Oldsmobile 455 knocking and rattling.
#47
Looks like someone hit it with an air hammer.
If the flexplate has cracks, they will be difficult to impossible to see with it in the car - you've got to look at the part you can see holding a light at several angles, then rotate the engine and look again. Look close to the center, by the crankshaft screws.
- Eric
If the flexplate has cracks, they will be difficult to impossible to see with it in the car - you've got to look at the part you can see holding a light at several angles, then rotate the engine and look again. Look close to the center, by the crankshaft screws.
- Eric
#48
logical thinking
Ok, time to think logically about this.
1. How did this metal get into the cylinder? Only 2 ways, either someone dropped something down the intake/carb or something got sucked into the intake/carb. It's not valve spring material that's too hard to get past valve guide, not metal head gasket or you would have coolant problems. It looks like you have an aluminum intake, so did someone drop something into the intake? Metal color looks wrong for a chunk of bathtub intake pan gasket. Are there any pieces missing from the inside of your air cleaner? Air door on the air cleaner still there?
2. You say you have a inspectioncamera, use it to check for rod bearing damage. You can leave the rockers off the cylinder you found the metal in. Pull all the spark plugs, using the inspectioncamera and manually turning the engine over bring that cylinder's piston up to TDC and watch for piston dwell at the top of the stroke. The piston will come up, stop (dwell), and then go back down, there should be no more than about 5 degrees of a turn on the harmonic balancer. If there is then the bearing is wiped out. If your not sure on the amount of dwell then compare it to another cylinder. I have taken engines apart that had 30 psi oil pressure, no knock, but on one I could push #2 piston down 1/4 inch. I had to cut the steel backing apart to get the bearing off, yet there was no knock.
3. Usually when the flex-plate is cracked you can here it when cranking the engine over. You can here a cracking/grinding noise, also you can see it from below when the engine is being cranked over, the flex-plate will move back-n-forth quite a bit.
4. I'm not kidding about the timing chain cam gear, your motor is doing/running exactly the same as my old motor did when I lost a few nylon teeth off the cam gear. For $30-40 I replaced the chain in 1 hour and all was well. A valve hitting that metal is a large jar to the valve train and will want to stop the timing chain dead in it's tracks, hell of a whip anyway, check it out.
Ray
1. How did this metal get into the cylinder? Only 2 ways, either someone dropped something down the intake/carb or something got sucked into the intake/carb. It's not valve spring material that's too hard to get past valve guide, not metal head gasket or you would have coolant problems. It looks like you have an aluminum intake, so did someone drop something into the intake? Metal color looks wrong for a chunk of bathtub intake pan gasket. Are there any pieces missing from the inside of your air cleaner? Air door on the air cleaner still there?
2. You say you have a inspectioncamera, use it to check for rod bearing damage. You can leave the rockers off the cylinder you found the metal in. Pull all the spark plugs, using the inspectioncamera and manually turning the engine over bring that cylinder's piston up to TDC and watch for piston dwell at the top of the stroke. The piston will come up, stop (dwell), and then go back down, there should be no more than about 5 degrees of a turn on the harmonic balancer. If there is then the bearing is wiped out. If your not sure on the amount of dwell then compare it to another cylinder. I have taken engines apart that had 30 psi oil pressure, no knock, but on one I could push #2 piston down 1/4 inch. I had to cut the steel backing apart to get the bearing off, yet there was no knock.
3. Usually when the flex-plate is cracked you can here it when cranking the engine over. You can here a cracking/grinding noise, also you can see it from below when the engine is being cranked over, the flex-plate will move back-n-forth quite a bit.
4. I'm not kidding about the timing chain cam gear, your motor is doing/running exactly the same as my old motor did when I lost a few nylon teeth off the cam gear. For $30-40 I replaced the chain in 1 hour and all was well. A valve hitting that metal is a large jar to the valve train and will want to stop the timing chain dead in it's tracks, hell of a whip anyway, check it out.
Ray
#49
#50
Hey Ray, thank you for your insights. I ordered a recording inspectioncamera. I used a friends camera the first time. I'll try to remove the timing chain cover tomorrow. I did a leaktest and it looks ok. Did a compressiontest also. 1 cilinder took a little longer building pressure. Maybe i did it wrong. On the one on the left i did only 5 cylinders and three cranks.
#51
Compression looks good for an engine with mileage, 114 psi for a low compression is not bad yet, no major damage. Boy I haven't seen a MotoMeter since I was a kid and yours still works! Cool.
Ray
Ray
#52
Pull the head on the side where the plug was mashed (if it was mashed?)?
The damage should be obvious.
#54
#55
the plug was not completely mashed. Gap was reduced to 1 mm. It was the cylinder with the metal piece. (second one on the left standing in front of the engine). It's hard to look at the flexplate. Outer three bolts look ok. As soon as i have the inspectioncamera i will try to record the whole plate.
maybe i can see something thru the fuelpump whole?
maybe i can see something thru the fuelpump whole?
#56
There is evidence of a fastener being ground up by those witness marks on the flywheel inspection cover. Does it make this noise now that that cover is off?
If yes then this thing is a ticking time bomb. You wont see much through the pump hole. If your reluctant to pull the engine out or apart then Im not sure what else to tell you. You need eyeballs on the rotating assembly. The trans needs to come off to get a good look at the flex plate. Heads need to come off to have a look at the top end. IMO if your that far into it pull the thing out and pull it apart and inspect everything. If you find nothing wrong (which we all doubt) you can slap it back together with a reseal kit and have confidence that all is well. Piece of mine I call it. FYI...A flex plate/flywheel can come through the floor tunnel and take off you foot at high RPMs with out a scatter shield in place.
Think safety too not just dollars.
If yes then this thing is a ticking time bomb. You wont see much through the pump hole. If your reluctant to pull the engine out or apart then Im not sure what else to tell you. You need eyeballs on the rotating assembly. The trans needs to come off to get a good look at the flex plate. Heads need to come off to have a look at the top end. IMO if your that far into it pull the thing out and pull it apart and inspect everything. If you find nothing wrong (which we all doubt) you can slap it back together with a reseal kit and have confidence that all is well. Piece of mine I call it. FYI...A flex plate/flywheel can come through the floor tunnel and take off you foot at high RPMs with out a scatter shield in place.
Think safety too not just dollars.
#58
https://www.youtube.com/watch?v=qHhU...ature=youtu.be
finally found some time to continue. Looks like the timing chain is really loose.
finally found some time to continue. Looks like the timing chain is really loose.
#59
Yeah, that timing chain's a little loose.
Looks like a steel sprocket, though, so it must have been changed.
When you say "There is no oil to the lifters," do you mean NO oil, or do you mean just a little oil?
- Eric
Looks like a steel sprocket, though, so it must have been changed.
When you say "There is no oil to the lifters," do you mean NO oil, or do you mean just a little oil?
- Eric
#61
there is a really small amount of oil under the valvecovers. But the engine had been sitting for a few years. It doesn't squirt out when it runs for 1 min. It idles really rough.
#63
#65
Sorry, i have been busy with work and more. Finally found some time to work on the engine.
It looks like piston number 5 kissed the head.
Need to pull the engine to look at the crankshaft. I guess I found the source of the knock.
It looks like piston number 5 kissed the head.
Need to pull the engine to look at the crankshaft. I guess I found the source of the knock.
#66
This goes around a lot when timing chain and gears are suspect but yours has been replaced. Is it possible some debris from the old synthetic timing gear has plugged the oil pick-up and starved the engine long enough to damage it?
Thread
Thread Starter
Forum
Replies
Last Post
Hetman
Small Blocks
10
August 24th, 2012 01:19 PM