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Crank Balancing?


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ok i picked up a b16a crank when i got my block the other night. i know honda cranks come balanced from the factory, but i was wondering.....should i have the crank rebalanced before i assemble the motor? or are they permanetly balanced? owner said it did not spin a main bearing. and the main cap bearings look good.

 

any advice?

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I dont trust people when they say it has been polished/turned because they can easily lie about the specs on it and also if they ever hit it or dropped it etc

 

 

 

 

i would just take the one you have to the machine shop so you KNOW its good

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ok. well ill have to make a hour trip to get this done. but its all good. my block work is going to cost $146 + tax and will take 3-4 days.

 

that includes honing($6 per cylinder), decking($50), hot tank/dipped($60), having the pistons and rods cleaned($3 each).

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Can't buy a "balanced" crank. They have to be balanced exactly to the pistons and rod assemblies you are using for your particular engine. That includes pistons, rings, pins, locks, rods, bolts, and bearings along with dimensions as there are dynamics related to how that weight is distributed that has to be accounted for. They even figure in the weight of the oil that hangs around on the assembly too. Only a few grams but it all adds up.

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ah i see. well i have the pistons/rods sitll attached. the crank. block, and mains. i know ill need new rings and bearings but i have to get it balanced first.

 

so when i go to get it balanced ill have to take everything?

 

 

about buying that balanced crank: it was balanced and micro polished by the owner. he runs a machine shop

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Balanced to what? That's the whole point...unless he had your parts he can't balance the crankshaft for you. It might be a lot closer than some aftermarket crank but it's still not balanced for your engine with the exact weights of all the little parts you are using. Friend just sold a "balanced" stroker kit off his old combination. Sold the crank, rods, and pistons that were all balanced together originally. New owner was told he needed to have everything checked because he was going with new bearings, rings, and his own pistons. Apparently the guy threw everything in the engine and it blew up on the first night he took it to the track.

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Yup...and the rods and their bolts. Maybe bring your flywheel and harmonic balancer too. Pretty much everything that gets attached to the crankshaft. I'd call the shop and find out exactly what they require and write it all down. Most shops that have computer driven balancing equipment get this stuff down to less than 2 grams for a race-prep balance.

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fk i dont have the flywheel or harmonic balancer yet. i still dont have the rear main seal cover. i gotta meet the guy again to get the rest of it.

 

 

i was wanting to use a lightweight flywheel on the setup because ill be staying naturally aspirated

 

 

ill just call the place tomorrow. its Pro Motion Motorsports

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might want to check into new pistons btw

 

 

depends on how much he takes out of the cylinder to get the lip out of the cylinde.. rings might be able to cover it but you never know.. and also since your decking it you are obviously going higher compression (no turbo ever).. so you could get pistons to help match that

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well thats if it needs decked. i tried to measure with a machinists level and everything is less than .001 away from each other. the pistons are a really tight fit in the cylinders. so after it gets honed they should fit fine.

 

this is gonig to stay naturally aspirated.so no worries about high compression. unless i cant run 93. but ill be getting a lightweight flywheel soon

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ok the only thing that is keeping me from having all the stuff balanced is three things:

 

1) i have to get the pistons cleaned along with the crank

 

2) i need pistons rings - does anyone have any suggestions? they are $80 at O' Reillys

 

3) i need a flywheel. should i pay 190 for a oem flywheel, or spend another 20 and get a 9.5lb flywheel?

 

i hear that the lightweight flywheels have issues with daily driving. seeing as ill be in the car everyday i want something that will last and is relaible.

 

 

 

btw crank balancing will be done for o$125 courtesy of Fast Racing Motorsports in Groveport ohio

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oreiley rings should be fine

 

 

i have a 7 pound flywheel.. only problem i ever had was when you rev quick it falls quite a bit but the idle catches it and bumps it back up.. and of course depending on clutch its a little different taking off but its nothing serious

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oreiley rings should be fine

 

 

i have a 7 pound flywheel.. only problem i ever had was when you rev quick it falls quite a bit but the idle catches it and bumps it back up.. and of course depending on clutch its a little different taking off but its nothing serious

 

I agree. I have said it numerous times as have you! My first Del Sol drove better, shifted smother than my second Del Sol. I really wish I would of sent with light weight flywheel on my second one.

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oreiley rings should be fine

 

 

i have a 7 pound flywheel.. only problem i ever had was when you rev quick it falls quite a bit but the idle catches it and bumps it back up.. and of course depending on clutch its a little different taking off but its nothing serious

 

http://www.oreillyauto.com/site/c/search/Piston+Rings+-+Premium/03383/C0365.oap?keyword=piston+rings+-+premium&year=1995&make=Honda&model=Civic%2BDel%2BSol&vi=1169041

 

well its 72.99 for sealed power rings and 80.99 for Beck/Arnley rings. for that much i may as well buy hastings rings

 

well i wanted at least 12.5 lb. but i talked to brian and he pushed for 7.5 lb lol. i might just get a 9.5lb since ill be driving it daily

I agree. I have said it numerous times as have you! My first Del Sol drove better, shifted smother than my second Del Sol. I really wish I would of sent with light weight flywheel on my second one.

 

hmmm then lightweight it will be lol

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  • 1 month later...

ok gonna revive this....when i tear my d16z6 down for a rebuild should i re balance that crank even though its already balanced? probably a stupid question but o well

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ok gonna revive this....when i tear my d16z6 down for a rebuild should i re balance that crank even though its already balanced? probably a stupid question but o well

 

They balance the rotating assembly..Makes sure it's allowed to do so though in what ever class you want to potentially run in though..It's not allowed in many.

 

That being said usually the bottom end gets balanced from the crank pulley to the Pressure plate...And yes I would recommend doing so.

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no not really. the build is actually not going anywhere but i wanted to make around 200whp n/a but do it reliably. 300 would require either extensive n/a work or boost(i doubt a b16 could have made it that high n/a)

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Good advice posted here - do have your build balanced - it's not that expensive and it will run better and last longer.

 

Everything explained above by others plus: There is no way to actually put an inline 4 banger in true balance. That's a misnomer. Yes the engine can be "Balanced", but won't really be fully in balance. It will be matched however and in better condition for high performance output than stock. A good shop will weigh, rods, pistons, wrist pins and all components and match the weights on the components using a process called "Shaving". Removing small amounts of metal to match the weights of the components with one another. Then, they will balance the crank to the rod/piston assemblies. This is done by using a correction formula. What is being done is the off balance of a reciprocating mass (piston, rings, rod, wrist pin, oil) is offset to a degree with the counterweights on the crankshaft. The side effect is at the 90 degree plane to the cylinder, the crank is out of balance. But not as much as the reciprocating mass is uncorrected.

 

An engine is corrected to a certain percentage. The only real balanced reciprocating IC engines are one's with a countershaft. They can offset more of the reciprocationg mass with the crank weights, then offset the side to side or front to back of the crank with the wieghts on the countershaft. I'm not sure how close to true balance a countershaft engine is, but it's pretty close.

 

Any build I do that's beyond stock performance will be balanced at the machine shop that does the work on the block/head.

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