Bent Crank?
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Joined: Aug 2013
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From: Terre Haute
Bent Crank?
I am building a 360 currently for a '75 F100 4x4 project. I just got the crank back from one machine shop, and the block back from another a few days ago. Crank was turned down .010 on rod and main journals. I put the bearing inserts (labeled .010) in the block, lubed them and lowered the crank into the block. It seemed to turn fine. I put the main caps on and tightened them down, in sequence, with a 3/8" air ratchet to maybe 25-35 ft-lbs just to check things. When I did this it was noticeably harder to get the crank to start turning but then feels pretty smooth after you get it "broke loose" Every subsequent time you stop and go to turn it again it starts out stuck feeling then seems to "free up" a little after it starts turning. I went ahead and torqued the caps to 50 ft-lbs after that and it seemed a little more hard to turn. I went ahead and torqued them to 70 and oddly enough it seemed a little easier to turn it after that. I have not tried any Plastigage yet to see what my clearances are. Plan on getting some today. I have never used it. Always just took things on faith. I have never had a crank feel this weird turning though (my 6th engine build). I don't think the bearings are too tight because it would be hard to turn all the time not just at first, right? Just wanted some opinions.
Laughing Gas
Joined: Jul 2010
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From: Chico, Ca.
According to Steve Christ's book, crankshaft endplay should be .004-.010 in, with .014 maximum. If you use plastigage, torque caps to 95-105 ft-lbs. Clearance should be .0005-.0025 in, with .0005-.0015 in desired. The main caps should not be torqued in order. Number 3 should be last. Before torquing center-number 3- main-bearing cap, force crank back and forth to seat thrust bearing. Torque center main cap while holding crank forward with screwdriver. I would suggest getting the book, since it seems to be comprehensive. Good luck.
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From: Terre Haute
I plasti-gaged all the mains and they all fell between .001 and just under .002. I was using Lucas Assembly Lube but wiped it off to use the plasti-Gage. Used the old thinner white Lubriplate assembly grease when I reassembled. The thinner lube helped a little with freeing things up. I'm going to talk to the machinist tomorrow and see if he'll swing by and look at it. It seems like I could turn all the other engines I've built over with just the counterweights and my hands before installing any pistons. Still cannot do that with this one, but it is not quite as "stuck" feeling as it was.
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From: Terre Haute
The old Chilton' s manual I have says between .001 and .0015 are acceptable main clearances for the '75 360. The very next column up says .0001 for the 302 though.
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Lead Driver
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From: **** hole San Jose ca.
What are you using to turn the crank with? your hand.
Plus heavy thick bearing grease. Right!
I'd say get a crank socket to turn it over. this is the right way.
I'd put a dial indicator on the block & crank flange to check your crank end play.
You need a large screw driver to force the check that thrust bearing clearance.
Remember your crank rides on the oil not the steel right!
I think the assembling lube is your real problem..
My 2cents.
Orich
Plus heavy thick bearing grease. Right!
I'd say get a crank socket to turn it over. this is the right way.
I'd put a dial indicator on the block & crank flange to check your crank end play.
You need a large screw driver to force the check that thrust bearing clearance.
Remember your crank rides on the oil not the steel right!
I think the assembling lube is your real problem..
My 2cents.
Orich
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