Balance after rods and pistons? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

LuckyX2 · 05-16-2012, 06:22 PM

Hi guys,

I'm gonna be putting in new rods, bearings and pistons in my SR20 shortly and was wondering if I'd have to balance everything to the crank. I'm tight on time and I'm not sure if sending everything to a machine shop to be balanced is an option...

I know at the very least I'm going to want to match the pistons and rods so that they are the same weight as each other but do I have to then balance it all to the crank since the new rods/pistons are lighter?

Thanks

LuckyX2 · 05-18-2012, 06:54 AM

Thoughts anyone?

rcdad123 · 05-18-2012, 12:27 PM

if you want the engine to last longer, yes. you need to balance everything that is connected to the crankshaft. crank pulley, pistons and rods, flywheel, and pressure plate. don`t forget to smooth out all of the sharp edges on the pistons. these sharp edges can cause detonation. good luck with your build.

4x4le · 05-18-2012, 11:02 PM

I know allot of people balance the pressure plate and flywheel on the engine, however i balance it without and balance the flywheel and pressure plate seperate so if that is changed the rest of the engine is not dependant on that.

LuckyX2 · 05-19-2012, 07:03 AM

Quote:

Originally Posted by 4x4le

I know allot of people balance the pressure plate and flywheel on the engine, however i balance it without and balance the flywheel and pressure plate seperate so if that is changed the rest of the engine is not dependant on that.

If you can balance the flywheel separate from the crank then why can't you balance the pistons/rods separate from the crank like I'm hoping I can do to save time?
Also, how do you go about balancing a flywheel and pressure plate? I know for pistons/rods you just scrape away material until they're all the same weight but I'd imagine it's more complex for a flywheel/pressure plate.

4x4le · 05-19-2012, 08:05 AM

I dont know, I dont do it myself. The machine shop does my rotating assemblys and I have had them do the clutch too. My clutch builder did my last clutch however I dont know if they did it in house or sent it out.

LuckyX2 · 05-21-2012, 11:24 AM

So I called two high performance engine builders in my area today and both of them said an inline engine like ours does not need the rods/pistons balanced to the crank.

The rods/pistons all have to be balanced to the same weight and the crank has to be balanced (like it is from the factory) but they do not need to be balanced to eachother. The one shop even said that they had tried balancing inline engines before but there was no difference so they stopped doing that.

05-16-2012, 06:22 PM	#1
LuckyX2 Zilvia Addict Join Date: Jul 2011 Location: Philadelphia Age: 30 Posts: 850 Trader Rating: (7) Feedback Score: 7 reviews	Balance after rods and pistons? Hi guys, I'm gonna be putting in new rods, bearings and pistons in my SR20 shortly and was wondering if I'd have to balance everything to the crank. I'm tight on time and I'm not sure if sending everything to a machine shop to be balanced is an option... I know at the very least I'm going to want to match the pistons and rods so that they are the same weight as each other but do I have to then balance it all to the crank since the new rods/pistons are lighter? Thanks

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05-18-2012, 06:54 AM	#2
LuckyX2 Zilvia Addict Join Date: Jul 2011 Location: Philadelphia Age: 30 Posts: 850 Trader Rating: (7) Feedback Score: 7 reviews	Thoughts anyone?

05-18-2012, 12:27 PM	#3
rcdad123 Zilvia Addict Join Date: Jul 2011 Location: san diego Posts: 639 Trader Rating: (0) Feedback Score: 0 reviews	if you want the engine to last longer, yes. you need to balance everything that is connected to the crankshaft. crank pulley, pistons and rods, flywheel, and pressure plate. don`t forget to smooth out all of the sharp edges on the pistons. these sharp edges can cause detonation. good luck with your build.

05-18-2012, 11:02 PM	#4
4x4le Zilvia FREAK! Join Date: Nov 2008 Location: Manchester, Tn Posts: 1,253 Trader Rating: (1) Feedback Score: 1 reviews	I know allot of people balance the pressure plate and flywheel on the engine, however i balance it without and balance the flywheel and pressure plate seperate so if that is changed the rest of the engine is not dependant on that.

05-19-2012, 08:05 AM	#6
4x4le Zilvia FREAK! Join Date: Nov 2008 Location: Manchester, Tn Posts: 1,253 Trader Rating: (1) Feedback Score: 1 reviews	I dont know, I dont do it myself. The machine shop does my rotating assemblys and I have had them do the clutch too. My clutch builder did my last clutch however I dont know if they did it in house or sent it out.

05-21-2012, 11:24 AM	#7
LuckyX2 Zilvia Addict Join Date: Jul 2011 Location: Philadelphia Age: 30 Posts: 850 Trader Rating: (7) Feedback Score: 7 reviews	So I called two high performance engine builders in my area today and both of them said an inline engine like ours does not need the rods/pistons balanced to the crank. The rods/pistons all have to be balanced to the same weight and the crank has to be balanced (like it is from the factory) but they do not need to be balanced to eachother. The one shop even said that they had tried balancing inline engines before but there was no difference so they stopped doing that.