Bottom end knock (not as bad when gets warm)
Bottom end knock (not as bad when gets warm)
Hi Guys,
I got my 03 from someone who did a **** poor job at doing a rebuild about 3 years ago... From day one it had a bit of a knock on cold starts and would almost go away once operating temp was reached... I am sick and tired of this noise and it has gotten worse with time.
Was thinking of doing rod and main bearings... Any thoughts? Advice? If so, any sizing advice would be great.
I got my 03 from someone who did a **** poor job at doing a rebuild about 3 years ago... From day one it had a bit of a knock on cold starts and would almost go away once operating temp was reached... I am sick and tired of this noise and it has gotten worse with time.
Was thinking of doing rod and main bearings... Any thoughts? Advice? If so, any sizing advice would be great.
Winching
Joined: Apr 2016
Posts: 524
Likes: 120
From: Chattanooga TN
If the bearings are bad enough to cause a rod to knock, the crank will probably want some attention as well. At that point, you're into full rebuild territory.
Are you sure it's a rod? I once had an exhaust leak between the header and Y-pipe and it sounded EXACTLY like rod knock on a cold startup.
Are you sure it's a rod? I once had an exhaust leak between the header and Y-pipe and it sounded EXACTLY like rod knock on a cold startup.
Recovery Vehicle
Joined: Jul 2016
Posts: 949
Likes: 54
Remember that a rod or crank knock will be a "double" knock. While idling, it will be two sounds in rapid succession, short interval of no sound, then tow knocks, so on and so forth. Clackclack....pause...clackclak. It will be fast but you can definitely tell the difference between and double knock and the alternative. If it is a steady rhythmic knock*knock*knock*knock then it is something other than the bottom end.
It could be piston slap. The stock skirts can collapse some or he could have undersized a new one. Could be a slipped liner. Could be a clogged lifter, have you ran any kind of detergent in the oil? A quart of detergent every oil change for a while could do wonders.
as far a rebuilding the bottom end in the vehicle, don't even think about it. If you want to actually do it right and not end up with the same problem all over again, you need to pull it and have it built or do the measuring yourself if you are competent and have it machined accordingly. Just rough guessing and throwing in new bearings from underneath the truck is not an option in my opinion.
It could be piston slap. The stock skirts can collapse some or he could have undersized a new one. Could be a slipped liner. Could be a clogged lifter, have you ran any kind of detergent in the oil? A quart of detergent every oil change for a while could do wonders.
as far a rebuilding the bottom end in the vehicle, don't even think about it. If you want to actually do it right and not end up with the same problem all over again, you need to pull it and have it built or do the measuring yourself if you are competent and have it machined accordingly. Just rough guessing and throwing in new bearings from underneath the truck is not an option in my opinion.
If the bearings are bad enough to cause a rod to knock, the crank will probably want some attention as well. At that point, you're into full rebuild territory.
Are you sure it's a rod? I once had an exhaust leak between the header and Y-pipe and it sounded EXACTLY like rod knock on a cold startup.
Are you sure it's a rod? I once had an exhaust leak between the header and Y-pipe and it sounded EXACTLY like rod knock on a cold startup.
Appreciate the feedback... Will need to go listen to it soon... I pulled it off the road for the winter.
Remember that a rod or crank knock will be a "double" knock. While idling, it will be two sounds in rapid succession, short interval of no sound, then tow knocks, so on and so forth. Clackclack....pause...clackclak. It will be fast but you can definitely tell the difference between and double knock and the alternative. If it is a steady rhythmic knock*knock*knock*knock then it is something other than the bottom end.
It could be piston slap. The stock skirts can collapse some or he could have undersized a new one. Could be a slipped liner. Could be a clogged lifter, have you ran any kind of detergent in the oil? A quart of detergent every oil change for a while could do wonders.
as far a rebuilding the bottom end in the vehicle, don't even think about it. If you want to actually do it right and not end up with the same problem all over again, you need to pull it and have it built or do the measuring yourself if you are competent and have it machined accordingly. Just rough guessing and throwing in new bearings from underneath the truck is not an option in my opinion.
It could be piston slap. The stock skirts can collapse some or he could have undersized a new one. Could be a slipped liner. Could be a clogged lifter, have you ran any kind of detergent in the oil? A quart of detergent every oil change for a while could do wonders.
as far a rebuilding the bottom end in the vehicle, don't even think about it. If you want to actually do it right and not end up with the same problem all over again, you need to pull it and have it built or do the measuring yourself if you are competent and have it machined accordingly. Just rough guessing and throwing in new bearings from underneath the truck is not an option in my opinion.
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