babaz7

are manley cranks balanced or not?

and how many of you are running the maley crank without balance?

LetsGetThisDone

iTrader: (1)

As with anything, having a skilled machine shop check the balance of your rotating assembly is good practice to ensure engine reliability.


Even if Manley balances them, what may have happened to the crank in between it coming off the balancer at Manley, and making it your door?

NJ9MR

iTrader: (56)

Yes to the above! I bought all Manley internals, and they aren't getting installed until the crank is double-checked.

meckert

iTrader: (11)

see above, are they balanced--yes, can other things effect them after the initial balance yes. The big question is, what was the tolerance balanced too? 1Gram, 3grams, 5grams, more? Speed of the balance? etc--, with or without the flywheel? you get the picture-- everyone will have a different acceptable idea of balanced.

LetsGetThisDone

iTrader: (1)

I would never balance with the flywheel. If you ever have to change the flywheel later on down the road, you now have a crank that was balanced with something attached to it, and that something is now different. Balance the flywheel and crank separately.

meckert

iTrader: (11)

I guess a difference of opinion on that. Its just what I do since its rotating mass-- to each his own, again- everyone will have a different acceptable idea of balanced.

RightSaid fred

That makes no sense?

You have to spin up the crank on the balancer with the bobweights fitted........drill the counterweights . The weight of the bobweights depends on the weight of the rods.
After that's done, you bolt on the flywheel onto the crank and spin it again.......drill the flywheel.


It's something that's left to the man who does the balancing 'cos he knows what he's doing?

Dynamic balance is measured in grams as well as distance from the centreline.
It's mass times distance, not just mass.

LetsGetThisDone

iTrader: (1)

Read what you just wrote. First, you balanced the crank. Then you balanced the flywheel. You DID NOT drill the crank when the flywheel was bolted to it, you drill the flywheel. So, when you change the flywheel later down the road, the crank is still independently balanced.

4b11slayer

Sounds like a build. $$
You should still have the rotating assembly as a whole balanced.

94AWDcoupe

iTrader: (125)

I dont know if the manley crank comes balanced. the answer in itself is a rubber ruler. I would call manley and ask. maybe report back on what they say.

eagle cranks had a tag that stated the cranks need to be balanced. I never did as there were clearly balance marks on the cranks. so clearly some balancing was done when they were made.

I did have a couple factory cranks balanced. this was a real trustworthy machiest who stated the cranks didnt really need to be balanced. it was a very high state of balance from the start. others around the net found the same thing.

now for some worth while data.
4g63 engines. I have taken many apart. pistons and rods from factory vary in the 6-12 grams window for early DSM engines. meaning the heaviest and lightest can vary that much. these are engines that were never taken apart. the evo 8 I measured were in the 3-6gram range. being acceptable from mitsubishi it is acceptable for me

I state that because when you buy after market rods and pistons they will be matched to within one gram. I measure them and mark them then I mate the lighter two pistons to the heavier two rods. in effect creating an even higher state of balance. it is my experience that tells me any motor built with 9000 rpm redline its is a waste of money to have things rebalanced. aftermarket parts are balanced extremely well.

another tip. and another reason I think balancing is a waste of money. getting all four cylinders to fire with the same amount of energy is far more important and far harder to achieve than a good mechanical balance. focus your effort there if you want a smooth running engine that will last a long time.

spoolin turbo

Balance everything separately