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| | | | Joined: Sep 2008 Posts: 105 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2008 Posts: 105 | I took my 51 3100 on about a 30 mile round trip to a cruise in. This is the farthest I have driven it since I've owned it. (Only a few months) I noticed that at partial throttle I have what can best be described as a rattle. From the cab it sounds like it is toward the back of the engine. When I let off the throttle it goes away and when I accelerate it goes away. I have good oil pressure. I experimented with pushing in the clutch to see if it was related to the clutch but with the clutch pushed in it still makes the sound.
Sorry for the long post. Any ideas are appreciated.
Sincerely,
Chris | | | | | Joined: Jan 2009 Posts: 1,644 Shop Shark | | Shop Shark Joined: Jan 2009 Posts: 1,644 | I would check and see if somthing is loose, air cleaner , inner fender , motor mts ,rear mts , oil filter can , starter ,EM brake rods , just shake stuff and You might find somthing that is loose and at a certain RPM it will vibrate and make noise.
Pete | | | | | Joined: Feb 2008 Posts: 202 Shop Shark | | Shop Shark Joined: Feb 2008 Posts: 202 | Hi Chris, sounds like you have something loose under the truck, I would check the exhaust system first. Next I would do a hand check of all things under the truck and engine compartment, you are looking anything loose that moves with the engine.
Keep the 216's running. 1949 1/2 ton model #1314 (US 3104) Brian
| | | | | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | Rod bearings knock on what is called the float, between accelerating and decelerating.
See the USA in your vintage Chevrolet! My Blog | | | | | Joined: Sep 2008 Posts: 105 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2008 Posts: 105 | What are the remedies for rod bearing knock? Do I need to worry about driving the truck? | | | | | Joined: Feb 2006 Posts: 1,867 Shop Shark | | Shop Shark Joined: Feb 2006 Posts: 1,867 | Id be worried if my 216 didnt rattle.  Let us know what you find. | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
If you "throw a rod", it could ruin the block.
| | | | | Joined: Feb 2004 Posts: 29,746 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,746 | It sounds like it's time to drop the oil pan off and take a shim out of the rods to close up the oil clearance a little. Use some Plastigage and try for 2 thousandths or slightly less clearance.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Feb 2008 Posts: 202 Shop Shark | | Shop Shark Joined: Feb 2008 Posts: 202 | Hi, Chris, I reread your post and remembered when I got my truck, it would rattle, ping ect.until I set the timing right.So for a quick check retard the timing a few degrees and try that.Use the octane gage at the base of the distributor for adjustment. Loosen the distributor and turn toward negative a little, try that and see how it runs.
Keep the 216's running. 1949 1/2 ton model #1314 (US 3104) Brian
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