Does the PMC models need a break in?
#1
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Hey All,
I am trying to get a PMC model for the '22 and was wondering does the PMC model's engines come broken in like the NSX when you get it brand new? Would love to see the manual of those that own a PMC as well![Smile](https://acurazine.com/forums/images/smilies/smile.gif)
Thanks!
I am trying to get a PMC model for the '22 and was wondering does the PMC model's engines come broken in like the NSX when you get it brand new? Would love to see the manual of those that own a PMC as well
![Smile](https://acurazine.com/forums/images/smilies/smile.gif)
Thanks!
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khuang94 (09-23-2021)
#3
The inconvenient truth
Isn't it the exact same engine and drivetrain as every 3g RDX?
So the break in would be no different than any 3g RDX which makes it sound strange that the pmc facility would break it in for you....
So the break in would be no different than any 3g RDX which makes it sound strange that the pmc facility would break it in for you....
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justnspace (09-23-2021)
#4
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iTrader: (1)
every publication, every article states the same engine is used, meaning no one at the PM Center hand builds the engine.
the PMC edition does get dyno-ran before delivery tho. (this tells us a lot!!!! this tells us that they did a high RPM run, meaning a gentle break-in isnt necessary.)
Last edited by justnspace; 09-23-2021 at 10:50 AM.
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FlopMeister (09-29-2021),
JB in AZ (09-23-2021)
#5
#7
Racer
Quick read about Porsche’s 2,000 mile break in recommendation and dyno testing at their factory. Take it for what you want….
https://pcaucr.org/12409/
“As the story goes… when the test was completed during a factory visit, a Porsche engineer came over to review the results. I couldn’t resist asking the question that I had been searching to find an answer to for all these years. I asked “why does Porsche feel it is safe for a new engine to run at nearly full throttle in the factory, while the customer must keep the engine speed to no more than 4,000 RPM for a 2,000 mile (3,200 km) break-in period?” I thought that was a logical question and if I do say so myself-well stated!
The engineer replied, “Herr Koop, you do not understand (that I already knew). When we do our engine test, the metals inside the engine never reach the temperatures they would when driven on the street since the test session is fairly short. In other words, the bearings, pistons and cylinders never get a chance to thermally expand to their maximum. Therefore, there is little wear on the moving components. But when you drive a car on the street, the engine parts expand considerably more because of the heat being generated from the engine running for an extended period of time. No matter how tight the tolerances are, there is always a slight amount of expansion in the material. The moving parts can wear quickly if exposed to excessive heat and not always in a uniform way. We also constantly vary the speed and allow the engine to run at both high and low RPM’s”.”
https://pcaucr.org/12409/
“As the story goes… when the test was completed during a factory visit, a Porsche engineer came over to review the results. I couldn’t resist asking the question that I had been searching to find an answer to for all these years. I asked “why does Porsche feel it is safe for a new engine to run at nearly full throttle in the factory, while the customer must keep the engine speed to no more than 4,000 RPM for a 2,000 mile (3,200 km) break-in period?” I thought that was a logical question and if I do say so myself-well stated!
The engineer replied, “Herr Koop, you do not understand (that I already knew). When we do our engine test, the metals inside the engine never reach the temperatures they would when driven on the street since the test session is fairly short. In other words, the bearings, pistons and cylinders never get a chance to thermally expand to their maximum. Therefore, there is little wear on the moving components. But when you drive a car on the street, the engine parts expand considerably more because of the heat being generated from the engine running for an extended period of time. No matter how tight the tolerances are, there is always a slight amount of expansion in the material. The moving parts can wear quickly if exposed to excessive heat and not always in a uniform way. We also constantly vary the speed and allow the engine to run at both high and low RPM’s”.”
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khuang94 (09-28-2021)
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#8
The Porsche engineer explained it well. The engine is "cold". Of course cold in this context means room temperature, not -20 F, so oil would flow properly so lubrication was not an issue. ( I have fixed more than one engine with thick, straight weight oil, that was started in twenty degrees below zero weather and then held wide open....no oil flow and the bearings welded to the crank and spun in the block. I love that 0W-20 oil in cold weather!).
Parts do expand a lot when heated. A cold piston isn't even round nor are its sides parallel. Its designed to expand to full size, be round and be straight on the sides, when the engine is up to normal operating temperatures.Same for piston rings. We have to allow quite a gap on their ends when cold (about .004" gap for each inch of bore as a general rule). When the engine warms up they expand and the ends nearly touch.
Parts do expand a lot when heated. A cold piston isn't even round nor are its sides parallel. Its designed to expand to full size, be round and be straight on the sides, when the engine is up to normal operating temperatures.Same for piston rings. We have to allow quite a gap on their ends when cold (about .004" gap for each inch of bore as a general rule). When the engine warms up they expand and the ends nearly touch.
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khuang94 (09-28-2021)
#9
Racer
Ideally, you want each heat/expansion cycle to be just a little bit more than the last. That way you gradually form fit all the metal-on-metal moving parts. Also, it’s important to remember that piston rings spin around the piston much like a wedding ring can spin around your finger. That spinning process happens more readily as the rpm (cylinder pressure) change. Ideally, you want all 360° of the piston ring to form fit to all 360° of the cylinder wall. That takes time. At constant rpm, the piston rings don’t spin much. That is one of the main reasons manufacturers recommend you avoid highway driving early in the break-in process. Fortunately the break-in process is much less important now than it was decades ago. But if done prudently, breaking in an engine can still eek-out marginally better efficiency. It certainly can’t hurt anything.
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khuang94 (09-29-2021)
#10
AZ Community Team
Ideally, you want each heat/expansion cycle to be just a little bit more than the last. That way you gradually form fit all the metal-on-metal moving parts. Also, it’s important to remember that piston rings spin around the piston much like a wedding ring can spin around your finger. That spinning process happens more readily as the rpm (cylinder pressure) change. Ideally, you want all 360° of the piston ring to form fit to all 360° of the cylinder wall. That takes time. At constant rpm, the piston rings don’t spin much. That is one of the main reasons manufacturers recommend you avoid highway driving early in the break-in process. Fortunately the break-in process is much less important now than it was decades ago. But if done prudently, breaking in an engine can still eek-out marginally better efficiency. It certainly can’t hurt anything.
https://en.wikipedia.org/wiki/Break-...hanical_run-in)
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khuang94 (09-30-2021)
#11
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The main reason to avoid constant RPM is developing a piston ring ridge on the cylinder bore when the piston starts/stops at the top of it's stroke. Varying the RPM causes slight differences as to how high the ring will go in the cylinder bore. Constant RPM promotes a ridge which can potentially break the upper ring
https://en.wikipedia.org/wiki/Break-...hanical_run-in)
https://en.wikipedia.org/wiki/Break-...hanical_run-in)
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Last edited by khuang94; 09-30-2021 at 05:14 PM. Reason: typo
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