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 Post subject: Crank oiling mods?
PostPosted: Wed Feb 24, 2016 2:13 pm 
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Turbo EFI
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Car Model: 1965 Plymouth Belvedere I
OK, I thought I read somewhere on the forum that the crank oil holes, the ones that run from the main journal to the rod journals, should be drilled out to 5/16 inch.
Well, it was a pain, but I did just that. I sent the crank to the machine shop to be checked/polished. The machinist thinks that I am nuts, and the holes are the biggest he has ever seen.
So, did I misread something somewhere? Do I need to start over with another crank?
I wasn't worried until I got the call from the machine shop.
Good news, the block is ready.
-Matt

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PostPosted: Wed Feb 24, 2016 2:14 pm 
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You were supposed to drill the feeds in the block. :shock:

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 Post subject:
PostPosted: Wed Feb 24, 2016 2:18 pm 
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Turbo EFI
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I did that, drilled the block. The block isn't the problem.
I thought I read somewhere to drill the crank as well.
Worst case, I'll need a new crank (but I hope not).

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PostPosted: Wed Feb 24, 2016 2:22 pm 
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I did that, drilled the block. The block isn't the problem.
Neither was the crank. Remember, Slant-6 engines tend to live long lives even without "improvements" that may or may not actually improve anything.

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 Post subject:
PostPosted: Wed Feb 24, 2016 2:39 pm 
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Supercharged
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If the crank breaks, you'll need a new one. :?

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 Post subject:
PostPosted: Wed Feb 24, 2016 2:44 pm 
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Turbo EFI
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If the crank breaks, you'll need a new one. :?
Well that is good to know. you guys have been so very helpful.
Don't think I don't appreciate it.

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PostPosted: Wed Feb 24, 2016 2:56 pm 
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You may end up with low oil pressure. :oops:

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 Post subject:
PostPosted: Wed Feb 24, 2016 3:02 pm 
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Supercharged
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I have heard of cleaning the crank holes with a pipe cleaner and/or a drill bit of the stock size, radiusing the oil feed holes in the crank, but never drilling the feeds out larger. The oil feed on a slant is is just dandy unless you are building a very high RPM motor.

Doctor Dodge wrote a great article about modifying the block to improve oiling behavior. HERE it is.

The good doctor also wrote a great thread about modifying the oiling system in the slant. Read it HERE.

Drilling the holes out likely weakened the crank abit and did very little to improve oiling. If you are brave, run it and tell us how it goes.

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 Post subject:
PostPosted: Wed Feb 24, 2016 3:11 pm 
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I would not worry about it. There is so much meat there... Folks have turned down the rod journals to <2" diameter and not had problems. I can't imagine that tiny diameter increase will hurt anything. The leakage of oil out of the bearings should not depend hardly at all on that oil hole diameter, so I would guess oil pressure will not suffer much either.

If you are trying for 500 HP, then maybe worry.

My 2 cents...

Lou

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 Post subject:
PostPosted: Wed Feb 24, 2016 3:23 pm 
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Supercharged
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Quote:
If the crank breaks, you'll need a new one. :?
Well that is good to know. you guys have been so very helpful.
Don't think I don't appreciate it.
You're blazing trails! Let us know how it goes!

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 Post subject:
PostPosted: Wed Feb 24, 2016 4:08 pm 
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be sure you have a smooth radius on the hole edges,,


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 Post subject:
PostPosted: Wed Feb 24, 2016 5:13 pm 
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Well that is good to know. you guys have been so very helpful. Don't think I don't appreciate it.
Ain't no call for that, now. It's no fun to learn we've gone ready-FIRE!-aim instead of the other way round, but usually we have only ourselves to blame for charging ahead based on what we thought we remembered recollecting we might have read some time back, without double-checking.

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 Post subject:
PostPosted: Wed Feb 24, 2016 6:46 pm 
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Turbo EFI
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Joined: Mon Jan 12, 2015 5:55 am
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Location: Brightwood, VA
Car Model: 1965 Plymouth Belvedere I
Quote:
Quote:
Well that is good to know. you guys have been so very helpful. Don't think I don't appreciate it.
Ain't no call for that, now. It's no fun to learn we've gone ready-FIRE!-aim instead of the other way round, but usually we have only ourselves to blame for charging ahead based on what we thought we remembered recollecting we might have read some time back, without double-checking.
No worries there. I am not that sensitive.
But I really thought I read that somewhere (drilling the crank oil holes).

That's funny though, I don't recall having a memory problem.

Anyhoo, I will be racing the dang thing so I might play it safe and get another crank. What's the worst that could happen?
:D

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 Post subject:
PostPosted: Wed Feb 24, 2016 6:51 pm 
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That's funny though, I don't recall having a memory problem.
:lol:

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