Connecting Rod Side Clearance - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevy55 · 07-24-2002, 11:58 PM

What Kind of damage could be done if there is too much side clearance and the vehicle is run anyway?

crazy longhorn · 07-25-2002, 12:21 AM

Stock runs about .0025 per side,or .010 per pair. you could open them up to about .018-.020, & they will pass a little more oil through the bearings, but other than possibly a little drop in oil pressure, i dont think it would cause a problem. How much clearance do you have?

chevy55 · 07-25-2002, 12:37 AM

It varies between the journals, the largest one that I measured was somewhere between .021 and .023, the crank has been machined before I had bought the engine so I don't know who machined it. It is .010 under. The reason I am checking is because I here a tap or a knock while the engine is running and I think that is where it is coming from. If it will damage it I don't want to run it anymore.

crazy longhorn · 07-25-2002, 10:05 AM

I dont think the extra side clearance will hurt you, but you may run that by a couple old racers. It was common practice to open up the side clearance on a high rpm engine......street or strip /strip apps due fine with stock type clearance. I tore down an old sb, that had .060 side clearance on 1 pair of rods(that was a "holy sh$t"). somebody had spun a bearing,then had the crank sub arced & reground,& the cleanup grind left the journal too wide. I have no idea how long it ran this way, as i had just purchased the truck(my old longhorn). Judging by the wear on the rest of the engine........it had been running for a while tho! good luck......AL

07-24-2002, 11:58 PM	#1
chevy55 Registered User Join Date: Nov 2001 Location: Mesa, AZ Posts: 105	Connecting Rod Side Clearance What Kind of damage could be done if there is too much side clearance and the vehicle is run anyway? __________________ 1955 Chevy Shortbed Stepside 2nd Series. http://community.webshots.com/user/chevy55truck

07-25-2002, 12:37 AM	#3
chevy55 Registered User Join Date: Nov 2001 Location: Mesa, AZ Posts: 105	It varies between the journals, the largest one that I measured was somewhere between .021 and .023, the crank has been machined before I had bought the engine so I don't know who machined it. It is .010 under. The reason I am checking is because I here a tap or a knock while the engine is running and I think that is where it is coming from. If it will damage it I don't want to run it anymore. __________________ 1955 Chevy Shortbed Stepside 2nd Series. http://community.webshots.com/user/chevy55truck

07-25-2002, 12:21 AM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Stock runs about .0025 per side,or .010 per pair. you could open them up to about .018-.020, & they will pass a little more oil through the bearings, but other than possibly a little drop in oil pressure, i dont think it would cause a problem. How much clearance do you have?

07-25-2002, 10:05 AM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	I dont think the extra side clearance will hurt you, but you may run that by a couple old racers. It was common practice to open up the side clearance on a high rpm engine......street or strip /strip apps due fine with stock type clearance. I tore down an old sb, that had .060 side clearance on 1 pair of rods(that was a "holy sh$t"). somebody had spun a bearing,then had the crank sub arced & reground,& the cleanup grind left the journal too wide. I have no idea how long it ran this way, as i had just purchased the truck(my old longhorn). Judging by the wear on the rest of the engine........it had been running for a while tho! good luck......AL



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