Big Knock in enigine Bottom end????? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67chevemall · 09-26-2003, 11:29 AM

My buddies truck just broke down!! He is in the dark ages so I thought I'd ask the pro's for him! Just wondering if any one has any idea what the problem could be????? The moter blew a gasket and spit the oil out on the highway. The motor still runs fine, but makes a loud Knock Knock Knock Knock !!!!!!!Knock!!!

Any Ideas??

dubie · 09-26-2003, 11:31 AM

sounds like he spun a main bearing and it's worn into the crank. This causes the connecting rod to knock against the crank since it's loose now.

Just my guess

jef5150 · 09-26-2003, 11:38 AM

i had a connecting rod "wrist pin" go bad,,,my knocking noise on deceleration,and idle only,,like you said the motor ran fine,,no noise under load

67chevemall · 09-26-2003, 12:34 PM

It knocks at idle and when you drive it! We drove it home about 15miles and nothing changed same knock while it's running!

tom hand · 09-26-2003, 12:40 PM

It won't be long before he finds the problem...it will be sticking out of the side of the block

oldsub86 · 09-26-2003, 02:35 PM

Either look for another engine or tear it down now. If you keep running it - it won't be for long.

krue · 09-26-2003, 02:36 PM

Stick a fork in it it's done! All he's doing now is circulationg bearing material throughout the block. Park and rebuild!

72shadetree · 09-26-2003, 03:04 PM

time for a rebuild a rod thru the block is not a nice pic

67chevemall · 09-26-2003, 03:15 PM

Thanks guys!
He just called and he took the oil pan off to see if it is a 4 Bolt Main so he doesn't get ripped off! I told him to rebuild it himself but he is worri!!

Time for a rebuild Book!LOL

Cheers

Class of 69 · 09-26-2003, 03:58 PM

It will need a crank for sure, and if it is a main that spun, the block will be toast as well. I wouldn't get my hopes up until I determined the source. It may need to be completely replaced....HHHmmm good time for a ZZ4???!

09-26-2003, 11:29 AM	#1
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Big Knock in enigine Bottom end????? My buddies truck just broke down!! He is in the dark ages so I thought I'd ask the pro's for him! Just wondering if any one has any idea what the problem could be????? The moter blew a gasket and spit the oil out on the highway. The motor still runs fine, but makes a loud Knock Knock Knock Knock !!!!!!!Knock!!! Any Ideas?? __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

09-26-2003, 11:31 AM	#2
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,855	sounds like he spun a main bearing and it's worn into the crank. This causes the connecting rod to knock against the crank since it's loose now. Just my guess __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

09-26-2003, 12:34 PM	#4
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	It knocks at idle and when you drive it! We drove it home about 15miles and nothing changed same knock while it's running! __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

09-26-2003, 12:40 PM	#5
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	It won't be long before he finds the problem...it will be sticking out of the side of the block __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

09-26-2003, 02:35 PM	#6
oldsub86 Registered User Join Date: Dec 2002 Location: Canada Posts: 695	Either look for another engine or tear it down now. If you keep running it - it won't be for long. __________________ 1968 Chevy - 292 with a powerglide

09-26-2003, 11:38 AM	#3
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	i had a connecting rod "wrist pin" go bad,,,my knocking noise on deceleration,and idle only,,like you said the motor ran fine,,no noise under load

09-26-2003, 02:36 PM	#7
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Stick a fork in it it's done! All he's doing now is circulationg bearing material throughout the block. Park and rebuild! __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

09-26-2003, 03:04 PM	#8
72shadetree KEEP ON TRUCKING Join Date: Sep 2000 Location: martinsville va Posts: 2,563	time for a rebuild a rod thru the block is not a nice pic __________________ 72 cheyenne 2wd lwb 71 k20 sons bassett va

09-26-2003, 03:15 PM	#9
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Thanks guys! He just called and he took the oil pan off to see if it is a 4 Bolt Main so he doesn't get ripped off! I told him to rebuild it himself but he is worri!! Time for a rebuild Book!LOL Cheers __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

09-26-2003, 03:58 PM	#10
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	It will need a crank for sure, and if it is a main that spun, the block will be toast as well. I wouldn't get my hopes up until I determined the source. It may need to be completely replaced....HHHmmm good time for a ZZ4???! __________________ 69 GMC K10 ..some restoration required....still..

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