I just had my GSR block sleeved by Benson. I am using a LS crank to gain some stroke (89mm up from the 87.2mm of the GSR) plus save weight on the rotational assembly. The LS crank weighs half a pound less than the GSR crank. I also went with LS length Pauter rods. Which are almost as light as other manufacturers' aluminum rods at 521 grams each. 84mm 9:1 CP pistons. Giving me a total of 1972.5 cc's.

I will be assembling this engine with a mix of ACL and OEM bearings depending on the clearance. I also plan on using a Fidanza 7.5lb Aluminum flywheel with stock OEM crank pulley/harmonic dampener.

Im trying to figure out a few things:
A.) Earl tells me balancing of the rotational assembly is unnecessary based on a two points. 1 - the crank itself is very well balanced from the factory. 2- the rods and pistons are balanced far closer than stock. This makes sense but is it still best practice to have the rotational assembly balanced?

So I don't plan on having the rotational assembly balanced or micro-polished.

B.) How high is my bottom end capable of reving to? I understand the stroke is 1.8mm longer than stock however Ive removed probably 2-3 lbs of weight off the rotational assembly (not including the flywheel gains) plus Im hoping its better balanced as is.

Ive talked to tuners who have rev'ed built B16s with LS cranks to 10k. Im hoping I can get at least 9k out of my setup.

 

Any opinions?

 

when i took my rotating assembly in to be balanced, i was told the same thing about it being unnecessary. The machinist told me to spend my money on something useful
i had the crank polished though, because it was relatively inexpensive.

 

thanks for the confirmation.

Anyone have know about how high I can rev it?

 

u gotta be dumb not to get it balanced, just in case u always wanna balance it cuz an unproperly balanced motor could cause a mess of problems if u rev to high. if i were u id tell them to do it anyway for the piece of mind.

 

I don't know what machine shop you talked to, but a crank is balanced to the piston. You need the pistons and rods you will be using in order to properly balance the crank to them.

I would take it ot be balanced at someone else.

But I would say, if PROPERLY BALANCED, that bottom end should be good to at least 9k......depending on how long you want the motor to last, how hard you drive it, etc.

 

Dumb? WTF? You guys are calling Earl Laskey dumb then as this is what he told me.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">Dumb? WTF? You guys are calling Earl Laskey dumb then as this is what he told me. </TD></TR></TABLE>

There are other well-renowned engine builders out there that balance every motor they build; everyone has their own techniques. But I go on the principle of "better safe than sorry" since motors are expensive to build.

I have personally seen a set of forged rods and pistons come that were supposedly "balanced" from the factory, but were actually up to a few grams off of each other!

Get it balanced; it's money well spent at a good shop.

 

exactly, ive seen it happen to my friends, they didnt balance the motor, tried to rev it high, and fucked there **** up. all cuz they didnt balance it. better spend $100 on balancing all of it instead of thousands to fix it.

 

Hang on Brian, you are getting me in trouble. Let's start with something I wrote a while ago on balancing...

Do not confuse balancing V-8's as compared to 4 cylinder engines. It is a completely different method. Since 2 cylinders are directly opposed to the other 2 cylinders, putting bob weights on the crank does not make any difference in the balance measurement as the added weights just cancel each other out when spinning the crank. Aftermarket pistons and rods come balanced to within a gram. (That is very close when you consider there is 453.6 grams in a pound.) Clutches and flywheels also come spun balanced from the manufacturer. This is necessary in order to have their SFI certification. Same with aftermarket balancers.
The crank is balanced by itself. It does not make sense to add a clutch and flywheel to the crank when you balance because then you are stuck with the same flywheel and clutch forever unless you want to throw your engine out of balance or rebalance the internals after each clutch change.
As to adding the balancer to the crank when balancing, I believe this is not done because you would rather read the out of balance condition on the crank itself and correct it rather than having the balancer mask the condition.

RPM potential is controlled much more by cam design, port design, manifold design, turbo size, etc...than whether your crank is balanced.
Honda cranks, with factory balance are ok to about 7000 rpms. After that rpm, you probably want to have the crank balanced more accurately than the factory job. This may increase rpm potential slightly but what it really does is allow the drive train to operate smoothly at high rpm. A few grams out of balance might turn into 30lbs of force at 6500 rpm. At 9000 rpm, it may go to 150lbs. The force multiplies at increasing rates by rpm.
BTW, evey engine I build, I balance.

 

Now Im kicking myself for not having you balance everything. I was under the impression that it was not nessecary. I'll look for a place to do it locally.

Thanks for the clarification Earl. Sorry for misunderstanding your explination earlier.

 

Took my crank to a local shop. Had him balance, polish and magnaflux the crank. All for $100. He told me it was balanced pretty good already. So all this was unnessecary, but better safe than sorry.

Earl told me the rods didnt have to be touched and we confirmed that after weighing them. The pauter rods were perfect!

Is polishing the same as micropolishing?

 

yeah, pretty much; it's just makin the crank journals nice and shiney!

 

the rods will probably be pretty close already, but the LS crank should probably be balanced just to make sure. The pistons arent a big deal, but make sure all the counter weights are perfect before revving the crap out of it.

Ultimatly its your descision, but I say get the crank done at LEAST.

Ive personally been in an LS/VTEC with s2s2's revving to 10.5k. I cant say anything about longevity, but I can say that it HAS happened.