Re: How do I locate the 360 flywheel drilling?
[Re: Phoenix]
#3205476
01/17/24 05:01 AM
01/17/24 05:01 AM
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Posts: 10,735 North Dakota
6PakBee
I Live Here
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I Live Here
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Posts: 10,735
North Dakota
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I'm not saying this is correct but years ago when I thought I was going to have to drill a flywheel for a 360 this is what I thought I saw:
1) establish the horizontal centerline through the pressure plate holes 2) establish the vertical centerline 90 degrees from the horizontal centerline through the center 3) establish the centerline of the middle hole by rotating 46 degrees 21 minutes clockwise from the vertical centerline through the center 4) establish the centers of the two outside holes by measuring 2.5 inches from the center hole at the 3.88 inch radius of the balance holes
Like I say, I never had to do this (found a flywheel) but this is the way I would have done it.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: How do I locate the 360 flywheel drilling?
[Re: Phoenix]
#3205510
01/17/24 10:19 AM
01/17/24 10:19 AM
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Joined: Jan 2003
Posts: 10,735 North Dakota
6PakBee
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I Live Here
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Actually, looking at the flywheel it appears to me that it's exactly 30° out from that diagram...
Is it possible that 143-tooth flywheels were drilled on that different axis? Mine is a 143-tooth. IIRC the 143 tooth is a truck flywheel and has a different drilling pattern. But don't take that as gospel, when I was contemplating this, it was with a 130 tooth flywheel.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: How do I locate the 360 flywheel drilling?
[Re: rustbuckett68]
#3205599
01/17/24 01:44 PM
01/17/24 01:44 PM
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Joined: Sep 2003
Posts: 19,485 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,485
north of coder
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as a machinist, what bothers me, there is no mention of what angle the drill is sharpened to. 135* ? 118*? 90*? something else ? just my life experience. your mileage will vary. and although not looking it up, if the flywheel is available from rock auto for less than $100.00, i wouldn't bother screwing around trying to balance one to the drawing either.
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Re: How do I locate the 360 flywheel drilling?
[Re: moparx]
#3205630
01/17/24 02:58 PM
01/17/24 02:58 PM
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Joined: Feb 2015
Posts: 2,079 CA
crackedback
top fuel
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top fuel
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Posts: 2,079
CA
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I agree that the datum line should be based off the crank holes as THAT is the item that your modifications are directly related. Datum off the pressure plate holes, as with the change in clocking, makes the entire process shot in the dark. Even if you are a little off, which drive me crazy as there should be base point, it's not likely to create an issue. JMO and the sentence below sums up some of this.
Balance tolerances on these factory setups was so poor, I doubt the drill cutting angle would make a material change in the acceptable range of error.
Just a guess here. There appears to be a locator hole in the pictured flywheel with the external balance reliefs. Does the flywheel in question have that locator. Bet it's on the datum line passing through the cranks centerline.
I'd prefer it to be spot on and for $100, wouldn't waste time on the process. Sell the current flywheel and buy a new one already balanced.
Last edited by crackedback; 01/17/24 03:04 PM.
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Re: How do I locate the 360 flywheel drilling?
[Re: moparx]
#3205645
01/17/24 03:18 PM
01/17/24 03:18 PM
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Joined: Jan 2003
Posts: 25,885 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
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Posts: 25,885
Rio Linda, CA
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as a machinist, what bothers me, there is no mention of what angle the drill is sharpened to. 135* ? 118*? 90*? something else ? I've been asking that for years...common consensus is 118 degrees which is considered the standard.
The INTERNET, the MISinformation superhighway
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Re: How do I locate the 360 flywheel drilling?
[Re: moparmarks]
#3205686
01/17/24 04:55 PM
01/17/24 04:55 PM
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Joined: Jan 2005
Posts: 53 The Summit
Phoenix
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Originally posted by moparmarks I believe that chart is for the 143T wheel which was used in trucks starting in 1972 while the 360 car 4-spd with the 130T wheel wasn't available until 1974. It is possible, but if it's possible (and it is) to drill to the same pattern as the 130-tooth flywheel it will (must) achieve the balance required. Originally posted by dvw [B]I think you are looking with the flywheel pressure plate side up. Flip the flywheel over and look from the crank face side. That's where the diagram is drawn. The drawing says to be looking from the 'engine side' of the flywheel, so that's what I am doing. Originally posted by moparx [b]as a machinist, what bothers me, there is no mention of what angle the drill is sharpened to. 135°? 118°? 90°? something else? Yes, a good point... I am pretty sure, however, that one of the diagrams I've seen was accompanied by a note saying 120°. I will be checking what my drill is, but it's a new and unused drill so I'd expect it to be right.
Last edited by Phoenix; 01/17/24 07:38 PM.
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