Crankshaft Balancing - Part 2

Steve Morris is back to tell you everything you want to know about crankshaft balancing. Now that the crankshaft and bob weights are set, watch to see the next steps for a proper balance job on the full rotating assembly.

[@StainlessTIG2]

Thanks Steve. Great video. I had my SBF rotating assembly balanced on the same machine, and it’s amazing how smooth the motor revs through the power band. Thanks for the informative overview!

[@genesisfrenn]

The best explanation of balancing crankshaft. I really appreciated your knowledge sir 😉.

[@larryburns7094]

Great explanation on balance work done many people think it has to be perfect .

[@Peternielsen88]

Very well explained, thank you!

[@guillermodavila9397]

The best teacher thanks God bless you.

[@allseeingeye1]

Fascinating stuff !! Wonder how this was done before the advent of balancing machines ?

[@Turte_Performance_Balancing]

Just wanna thank you abou the idea with the bolt. We run a CWT 3000 in the smallest Balancing shop in Europe called TURTLE PERFORMANCE BALANCING..if anyone in Germany needs balancing Service.. We love the CWT, it´s agreat (and heavy) tool to work with!

[@josephnubile1970]

Thank you.

[@user-Betty_white93]

vary helpful and knowledgeable of information thanks🤔

[@tommyrafajko3043]

Hello thank you for the video, the next time you are balancing a stock crank shaft can you please set it up and balance it with no counter weights at all just plane crankshaft alone and let us know how far out it is?

[@raymondpetracca6208]

Thank you so much really good presentation got a good idea what really goes on my hats off to you guys

[@causeimbatmaaan]

8 grams at 4" at 8000 rpm is about 250 lbs (if memory serves)of side thrust on the bearings so that's rpm capability and horsepower loss. We never balance outside 2 grams, better is always better. Not saying 8 or 10 grams is horrible but it barely takes any more time to get to 1 gram on each end.

[@ChiefCabioch]

8 grams 8" from center at 8000 is 112 pounds of out of balance force

[@ChiefCabioch]

I've been balancing engines since the mid 70s, on a Stewart Warner model 2000

[@krusher74]

i'd love to know what extremes of balance F1 went to in the 18k rpms days.

[@krnt13]

What I don't understand is that he said in the last video that the post it was about 0.8 grams but now he is saying its 8 grams?

[@ChiefCabioch]

Incorrect, 8 grams 8" from center at 8000 rpm is 112 pounds of out of balance weight...

[@bigblockpop]

Love you videos

[@trevcessna1723]

Is a NEW crankshaft properly balanced or can it be way off? I am balancing my rods rings pins pistons so what do you think? Great videos Thanks!

[@EngineBuilder]

A new crankshaft will still need to be balanced. Many crank manufacturers offer balancing as an option, but it's typically not included if you don't ask for it.

[@trevcessna1723]

Oh well that explains why some newly rebuilt engines just don’t sound quite right. Thank you for your help!

[@zadynsmom]

@@EngineBuilder about how much does this cost to get done? Working on my very first build this summer.

[@EngineBuilder]

@@zadynsmom the price depends on the crank manufacturer or the shop you bring a crank to for balancing.

[@camilosanchez5477]

Excelent!!!

[@pistoninthewind]

To the haters get a life, this cat knows and has done things you couldn't possibly do. If you could you would be doing it now...

[@stuartbuckley8720]

Any thing + - a gram is great. Over or under balance is a builders choise and oil and windage are not a constant variable do to rpm / engine load and engine acceleration/ deceleration deloading. A engine like industrial type at a constant rpm / load is completely different from a drag / oval track race engine. Dynamics are a factor

[@garylogan8555]

That was a great video, until I actually had it explained by you and observed the process had no idea what was involved. Thanks.

[@joequillun7790]

Thanks for the tutorial Steve. If you still have your ears on, could you comment on externally balanced engs.? (Or maybe a viewer who knows.) A Pontiac 301 smog motor, (built from 77-81) has what's called a "rope" crankshaft. Only has 2 opposing counterweights, (one at ea end). Like a 400 SBC, it has a corresponding damper, and flywheel. If the rotating weight is changed, (say .030 over pistons, and lighter rods), what would you recommend for balancing? Or would it need it, if kept under 5K RPMs? Thanks.

[@kasp1971]

The weight distribution of the bobweight itself may not be ideal evenly. Therefore, it is not relevant to put them on necks with a rotation angle of 90g. You can check the bobbin unbalance by placing it on a balanced rolling pin equal to the crankpin diameter. This is very easy to do. After doing this, you can explain about another approach to installing bobweights on the necks. Good luck checking out the bobweight imbalance.

[@Stephenc4877]

thanks stevie, just a quick question i've seen cranks knife edged and balances without any bob weights what effect would this have on an engines running and performance it was a 4 cylinder don't know if that has any bearing.

[@cumberlandfleetservice6152]

I would like to have seen you drill& add the mallory metal.

[@bigbothoee8617]

Why is the weight 90deg to the most extended weigh ? I've never done it before want bit more info onit

[@yarrdayarrdayarrda]

If you balance a crank perfect, then remove the bobweights and reinstall them, it will always be out a couple of grams.

[@paulprecht9786]

Not sure how you align the first one but I let its weight bring it down and then level it, the rest are all done to the first after that.

[@Greensmachine]

In the end result there’s a given amount of imbalance. I generally like to get my imbalance 180° from the throw. Where do you like to end up on the counter weight.

[@shanawazkhan6969]

Hi bro how to balance motorcycle crankshaft my new motorcycle having terrible vibration issue

[@amandacollins2058]

Do u always have to take the extra weight into consideration? Can u not balance the crank shaft without adding the weight of the piston, rods etc?

[@EngineBuilder]

No, you always want to take into account your entire rotating assembly, which includes pistons, rods and rings, etc.

[@dielauwen]

Itis informative but still leaves one to wonder. This is how it is done but not how it works. How was it done without electronics would be beneficial.

[@craigdoesthingswithhissons]

Awesome video.

[@albertosibuyas1697]

How to know the tolerance for that kind of crankshaft sir is there calculation to get correct tolerance

[@Rob-pg7rb]

Get you some of those small powerful Neodymium magnets to stick on the crank in different spots. There cheap on Amazon.

[@ellieprice3396]

May stay on a 500 rpm but what happens at 10,000?

[@andrewevans1658]

@@ellieprice3396 I'm pretty sure he was using magnets like the jamb bolt used in the video. Used as reference because heavy metal can't always be added in the exact spot the machine says to put it.

[@stuartbuckley8720]

@@andrewevans1658 true.

[@terrysibley9636]

Question, what is the reason for balancers, stick type,but some are 28 oz, 50 oz. The balancer im replacing has no balance weights that I can see,removable or otherwise. I do know the new flywheels or sold in conjunction with 28, or 50 oz balancers. Can you please explain this. I don't want to buy the wrong parts. Putting together a reasonably hot sbf.externalky balanced. Just want to understand the protocol. Thank you

[@blueblood76]

All stock OEM 351W are 28 oz imbalance. That means from combined imbalance weight of flex/fly wheel and balancer are 28 oz more. On 302's Ford changed the imbalance from 28 oz (from 1968 to 1978) to 50 oz imbalance (1979 up) This was because Ford removed 22 oz from the cranks 79 and up. So they had to make up for removing 22 from crank by adding it to flex/flywheel to keep things the same. 28 + 22 = 50

[@puppygadget3189]

Steve how long a wait is it to have you balance my BBC blower motor aluminum rod rotating assembly?

[@krusher74]

really long if your expect an answer to that through youtube comments.

[@josepeixoto3384]

Is that a makeshift thinggy? why not balance the whole assembly in a/the block? externally driven,no explosions, no need for oil pressure,grease will do for those seconds at a time..

[@andrewmyers5299]

What happens if u dont balance a 454 engine?

[@stuartbuckley8720]

It will shake like a dog craping peach pits and break the crankshaft causing catastrophic failure.

[@josepeixoto3384]

@@stuartbuckley8720 when, at what rpms? will it shake itself to pieces right off idle? at full bore?will it idle?

[@pmreng]

Good video...

[@Ticeracing33]

So anyone that works at autozone couldnt possibly know how to build an engine. How about get it as close as possible instead if just saying well who knows how much oil gets splashed on it.

[@m3kgt]

I laughed at this, I worked nights at Advanced Auto, all while running this same Cwt balancer for over 6 years. I caught a lot of his errors as well.

[@joshlower1]

Hes a fucking hack man, my grandpa did all this shit for years with no computers

[@dr.michaelbennett8597]

You missed the most important part of mounting the bob weights. Clock position or level as you used is nearly irrelevant. It is absolutely essential for the bob weight to be in the center of the journal (Neal, 2007, 2023). Additionally, do not rotate the crank by the bob weight.

[@Tatertot_Tommy]

But are you getting paid to KINDA balance it, or to get it "close enough"? NO.

[@krusher74]

balance within the spec paid for/needed

[@joshlower1]

​@@krusher74no balance it as best as you possibly can and take pride in your work and have honor and integrity, anything less is inexcusable.

[@mikaelgaiason688]

Don't work at Auto Zone, I work on bikes that rev to 15k. 8 grams DOES matter. Unless you only work on crap American engines. XD

[@ellieprice3396]

"Crap" American engines? don't think so. Former Holman and Moody machinist.

[@mikaelgaiason688]

@@ellieprice3396 Nobody's impressed old man. I do think so. They're crap. Always have been, always will be. Former machinist and current chassis tech on a national team. Show me an American engine that makes over 100hp/liter and runs half a million miles. There isn't one. Because they're crap.

[@stuartbuckley8720]

Sounds like a pissing match to me, you boys need to chill and get some beers.

[@mikaelgaiason688]

@@stuartbuckley8720 Not really, but ok

[@rotorblade9508]

@@mikaelgaiason688 100hp/l (naturally aspirated) can be done in an overly complicated engine. american V8 are extremely simple engines, much easier to work on and less chances to go wrong. For high power applications they use aggressive cam profiles and higher rpms, not suitable for street. So they are not worse they simply have a different cost effective and reliability approach, plus the crossplane v8 sounds really good. Anyway these engines are nice for sports cars not daylidrivers where you need better economy.