Loose Rod Bolt...question....
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
Loose Rod Bolt...question....
If I had a loose rod bolt or a spun rod bearing, could I just pull all the bearings and replace them and be on my merry way? or would I need to have the block machined and what not? The car has only a loss in perfomance like it doesn't want to run (sorta like it's missing I guess you could say) which leads me to believe it may be a rod bolt loose, making a piston not completely fire...causing the clanging noise. Because I drove it 50 miles at 65mph and it didn't blow up...just kept clanging. Any ideas? I really don't want to completely pull this entire motor...
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: Loose Rod Bolt...question.... (TIMSPEED)
You can replace bearings by dropping the oil pan. It is, however, not a very good option. And before you plan on doing that, make sure it's a bearing.
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: Loose Rod Bolt...question.... (TIMSPEED)
I thought I had a spun bearing .. it turned out to be a piston rocking inside the cylinder. The piston skirts of stock pistons are very small and after time they don't fit 100%. Had 3 people varify it was a spun bearing too! :crazy: All my bearings looked normal for 134k miles.
[Modified by Glock'94, 5:31 PM 4/16/2002]
[Modified by Glock'94, 5:32 PM 4/16/2002]
[Modified by Glock'94, 5:31 PM 4/16/2002]
[Modified by Glock'94, 5:32 PM 4/16/2002]
Melting Slicks
Joined: Aug 2001
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From: Lockport NY
Re: Loose Rod Bolt...question.... (TIMSPEED)
If I had a loose rod bolt or a spun rod bearing, could I just pull all the bearings and replace them and be on my merry way? or would I need to have the block machined and what not?
If you've spun a bearing, you'll probably have no oil pressure.
If you had a loose rod bolt, it would hammer itself & the bearing to pieces soon. And ruin the rod.
The good news is that the block itself (probably) won't be damaged...
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Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
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From: Modesto CA
Re: Loose Rod Bolt...question.... (Glock'94)
It's ABSURD! The oil pressure is FINE, no loss in pressure, but the clanging is still there. I may take a clip of the clanging, so you guys can hear it. I know when you lose a piston, the oil pressure drops and it starts smoking pretty bad (cuz it's burning oil more). None of these symptoms, and I think if the rod was loose...after 50 miles at 65mph, I would THINK it would just shoot itself right out! But it hasn't. It just acts like it misses. It's got me going up the wall! (Cuz I really don't wanna replace the motor if I don't have to) I'm gonna pull the oil pan and check all rod bolts, etc. My buddy said I have alot of end play in my crankshaft, what would this be? He suggested a piston pin. Maybe a piston's let go, and the rod is smacking the piston? But wouldn't I have crushed a valve by now? I also tried to pull plugs, and see if maybe the sound decreased...no luck, sound is still just as loud firing on 7 cylinders (pulled one at a time) It's MIND boggling. I think I'll pull the heads off and check out the valves and stuff.
Advanced
Joined: Jan 2002
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From: Belleville Illinois
Re: Loose Rod Bolt...question.... (TIMSPEED)
How about a cracked flexplate, or loose flexplate bolts. These will make a knock. I would think your oil pressure would be down if you had lower end problems. You can unbolt the torque converter, and slide it back, start the engine and see if knock is there. This would be less work than pulling the oil pan.
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: Loose Rod Bolt...question.... (jimbos86vette)
How about a cracked flexplate, or loose flexplate bolts. These will make a knock. I would think your oil pressure would be down if you had lower end problems. You can unbolt the torque converter, and slide it back, start the engine and see if knock is there. This would be less work than pulling the oil pan.
Team Owner
Joined: Mar 2001
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From: Cincinnati, Oh USA
Re: Loose Rod Bolt...question.... (TIMSPEED)
If its rod bearing or piston pin related you will hear two clunks each crank revolution and it sounds like a clunk, not a clank. Piston skirt slap isn't very loud and doesn't clank, but sounds like a muffled rattle. A stethascope will help locate the source. You might have a stuck valve which makes a loud clanking sound and it comes from under one of the valve covers. First try and find the source of the sound, then start taking things apart. In the future when you hear scary noises , don't drive 65 mph for 50 miles......don't drive it at all......start looking for the cause! :eek:
Team Owner
Joined: Apr 2001
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From: Dallas TX
Re: Loose Rod Bolt...question.... (jfb)
In the future when you hear scary noises , don't drive 65 mph for 50 miles......don't drive it at all......start looking for the cause! :eek:
Thread Starter
Le Mans Master
Joined: Mar 2001
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From: Modesto CA
Re: Loose Rod Bolt...question.... (BrianCunningham)
I've had the inspection cover off and COMPLETELY looked at the flexplate, because that's what I thought the problem was too. Five different mechanics have said it's NOT the flexplate (but I STILL think it is) If it was anything wrong with the bottom end, I couldn't have drove that long without actually doing MAJOR damage (ie: shooting a rod through the oil pan) I'll pull the tranny back and take a look.
Team Owner
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From: This vette goes to 11 Milford MA
St. Jude Donor '03-'05
Re: Loose Rod Bolt...question.... (TIMSPEED)
Drain the oil and inspoect it, cut open the filter. Hammered bearings leave evidence. If the oil has a silvery shimmer in it, you have BAD THINGS going on inside. To fix BAD THINGS, the engine should come out.
Burning Brakes
Joined: May 2001
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Re: Loose Rod Bolt...question.... (Fastguy)
If it's a steady miss on one cylinder, determine which cylinder it is by pulling one plug wire at a time. Each time you pull one that's working, you'll know it. When you pull the one that's bad, you'll notice no difference. Once you've determined which cylinder is missing, pull that valve cover. I suspect you have a stuck valve that's hammering the top of the piston OR you have a broken rocker arm. Stock rocker arms flex and crack after long usage and can completely come apart. When they do, they make a clanging notice. I betcha!
Burning Brakes
Joined: May 2001
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Re: Loose Rod Bolt...question.... (emoshn)
By the way, if you've got good oil pressure, you don't have a spun bearing or loose rod. If you've got a messed up piston (which I doubt), you'll have huge amounts of blowby.
Do you still have good oil pressure? are you burning lots of oil? Do you have a lot of blow by?
Do you still have good oil pressure? are you burning lots of oil? Do you have a lot of blow by?
Burning Brakes
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Re: Loose Rod Bolt...question.... (emoshn)
Reread your post. A blown piston will not necessarily affect oil pressure. In fact, i doubt it would affect it at all. Excessive end play in crankshaft? How was this measured, and after high mileage, more than stock end play is acceptable...but piston pins have NOTHING to do with end play of a crankshaft, that is determined by the main journal bearings and shimming.
It REALLY sounds like valve problems. Let us know.
It REALLY sounds like valve problems. Let us know.
Pro
Joined: Nov 1999
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From: Auburn Georgia
Cruise-In II Veteran
Re: Loose Rod Bolt...question.... (emoshn)
If it's a steady miss on one cylinder, determine which cylinder it is by pulling one plug wire at a time. Each time you pull one that's working, you'll know it. When you pull the one that's bad, you'll notice no difference. Once you've determined which cylinder is missing, pull that valve cover. I suspect you have a stuck valve that's hammering the top of the piston OR you have a broken rocker arm. Stock rocker arms flex and crack after long usage and can completely come apart. When they do, they make a clanging notice. I betcha!