People who have rebuilt rotary engines
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Senior Member
Joined: Sep 2001
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From: Monument Colorado
People who have rebuilt rotary engines
I want to know how many people here have or atempted to rebuild there engines and answer a couple of questions for me!.
-why did you rebuild it?(ate a seal,smoked,oil leaks,nothing better to do)
-did you do it yourself or have someone thats done it before help?
-did you measure everything?(seals,rotors,housings,e-shaft)
-were the rotor housings perfect?(was there any flaking)
-what seals or springs did you reuse?(if any)
-did you have the side housings lapped?
-if ported did you use a templete?(how hard was it?)(what kind of port?)
-how hard was it to reassemble?(fitting all the seals and springs)
-any secrets or tricks you know about building these engines?
-how did your first rebuild turn out?(run good,still running,blow-up when you first started it?)
-is a 13b about the same to rebuild?
-how many have you built since the first one?
-ever mess one up?
Any information or stories are welcome and encouraged!!!!!!!
-why did you rebuild it?(ate a seal,smoked,oil leaks,nothing better to do)
-did you do it yourself or have someone thats done it before help?
-did you measure everything?(seals,rotors,housings,e-shaft)
-were the rotor housings perfect?(was there any flaking)
-what seals or springs did you reuse?(if any)
-did you have the side housings lapped?
-if ported did you use a templete?(how hard was it?)(what kind of port?)
-how hard was it to reassemble?(fitting all the seals and springs)
-any secrets or tricks you know about building these engines?
-how did your first rebuild turn out?(run good,still running,blow-up when you first started it?)
-is a 13b about the same to rebuild?
-how many have you built since the first one?
-ever mess one up?
Any information or stories are welcome and encouraged!!!!!!!
Old [Sch|F]ool
Joined: May 2001
Posts: 12,865
Likes: 571
From: Cleveland, Ohio, USA
Re: People who have rebuilt rotary engines
Originally posted by 81dragrx7colorado
I want to know how many people here have or atempted to rebuild there engines and answer a couple of questions for me!.
-why did you rebuild it?(ate a seal,smoked,oil leaks,nothing better to do)
Leaked at dowel O-rings and I wanted a ported engine.
-did you do it yourself or have someone thats done it before help?
By myself, with a Haynes for specs.
-did you measure everything?(seals,rotors,housings,e-shaft)
Absolutely! I bought $200 worth of measuring tools to do it.
-were the rotor housings perfect?(was there any flaking)
Yes. The engine only had 60k on it. No flaking, no scoring, housings even still had the factory hone-marks on them. Side housings just a little grooved - no big deal.
-what seals or springs did you reuse?(if any)
All of 'em!
-did you have the side housings lapped?
Nope! That would cost far FAR too much money... besides all of the seals were being reused, so why bother?
-if ported did you use a templete?(how hard was it?)(what kind of port?)
No templates, just common sense and LOTS of reading-up. Mild extend port. The side housings took 3 hours total... probably 8 hours on the ehxuats ports because there's SO much material to remove + aluminum is more difficult to cut believe it or not. I had to use nasty metal-eating bits on the aluminum, and then I polished the whole port, but on the intake side I just used sanding wheels (actually worked better than metal-eaters) to radius the closing side of the intake ports, only went up maybe 1/2" and most of the work was blending it all in, and I did NOT touch the intake runners at all.
-how hard was it to reassemble?(fitting all the seals and springs)
Piece o' cake. Took about an hour to put the shortblock together.
-any secrets or tricks you know about building these engines?
Forget gluing the apex seals together... they'll just pop apart when you're trying to put the rotor housing on over the rotor and the springs compress, and you'll spend forever looking for the corner piece. (BTW I put the rotor on the side housing, then put the rotor housing on over it) Put the apex seal in without the spring or corner piece installed, also don't put on the corner seals or springs for that side yet. Put the apex seal springs in, then the corner springs and seals. Now the tricky part... pop the corner pieces in (make sure you get the spring on the correct side of it). They won't go in all the way, the spring will push the tips upward. Carefully push the tips down so they're flush with the rotor housing or at least so they're not sticking up. Then WITHOUT ROTATING THE E-SHAFT put the next side housing on.
-how did your first rebuild turn out?(run good,still running,blow-up when you first started it?)
Fired right up, gave me 23k miles of fine use/abuse till I overrevved it.
-is a 13b about the same to rebuild?
Same engine, just longer. Post '85 models have minor differences that are insignificant, except for the apex seals - those are 3 piece. Never had to wrestle with those yet.
-how many have you built since the first one?
Just the one so far.
I want to know how many people here have or atempted to rebuild there engines and answer a couple of questions for me!.
-why did you rebuild it?(ate a seal,smoked,oil leaks,nothing better to do)
Leaked at dowel O-rings and I wanted a ported engine.
-did you do it yourself or have someone thats done it before help?
By myself, with a Haynes for specs.
-did you measure everything?(seals,rotors,housings,e-shaft)
Absolutely! I bought $200 worth of measuring tools to do it.
-were the rotor housings perfect?(was there any flaking)
Yes. The engine only had 60k on it. No flaking, no scoring, housings even still had the factory hone-marks on them. Side housings just a little grooved - no big deal.
-what seals or springs did you reuse?(if any)
All of 'em!
-did you have the side housings lapped?
Nope! That would cost far FAR too much money... besides all of the seals were being reused, so why bother?
-if ported did you use a templete?(how hard was it?)(what kind of port?)
No templates, just common sense and LOTS of reading-up. Mild extend port. The side housings took 3 hours total... probably 8 hours on the ehxuats ports because there's SO much material to remove + aluminum is more difficult to cut believe it or not. I had to use nasty metal-eating bits on the aluminum, and then I polished the whole port, but on the intake side I just used sanding wheels (actually worked better than metal-eaters) to radius the closing side of the intake ports, only went up maybe 1/2" and most of the work was blending it all in, and I did NOT touch the intake runners at all.
-how hard was it to reassemble?(fitting all the seals and springs)
Piece o' cake. Took about an hour to put the shortblock together.
-any secrets or tricks you know about building these engines?
Forget gluing the apex seals together... they'll just pop apart when you're trying to put the rotor housing on over the rotor and the springs compress, and you'll spend forever looking for the corner piece. (BTW I put the rotor on the side housing, then put the rotor housing on over it) Put the apex seal in without the spring or corner piece installed, also don't put on the corner seals or springs for that side yet. Put the apex seal springs in, then the corner springs and seals. Now the tricky part... pop the corner pieces in (make sure you get the spring on the correct side of it). They won't go in all the way, the spring will push the tips upward. Carefully push the tips down so they're flush with the rotor housing or at least so they're not sticking up. Then WITHOUT ROTATING THE E-SHAFT put the next side housing on.
-how did your first rebuild turn out?(run good,still running,blow-up when you first started it?)
Fired right up, gave me 23k miles of fine use/abuse till I overrevved it.
-is a 13b about the same to rebuild?
Same engine, just longer. Post '85 models have minor differences that are insignificant, except for the apex seals - those are 3 piece. Never had to wrestle with those yet.
-how many have you built since the first one?
Just the one so far.
Rotary Freak
Joined: Mar 2001
Posts: 1,611
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From: LA.,California USA
Im almost ready to build my first turbo motor. Unlike the other guy that re-used all parts im using brand new parts except rotors and e-shaft. I've dis-assembled to motors so far just to study them. It looks very e-z. TRICKS--measure, measure,& more measure...ohh and be carefull not to pinch any o-rings..this is according to some people that have experience.
Joined: Dec 1999
Posts: 7,855
Likes: 517
From: Behind a workbench, repairing FC Electronics.
Hmmm.. Maybe I should rebuild mine instead of bringing it to PFS or Rotary Performance (Of Winchester Virginia... Not Texas.) Just have teh shop do the lapping and clearancing.
The basic engine seems simple enough except for getting those two piece apex seals in.
Any special tools needed except for the socket for the nut on the flywheel?
Anyone used apex seals other than stock like the Hurley engineering or Atkins rotary ones?
The basic engine seems simple enough except for getting those two piece apex seals in.
Any special tools needed except for the socket for the nut on the flywheel?
Anyone used apex seals other than stock like the Hurley engineering or Atkins rotary ones?
Old [Sch|F]ool
Joined: May 2001
Posts: 12,865
Likes: 571
From: Cleveland, Ohio, USA
Special tools... well besides the obvious problems of the flywheel and the front pulley bolt (usually incredibly tight and rusted on too) you need an engine stand, a soft faced deadblow hammer (to smack the engine apart), some way of keeping the seals sorted if you're reusing, or after clearancing new ones (will explain), a way of cleaning years of carbon and gasket material and sealant off, a GOOD way of measuring things ranging from .01mm or so all the way up to over 70-80mm (specs can also be had in inches but i forget 'em), and PATIENCE. Trust me you'll spend more time scraping gasket and cleaning carbon and removing bits of old O-rings and cleaning more carbon and flushing oit passages and measuring this and that than you will spend disassembling it, and reassembling it, and possibly even the R&R job too.
Anyway. About the only "specialty tool" you may need is a way of pulling stubborn dowel pinds out. I found that some of the bolts I pulled in disassembly, i *think* they were 12x1.5 pitch (not certain), match the threading inside the dowels. Thread a nut a ways onto the bolt, thread the bolt loosely into the dowel, use the nut to tighten it to the dowel, and twist/yank as necessary with Vise-Grips. RB sells the same thing except it's a piece of metal rod welded to the end of a bolt... my way costs nothing.
I made seal trays out of 1" styrofoam wall insulation. I broke it into pieces small enough to fit in a board game box, cut trenches into the styrofoam, and pressed the seals in. Magic marker was used to mark the tray as to where the seal came from. (Each corner/side of a rotor is numbered) Two trays and a "top cover" piece of syrofoam fit into one box. I had one box with all the seals in it, another box with the rotors in it, a third box with the E-shaft and a couple baggies of parts, and a fourth box with the tension bolts in it. If I did it again I'd spend more time making trays out of cardboard, because pieces of styrofoam would stick to the seals (static electricity) and it was a PITA trying to take them off.
Anyway. About the only "specialty tool" you may need is a way of pulling stubborn dowel pinds out. I found that some of the bolts I pulled in disassembly, i *think* they were 12x1.5 pitch (not certain), match the threading inside the dowels. Thread a nut a ways onto the bolt, thread the bolt loosely into the dowel, use the nut to tighten it to the dowel, and twist/yank as necessary with Vise-Grips. RB sells the same thing except it's a piece of metal rod welded to the end of a bolt... my way costs nothing.
I made seal trays out of 1" styrofoam wall insulation. I broke it into pieces small enough to fit in a board game box, cut trenches into the styrofoam, and pressed the seals in. Magic marker was used to mark the tray as to where the seal came from. (Each corner/side of a rotor is numbered) Two trays and a "top cover" piece of syrofoam fit into one box. I had one box with all the seals in it, another box with the rotors in it, a third box with the E-shaft and a couple baggies of parts, and a fourth box with the tension bolts in it. If I did it again I'd spend more time making trays out of cardboard, because pieces of styrofoam would stick to the seals (static electricity) and it was a PITA trying to take them off.
standard combustion
Joined: Dec 2001
Posts: 1,374
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From: Twin Cities Minnesota
I did basically what PeeJay did on installing used apex seals. You need to put rotor fully assembled except the apex seal, spring and corner piece. The solid end of the apex need to be in first with the rotor housing inserted to the dowl pins> but from there I did a slightly different proceedure from there, next I put the corner piece with a gub of grease, then the spring went in. The grease kinda holds in the corner piece down and gives you a chance to put the next plate on weather its the center plate or end plate. That is the trickest part to me.
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Thread Starter
Senior Member
Joined: Sep 2001
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From: Monument Colorado
thanks for your posts, they will help out some. I have a good running 12a with about 120,000miles on it, it has perfect compression but the o ring seals are leaking everywhere!. I am going to bridge port it after I make sure everythings ok in side there!. I am only planning on replacing the apex seals(steel or carbon) and the corner seals(from a 3rd gen 13b). I heard those will work from my friend bad-***. I currently just bought a "cherry" 85gs thats goona be my nice *** 7. The mods i have now are a weber sidedraft and a mindtrain racing exhaust! I am looking forward to building this and many more rotaries! With the setup I just described how much hp. do you think this motor will put out?. Later. Jami-intermountainRX7club.
Rotary Freak
Joined: Mar 2001
Posts: 1,611
Likes: 0
From: LA.,California USA
Originally posted by Felix Wankel
A bigass zip tie will work to hold the apex seals and springs in the rotor if you decide to put it in that way.
A bigass zip tie will work to hold the apex seals and springs in the rotor if you decide to put it in that way.
The AUTO DOCTOR
Joined: Mar 2001
Posts: 1,952
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From: South Side of ATL. Ga.
yep i rebuilt mine with a new seal kit, new oil seals and new apex seal and 3rd gen c.s.springs. the housings were ok not new and not scared but should last 60-100k. i used stock mazda parts as i had 2 days notice and had to have the car, it took me 3 days to pull, and rebuild, and install........ that includes a good drunk day so we didnt do much. so in 2 days we pulled, ported stacked, installed and started my new motor. 24k and pulls great its seen MANY past tach rpm pulls in racing so its holding up great other than a low oil pressure reading that just showed up. I have helped in 3 13b rebuilds a -se a t2 and a gxl . all run good and have the normal crap that you need to tend to, a oil leak, tighten this or that... just check it all 3 times do it once. and jamie change your name sence your selling the 81 (BASTERD) ill get the bridgeports off asap. and bring it on when u want to get some of the dual 36mm downdrafts
Joined: Dec 1999
Posts: 7,855
Likes: 517
From: Behind a workbench, repairing FC Electronics.
I plan on rebuilding ine because I'd like to port it and have it nice and new like the rest of the car is going to be, hopefully.
She's got 175K miles on her. (11K of those are mine.)
How bad should I expect the rotor housings to be? Should I see flaking? If I don't, should I replace em anyway?
She's got 175K miles on her. (11K of those are mine.)
How bad should I expect the rotor housings to be? Should I see flaking? If I don't, should I replace em anyway?
Senior Member
Joined: Feb 2001
Posts: 366
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From: Canada
mine was leaking at the rear housing, just ran like crap. Had a shop rebuild it cause i needed my car right away, and i didn't know a whole lot about them at the time. all new springs ,carbon apex seals etc...
rebuilt at 181,000 km, now running strong at 265,000. i didn't get it ported
they were talking about starting emmision testing here and my old mechanic couldn't promise i would pass the test STOCK so i didn't bother.
rebuilt at 181,000 km, now running strong at 265,000. i didn't get it ported
they were talking about starting emmision testing here and my old mechanic couldn't promise i would pass the test STOCK so i didn't bother.
---------------------
Joined: Nov 2001
Posts: 2,029
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From: Kamloops BC Canada
I have a question about rebuilding, or should I say overhauling....
I have posted numerous posts about my problem. I have a ripped up rag in my rear housing somewhere, and the car won't start at all, (it just backfires)
If I pull the motor out, can I ONLY take the back half of it apart? Like, just pull apart up to the rear housing.
Also, what seals can I re-use? Can I re-use the water jacket seals? O-rings?
All I have to do is take the rag out of the housing wherever it's jammed, so I don't want to spend lots (or any) money on the engine. If I could do it all for free using some gasket paper and some gasket silicone and have the motor last for 75,000 miles I'd be happy.
Jeff
I have posted numerous posts about my problem. I have a ripped up rag in my rear housing somewhere, and the car won't start at all, (it just backfires)
If I pull the motor out, can I ONLY take the back half of it apart? Like, just pull apart up to the rear housing.
Also, what seals can I re-use? Can I re-use the water jacket seals? O-rings?
All I have to do is take the rag out of the housing wherever it's jammed, so I don't want to spend lots (or any) money on the engine. If I could do it all for free using some gasket paper and some gasket silicone and have the motor last for 75,000 miles I'd be happy.
Jeff
Old [Sch|F]ool
Joined: May 2001
Posts: 12,865
Likes: 571
From: Cleveland, Ohio, USA
Originally posted by Keaponlaffen
I have a question about rebuilding, or should I say overhauling....
If I pull the motor out, can I ONLY take the back half of it apart? Like, just pull apart up to the rear housing.
Also, what seals can I re-use? Can I re-use the water jacket seals? O-rings?
I have a question about rebuilding, or should I say overhauling....
If I pull the motor out, can I ONLY take the back half of it apart? Like, just pull apart up to the rear housing.
Also, what seals can I re-use? Can I re-use the water jacket seals? O-rings?
If the engine has been run for any length of time before disassembly, you'll have to replace at a minimum the coolant O-rings. if it's a well run engine like yours all O-rings will been replaced. Y'see, the housings tend to stick together after they've been assembled for so long, partically also because the dowels are a tight fit. You have to use a hammer to knock the housings apart. When you go to knock the rear end plate off, it's also forcing all of the other housings away from each other too, so all of their sealing is compromised.
Have you tried removing the intake manifold and/of exhaust manifold? That might work for ya, unforntuately the way our engines work it's possible that the rag could be caught between the rotor and a side housing, in fact I'd bet on it.
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Joined: Nov 2001
Posts: 2,029
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From: Kamloops BC Canada
I've tried the intake manifold thing, and it's not there, or in the exhaust, so I'm guessing it's stuck against one of the side seals. So if I pull it apart, all I have to do is replace the o-rings then?
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