Balancing Crank And Flywheel If They Are New From Nissan

[ZimNismoBoy]

Right so here i am studying the rb26 and other engines as a whole.

I sent a request to japan to a good friend regarding the balancing of the bottom end of a rb26dett.

The response i got from the Nismo shop was something like this .

Imagine we have customers who come in daily who request a after market clutch (Nismo Single or Twin plate ) that comes with its own flywheel.

So they replace these daily and have never not once ever had a come back on any of their jobs where the engine runs a bearing etc because of the bottom end becoming out of balance.

So here is the scenario, you get a balanced crank shaft that has been balanced from the factory .

You get a clutch assembly that has also been balanced from factory by nismo or hks or Exedy.

These two seperate articles are balanced in their own right .

Now you get them balanced and matched to each other so that when you assemble the engine you dont have a crank and flywheel that are out of balance that would damage your engine at high rpm.

Never the less you also have the damper fitted when they balance everything .

Then you have your engine running and 25 000kms later because you have beebn enjoying the car and have been launching it just too many times the clutch packs in, you go off and purchase a new clutch system like you would in Japan .

A complete Kit that comes with the flywheel etc.

Now comes the question, do you take the engine out and remove the crank then send off the flywheel and clutch cover and damper pulley to the balancing shop because its what you did the first time ?

Or do you leave it in like most shops would and then fit the new flywheel solid or dual mass with some loctite and let the customer go off and pay your labour cost because you know as long as the flywheel is balanced and the crank is balanced that both should be balanced when assembled ?

This is something that i have been thinking about for a long time and i have been wanting to post the question up for quite a while now .

I have even gone across the net looking for a similar situation to try and see what other owners of straight six engines are doing but havent found anything .

So im asking on here and on other forums, you have the facts and you even have the fact that nismo doesnt follow the practises that we do so why are we doing it then ?>

Should it be done ?

[ZimNismoBoy]

Found these after some serious searching

http://www.ten-tenths.com/forum/showthread.php?t=112749

http://www.circletrack.com/enginetech/ctrp_0504_engine_balancing_tech_terminology/piston_rod_crank_balancing.html

http://www.rpmmachine.com/engine-balancing.shtml

[ZimNismoBoy]

Ok im not sure if i have posted in the wrong section, no responses lol.

Any ways im going to ask if there is any one who can comment ?

OR shouldi move the post to a technical section rather sorry op's maybe posted this in the wrong place please correct me if im wrong .

Thanks

Adam

[KT_87]

Those links above are quite helpful mate so you should check em out, but what i would also say is your RB26 gonna be seeing some serious track time,Week end warrior or just a streeter on a hardcore race engine id say yes because at high engine load+high RPM the flywheel/clutch assembly not being balanced with the crank shaft and harmonic/Dampener assemblies will create Crankshaft wobble at high RPM/High speed/Engine load witch isn't a good thing. the RB26 is well known for decent crankshaft wobble at high RPM a harmonic dampener should be invested in after upgrading the oil delivery system in my opinion then the T25's, like it says in one of the articles you should get your pistons, conrods Big end and small end measured and balanced then you can properly balance the crankshaft and harmonic/dampener-Flywheel/clutch assemblies. on a weekend warrior id probably do it to just for piece of mind but if its just a streeter i wouldn't worry about it you wont generate enough High speed/High RPM/Engine loads to cause you problems . One thing to remember to is even though some thing is mass produce doesn't mean there all the same tolerances there is variation from kit to kit and there definitely not gonna be the same as whats in your car currently aslo due to ware on components Fraction of a gram counts when balancing a engine hope this helps you out mate

Edited July 28, 2011 by KT_87

[Bl4cK32]

when i had my engine built, they balanced everything from the front pulley, back to the os giken twin plate clutch. I brought the motor home, the crank had been marked, as well as the clutch where to line them up when installed. If i replaced the clutch, then it would get balanced the same as this clutch was.

[KT_87]

when i had my engine built, they balanced everything from the front pulley, back to the os giken twin plate clutch. I brought the motor home, the crank had been marked, as well as the clutch where to line them up when installed. If i replaced the clutch, then it would get balanced the same as this clutch was.

my point is different clutch kits weight different amounts it may only be grams but that's a huge difference when balancing an engine so it'll will need to be balanced as mentioned above what application its it being used for

[Bl4cK32]

my point is different clutch kits weight different amounts it may only be grams but that's a huge difference when balancing an engine so it'll will need to be balanced as mentioned above what application its it being used for

im not disagreeing, they balanced mine to something like 0.5g using a hines balancer. Its definitly worth doing to a street engine though as it can help with engine life and fuel economy.

[KT_87]

no worries man i wasn't getting ticked off sorry if it sounded like that and I've never thought of it benefiting fuel economy before nice one you learn something new everyday

[ZimNismoBoy]

Thanks for that KT_87 though i am still wondering about this

So we have everything balanced balancer, then crank then the flywheel assembly, then the clutch cover etc.

But here i have a new crank, new ATI damper pulley, new Nismo twin plate clutch coppermix.

So should i be getting this all rebalanced again ?

And now after i get this all balanced, then does this mean that when i do a clutch change job i have to strip the motor, and re balance everything ?

See my theory is this, they say for high performance engines you need to balance the whole rotating assembly, and i agree with this.

But on a high performance engine you would be stripping it more frequently to get everything redone bearings etc, as this type of engine will be running High BHP and also will see track use all the time pretty much .

Now on a streeter like my nur engine is going to be, its going to be a engine that doesnt see much track use, but more street use, the factory rpm rev limit is at 8400rpm .

So the Nur spec engine is finely balanced and through nissan you have the option of ordering a Complete long block assembly, as well as purchasing a Nur spec short block assembly.That is high balanced too ?

And if this is the case would i still need to strip the engine and resend all the parts excluding the ATI damper pulley for balancing ?

This the reason i ask all these questions lol.

Alot to take it i know but its all for peace of mind, and also for the other users of the forum that seek some good solid answers .

[ZimNismoBoy]

just an update .

Sent my crank and Nismo twin plate copper mix flywheel and cover for balancing .

And guess what all was in balance not a thing needed touching .

So this means that a N1 crank if there is such a thing is fine balanced from Factory and the Nismo Coppermix twin plate is also balanced from factory and the two articles together are in balance with each other

Brilliant stuff.

Now to balance pistons and rods .