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Sun Feb 18, 2018 9:58 am

Hello,

I'm rebuilding a 1600 with the Tom Wilson book. Once the case halves are together, how much resistance, if any, should I have when turning the crankshaft? Tom's book refers to no binding while torquing the main-bearing hardware. It rotates without binding, but it takes 12 pounds of torque to rotate. Is this correct or should it be able to turn by hand?

Many thanks!
Mike

Sun Feb 18, 2018 10:02 am

With the crank pulley on it should easily turn by hand.

Sun Feb 18, 2018 11:07 am

12 foot pounds or inch pounds?

How much and what kind of assembly lube is on the crank & bearings?

What temperature is it in the assembly room?

Sun Feb 18, 2018 12:57 pm

12 ft-lbs seems a bit heavy, but others may disagree.
No mention of a torqued flywheel, nor what type/if any lube is utilised.
A complete rebuild? Ala:
Reground (or verified straight) crank, align-bored case w/ correct main bearings installed, bearings properly/correctly seated in place over their dowel pins?

Fingertips should be adequate to spin a properly-lubed crankshaft. If conrods are installed, more resistance should be expected.
If the endplay is not set: preload the crank towards the #1 (thrust) bearing while turning it - o/wise it might be binding.

Sun Feb 18, 2018 3:04 pm

That sounds too tight. Did you check the main bearing to crank to case dimensions? You may have one on the tight side, or possibly a pinched main bearing by the dowel - very common

Sun Feb 18, 2018 4:02 pm

Thank you all for your replies!

The problem was a pinched thrust bearing, it was not on it's dowel pin. It's seated on the pin now and the assembly can be rotated easily by hand with the case halves torqued.

That was foot pounds, sorry I didn't add that. I'm using sta-lube assembly lube and permatex ultra slick. The garage is a balmy 40ºf

Cheers!
Mike

Sun Feb 18, 2018 4:19 pm

If you pinched the bearing, you MUST replace it. If you dont, the bearing may seize later

Sun Feb 18, 2018 4:28 pm

Quote: That was foot pounds, sorry I didn't add that.

No worries, That was just me being an A** Glad you resolved it. Make sure you have three shims for the end play of around .003" to .005"

Sun Feb 18, 2018 4:35 pm

Quote: The problem was a pinched thrust bearing, it was not on it's dowel pin.

Before finding this was the case torqued to spec? If so like Chrisflstf is right you may have ruined the rear bearing and need to replace it. Put it in the case without the crank, torque case, measure bearing. If it ain't round it's junk. Think of it as education is expensive.

Sun Feb 18, 2018 4:41 pm

AC.net sells single bearings to replace crushed ones.

Sun Feb 18, 2018 4:59 pm

Put #4 bearing on the pin, push down into case all the way, mark it with a fine point sharpie where it meets the case on sides and ends so you can tell where it has to be the next time you assemble it. Ditto#3 and #1 bearing or just eyeball the oil drain "teardrop". Ideally if you had to replace a single bearing it would be the same manufacturer.

Sun Feb 18, 2018 5:19 pm

Thanks again! I suspected it sustained damage from being installed incorrectly and I was about to ask if I should replace it. Thanks for all the information.
Cheers!
Mike