Crankshaft - The 1947 - Present Chevrolet & GMC Truck Message Board Network

87chev_silverado · 07-16-2005, 09:29 AM

First off i'd like to stay i until yesterday have never seen nor even heard of most the internals of an engine. I am rebuilding the bottom half of my 350ci and i was wondering .can i switch out my crankshaft without pulling the heads. and i could sure use tips on buying crank kits . or putting them in hope ya'all can help thanks

NeCrOmAnCeR · 07-16-2005, 11:20 AM

Yes it can be done without removing the heads. The question is why? What happened to the engine which requires the replacement of the crankshaft? (mak be metal spread throughout the engine which will destroy the new crank in a short ammount of time)

As far as getting a crank kit, check around at your local parts houses for crank kits which will include main and rod bearings of the correct size.

You should also get a new timing chain set and oil pump while you have it torn apart.

SSC's76 · 07-16-2005, 03:20 PM

Usually a crank just wont go bad and thats it, end of damage. Like Necro mentioned you could just replace the crank with heads on. I highly doubt you could wiggle it in, then get the rods back down without making gouges in the new crank, ruining it. If you do this you need to have exact specs on the new crank journal diameter, your existing rod size and main bearing size. If you dont it wont last long at all.

87chev_silverado · 07-16-2005, 03:39 PM

i actually spun a bearing im getting the timing chain and oil pump . the one closest to the oil pump is the only one that seems messed up but the crank is tore up so im gonna replace it .i figured it might be easier to cut corners and do it without taking the heads off but it doesnt sound like it would be worth it in the long run

white82 · 07-16-2005, 05:29 PM

whatever rod u spun the bearing on it will need to be resized and the one next to it. my 2 cents

SSC's76 · 07-16-2005, 08:14 PM

If thats the case what your planing on doing wont work. You need to rip the whole engine apart and send it in for machine work. Here's a link so you can read up on some of the involed and now nessasary procesess. Engine Work

Edit: Any time a main bearing has spun the block must be align bored or it wont last.

07-16-2005, 09:29 AM	#1
87chev_silverado Registered User Join Date: Jun 2005 Location: north west washington Posts: 19	Crankshaft First off i'd like to stay i until yesterday have never seen nor even heard of most the internals of an engine. I am rebuilding the bottom half of my 350ci and i was wondering .can i switch out my crankshaft without pulling the heads. and i could sure use tips on buying crank kits . or putting them in hope ya'all can help thanks Last edited by 87chev_silverado; 07-16-2005 at 11:03 AM.

07-16-2005, 11:20 AM	#2
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Yes it can be done without removing the heads. The question is why? What happened to the engine which requires the replacement of the crankshaft? (mak be metal spread throughout the engine which will destroy the new crank in a short ammount of time) As far as getting a crank kit, check around at your local parts houses for crank kits which will include main and rod bearings of the correct size. You should also get a new timing chain set and oil pump while you have it torn apart. Last edited by NeCrOmAnCeR; 07-16-2005 at 11:21 AM.

07-16-2005, 03:20 PM	#3
SSC's76 No No Join Date: Jun 2005 Location: Pueblo Colorado Posts: 1,781	Usually a crank just wont go bad and thats it, end of damage. Like Necro mentioned you could just replace the crank with heads on. I highly doubt you could wiggle it in, then get the rods back down without making gouges in the new crank, ruining it. If you do this you need to have exact specs on the new crank journal diameter, your existing rod size and main bearing size. If you dont it wont last long at all. __________________ 1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler

07-16-2005, 05:29 PM	#5
white82 White 82 Join Date: Feb 2004 Location: Eustace, Texas Posts: 100	whatever rod u spun the bearing on it will need to be resized and the one next to it. my 2 cents __________________ 1966 GTO 455 e-heads, 1982 Chevy k10 4'' lift 33’' tires, 2008 Pontiac g6 v6

07-16-2005, 08:14 PM	#6
SSC's76 No No Join Date: Jun 2005 Location: Pueblo Colorado Posts: 1,781	If thats the case what your planing on doing wont work. You need to rip the whole engine apart and send it in for machine work. Here's a link so you can read up on some of the involed and now nessasary procesess. Engine Work Edit: Any time a main bearing has spun the block must be align bored or it wont last. __________________ 1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler Last edited by SSC's76; 07-16-2005 at 08:17 PM.

07-16-2005, 03:39 PM	#4
87chev_silverado Registered User Join Date: Jun 2005 Location: north west washington Posts: 19	i actually spun a bearing im getting the timing chain and oil pump . the one closest to the oil pump is the only one that seems messed up but the crank is tore up so im gonna replace it .i figured it might be easier to cut corners and do it without taking the heads off but it doesnt sound like it would be worth it in the long run



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