Offshoreonly.com - 496 Vibrations

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getrdunn

01-30-2017 03:28 PM

Stroker kits. Some balance and some not.

2 Attachment(s)

Here's an example and even same company. Note one kit externally balance and other internally balanced.

vanmejt

01-30-2017 05:10 PM

Scat Series 9000 Cast Pro Comp Stroker Lightweight Crankshafts 9-454-4250-6135
Thanks men, I don't plan on running it any longer....this is the P/N of the crank. I am trying to get a hold of a solid mercruiser contact to help determine the specs on the flywheel and outdrive coupler.

SB	01-30-2017 05:16 PM

GEN V and GEN VI have externally balanced flywheels from GM and Merc. FYI Merc uses GM Flywheels, in fact, the whole damn motor is from GM, minus some of the accessories and hoses. :)

Edit in: and as stated from others, even if a kit comes 'balanced' and 'drop in' , one still has to have a machine shop check/balance and you or the machine shop needs to check all dimensions and clearances.

vanmejt

01-30-2017 05:20 PM

So should I get the crank, pistons, and rods balanced with the flywheel and damper?

SB	01-30-2017 05:39 PM

Yes. Check with your machine shop...some will want everything including hat you said and wristpins/locks if used , rings, and etc.

Here is a good quote from this forum on flywheels that GM and Merc used. The Pat #'s are GM.

Quote:

Originally Posted by Rockfish71 (Post 2667646)

here's more information

Part # Dia" Clutch Dia" Teeth Application
14085720 12 3/4 10.4" 153 65-69 Mark IV, Lightwweight (15 lbs), nodular iron, two-piece seal, internally balanced.
3963537 12 3/4 10.4" 153 70-90 Mark IV external balance 454, 15 lbs
3991469 14" 11" 168 66-69 Mark IV internal balance 454
3993827 14" 11" 168 70-90 Mark IV external balance 454
14096987 14" 11" 168 91-up Gen. V/IV external balance with 4" stroke forged steel crank, 454, 502
10101169 14" 11" 168 91-up Gen. V/IV external balance with 4" stroke cast nodular iron crank, 454, 502

vanmejt

01-30-2017 05:43 PM

That sux....I hate to completely disassemble the whole damn thing 😠

SB	01-30-2017 05:56 PM

Do some searching here and you'll see a few thousand of us have had to pull/remove/re-install. Multiple times.

vanmejt

01-30-2017 05:57 PM

Thanks man....lol

vanmejt

01-30-2017 06:19 PM

Can I use an automatic style flex plate in lieu of that heavy flywheel?

mike tkach

01-30-2017 06:23 PM

Quote:

Originally Posted by getrdunn (Post 4524318)

Right on. Many of the cast rotating stroker assm are externally balanced from I remember. Why I have no clue but remember seeing some that are externally ballanced but only the cast ones.

Like everyone said don't run it til you get this taken care of or you'll be pulling engine and not happy.

i have a 489 in the shop that i am rebuilding,i finished the disassembly today ,it has a forged scat crank and it is externally balanced.they offer it for folks that don,t want to replace the existing balancer&flywheel.it was built 13 years ago and the assembly was balanced at a machine shop,i know this because the shop that did the balance job scribed their name and the bob weight and the date it was done on the crankshaft.

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