[C2] 454 developed sudden loud hammering sound
08-08-2017, 10:43 PM
#43
Instructor
Thread Starter
No bent spark plug electrodes. I carefully cut the oil filter open using shears to avoid making my own metal fragments and checked the filter media. No apparent sparkles or observable metal pieces. I purchased a higher quality endoscope and and found nothing abnormal in the cylinders. Drained the pan and the oil was already a bit dark (not black) and looked like it might have metal flakes in it but if so they were the size of dust particles. My honey is pushing me to finish 3 major projects on house and land before the rains start in October so I'm working only in the evenings on the Vette. Every one of you guys have given me thoughtful and insightful suggestions which I much appreciate. Question: If a piece of RTV made it passed the filter and lodged in an oil passage how will I ever determine that happened or even find it without pulling the engine and field stripping it and/or running a rifle brush though the lines?
08-08-2017, 11:12 PM
#44
Safety Car
I would doubt that silicone would cause any issues.
08-09-2017, 02:17 AM
#45
I have seen Silicon sealer destroy a few caterpillar engines.
a blocked port by a bead of silicon can have catastrophic results.
The trend to use silicon on the front and rear of BB manifolds these days, could cause problems.
a blocked port by a bead of silicon can have catastrophic results.
The trend to use silicon on the front and rear of BB manifolds these days, could cause problems.
08-09-2017, 06:42 AM
#46
Safety Car
No bent spark plug electrodes. I carefully cut the oil filter open using shears to avoid making my own metal fragments and checked the filter media. No apparent sparkles or observable metal pieces. I purchased a higher quality endoscope and and found nothing abnormal in the cylinders. Drained the pan and the oil was already a bit dark (not black) and looked like it might have metal flakes in it but if so they were the size of dust particles. My honey is pushing me to finish 3 major projects on house and land before the rains start in October so I'm working only in the evenings on the Vette. Every one of you guys have given me thoughtful and insightful suggestions which I much appreciate. Question: If a piece of RTV made it passed the filter and lodged in an oil passage how will I ever determine that happened or even find it without pulling the engine and field stripping it and/or running a rifle brush though the lines?
08-09-2017, 09:08 AM
#47
Safety Car
Fine metallic particles are normal. For silicone to be an issue it would have to be pretty good size. A piece big enough to cause problems wouldn't go through the pickup screen on the pump. I'm not saying it's impossible but highly unlikely. One more thing to try is push the crank to the rear then lightly pry it forward from the rear of the balancer. It should move no more than .015". You will be checking to make sure the thrust bearing isn't worn out. The lack of metal or cylinder damage is at least good. Have you gone through each valve to make sure none backed off?
08-09-2017, 01:07 PM
#48
Instructor
Thread Starter
Fine metallic particles are normal. For silicone to be an issue it would have to be pretty good size. A piece big enough to cause problems wouldn't go through the pickup screen on the pump. I'm not saying it's impossible but highly unlikely. One more thing to try is push the crank to the rear then lightly pry it forward from the rear of the balancer. It should move no more than .015". You will be checking to make sure the thrust bearing isn't worn out. The lack of metal or cylinder damage is at least good. Have you gone through each valve to make sure none backed off?
The lifters are hydraulic but I checked for collapsed or broken plus bent push rods or valve spring issues and found none. When the tappets are on the heal of the cam each rocker has a slight amount of pressure which leads me to the conclusion the hydraulic lifters are okay. The trunnions on the roller rockers appear intact as well. I'm pulling the pan to have a look at the bottom end and if I find nothing I will pull the heads to look further. Odd problem and even more so on what caused it. Thanks for sharing your knowledge.
08-09-2017, 02:05 PM
#49
Le Mans Master
Member Since: Sep 2009
Location: "You may all go to Hell- and I will go to Texas- Davy Crockett
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St. Jude Donor '12
Fine metallic particles are normal. For silicone to be an issue it would have to be pretty good size. A piece big enough to cause problems wouldn't go through the pickup screen on the pump. I'm not saying it's impossible but highly unlikely. One more thing to try is push the crank to the rear then lightly pry it forward from the rear of the balancer. It should move no more than .015". You will be checking to make sure the thrust bearing isn't worn out. The lack of metal or cylinder damage is at least good. Have you gone through each valve to make sure none backed off?
08-09-2017, 05:52 PM
#50
Le Mans Master
A spun rod brg will leave a lot of copper in your oil and oil pan. Spun bearings usually continue to get louder the longer you run.
If you are running aluminum bearings they will Gaul to your crankshaft bearing surface in failure but not put much in the pan.
Both failures normally happen do to oil starvation.
I have seen an oil screen on the pick up tube 75% plugged by a builder that overdosed with silicone and many chunks got into the oil system.
On cold start up most Chevy pick up screens flex open and unfiltered oil is pumped through the engine. As the oil warms the by pass closes and you get filtered oil.
That is how chunks flow to cause you issues.
I have seen a piston hydro lock where it slightly bent a connecting rod. Enough that the piston hit my head with every revolution. Left a small dent on one side of the piston and a small shiny spot in the head. Engine ran perfect other than the knock. Leaking fuel or coolant can cause hydro lock.
I would pull the heads first. That repair can be done in the car.
If the problem does not show up there you will be removing the engine to repair crank and rod damage.
Not a bad idea to check the thrust bearing clearance front to back movement as that could potentially be repaired in the car and I have seen some make knocking noises.
Is this an automatic car? Turbo 400's are known to balloon and pressure the thrust.
If it's a 4 speed did you recently work on the clutch?
If you are running aluminum bearings they will Gaul to your crankshaft bearing surface in failure but not put much in the pan.
Both failures normally happen do to oil starvation.
I have seen an oil screen on the pick up tube 75% plugged by a builder that overdosed with silicone and many chunks got into the oil system.
On cold start up most Chevy pick up screens flex open and unfiltered oil is pumped through the engine. As the oil warms the by pass closes and you get filtered oil.
That is how chunks flow to cause you issues.
I have seen a piston hydro lock where it slightly bent a connecting rod. Enough that the piston hit my head with every revolution. Left a small dent on one side of the piston and a small shiny spot in the head. Engine ran perfect other than the knock. Leaking fuel or coolant can cause hydro lock.
I would pull the heads first. That repair can be done in the car.
If the problem does not show up there you will be removing the engine to repair crank and rod damage.
Not a bad idea to check the thrust bearing clearance front to back movement as that could potentially be repaired in the car and I have seen some make knocking noises.
Is this an automatic car? Turbo 400's are known to balloon and pressure the thrust.
If it's a 4 speed did you recently work on the clutch?
Last edited by Westlotorn; 08-09-2017 at 06:22 PM.
08-12-2017, 02:52 PM
#51
Melting Slicks
Thinking about this I remembered an incident from the 80s. I was supervising a shop where we built 40 performance motors a week. All of the sudden a pattern developed where big blocks were crashing intake valves. We had a book with serial numbers to track who built each engine. I quickly figured out all of the motors, 9 in total, were built by the same guy. I grabbed a timing chain set went to his assembly area and laid it on the bench. I said now show me how you are timing your engines. The timing sets were the three key way sets that have been used forever. He goes about showing me how he's doing it. I watched him and I said that is what I was afraid of. He had installed everyone of them with the cam three teeth advanced. Some only bent the valves, some had not been cranked and we were able to do the easy fix, and one dropped a valve and destroyed the engine. Are you certain one that is timed right and two you had enough piston to valve clearance. When you say you installed a cam with milder manners I assume that means smaller and therefore should have more clearance. But if it's not timed correctly you could have trouble.
08-12-2017, 10:35 PM
#52
Le Mans Master
Member Since: Sep 2009
Location: "You may all go to Hell- and I will go to Texas- Davy Crockett
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St. Jude Donor '12
Thinking about this I remembered an incident from the 80s. I was supervising a shop where we built 40 performance motors a week. All of the sudden a pattern developed where big blocks were crashing intake valves. We had a book with serial numbers to track who built each engine. I quickly figured out all of the motors, 9 in total, were built by the same guy. I grabbed a timing chain set went to his assembly area and laid it on the bench. I said now show me how you are timing your engines. The timing sets were the three key way sets that have been used forever. He goes about showing me how he's doing it. I watched him and I said that is what I was afraid of. He had installed everyone of them with the cam three teeth advanced. Some only bent the valves, some had not been cranked and we were able to do the easy fix, and one dropped a valve and destroyed the engine. Are you certain one that is timed right and two you had enough piston to valve clearance. When you say you installed a cam with milder manners I assume that means smaller and therefore should have more clearance. But if it's not timed correctly you could have trouble.
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Stan's Customs (08-15-2017)
08-16-2017, 12:33 AM
#54
Instructor
Thread Starter
Guys I'm not ignoring all your helpful ideas/suggestions, I'm just deep into getting water and electric service run to my new shop plus some concrete projects I promised by better half would be done before the rains start.
I did a compression test and all 8 cylinders are at 225 lbs (+/- 5 lbs).
I removed the pan and there is no evidence of RTV in the pump screen or the filter. I tried to move each of the rods perpendicular to the crank throws and felt no movement. With a fair amount of effort they will move side to side but minimally...maybe .010" or so and they're all about the same. I'm down to pulling rod bearing caps just to look see anyway but I do not think it's a rod. I'm hoping for some more free time so I can get a small jack under the crank to take up the weight so I can check for any main bearing movement. There are no broken skirts or metal pieces of any sort in the pan. What the heck could make such an enormous hammering sound and still have the engine run is still the mystery.
Any quick ways to check main bearings other than lifting up the weight of the crank/rods/pistons to measure play? Thanks and please don't give up on me I just have other irons in the fire at the same time. Cheers.
I did a compression test and all 8 cylinders are at 225 lbs (+/- 5 lbs).
I removed the pan and there is no evidence of RTV in the pump screen or the filter. I tried to move each of the rods perpendicular to the crank throws and felt no movement. With a fair amount of effort they will move side to side but minimally...maybe .010" or so and they're all about the same. I'm down to pulling rod bearing caps just to look see anyway but I do not think it's a rod. I'm hoping for some more free time so I can get a small jack under the crank to take up the weight so I can check for any main bearing movement. There are no broken skirts or metal pieces of any sort in the pan. What the heck could make such an enormous hammering sound and still have the engine run is still the mystery.
Any quick ways to check main bearings other than lifting up the weight of the crank/rods/pistons to measure play? Thanks and please don't give up on me I just have other irons in the fire at the same time. Cheers.
08-16-2017, 12:51 AM
#56
Instructor
Thread Starter
Can anyone describe just how loose a rod bearing should feel to make a solid and loud hammering sound? I can pry the rods minimally front to rear using a large screwdriver but none at all lateral to the crank throws.
08-16-2017, 05:53 AM
#57
Race Director
If you had enough lateral rod clearance at the crank to cause noise I believe it would be very apparent. I have a Mopar that probably has close to .10 inch and it's pretty quiet. Better to be a little large than too tight. I would keep looking.
Have you checked to make sure your pressure plate bolts are not coming through the forward side of the flywheel and hitting the block?
Have you checked to make sure your pressure plate bolts are not coming through the forward side of the flywheel and hitting the block?
Last edited by DansYellow66; 08-16-2017 at 05:55 AM.
08-16-2017, 07:15 AM
#58
Drifting
I am reminded of a situation that happened to me. I replaced the heads on our car, and at startup there was a loud racket coming from one side of the engine. Wife said, "That sounds like s**t". I was so glad she told me that. 
Anyway, while replacing the heads, a 9/16 wrench had slipped down into the top of the open side pipe and was making a LOUD racket in there when the engine was running.
You didn't say anything about disconnecting your exhaust, so that can't be the problem though.
Gerry
Anyway, while replacing the heads, a 9/16 wrench had slipped down into the top of the open side pipe and was making a LOUD racket in there when the engine was running.
You didn't say anything about disconnecting your exhaust, so that can't be the problem though.
Gerry
08-16-2017, 08:39 AM
#59
Race Director
I am reminded of a situation that happened to me. I replaced the heads on our car, and at startup there was a loud racket coming from one side of the engine. Wife said, "That sounds like s**t". I was so glad she told me that.
Anyway, while replacing the heads, a 9/16 wrench had slipped down into the top of the open side pipe and was making a LOUD racket in there when the engine was running.
You didn't say anything about disconnecting your exhaust, so that can't be the problem though.
Gerry
Anyway, while replacing the heads, a 9/16 wrench had slipped down into the top of the open side pipe and was making a LOUD racket in there when the engine was running.
You didn't say anything about disconnecting your exhaust, so that can't be the problem though.
Gerry
Last edited by DansYellow66; 08-16-2017 at 08:39 AM.
08-16-2017, 10:42 AM
#60
A little side to side play in the rod bearings on the crank is ok. As Dan stated, you would easily find the spun rod bearing. Everyone that I've seen, you can move the rod the thickness of the bearing, or one side of the bearing, up and down on the crank with your fingers. Visually inspect it as well.
When you did the compression check, I assume you had all the plugs out and spun the engine. No noise? Maybe that's a clue. I like the thought about the flywheel, but also check the harmonic balancer. It appears as though you have eliminated a lot of the serious issues so hopefully it'll be something simple.
Why do these things always happen when we have major projects happening around the house? I feel your pain there.
When you did the compression check, I assume you had all the plugs out and spun the engine. No noise? Maybe that's a clue. I like the thought about the flywheel, but also check the harmonic balancer. It appears as though you have eliminated a lot of the serious issues so hopefully it'll be something simple.
Why do these things always happen when we have major projects happening around the house? I feel your pain there.