crankshaft and main caps.

andersonxxl · 07-08-2009, 11:19 AM

Im trying to rebuild the motor for my truck. I bought a brand new crank for it. The motor is a 1 piece rear 4 bolt main out of a camaro. With brand new bearings and lube, the crank will spin freely by hand, but as soon as you tighten the mains(not even torqued yet) you cant move it at all, not even with force. any ideas?

andersonxxl · 07-08-2009, 11:25 AM

also, does it make any difference what year the main caps are as long as the rear main is for a 1 piece?

wild bill · 07-08-2009, 01:13 PM

i think you better pull the crank out and verify the size bearing's and journals you have take a look on the box or on the back side of the bearings .either they are under sized bearings or maybe the thrust journal is sized wrong . verify the crank and block number to make sure of the fit .

andersonxxl · 07-08-2009, 01:24 PM

everything is std size. bearings, crank, journals, mains...

mudseeker · 07-08-2009, 02:41 PM

make sure you are torquing them in the right order. the problem is probably your thrust bearing, give the crank a few smacks on both ends with a rubber mallet and see if it loosens up.

plastigauge wouldn't be a bad idea either.

leolkfrm · 07-08-2009, 03:27 PM

a block is line bored with teh mains attached, they should be reassembled in the same position, normally they are also stamped with a #. Did you mix them up

andersonxxl · 07-09-2009, 11:42 AM

when you tighten the thrust bearing the crank will still move. it is the front that causes the problem im pretty sure, i just cant figure out what it is. is there a certain sequence to tighten them?

NCroadracer · 07-09-2009, 10:04 PM

A.. The caps for the mains should be the original from that motor.. or they have to be line bored to match.

B.. The new crank should have a spec card specifying what thickness bearings to use.. If it didn't come with a set to begin with.

C.. If the caps are not from that block.. they are the problem.

andersonxxl · 07-10-2009, 03:29 PM

the caps are off a 79 motor. so that is probably the problem. i dont have the original caps so should i buy new ones and get it aligned or can i use the ones off the79 motor and align it with those?

wild bill · 07-10-2009, 04:44 PM

better have it line bored ,you would still have to do it with new or different ones .

07-08-2009, 11:19 AM	#1
andersonxxl Full Member Join Date: Mar 2008 Location: NY Posts: 43	crankshaft and main caps. Im trying to rebuild the motor for my truck. I bought a brand new crank for it. The motor is a 1 piece rear 4 bolt main out of a camaro. With brand new bearings and lube, the crank will spin freely by hand, but as soon as you tighten the mains(not even torqued yet) you cant move it at all, not even with force. any ideas? __________________ Smoke 'Em If You Got 'Em

07-08-2009, 11:25 AM	#2
andersonxxl Full Member Join Date: Mar 2008 Location: NY Posts: 43	also, does it make any difference what year the main caps are as long as the rear main is for a 1 piece? __________________ Smoke 'Em If You Got 'Em

07-08-2009, 01:24 PM	#4
andersonxxl Full Member Join Date: Mar 2008 Location: NY Posts: 43	everything is std size. bearings, crank, journals, mains... __________________ Smoke 'Em If You Got 'Em

07-08-2009, 02:41 PM	#5
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,374	make sure you are torquing them in the right order. the problem is probably your thrust bearing, give the crank a few smacks on both ends with a rubber mallet and see if it loosens up. plastigauge wouldn't be a bad idea either. __________________ i'd rather be hunting

07-08-2009, 03:27 PM	#6
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	a block is line bored with teh mains attached, they should be reassembled in the same position, normally they are also stamped with a #. Did you mix them up __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

07-08-2009, 01:13 PM	#3
wild bill Senior Member Join Date: Jul 2008 Location: davenport iowa 52806 Posts: 246	i think you better pull the crank out and verify the size bearing's and journals you have take a look on the box or on the back side of the bearings .either they are under sized bearings or maybe the thrust journal is sized wrong . verify the crank and block number to make sure of the fit .

07-09-2009, 11:42 AM	#7
andersonxxl Full Member Join Date: Mar 2008 Location: NY Posts: 43	when you tighten the thrust bearing the crank will still move. it is the front that causes the problem im pretty sure, i just cant figure out what it is. is there a certain sequence to tighten them? __________________ Smoke 'Em If You Got 'Em

07-09-2009, 10:04 PM	#8
NCroadracer Senior Member Join Date: Apr 2007 Posts: 295	A.. The caps for the mains should be the original from that motor.. or they have to be line bored to match. B.. The new crank should have a spec card specifying what thickness bearings to use.. If it didn't come with a set to begin with. C.. If the caps are not from that block.. they are the problem.

07-10-2009, 03:29 PM	#9
andersonxxl Full Member Join Date: Mar 2008 Location: NY Posts: 43	the caps are off a 79 motor. so that is probably the problem. i dont have the original caps so should i buy new ones and get it aligned or can i use the ones off the79 motor and align it with those? __________________ Smoke 'Em If You Got 'Em

07-10-2009, 04:44 PM	#10
wild bill Senior Member Join Date: Jul 2008 Location: davenport iowa 52806 Posts: 246	opps better have it line bored ,you would still have to do it with new or different ones .

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