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Old 13-07-2012, 04:15   #16
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Re: Crankshaft replacement, does it need balancing?

If the journals are ground and polished and you have the correct bearings I would put it together and not be concerned. It is a diesel too; and a common one at that. These engines have powered cars for decades so I would expect more than one was rebuilt with a crank that had not been Merceded.
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Old 13-07-2012, 04:29   #17
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Re: Crankshaft replacement, does it need balancing?

What does Mercedes know?!!--THEY'VE ONLY BEEN BUILDING ENGINES FOR 100 YRS.
Put it together, hook it up, jack the throttle open, and see what happens
Formula 1 be damned !!., CF gives you 50-50 that we are right.
One thing for sure--it won't effect my Westerbeke .
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Old 13-07-2012, 05:21   #18
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Re: Crankshaft replacement, does it need balancing?

The latest from Mercedes suppliers below............

"The way these engines were built was that each component of the crank assembly was roughly balanced and then the entire assembly was balanced. I was once presented with an engine that had been converted from a manual to an auto by replacing the Flywheel with a flex plate for the auto. It shook like mad at anything over 1500rpm.

The crank we have sent you has the front sprocket and pulley on it, so to be honest no idea if it is balanced. The MB bible tells you to balance everything and double check everything..

If your guys have a good lathe it is reasonably easy to do a very rough check of the balance. Simply machine a pin to center the front and put the spigot bearing in the drill chuck. Remove the belts from the drive motor and see if it falls one way or the other. There is a special MB tool to be used to replace flywheels without balancing the entire assembly, it is kind of similar where you mount one fly wheel 180 degrees out of phase with the other and check them."

Cheers from Keith
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Old 13-07-2012, 05:36   #19
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Re: Crankshaft replacement, does it need balancing?

Look on the edge of the crank webs, - the flat sides diametrally opposite the journal on each cylinder and there are generally a few drill holes about 3/8ths dia and 1/2in deep. These are balancing holes. Much the same as you add weights to your car's wheel rims, only they've removed some metal to balance the crank. With reference to racing shops, ; racing engines are going to be revving at 8000rpm, so balance becomes more of an issue and racers are trying to get the ultimate power out of their engines. Your engine will be turning at probably max 3000. Let's say over time one of your injectors starts dripping and the diesel in that cylinder is not properly burned.You are unaware of it, but over time you'll get a build up of carbon on that piston, now it is no longer balanced with the rest. Whatcha gonna do? Don't let this thing get to you.
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Old 13-07-2012, 07:11   #20
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Quote:
Originally Posted by holmek
Look on the edge of the crank webs, - the flat sides diametrally opposite the journal on each cylinder and there are generally a few drill holes about 3/8ths dia and 1/2in deep. These are balancing holes. Much the same as you add weights to your car's wheel rims, only they've removed some metal to balance the crank. With reference to racing shops, ; racing engines are going to be revving at 8000rpm, so balance becomes more of an issue and racers are trying to get the ultimate power out of their engines. Your engine will be turning at probably max 3000. Let's say over time one of your injectors starts dripping and the diesel in that cylinder is not properly burned.You are unaware of it, but over time you'll get a build up of carbon on that piston, now it is no longer balanced with the rest. Whatcha gonna do? Don't let this thing get to you.
Not suggesting a low reving diesel needs to be balanced like a race engine. The lead is to find a shop that can do balancing.

Maybe its worth the price of a ohone call to get in touch with these guys.

Fact is it will probably be fine without balancing. But stick it together and get a harmonic imblalance that hangs around at 1500 rpm and you either live with it, double guessing yourself forever about balancing the rotating parts, or tear it down.

As someone said, "Won't affect my westerbeke."

http://www.malaysia.com/directory/wh...d._215042.html
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Old 13-07-2012, 08:04   #21
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Re: Crankshaft replacement, does it need balancing?

Hell! My 3 cyl Yanmar dances around so bad, one would never know if it were out of balance.
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Old 13-07-2012, 09:47   #22
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Re: Crankshaft replacement, does it need balancing?

If locating proper facilities is a problem now, think about when it spews up on you in the middle of the ocean. ( I don't wish that upon you, BTW)
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Old 31-07-2012, 08:37   #23
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Re: Crankshaft replacement, does it need balancing?

Cheers guys.
I bought a new one from mercedes in australia, but they sent a 220d crank and the wrong bearings, so I remiked the old crnk and it is fine, but have to put one original set of bearings for num1 conrod as the crank had been ground 1.25mm undersize and cant get those bearings again.
So, motor is in the boat and running sweetly and I splash her tomorra!!
Thanks for all your advice.
ps, merc said keep the crank and bearings, too hard to send it back from Malaysia, a full refund coming, but, still waiting !!!!!!!!!!!!!!!!!!
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Old 31-07-2012, 13:33   #24
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Re: Crankshaft replacement, does it need balancing?

Glad that you're good to go!!!
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