Building the RX-8 Motor - AutoWeek
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Building the RX-8 Motor - AutoWeek
Done by Hand: Mazda's new Renesis engine receives surprisingly low-tech final assembly
By JAMES B. TREECE | Automotive News
HIROSHIMA, Japan - It is a surprisingly low-tech finale for such a high-tech process.
In a sealed, soundproofed and temperature-controlled room at Mazda's engine plant No. 2 here, parts that elsewhere have been engineered and manufactured using computers are painstakingly assembled by hand into the Renesis engines that power the RX-8.
Working with palpable concentration, seven workers hand-assemble rotors, housings, eccentric shafts, stationary gears, seals, bolts and other parts into the final engine. Time per engine: 35 to 40 minutes.
Executives say production could be speeded up but declined to give specifics.
"We could automate it. The question is cost," said Hisakazu Imaki, Mazda's executive vice president and chief engineering and manufacturing officer.
Although it is possible for computer technology to emulate the workers' craftsmanship, doing so would be hugely expensive, he said.
The new Renesis rotary engine features a number of design changes that allowed Mazda to eliminate the turbocharger that had pushed up the price of the former RX-7's rotary engine.
While incorporating those design changes, Mazda introduced several manufacturing changes as well. Here are two:
1. To cast the rotor, which is shaped like a triangle with slightly rounded corners, Mazda in the past poured molten metal into the top of a mold designed to produce two stacks of three rotors each. But the metal cooled at different speeds in different parts of each rotor, leading to different weight distributions.
The weight differences were slight, less than the weight of two pennies, but enough to cause an uneven rotor rotation. Mazda had to drill tiny holes in the rotor to rebalance it, an inelegant solution at best.
Now, Mazda uses a mold that makes only three rotors at a time and pours the molten metal into the center of the rotor. From there, it spreads out evenly toward the three points of each triangular rotor and the cooling occurs evenly in each point.
2. Testing has been computerized. One engine out of every 100 is sent to a coordinate measurement room, where precision equipment measures the dimensions of each part to ensure that all of the drilling and machining is exact. Formerly, tests of the RX-7 engine included a master operator rotating the engine's rotor to feel whether it seemed balanced.
Every engine is tested after assembly. The tests include one that measures compression in each stage of the engine's cycle: intake, fuel compression and exhaust.
To demonstrate to a group of reporters the reduced vibrations of the new engine, testers placed a glass of wine atop an engine, then revved it to 5,000 rpm, which they said would be the typical speed on a Japanese highway.
The wine barely rippled.
By JAMES B. TREECE | Automotive News
HIROSHIMA, Japan - It is a surprisingly low-tech finale for such a high-tech process.
In a sealed, soundproofed and temperature-controlled room at Mazda's engine plant No. 2 here, parts that elsewhere have been engineered and manufactured using computers are painstakingly assembled by hand into the Renesis engines that power the RX-8.
Working with palpable concentration, seven workers hand-assemble rotors, housings, eccentric shafts, stationary gears, seals, bolts and other parts into the final engine. Time per engine: 35 to 40 minutes.
Executives say production could be speeded up but declined to give specifics.
"We could automate it. The question is cost," said Hisakazu Imaki, Mazda's executive vice president and chief engineering and manufacturing officer.
Although it is possible for computer technology to emulate the workers' craftsmanship, doing so would be hugely expensive, he said.
The new Renesis rotary engine features a number of design changes that allowed Mazda to eliminate the turbocharger that had pushed up the price of the former RX-7's rotary engine.
While incorporating those design changes, Mazda introduced several manufacturing changes as well. Here are two:
1. To cast the rotor, which is shaped like a triangle with slightly rounded corners, Mazda in the past poured molten metal into the top of a mold designed to produce two stacks of three rotors each. But the metal cooled at different speeds in different parts of each rotor, leading to different weight distributions.
The weight differences were slight, less than the weight of two pennies, but enough to cause an uneven rotor rotation. Mazda had to drill tiny holes in the rotor to rebalance it, an inelegant solution at best.
Now, Mazda uses a mold that makes only three rotors at a time and pours the molten metal into the center of the rotor. From there, it spreads out evenly toward the three points of each triangular rotor and the cooling occurs evenly in each point.
2. Testing has been computerized. One engine out of every 100 is sent to a coordinate measurement room, where precision equipment measures the dimensions of each part to ensure that all of the drilling and machining is exact. Formerly, tests of the RX-7 engine included a master operator rotating the engine's rotor to feel whether it seemed balanced.
Every engine is tested after assembly. The tests include one that measures compression in each stage of the engine's cycle: intake, fuel compression and exhaust.
To demonstrate to a group of reporters the reduced vibrations of the new engine, testers placed a glass of wine atop an engine, then revved it to 5,000 rpm, which they said would be the typical speed on a Japanese highway.
The wine barely rippled.
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Re: Building the RX-8 Motor - AutoWeek
Originally posted by Vancouver
To demonstrate to a group of reporters the reduced vibrations of the new engine, testers placed a glass of wine atop an engine, then revved it to 5,000 rpm, which they said would be the typical speed on a Japanese highway.
The wine barely rippled.
To demonstrate to a group of reporters the reduced vibrations of the new engine, testers placed a glass of wine atop an engine, then revved it to 5,000 rpm, which they said would be the typical speed on a Japanese highway.
The wine barely rippled.
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Re: Building the RX-8 Motor - AutoWeek
Originally posted by Vancouver
... revved it to 5,000 rpm, which they said would be the typical speed on a Japanese highway.
... revved it to 5,000 rpm, which they said would be the typical speed on a Japanese highway.
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Originally posted by tribal azn
what the hell only 7 workers?
24 hours=1440 mins / 35 min = 41.14
41.14 x 7 workers = 288 engines
so they make 288 engines in a 24 hour period. but the workers arent working 24 hours a day.
what the hell only 7 workers?
24 hours=1440 mins / 35 min = 41.14
41.14 x 7 workers = 288 engines
so they make 288 engines in a 24 hour period. but the workers arent working 24 hours a day.
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Yah something is fishy with the 35 minutes per engine. At 35 minutes per engine for one worker and working 48 weeks a year at 8 hours a day this equals 3,291 engines per worker and 23,037 engines for all seven workers. This is half of the projected production level. Plus I saw the assembly video and 35 minutes seems like a long time to assemble one of these pups.
Now that I think about it maybe the numbers are correct. 23,037 engines annual rate is probably correct since they are just now ramping up production. If demand warrants they can always increase the staff.
Now that I think about it maybe the numbers are correct. 23,037 engines annual rate is probably correct since they are just now ramping up production. If demand warrants they can always increase the staff.
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i think that's 35 mins for the ENTIRE engine, including the installation of headers, the induction system, ignition, pumps, yada yada yada... the video only showed us that it takes about <10mins to put the block together ![Wink](https://www.rx8club.com/images/smilies/wink.gif)
but yes, i sure hope Mazda's got a bunch of "kids" watching these guys through the glass walls, so that there'll be enough people puttin' 'em together to satisfy their global sales target...
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
but yes, i sure hope Mazda's got a bunch of "kids" watching these guys through the glass walls, so that there'll be enough people puttin' 'em together to satisfy their global sales target...
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Re: Re: Building the RX-8 Motor - AutoWeek
Originally posted by m477
Hmm, let's see your piston engine do that. :p
Hmm, let's see your piston engine do that. :p
#11
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Re: Re: Re: Building the RX-8 Motor - AutoWeek
Originally posted by visitor
I bet there's a piston engine that could do that.
I bet there's a piston engine that could do that.
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About 15 years ago on TV in England they showed an add which featured a V12 (piston) engine in a car - I think a BMW 750iL. They popped the hood and balanced a coin (50 pence piece - 7 sided coin) on the engine and revved it to 5k or thereabouts - the coin didn't move.
Will you be wanting ketchup with that hat?
Will you be wanting ketchup with that hat?
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Originally posted by wakeech
... the video only showed us that it takes about <10mins to put the block together
...
... the video only showed us that it takes about <10mins to put the block together
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
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Originally posted by pelucidor
About 15 years ago on TV in England they showed an add which featured a V12 (piston) engine in a car - I think a BMW 750iL. They popped the hood and balanced a coin (50 pence piece - 7 sided coin) on the engine and revved it to 5k or thereabouts - the coin didn't move.
Will you be wanting ketchup with that hat?
About 15 years ago on TV in England they showed an add which featured a V12 (piston) engine in a car - I think a BMW 750iL. They popped the hood and balanced a coin (50 pence piece - 7 sided coin) on the engine and revved it to 5k or thereabouts - the coin didn't move.
Will you be wanting ketchup with that hat?
It's interesting that the Renesis is hand assembled.. Would you say this will make it a better quality product or less?
#16
Originally posted by Quick_lude
Correct.. I've also seen this done with a Mercedes and BMW engine.. Lexus stacked a champagne glasses in a pyramid configuration on their V8's.. Sometimes the ignorant contempt for piston engines and "rotary elitism/snobism" on a rotary related site makes me laugh and shake my head in wonderment.. Are you guys really that insecure? The rotary is a great engine design, no doubt about it.. But bashing other designs, especially using unjustified claims makes you look weak and ignorant. Shrug.
It's interesting that the Renesis is hand assembled.. Would you say this will make it a better quality product or less?
Correct.. I've also seen this done with a Mercedes and BMW engine.. Lexus stacked a champagne glasses in a pyramid configuration on their V8's.. Sometimes the ignorant contempt for piston engines and "rotary elitism/snobism" on a rotary related site makes me laugh and shake my head in wonderment.. Are you guys really that insecure? The rotary is a great engine design, no doubt about it.. But bashing other designs, especially using unjustified claims makes you look weak and ignorant. Shrug.
It's interesting that the Renesis is hand assembled.. Would you say this will make it a better quality product or less?
Besides, I think as demand increases for the RX-8 and also the RX-7 later, they will move to a robot assembly to save time on delivery. But I rather like the fact that my engine was lovingly put together by hand
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#18
Originally posted by Quick_lude
I just hope those guys don't stay out late and party.... then assemble my Renesis hung over.. haha..
I just hope those guys don't stay out late and party.... then assemble my Renesis hung over.. haha..
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Originally posted by Hercules
Every 100th engine is tested, so I think the QC is quite good. Considering they have a 30k production goal, 10% of those engines will pass, which for any industry is a good QC number.
Every 100th engine is tested, so I think the QC is quite good. Considering they have a 30k production goal, 10% of those engines will pass, which for any industry is a good QC number.
#21
Last edited by P00Man; 04-16-2011 at 04:47 PM.
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Originally posted by Quick_lude
Correct.. I've also seen this done with a Mercedes and BMW engine.. Lexus stacked a champagne glasses in a pyramid configuration on their V8's.. Sometimes the ignorant contempt for piston engines ... using unjustified claims makes you look weak and ignorant. Shrug.
Correct.. I've also seen this done with a Mercedes and BMW engine.. Lexus stacked a champagne glasses in a pyramid configuration on their V8's.. Sometimes the ignorant contempt for piston engines ... using unjustified claims makes you look weak and ignorant. Shrug.
Just kidding guys. We're not ignorant though, no need to resort to that. We just dig that new engine that's all. Peace.
#23
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Originally posted by Quick_lude
Correct.. I've also seen this done with a Mercedes and BMW engine.. Lexus stacked a champagne glasses in a pyramid configuration on their V8's.. Sometimes the ignorant contempt for piston engines and "rotary elitism/snobism" on a rotary related site makes me laugh and shake my head in wonderment.. Are you guys really that insecure? The rotary is a great engine design, no doubt about it.. But bashing other designs, especially using unjustified claims makes you look weak and ignorant. Shrug.
It's interesting that the Renesis is hand assembled.. Would you say this will make it a better quality product or less?
Correct.. I've also seen this done with a Mercedes and BMW engine.. Lexus stacked a champagne glasses in a pyramid configuration on their V8's.. Sometimes the ignorant contempt for piston engines and "rotary elitism/snobism" on a rotary related site makes me laugh and shake my head in wonderment.. Are you guys really that insecure? The rotary is a great engine design, no doubt about it.. But bashing other designs, especially using unjustified claims makes you look weak and ignorant. Shrug.
It's interesting that the Renesis is hand assembled.. Would you say this will make it a better quality product or less?
Quick i was not dissing piston engines. i am not a rotary elitist snob and in fact have never owned a rotary before. i dont believe 1 i bashed any design. but i don't think i could balance a coin or stack of coins or whatever on piston engines i have had in the past. i'm sure there are there some really good well balanced engines out there that can perform a similar feat. but in general i would say that most of them could not. actually i dont think you were directly flaming or intending to flame me but i hope this clarifies my position.
sheesh the first time i metion eating an article of clothing i lose
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Originally posted by zoom44
thanks TJ as i had missed Quickludes remark.
.... you could have at least offered me something to wash it down with or some hot sauce or something:p :D
thanks TJ as i had missed Quickludes remark.
.... you could have at least offered me something to wash it down with or some hot sauce or something:p :D
Have that glass of wine, just keep it away from a piston clanker...wouldn't want it to spill
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Haha.. How about some Dave's Insanity Sauce with that clothing article? That stuff will blow your mouth and intestines to hell..
I wasn't really directing this at you guys, just the general attitude of rotary boards. Maybe I'm just not that passionate about engine design, to me both rotary and piston engines have their plusses and minuses.. I just never understood why people get so hot and bothered to the point of posting innacurate info to bring something down and thus improving the image of the product you like.. shrug..
In Canada we have a show on TSN called Motoroing. For the longest time during Test Drives, Graham Fletcher would do the loonie test.. he would stand up a loonie coin on the engine while at idle. Now I'm sure if he revved the engine to 5K rpm, most would not pass that.. not too many piston engines would. The rotary definitely wins in the smoothness department, this is one of the reasons I'm dying to test drive one asap.
![EEK!](https://www.rx8club.com/images/smilies/eek.gif)
I wasn't really directing this at you guys, just the general attitude of rotary boards. Maybe I'm just not that passionate about engine design, to me both rotary and piston engines have their plusses and minuses.. I just never understood why people get so hot and bothered to the point of posting innacurate info to bring something down and thus improving the image of the product you like.. shrug..
In Canada we have a show on TSN called Motoroing. For the longest time during Test Drives, Graham Fletcher would do the loonie test.. he would stand up a loonie coin on the engine while at idle. Now I'm sure if he revved the engine to 5K rpm, most would not pass that.. not too many piston engines would. The rotary definitely wins in the smoothness department, this is one of the reasons I'm dying to test drive one asap.
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)