Characteristics of a spun bearing?
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: Characteristics of a spun bearing? Im not sure what your asking with "characteristic" but i know spun main would make oil pressure fluctuate, makes a screeching sound and or knocking, oil will smell burned and there will be material in oil , same for rod bearing except oil pressure wouldnt be affected much.Does this help?
Thread Starter
Launching!
Joined: Nov 2001
Posts: 253
Likes: 0
From: Tampa, FL
Re: Characteristics of a spun bearing? OK, the car once moving runs fine with the exception of a loud tapping. The car will idle in park/neutral OK with no audible abnormal sounds. The car does not want to idle in gear, and is hard to start. The car dies when coming to a stop or slow turn... The tapping gets louder with RPM's. I have the valve covers off and so far everything looks good up top... I am still working on getting the last of the p=rods out to check them.
Any ideas?
Any ideas?
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: Characteristics of a spun bearing? I would take oil filter off and cut open filter to expose paper media, than if you see bearing on the paper its time to pull the motor, if its clean than it has to be something else like a bent pushrod or valve.
Re: Characteristics of a spun bearing? I hope you do not have anything major Joey.. This would mean some major upgrades for you and the death of the rest of us.. Please be something simple so the rest of us can sleep.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Re: Characteristics of a spun bearing? Hey Joey, a spun rod bearing is a deep knock, not a tap. The sound sounds like it in the middle of the motor. Heres a way to tell. If when you drove it at a steady speed and bearly pushed the gas, did the oil pressure drop? Or, a bad rod would stop the noise under acceleration (under load, taking up the slack) and return when you let off the gas. If I could listen to it, I could tell ya, but a tap is a valvetrain problem. Maybe lifter, pushrod, spring, bent valve......
Re: Characteristics of a spun bearing? Joey,
I'm wanting to believe that it is not someting in the shortblock, wishfull thinking <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> But I do agree that rod or bearings usually cause a knock, not really ticking. I spun a beaing in a truck with a 454 in it and I first thought that I had been hit because the knock was so loud and shook the truck violently. Scared the crap out of me.
Are you getting any codes or flashing SES? I'm hoping for maybe a broken spring or pushrod. Have you spoken to Mike yet, he might be able to give you some insight as well, just hold the phone up to the car and let him listen <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
I'm trying to be lighthearted, but I know it sucks to be broken. Good luck and let me know if you would like a hand turning wrenches.
Mark
I'm wanting to believe that it is not someting in the shortblock, wishfull thinking <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> But I do agree that rod or bearings usually cause a knock, not really ticking. I spun a beaing in a truck with a 454 in it and I first thought that I had been hit because the knock was so loud and shook the truck violently. Scared the crap out of me.
Are you getting any codes or flashing SES? I'm hoping for maybe a broken spring or pushrod. Have you spoken to Mike yet, he might be able to give you some insight as well, just hold the phone up to the car and let him listen <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
I'm trying to be lighthearted, but I know it sucks to be broken. Good luck and let me know if you would like a hand turning wrenches.
Mark
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
Launching!
Joined: Nov 2001
Posts: 253
Likes: 0
From: Tampa, FL
Re: Characteristics of a spun bearing? Thanks guys... So far the oil looked and smelled good. All 8 plugs look the same, and are OK. The pressure didn't drop under intial acceleration and the tapping did not go away under load. The tapping is consistent with RPM, not double time. Under intial inspection, all springs look/feel OK and all rockers were solidly in place with no play. I felt the pushrods for anything obvious and nothing jumped out at me so I'm in the process of pulling them out.
Mark, I spoke with Mikey and he said to go ahead and get the pushrods out and hopefully I'll find a pretzel or a broken one, if not we'll go from there... Either way I think I'm over the shock of it now and who knows, maybe I'll have some fun with it while I have it apart... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I just wish I didn't have 2 project cars sitting here now... The Vette I'm really not worrying about, the SS is still my priority so however long it takes...
Mark, I spoke with Mikey and he said to go ahead and get the pushrods out and hopefully I'll find a pretzel or a broken one, if not we'll go from there... Either way I think I'm over the shock of it now and who knows, maybe I'll have some fun with it while I have it apart... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I just wish I didn't have 2 project cars sitting here now... The Vette I'm really not worrying about, the SS is still my priority so however long it takes...
Thread Starter
Launching!
Joined: Nov 2001
Posts: 253
Likes: 0
From: Tampa, FL
Re: Characteristics of a spun bearing? Also the tapping is faint when at idle and gets louder with RPM... It is loud when driving though, and honestly it didn't sound like the bottom or middle og the motor, more like topend, but when I didn't see anything obvious in the valvetrain I started thinking the worst...
**EDIT - there have been no codes or SES lights
<small>[ March 25, 2002, 11:16 PM: Message edited by: Joe99SS ]</small>
**EDIT - there have been no codes or SES lights
<small>[ March 25, 2002, 11:16 PM: Message edited by: Joe99SS ]</small>
Re: Characteristics of a spun bearing? As long as it is not the bottom.. I have to call Mikey tomorrow to see if he has touched my car yet.. Tapping up top sounds like valvetrain, but I agree with Mikey about pulling the pushrods and checking.. I still have my stock length ones if you need them..
Thread Starter
Launching!
Joined: Nov 2001
Posts: 253
Likes: 0
From: Tampa, FL
Re: Characteristics of a spun bearing? I have my stockers also, but they won't work anymore as the new ones are a different size I believe... I know they are moly anyhow... I know he was finishing up Bill's car today, so he might have started your's too. I just hope it is something in the valvetrain...
On The Tree
Joined: Dec 2001
Posts: 112
Likes: 0
From: Bucks County, PA
Re: Characteristics of a spun bearing? I had the same kind of sound... changing with RPM... loud tapping coming from the engine. I attempted to drive to the dealer and 5 minutes before I got there, a rod busted in half and punched a hole in my block. Oil sprayed everywhere and the car just died.
DO NOT DRIVE YOUR CAR UNTIL YOU GET THIS FIXED. Just my opinion...
-Jim
DO NOT DRIVE YOUR CAR UNTIL YOU GET THIS FIXED. Just my opinion...
-Jim
Re: Characteristics of a spun bearing? He did a leak down test today Joey.. He still needs to pull the heads to isolate the problem to the heads. I suspect bent valves.. Thats what I am hoping anyway.. Any news on your car?
Teching In
Joined: Dec 2001
Posts: 47
Likes: 0
From: Tarpon Springs FL
Re: Characteristics of a spun bearing? Joey- Sorry to hear about the problems. When I spun a rod bearing (on the GNX) is was a constant tap noise at idle but oil PSI was a little lower but didn't drop with RPM. When I spun the main (another occassion) the noise increased with RPM and like the others said oil PSI dropped off with RPM. In both cases the oil showed a shiney film from the bearing material. I hope everything works out. By the way, the Thunder rocks!!!
Vince- It must be catchy this week with Joey and you. I saw Mike do the leak down, the odd cylinders seemed to all have problems. Once again I hope all turns out OK. Nice car.
Vince- It must be catchy this week with Joey and you. I saw Mike do the leak down, the odd cylinders seemed to all have problems. Once again I hope all turns out OK. Nice car.
Re: Characteristics of a spun bearing? Spun main bairing...
-lot of metal shavings in the oil, i mean huge streaks of gray...
-oil pressure flucuates like crazy once car is warmed up.
-mid frequency tapping when rpms were taken over 2000 rpms.
-dramatic loss of power over 2500 rpms
This was my car a few years ago. The knock was more mid-freqnency than a SBC IMO.
Bent valves would make a car idle really shitty.
-lot of metal shavings in the oil, i mean huge streaks of gray...
-oil pressure flucuates like crazy once car is warmed up.
-mid frequency tapping when rpms were taken over 2000 rpms.
-dramatic loss of power over 2500 rpms
This was my car a few years ago. The knock was more mid-freqnency than a SBC IMO.
Bent valves would make a car idle really shitty.
