Flywheel questions

jgerardi

Seaman
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Feb 27, 2019
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61
I have a chaparral with a 496 (8.1) . 375 hp. It is a 2007. I bought this boat back in Feb in Fla and brought it home to NY with me. I put 25 hours on it while i was in Fla, then when i put it in the water here in NY, i took it out once and had to be towed back due to a bad ground on the starter, I took it out a second time and blew a piston. I know have 7000 invested in a remanufactured engine along with many other items. I had to replace the started because the solenoid cracked when i was reinstalling it after the engine replacement. I went to start the boat, it turned, started for 2 or 3 seconds then stalled. Then every time i tried to crank it, the starter would just grind. Once again i removed the starter and could see the teeth on the flywheel were chewed up.
I am looking at nearly 400.00 for a new flywheel. That on top of the nearly 7000 i have invested. Im wondering if this is just a standard GM 8.1 flywheel. Does anyone have any idea or knowledge about this?
 

jgerardi

Seaman
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Feb 27, 2019
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61
This gets a little confusing. Several posts say use the one that came with the motor. I cant as that one is damaged. Or do they mean buy one that is made for that specific motor. I am looking at the ones that Michigan Motors has and it says "Metric" on it. Mine does not. According to Michigan Motors (MM) there are only two flywheels for these motors. One for an inboard and one for an I/O. Mine is an I/O but my flywheel looks exactly like the one for the inboard excepting the placement of the ring gear. Can i just change the ring gear?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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you dont need a flywheel

you need a $15 168 tooth ring gear available at any Napa, AutoZone, Advance Auto, O'Reilies, etc.

there are two flywheel ring gears for GM V8's from 1955 on. 153 tooth and 168 tooth.

if you spend $400 for a $75 GM flywheel that is just plane nuts.
 

Bondo

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Ayuh,...... What Scott said,.... You need a new Ring Gear, not the flywheel,......

Most likely a 168 tooth,....
 

Bondo

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yes, this is a 168 tooth but there are different pitches as well

Ayuh,...... Yer over-thinkin' this,....... There are 2 sizes of chevy ring gears, 153 tooth, 'n 168 tooth,......

Get a new 168 tooth ring gear, 'n install it on yer flywheel, 'n go Boating,......
 

alldodge

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Don't pay any attention to the "metric", note the position of the ring gear on the flywheel. Do note that if yours in it the wrong place it can be moved/replaced

Click image for larger version  Name:	flywheel.jpg Views:	1 Size:	56.9 KB ID:	10766445
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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And here is how you change the ring gear, because based on your trepidation with the information we have given to date, you most likely dont know how to swap ring gears

Check to see if ring gear is tack welded to flywheel (most are not, some are)

If it is tack welded, cut the welds with a die grinder and cookie wheel

Place flywheel on bench with ringgear down

Block of wood such as a few pieces of 2x4 inder the flywheel

Use a torch to heat a 2" section of the ring gear, when that is red hot, use a brass drift and a ballpeen hamer and drive the ring gear off the flywheel

Let flywheel cool, grab a beer

Clean up rust on flywheel land where ring gear was with a wire brush

Put flywheel in freezer for about an hour
45 minutes after the flywheel en in the freezer, put new ring gear in oven at 400-450 degrees

Then put cold flywheel on bench, ring gear groove up

With welding gloves, pull ring gear from oven and drop in place

You may have to tap it straight and flat with your brass drift and ballpean

if old ring gear was tack welded, then tack weld new one

Enjoy a beer

Install flywheel

Reinstall motor

Align

Install drive

Go boating
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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on a related topic, did you take care of what ever killed your original motor in the first place? you either ran lean or some other external to the block and heads factory took out your piston.
 

jgerardi

Seaman
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Feb 27, 2019
Messages
61
I cant draw any definitive conclusion as to what happened. If the fuel ran lean, i cant be sure why. I set up a system to run carb cleaner through each in injector one at a time at 50psi. Each injector had a very clean even flow. I ran clean gasoline through the fuel line and fuel rail and ran it through a white paper towel to see if there were any particles or paint chips. The fuel was clean. Truth is i was pushing it a bit but i really am hard pressed to believe that caused it.

I did due diligence to try and determine what caused all of this. I have a ton of possibilities but no conclusions.
And on the issue of my flywheel. I was able to get a ring gear at my local auto parts store and i popped the old one off with no problem. I threw the new one on the gas bbq for 20 minutes on medium and it fell right in to place. I got the motor back in the boat and it started a few times briefly but now the brand new starter engages for about 3 seconds and then just spins. No grind but it just spins.
I am assuming that is an issue with the solenoid on the starter. Im going to order another one and take it from there.
 

jgerardi

Seaman
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Feb 27, 2019
Messages
61
Thanks everyone for some great tips on this. I heated the ring gear for 10 minutes or so and knocked it off by hitting it with a cold chisel and hammer. Came off pretty easily. Picked one up at my local auto parts store for 18 dollars. Threw it on the grill to 400 degrees and it just fell into place. Now for my next disaster, see my latest post.
 
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