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Old 06-22-2008, 12:17 AM   #1
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Default Differences between o.s speed .21 v-spec speed alum and magnesium.

Is there any difference between these engines other than the heads?
Im looking to buy one, and i have found one for a good price.

There is a 20-30 dollar difference between the engine and since the difference is so small i wonder what engine will hande heat best. The aluminum head or the Mag head.

Alu head

Magnesium
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Old 06-22-2008, 12:39 AM   #2
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Searched more and found this.

O.S. Speed .21VZ-B V-Spec ......Alloy Head or Magnesium??

Sorry for any anoyance.
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Old 06-22-2008, 02:43 AM   #3
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Yes thats correct, the thermal conductivity of aluminium is greater than magnezium... therefore better heat transfer and better cooling.
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Old 06-22-2008, 06:26 AM   #4
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I didn't read that but Magnesium is harer to work with and is more expensive. It doesn't handle the heat quite as well but it's lighter. That was the advantage of it.

The Aluminum ead Speed is the same motor with an aluminum head to help dissipate the heat better. When it's a little cooler out I'll use my Mag head. I was using the Mag head motor in Arizona for awhile though, and I had no issues.
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Old 06-22-2008, 07:51 AM   #5
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Weight is the biggest difference between the two. The magnesium version will take some weight off the top of the car. Other than that, I have seen no heat related differences or issues between the two versions. I have been around quite of few of these engines so far, personally owning two Mag versions myself, and tuning a couple AL versions at the same time.
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Old 06-22-2008, 08:20 PM   #6
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Can anyone tell me which engine is better overall and why ? Reg V-Spec or speed version?
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Old 06-22-2008, 09:49 PM   #7
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IMO, overall the Speed is better in the long run. Smoother power deliver and faster bottom end spool up for jumps. The DLC coated crank has almost no wear in most cases when time for a rebuild, as the stock V-Spec crank pin will most likely be oval.
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Old 06-23-2008, 03:43 AM   #8
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Quote:
Originally Posted by ezveedub View Post
IMO, overall the Speed is better in the long run. Smoother power deliver and faster bottom end spool up for jumps. The DLC coated crank has almost no wear in most cases when time for a rebuild, as the stock V-Spec crank pin will most likely be oval.
Thanks, now if i just knew what a crank pin was....
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Old 06-23-2008, 03:49 AM   #9
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crank pin is the small pin found on the end of a crankshaft that the conrod pivots on. most crankshafts show some wear here, but because of the DLC (hardcoating) process of the OS speed, there is pretty much no wear at all
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Old 06-23-2008, 10:02 AM   #10
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Quote:
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crank pin is the small pin found on the end of a crankshaft that the conrod pivots on. most crankshafts show some wear here, but because of the DLC (hardcoating) process of the OS speed, there is pretty much no wear at all
Thanks. Now i have a speed crank and reg OS conrod, can i put them in my OS and made it a "speed"?
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Old 06-23-2008, 03:33 PM   #11
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I believe you'll need the p/s set also. Just the crank may not yield the same performance. I believe the piston is differnent from the stock V-spec version. Also add the ceramic bearing.
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Old 06-23-2008, 05:02 PM   #12
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if you use a speed crank, you have to use a speed rod...
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