i have been doing some research and came to this conclusioin. i want to balance and blueprint an engine. if my rods and pistons are brand new meaning the rods are basically same weight to the 1000's and the pistons are now same weight to the thousands, why do i need to send my pistons rods crank, and sometimes crank pulley and flywheel to the machine shop? they are not going to put it together and spin it since there is not enough oil to supply the recipricating motion. i read an article where erick builds a block and the crank was spun by itself. But i guess my real question is "does anyone know a good machine shop to balance a crank in s. cali?" i also read something about making the oil passages bigger? tia.

 

to the top

 

FYI honda cranks are already balaced pretty good from the factory. concentrate on the other parts.

 

They will balance the crank counterweights for optium weights for your rod/piston combo. Whether it needs heavy weight added to it, or more removed.

http://www.victorylibrary.com/...c.htm

 

I was told that that it's pointless because the rods are all moving in the same direction. It is more necessary with a V6/8. Correct me if I'm wrong.

 

I also have ran into the same thing. A very reputable machine shop Pauls Automotive eng. they specialize in Mustangs. Have also told me balancing the Honda Bottom-end is point unless if the rods and pistons don't come in balanced.

 

http://www.hondatuningmagazine...ight/

 

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.

 

so should i balance or not? it's like $150 bucks.

 

Well, the last link I posted they went thru and balanced a Honda crank. I would think you'd only want to do it when building an all out racing motor. Its VERY important to make sure everything is perfect when blueprinting an engine. I wouldn't trust anyone but myself. I have working in some race shop, while they mostly worked on V8's, all the pistons and connecting rods where always checked for weight and balance.

As for your case, if you are doing a serious race engine, send it off to balance. If you are just building a street motor, don't worry about it.

 

A few oz out of balance at 7000 rpm can turn into a 140lb out of balance condition at 10,000 rpm. Out of balance multiply quickly by rpms. Low rpm street motors really don't need to be balanced but high rpm does need it. We do balance/micropolish cranks for customers almost everyday at Bensons.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by earl &raquo;</TD></TR><TR><TD CLASS="quote">A few oz out of balance at 7000 rpm can turn into a 140lb out of balance condition at 10,000 rpm. Out of balance multiply quickly by rpms. Low rpm street motors really don't need to be balanced but high rpm does need it. We do balance/micropolish cranks for customers almost everyday at Bensons.</TD></TR></TABLE>

Earl got my crank balanced and micropolsished with a 1 day turnaround. The motor has seen 9500rpm and is still living. Earl has great service. HIghly recommended.

 

ne1 know any good shops in s. cali? i know bensons, ge, maybe ericks?