how not to build a motor // upside down 13 BREWeird
06-12-10, 09:45 PM
#1
Racing Rotary Since 1983
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how not to build a motor // upside down 13 BREWeird
i still get a thrill disassembling a motor. all of them talk to me and there is something to learn from each motor even after a bunch of years...
the one today left me speechless.
it was almost like it was assembled in an upside down world. all of the apex seals were upside down.
the outer coolant seals were 90 degrees off. the painted (white) surface should be vertical, instead they were facing up looking at me. weird.
going along w the upside down motif, the sideseal springs were, you guessed it upside down.
but there's more, i wish i could type upside down.
someone was smart enough to buy Atkins low drag cornerseals and then installed them upside down!
then there's things like .02 sideseal clearance! it should be .002. last week doing a motor i screwed up one side seal and my .003 feeler gauge worked so i trashed it and started over. that's how important tight sideseals are... and this motor after 5000 miles had ten times the proper number.
proper seal clearance =s NO (ZERO) CARBON on the inner side of the side seals.
happily, the main parts of the motor are fine and it will be a good motor properly assembled.
weirdness
hc
the one today left me speechless.
it was almost like it was assembled in an upside down world. all of the apex seals were upside down.
the outer coolant seals were 90 degrees off. the painted (white) surface should be vertical, instead they were facing up looking at me. weird.
going along w the upside down motif, the sideseal springs were, you guessed it upside down.
but there's more, i wish i could type upside down.
someone was smart enough to buy Atkins low drag cornerseals and then installed them upside down!
then there's things like .02 sideseal clearance! it should be .002. last week doing a motor i screwed up one side seal and my .003 feeler gauge worked so i trashed it and started over. that's how important tight sideseals are... and this motor after 5000 miles had ten times the proper number.
proper seal clearance =s NO (ZERO) CARBON on the inner side of the side seals.
happily, the main parts of the motor are fine and it will be a good motor properly assembled.
weirdness
hc
Are those McMaster-Car orange Viton coolant o-rings. 
06-13-10, 08:36 AM
#6
RX-7 Bad Ass
iTrader: (55)
Next one would be if the oil seal springs were installed wrong ways, the front sides on the back.
The coolant seals are Mazda OEM from the pictures.
Seriously, that is all plain as day in the shop manual. Damn!
Dale
The coolant seals are Mazda OEM from the pictures.
Seriously, that is all plain as day in the shop manual. Damn!
Dale
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06-13-10, 09:01 AM
#8
Original Gangster/Rotary!
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Still doesn't beat the engine I tore down recently with butchered ports, 1st gen tension bolts, 2nd gen stat gear bearings, and a pair of flimsy 1st gen side seal springs under each seal (all of them with pieces broken off). I'll protect the guilty, but they were a NJ shop since closed down by the police thank goodness 
06-13-10, 10:14 AM
#10
We see this type of stuff all the time. It is a pretty sad, some of the worst engines we have torn down come from "shops". One that always sticks out in my mind is when I found an apex seal spring bridging the gap of a failed coolant seal retaining wall. Came out of a PA shop and of course we were rebuilding it for a coolant seal failure.
As Dale said, one of the most common mistakes we see made it the oil seal spring orientation.
As Dale said, one of the most common mistakes we see made it the oil seal spring orientation.
06-13-10, 11:01 AM
#11
What I don't understand is why some do not even look up what would be obviously important details when building an engine. Piston or rotary. Items have specific orientations as well as clearences. All you have to do is look em up...
I am taking my first stab at rebuilding my motor at the current moment. So far (knock on wood) has not been too bad. I purchased the RA video and I have read through the FSM several times before I take on a new task in the rebuild. I am not in a hurry and so far everything is coming together great. It just goes to show that if you take your time, and reference the proper material, you will never be one of these goobers that someone has to go back and ask wtf were they doing?
I am taking my first stab at rebuilding my motor at the current moment. So far (knock on wood) has not been too bad. I purchased the RA video and I have read through the FSM several times before I take on a new task in the rebuild. I am not in a hurry and so far everything is coming together great. It just goes to show that if you take your time, and reference the proper material, you will never be one of these goobers that someone has to go back and ask wtf were they doing?
06-13-10, 11:23 AM
#12
I love when guys stop to talk to me about rotary's and how many engines they have built and cars they have race. Maybe true but I am a true GOTTA SEE IT TO BELIEVE IT kinda guy.
06-13-10, 12:55 PM
#15
What happens is a lot of guys claim they know rotary's and building engines so they can get Idolized by newbies mean while they are learning as they go experimenting with other guys cars.
I love when guys stop to talk to me about rotary's and how many engines they have built and cars they have race. Maybe true but I am a true GOTTA SEE IT TO BELIEVE IT kinda guy.
I love when guys stop to talk to me about rotary's and how many engines they have built and cars they have race. Maybe true but I am a true GOTTA SEE IT TO BELIEVE IT kinda guy.
-Dan
06-13-10, 03:42 PM
#16
Racing Rotary Since 1983
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actually i haven't yet checked the oil ring springs. that will be fun. taking bets
other fun things were 4.8 thou endplay. pan bolts were 30 inch pounds and leaking like a sieve . the thrubolts were 15 pounds as the builder had used lots of silicone on the rotor housing faces. the oil was the blackest i have ever seen and had only 500 miles on it.
thank god the guy didn't have a die grinder.
other fun things were 4.8 thou endplay. pan bolts were 30 inch pounds and leaking like a sieve . the thrubolts were 15 pounds as the builder had used lots of silicone on the rotor housing faces. the oil was the blackest i have ever seen and had only 500 miles on it.
thank god the guy didn't have a die grinder.
06-14-10, 12:26 PM
#19
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06-14-10, 12:46 PM
#20
what do you mean apex seals upside down? spring side towards the rotor housing? or you mean side plate to side plaste wise?
Don't half bridge motors use apex seals the other way so that the larger part of the seal is the one that crosses the bridgeport instead of the small triangular piece?
Don't half bridge motors use apex seals the other way so that the larger part of the seal is the one that crosses the bridgeport instead of the small triangular piece?
06-14-10, 01:26 PM
#21
Yes. He means upside down as in the small corner end of the apex seal should be facing the flywheel. Whereas these are facing (at least the ones in the pic) are facing the front bolt.
After speaking with a few experts you are correct on the half-bridge motors. BUT it really depends on the corner piece. As per a HBP expert told me just a few days ago it depends on how the corner end of the apex seal is designed. If it has a bit of a top (4 sides as apposed to 3) it may face like normal, towards the fw. If you are using an aftermarket apex seal you may check with the manufacturer as to what they recommend with their seals.
If I have misspoken one of the experts should correct me please.
After really looking at those pics it makes me even more depressed just how good of shape my motor was in when this coolant seal turned lose for a still unknown reason. My engine had 30K+ on it and looked much better.
After speaking with a few experts you are correct on the half-bridge motors. BUT it really depends on the corner piece. As per a HBP expert told me just a few days ago it depends on how the corner end of the apex seal is designed. If it has a bit of a top (4 sides as apposed to 3) it may face like normal, towards the fw. If you are using an aftermarket apex seal you may check with the manufacturer as to what they recommend with their seals.
If I have misspoken one of the experts should correct me please.
After really looking at those pics it makes me even more depressed just how good of shape my motor was in when this coolant seal turned lose for a still unknown reason. My engine had 30K+ on it and looked much better.
06-14-10, 03:44 PM
#22
Racing Rotary Since 1983
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in a non BP'd motor you can run the seals backwards, or as i first described upside down. if, for example, there is a touch of wear on the rearward edges of the rotor housing you can flip the seal around and give the RH a slight help. obviously you have to glue the seal together etc...
as to the oil seals springs in the rotors, the front was fine and the rears were all heading in the wrong directions and not in their pockets.
batting 50%
as to the oil seals springs in the rotors, the front was fine and the rears were all heading in the wrong directions and not in their pockets.
batting 50%
06-14-10, 05:43 PM
#23
Speed Mach Go Go Go
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Are the corner seals not solid? Otherwise, how would one know that they were intalled incorectly? So the water seals are on their sides? The white part should be facing towards the inner center and outer sides of the iron, instead of front and back? None of the videos I watched go in to that much detail.
06-14-10, 07:07 PM
#24
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Are the corner seals not solid? Otherwise, how would one know that they were intalled incorectly? So the water seals are on their sides? The white part should be facing towards the inner center and outer sides of the iron, instead of front and back? None of the videos I watched go in to that much detail.
the water seal thing is in the FSM, it might even be in bold print. there is certainly a picture
06-14-10, 07:34 PM
#25
Original Gangster/Rotary!
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Sounds like 'builder' pretty much screwed up everything he could have.....
I'd be curious to know the endplay on that bad boy. I'll bet the stationary gear set screws are loose/missing, and the oil passage plugs on the e-shaft are probably all loose too
I'd be curious to know the endplay on that bad boy. I'll bet the stationary gear set screws are loose/missing, and the oil passage plugs on the e-shaft are probably all loose too
Last edited by GoodfellaFD3S; 06-14-10 at 07:36 PM.