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> Value of 'dynamic' balancing when rebuilding a 7A-FE
post Dec 10, 2017 - 6:17 PM
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Langing

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The crankshaft is originally balanced by the manufacturer. After 320 K miles and then suffering an extreme heat event, should the crankshaft be re-balanced during the engine overhaul? Is it worth the money? Is it necessary? Will it make me happier because of reduced engine vibrations?

Then, would a 'dynamic' balancing be even more valuable, since it would simulate the weights of the four piston assemblies being hung on the crank pins? Or, would it be unnecessary since two of the pistons are going up while the other two are going down, pretty much cancelling out their forces?

While doing a 'dynamic' balancing, is it possible to attach the fly-wheel and main crank pulley, so the entire spinning assembly is balanced as a single unit.

Both the fly-wheel and pulley show signs of having been balanced by the manufacturer. Guessing that they have not changed since the beginning of time, is it worth being concerned about them when balancing the 'system'?

Anything you know that could help me understand the process of balancing my engine during its rebuild would be appreciated. Smaay, here is where your engine building experience probably would be most useful to me.
 
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post Dec 10, 2017 - 8:36 PM
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njccmd2002



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how much will it cost you to rebuild the engine? Just asking, because now will be the time to upgrade. Unless your heart is set on driving the 7a

even so, i would buy a used engine, for less money... unless you are keeping the celica forever, you will spend more than the value of the car


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post Dec 10, 2017 - 8:54 PM
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Bitter

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Balancing isn't worth it, the 7A doesn't rev high enough to make it an issue. What you do need to do is to have all the bearing clearances checked correctly and the correctly sized bearings installed.


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post Dec 10, 2017 - 10:14 PM
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Smaay

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the above 2 responses are all you need.


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post Dec 11, 2017 - 9:39 AM
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Langing

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Thank you all for your comments. They are much appreciated, as I believe all are correct.

Please see my response to Smaay in the thread about the connecting rod bolts to understand why I am stuck putting in effort on the 7A-FE, rather than upgrading.

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