Rotary vs. Piston rebuild
#3
I think so too, i post this thread up bcuz my friend thinks i am retarded and inexperienced to engine knowledge for thinking rebuilding and working on rotary is easier. Well this basically opinion base and there is no right or wrong. But my friend got flare up over this convo.
#6
moon ******
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Depends on the engine, lol. 32 valve DOHC v8 vs a SOHC 4banger? Riiiiiiiight :P
The real thing is with a lot of piston engines you can do quite a lot with the engine still in the car.
The real thing is with a lot of piston engines you can do quite a lot with the engine still in the car.
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#9
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After rebuilding a few 4 cylinder, and 6 cylinder and 8 cylinder motors (I do it at work, so I'm forced too) A rotary is 1000 times easier to rebuild. A piston engine to be fully rebuilt, and done right, will need lots of machining to the engine block, heads, and crank. Then the Valve seals, springs, lifters is a complete nightmare. A rotary can be rebuilt in your own home, and at most the sideplates will need a re-grind at most, and is rare. In fact this is why I am forcing my girl to get a Rx-4 and sell the Mx-6, after two V-6's dying slowly, I dont even want to start to rebuild that damn V-6, would cost a fortune to do it right.
#10
Come to think of it I cant think of anything that can potentially hurt you inside of a wankel, In my aviation maintance class we learned that (in airplanse at least) that the exaust valves have something (dont remember what) in them that melts and moves (in a sloshing movement to help keep cooler, and if this core touches oxygen such as grinding to far or cutting witha band saw it could explode, injure, or blind you or something like that.
I think it is sulfur. not sure though, and dont know why sulfur does such a thing, but I will take my teachers word for it and not find out for myself.
I think it is sulfur. not sure though, and dont know why sulfur does such a thing, but I will take my teachers word for it and not find out for myself.
#12
Bourbon King
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Ive helped rebuild a couple and I was very worried at first. After I saw how easy it was I was amazed. If the parts were cleaned you could rebuild a rotary in an couple hours. Im sure some of the more experienced builders could do it in less than that.
#14
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to rebuild an A-series piston engine for a mini requires the following to be done:
rebore by 20 thou (minimum)
suitable replacement pistons
new piston rings + oil control rings fitted
crankshaft re-ground to next size
cylinder head total stripdown, light skim to clean
valve guides replaced and reamed to suit
valve seats re-cut (if bad)
valves re-seated
8 springs to be compressed, then valve caps and collets fitted
new main bearings an big-end bearings to be fitted (5 total)
new timing chain fitted
new oil pump
new clutch
a billion new gaskets
and thats not including the gearbox which is also the sump!
and to rebuild a rotary, it's just a general bit of measuring to make sure things are within their limits, some new apex seals, some new side seals, and a new oil pump if needed
mini's are my passion, but I'd rather rebuild a rotary any day!
rebore by 20 thou (minimum)
suitable replacement pistons
new piston rings + oil control rings fitted
crankshaft re-ground to next size
cylinder head total stripdown, light skim to clean
valve guides replaced and reamed to suit
valve seats re-cut (if bad)
valves re-seated
8 springs to be compressed, then valve caps and collets fitted
new main bearings an big-end bearings to be fitted (5 total)
new timing chain fitted
new oil pump
new clutch
a billion new gaskets
and thats not including the gearbox which is also the sump!
and to rebuild a rotary, it's just a general bit of measuring to make sure things are within their limits, some new apex seals, some new side seals, and a new oil pump if needed
mini's are my passion, but I'd rather rebuild a rotary any day!
#15
Rotors still spinning
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Originally Posted by Brody8877
wow, i guess i kinda prove my friend wrong about rotary engine.
#16
MazdaTed there sodium filled valves and yes cars can Have them too, As an automotive tech I can say a Rotary is easier to rebuild than any piston engine. people are just afraid of Rotarys beacuse must people don't even know how they work!!!!! even in my feild of work!!!!
#17
Originally Posted by GentlemenVII
MazdaTed there sodium filled valves
AHH sodium, I knew it was smething with an "S"
Thanks for clearing that up, that will probably be on my FAA powerplant test in a couple of months.
#18
I'd have to say a rotary is easier to rebuild, since there's really not much to do comparibly, and it's reasonably simple to put back together apart from the seals.
Definetely rotary easier than piston
Definetely rotary easier than piston
#19
7th Heaven
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a piston rebuild makes it run like a new engine...
i.e. reuse blocks, but bored up, new pistons, turned crank, oversized bearings, resized rods, etc etc
a rotary rebuild is more like an engine refreshen up...
i.e. reuse irons/housings, you can lap irons.... but new seals...
i.e. reuse blocks, but bored up, new pistons, turned crank, oversized bearings, resized rods, etc etc
a rotary rebuild is more like an engine refreshen up...
i.e. reuse irons/housings, you can lap irons.... but new seals...
#20
moon ******
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Uhh.... What?
You dont need to do a rebore, new pistons, or any of that crap, unless you ACTUALLY need to. Most people do a small bore for better breathing anyway, plus more displacement never hurts... but you dont HAVE to.
Longer rods mean you need shorter pistons, and you dont always need bigger bearings - but obviously, new bearings/rings cant ever be a bad thing. But you dont need to go to a damn machine shop to clean it up and put in new bearings and re-ring.
Hell, you can re-ring from below and leave the heads on, if youve recently done topend work and CBF'd to remove the heads, lol.
You dont need to do a rebore, new pistons, or any of that crap, unless you ACTUALLY need to. Most people do a small bore for better breathing anyway, plus more displacement never hurts... but you dont HAVE to.
Longer rods mean you need shorter pistons, and you dont always need bigger bearings - but obviously, new bearings/rings cant ever be a bad thing. But you dont need to go to a damn machine shop to clean it up and put in new bearings and re-ring.
Hell, you can re-ring from below and leave the heads on, if youve recently done topend work and CBF'd to remove the heads, lol.
#21
Rotor Head Extreme
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I see your point but why go through the trouble of just re-ringing the engine from underneith and not do a full inspection of the engine? There's more to a piston engines compression than just new rings. Youv'e got valve seats and head gaskets to worry about so the heads will need to come off and things taken apart to do the job right. I mean something else could go wrong that you could have fixed in the first place.
#22
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You dont need a teardown to inspect it, and generally if nothing is acting up the valve seats and head gaskets are just fine.
You tend to know when one or the other is screwing up
You tend to know when one or the other is screwing up
#23
7th Heaven
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Originally Posted by Nihilanthic
Uhh.... What?
You dont need to do a rebore, new pistons, or any of that crap, unless you ACTUALLY need to. Most people do a small bore for better breathing anyway, plus more displacement never hurts... but you dont HAVE to.
Longer rods mean you need shorter pistons, and you dont always need bigger bearings - but obviously, new bearings/rings cant ever be a bad thing. But you dont need to go to a damn machine shop to clean it up and put in new bearings and re-ring.
Hell, you can re-ring from below and leave the heads on, if youve recently done topend work and CBF'd to remove the heads, lol.
You dont need to do a rebore, new pistons, or any of that crap, unless you ACTUALLY need to. Most people do a small bore for better breathing anyway, plus more displacement never hurts... but you dont HAVE to.
Longer rods mean you need shorter pistons, and you dont always need bigger bearings - but obviously, new bearings/rings cant ever be a bad thing. But you dont need to go to a damn machine shop to clean it up and put in new bearings and re-ring.
Hell, you can re-ring from below and leave the heads on, if youve recently done topend work and CBF'd to remove the heads, lol.
do you know how a piston engine works?
rering while leaving head on? i want to see YOU do that. have you ever tried pulling a piston out from the bottom?
#24
I
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Originally Posted by slpin
a piston rebuild makes it run like a new engine...
i.e. reuse blocks, but bored up, new pistons, turned crank, oversized bearings, resized rods, etc etc
a rotary rebuild is more like an engine refreshen up...
i.e. reuse irons/housings, you can lap irons.... but new seals...
i.e. reuse blocks, but bored up, new pistons, turned crank, oversized bearings, resized rods, etc etc
a rotary rebuild is more like an engine refreshen up...
i.e. reuse irons/housings, you can lap irons.... but new seals...
on a rotary to make it like new, you would use new housings, or very lightly used housings..... and lap or get barly used irons ......
so both engines can be fully rebuild to like new, or reuse alot of parts....
#25
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rebuilding my motor was easy, although i failed in one part, and that was a coolant seal i didnt put enough of that hylomar stuff on so it got stuck between the motor when i slapped it together =(
Flame if you want, i figured i didnt do that bad considering that pulling out hte motor, dissasembling and reassemble, etc, was the first biggest thing i have ever done on a car other then install my intake! The car did run, i drove it for about 4 miles. but it ate coolant etc. Almost had it down my first time tho. I was 17 at the time. Im 19 now and im sure i could rebuild it again and just be more careful at the coolant seals and have a good running motor.
Flame if you want, i figured i didnt do that bad considering that pulling out hte motor, dissasembling and reassemble, etc, was the first biggest thing i have ever done on a car other then install my intake! The car did run, i drove it for about 4 miles. but it ate coolant etc. Almost had it down my first time tho. I was 17 at the time. Im 19 now and im sure i could rebuild it again and just be more careful at the coolant seals and have a good running motor.