Help Diagnosing Ticking Sound
#46
Three Wheelin'
IMS was done a while back and a certified shop, so I am confident that is good.
I agree, I am not yet sold on bore scoring, it just sounds so awful. I did just see another thread with a really awful sound being caused by a bad injector, so I haven’t lost hope yet.
I could look at values with my durametric but I am afraid to run it too much in fear that if it is like a spun bearing or broken chain guide it is doing more damage. I think I am going to pull the filter and take it up to my Indy to cut open while I wait for a bore scope to arrive.
I agree, I am not yet sold on bore scoring, it just sounds so awful. I did just see another thread with a really awful sound being caused by a bad injector, so I haven’t lost hope yet.
I could look at values with my durametric but I am afraid to run it too much in fear that if it is like a spun bearing or broken chain guide it is doing more damage. I think I am going to pull the filter and take it up to my Indy to cut open while I wait for a bore scope to arrive.
#47
Three Wheelin'
Thread Starter
#48
Three Wheelin'
Thread Starter
it could be a lifter is permanently bled down, sounds super similar to bore score, would tap longer into the rev range than bore score which is what threw me off in your first video. Bore score tap usually goes away after about 2K rpm as it does doesn't have the dwell to slap. the vario cam lifters are known to crack, and if it cracks too much it wont hold pressure and you get a very similar tap to bore score. its rare but happens, could explain the sudden onset.
The sound definitely goes away after 2.5k. I think I should follow a process of investigation that eliminates scoring or major internal failure first, which is what I think you are advocating.
Last edited by bgoetz; 08-04-2021 at 06:02 PM.
#49
Former Vendor
Focus On: Bore Scoring Video Series
In one of Jake's videos, he isolates the tick using a stethoscope. From underneath, he probes each cylinder. It was clear. I suspect you are not putting the stethoscope in the right places. I don't know which video it was.... you can go fishing on his YouTube channel.
Start here by joining:
https://www.youtube.com/channel/UCvI...Fh9qy9ZvA/join
After joining, click this playlist:
The series can also be view on Amazon Prime:
Thank you for your support!
Last edited by Flat6 Innovations; 08-04-2021 at 06:17 PM.
#50
Nordschleife Master
#51
Three Wheelin'
Thread Starter
I am fairly handy with cars and could easily swap out an engine. My brother in law has a shop and a nice lift. My goal is to try to figure out if I am dealing with a rebuild situation before doing anything with the car. From there I can decide the course of action because that might not involve the car going to my indy. If we can’t conclusively determine if it needs rebuilt then yes it will be trailered up to him.
If there is crap in the filter it is pretty much a stop point because then we know it is internal damage. I might drop the sump at that point to get a better idea of just how bad it is and if it might impact a rebuild budget.
If there is crap in the filter it is pretty much a stop point because then we know it is internal damage. I might drop the sump at that point to get a better idea of just how bad it is and if it might impact a rebuild budget.
#52
I am fairly handy with cars and could easily swap out an engine. My brother in law has a shop and a nice lift. My goal is to try to figure out if I am dealing with a rebuild situation before doing anything with the car. From there I can decide the course of action because that might not involve the car going to my indy. If we can’t conclusively determine if it needs rebuilt then yes it will be trailered up to him.
If there is crap in the filter it is pretty much a stop point because then we know it is internal damage. I might drop the sump at that point to get a better idea of just how bad it is and if it might impact a rebuild budget.
If there is crap in the filter it is pretty much a stop point because then we know it is internal damage. I might drop the sump at that point to get a better idea of just how bad it is and if it might impact a rebuild budget.
#53
Rennlist Member
If you have access to a shop and a lift I think dropping the sump and doing a complete bore scoping would be the step that would be most revealing. Not sure why a car suddenly produces the piston slap noise out of nowhere. Have never heard an explanation of what physically changes in that moment but something must happen. Best of luck and I will be following along.
#54
If you have access to a shop and a lift I think dropping the sump and doing a complete bore scoping would be the step that would be most revealing. Not sure why a car suddenly produces the piston slap noise out of nowhere. Have never heard an explanation of what physically changes in that moment but something must happen. Best of luck and I will be following along.
The following users liked this post:
Optionman1 (08-05-2021)
#55
Rennlist Member
Just came across this in a 996 thread and thought it couldn't hurt to copy it here:
You are correct in that "most " rod bearing failures on common engines have that deep knock sound, but M96/7 engines have a really tight clearance from the piston crown to the head quench area.
So much so that any carbon build-up in the piston crown of over 1mm can also lead to a sound like "piston slap".. Case in point a Rennlister here (3/98 911 Coupe ) had a knock that everyone assumed was a bore-score/piston-slap, I suggested he do a de-carbon of the pistons and TexSquirrel did it ( thread in here for some if interested) and it totally stopped the knock.
I went over to the 986 forum and looked/listened to the video/audio, that engine with only 5 psi oil pressure and that sound for sure has a failed rod bearing.
This was posted by @Porschetech3 who is an expert.
You are correct in that "most " rod bearing failures on common engines have that deep knock sound, but M96/7 engines have a really tight clearance from the piston crown to the head quench area.
So much so that any carbon build-up in the piston crown of over 1mm can also lead to a sound like "piston slap".. Case in point a Rennlister here (3/98 911 Coupe ) had a knock that everyone assumed was a bore-score/piston-slap, I suggested he do a de-carbon of the pistons and TexSquirrel did it ( thread in here for some if interested) and it totally stopped the knock.
I went over to the 986 forum and looked/listened to the video/audio, that engine with only 5 psi oil pressure and that sound for sure has a failed rod bearing.
This was posted by @Porschetech3 who is an expert.
#56
Nordschleife Master
I am fairly handy with cars and could easily swap out an engine. My brother in law has a shop and a nice lift. My goal is to try to figure out if I am dealing with a rebuild situation before doing anything with the car. From there I can decide the course of action because that might not involve the car going to my indy. If we can’t conclusively determine if it needs rebuilt then yes it will be trailered up to him.
If there is crap in the filter it is pretty much a stop point because then we know it is internal damage. I might drop the sump at that point to get a better idea of just how bad it is and if it might impact a rebuild budget.
If there is crap in the filter it is pretty much a stop point because then we know it is internal damage. I might drop the sump at that point to get a better idea of just how bad it is and if it might impact a rebuild budget.
#57
Three Wheelin'
Thread Starter
Small update. I drained a bit of oil to grab a sample and look at the magnetic drain plug and also pulled the filter. The drain plug clean minus the typical small amount of sludge it collects. The oil looked mostly clean with only a couple of small aluminum flakes. Based on the sound the engine is making I would expect to see more metal, but I will know more this afternoon when we cut open the filter.
Right now I am still considering something as simple as a hydraulic chain tensioner failing. I was occasionally getting chain slap on startup and it actually started to happen more frequently. I think a chain tensioner could also result in a little aluminum from the chain slapping the case. But again hopefully the filter will tell us a bit more.
Right now I am still considering something as simple as a hydraulic chain tensioner failing. I was occasionally getting chain slap on startup and it actually started to happen more frequently. I think a chain tensioner could also result in a little aluminum from the chain slapping the case. But again hopefully the filter will tell us a bit more.
#58
Three Wheelin'
Pics of debris?
#59
Three Wheelin'
Thread Starter
#60
Any chance you can drop the sump at your house? That will give you a clear view of the bottom of the cylinders and might paint a more accurate picture of what is going on. According to the experts, that is where scoring begins.
I suspect most, if not all of our cars with 30k or 40k plus miles have some degree of "streaking" or "scuffing", but full on scoring is hard to miss if you're looking at the cylinder from the bottom with the sump removed.
I suspect most, if not all of our cars with 30k or 40k plus miles have some degree of "streaking" or "scuffing", but full on scoring is hard to miss if you're looking at the cylinder from the bottom with the sump removed.