much you want to learn/know really :D  
 
Thanks again for the comments

[Fats]

Nice one mate! Where did you get the manual from if you don\'t mind me asking?

Cheers
Andy

[SmbFD3S]

The manuals are all free online matey, got mine from rx7club but IIRC Rotaryart also has them for download

[Fats]

I\'ve had a look but havin no joy, could you post up a link for the manual\'s dude

cheers

[shaunwil]

http://www.google.co.uk/search?hl=en&q=rx7+manuals&btnG=Google+Search&meta=

1st link :Giggle

Shaun