Engine Ticking Noise driving me crazy!
Posted: November 2nd, 2015, 10:56 pm
I've got a tap noise that I think I've tracked to the 6th cylinder exhaust but I'm pretty stumped and not sure where to go from here.
TL;DR Bad tap noise, lots of tests with little turn up, video below.
Background-
I have a 4.6L Icon 944 Pistons with an Erson Cam #RV12H 280/288 deg, .448/.458 lift, 112LCA. Broke it in on 30w and comp cams break in oil and it ran great except for the 24lb/hr injectors running super rich on my Renix. Switched to stock injectors after 100 miles and it ran fine. Changed oil at 300 miles with 30w Rotella T1 and Lucas Break in additive. Took it on a trip (130 miles, varied throttle) out to an off road park and had some fun but didn't push it too hard. Ran great and temps never got over 215*F. Let a friend drive it that night, went up a long, steep road and didn't notice till the top that the temperature started getting pretty high (240*F). Radiator cap might have been failing as steam was coming out. Let it cool and went back with no issues.
Issue Began-
Left on a cold morning (40*F) next day and was gentle to let it warm up while driving. 10 minutes into the trip home before I hit the highway I noticed a loud tapping noise start up, temp was 160*F. Pulled over to take a look and it seemed like valve train and it was loud. Fluids were good, nothing was damaged and I had to make it back home that day so I drove it 130 miles back home going easy on it. Temps rose to around 230*F which was higher than the way up, may have had a little air in the cooling system. Still had plenty of power and ran well, just didn't sound very happy. Haven't driven it since.
Investigation-
It's a very distinct, loud, tap coming from the rear top of the engine from what I can tell. It increases with engine speed and happens regardless of engine temperature. Popped the valve cover and all rockers had oil and nothing was loose or out of place. Popped oil pan and there were no chunks in the pan and nothing looked majorly bad. Rods weren't bouncing around and I didn't see any huge scuffs on the Camshaft from what little I checked.
6th cylinder at the top, 1st cylinder towards the bottom.
Tried easiest stuff first, replaced oil with 10w30 Dino and some Risoline additive to see if lighter weight helped free anything, no luck. Pulled spark plugs, some were light tan, some were blacker (Most likely from running rich the first 100 miles.) Tops of pistons were completely black.
Spark plugs from 6th(left) to 1st(right)
Did a compression test and everything looked good:
Cyl 1: 162psi
Cyl 2: 162psi
Cyl 3: 178psi
Cyl 4: 174psi
Cyl 5: 164psi
Cyl 6: 159psi
Interesting note: When testing cylinder 6 I could hear a tap while cranking the engine over, so maybe compression is a factor in producing the noise?
Let some seafoam sit in the cylinders for half an hour, then ran it and poured half the bottle down the throttle body and let that sit again. On start up it started running at 3k so I let it go for a minute then shut it off. Put the other half of the bottle of seafoam in the oil and drove it around the block but no luck. Put a bottle of Valve Medic oil detergent in and drove it around the block but still no change, looks like i'm not getting out easy. Time to find the noise.
Diagnostic-
Hooked up a spark plug test light to time the tapping sound to the engine speed. Once per blink is half engine speed (Camshaft) and twice per blink is engine speed (Crankshaft.) After watching the video and slowing it down 1/4 speed it sounds like it ticks once per flash, but at 1/8 speed you hear the tick followed closely by a tock. I'm going to assume this is still half engine speed which points us to the Valve Train.
Pulling the valve cover and filming the rockers, it looks like the tap aligns perfectly with the 6th cylinder exhaust rocker as it is being extended by the Camshaft. Some better slow motion video seems to verify this. I tried pushing down on the rocker arms but none of them moved down at all so the lifters are solid. Tried picking up and twisting the pushrods but none of them had any play in them.
Decided to take off 6 cyl intake and exhaust rockers and pushrods, held the lifters up with magnets, disconnected spark plug wire and fuel injector, then started the engine. The loud tapping noise was not there anymore, but once it settle there was a light chatter. Might have been a tool or something rattling so not sure for certain but it sound damn near normal again.
Took off the whole upper valve train to inspect it. None of the pushrods were bent, none of the rockers were cracked or had bad wear, none of the valve springs were cracked or were stuck shut. I figured maybe there was an unruly lifter so I pulled the head to take a look. Pulled all the lifters to inspect them, none of them seemed too bad. Most still had a very clean bottom and a few had a very light surface wear but nothing crazy. Didn't see any dirt or gunk but I replaced the lifters on 5th and 6th cylinder just to be sure.
I scrubbed the pistons clean and looked at the head but nothing stuck out at me. Replaced the intake and exhaust gasket because I had a very small exhaust leak from the ebay header I got. It seems to have warped and bowed out a tad from the heat and you could see the carbon traces on 1 and 6. Tightened it all down with a new Victor Reinz gasket and put the head back on.
Started it up and still have the exact same noise. Bummer. Waited a bit for the new lifters to pump up and cover the rockers with oil but the noise still remained. No play in the rockers still. Took some of the parts to my engine guy and he thought maybe the rocker bridge was bent and the rockers were hitting it because there was a small mark on either side of the bridge. Took it home, straightened it but still no luck. After looking carefully though it doesn't look like the rockers could hit where the marks were because the bearing mount would hit before anything and there were no marks at all between bearing foot and rocker bottom. Even marked the max rock points and ran the engine and the rockers don't go that far.
Tried moving that rocker set and pushrods to the front, and the front to the back but the noise still remained in the back. I am absolutely stumped at this point. What on earth could it possibly be?! It is killing me because I've exhausted every possible thing I could think of so maybe someone on here know's something more on the subject then I.
Youtube Video Here:
Link if that doesn't work: https://www.youtube.com/watch?v=gzslg8owJ5s
TL;DR Bad tap noise, lots of tests with little turn up, video below.
Background-
I have a 4.6L Icon 944 Pistons with an Erson Cam #RV12H 280/288 deg, .448/.458 lift, 112LCA. Broke it in on 30w and comp cams break in oil and it ran great except for the 24lb/hr injectors running super rich on my Renix. Switched to stock injectors after 100 miles and it ran fine. Changed oil at 300 miles with 30w Rotella T1 and Lucas Break in additive. Took it on a trip (130 miles, varied throttle) out to an off road park and had some fun but didn't push it too hard. Ran great and temps never got over 215*F. Let a friend drive it that night, went up a long, steep road and didn't notice till the top that the temperature started getting pretty high (240*F). Radiator cap might have been failing as steam was coming out. Let it cool and went back with no issues.
Issue Began-
Left on a cold morning (40*F) next day and was gentle to let it warm up while driving. 10 minutes into the trip home before I hit the highway I noticed a loud tapping noise start up, temp was 160*F. Pulled over to take a look and it seemed like valve train and it was loud. Fluids were good, nothing was damaged and I had to make it back home that day so I drove it 130 miles back home going easy on it. Temps rose to around 230*F which was higher than the way up, may have had a little air in the cooling system. Still had plenty of power and ran well, just didn't sound very happy. Haven't driven it since.
Investigation-
It's a very distinct, loud, tap coming from the rear top of the engine from what I can tell. It increases with engine speed and happens regardless of engine temperature. Popped the valve cover and all rockers had oil and nothing was loose or out of place. Popped oil pan and there were no chunks in the pan and nothing looked majorly bad. Rods weren't bouncing around and I didn't see any huge scuffs on the Camshaft from what little I checked.
6th cylinder at the top, 1st cylinder towards the bottom.
Tried easiest stuff first, replaced oil with 10w30 Dino and some Risoline additive to see if lighter weight helped free anything, no luck. Pulled spark plugs, some were light tan, some were blacker (Most likely from running rich the first 100 miles.) Tops of pistons were completely black.
Spark plugs from 6th(left) to 1st(right)
Did a compression test and everything looked good:
Cyl 1: 162psi
Cyl 2: 162psi
Cyl 3: 178psi
Cyl 4: 174psi
Cyl 5: 164psi
Cyl 6: 159psi
Interesting note: When testing cylinder 6 I could hear a tap while cranking the engine over, so maybe compression is a factor in producing the noise?
Let some seafoam sit in the cylinders for half an hour, then ran it and poured half the bottle down the throttle body and let that sit again. On start up it started running at 3k so I let it go for a minute then shut it off. Put the other half of the bottle of seafoam in the oil and drove it around the block but no luck. Put a bottle of Valve Medic oil detergent in and drove it around the block but still no change, looks like i'm not getting out easy. Time to find the noise.
Diagnostic-
Hooked up a spark plug test light to time the tapping sound to the engine speed. Once per blink is half engine speed (Camshaft) and twice per blink is engine speed (Crankshaft.) After watching the video and slowing it down 1/4 speed it sounds like it ticks once per flash, but at 1/8 speed you hear the tick followed closely by a tock. I'm going to assume this is still half engine speed which points us to the Valve Train.
Pulling the valve cover and filming the rockers, it looks like the tap aligns perfectly with the 6th cylinder exhaust rocker as it is being extended by the Camshaft. Some better slow motion video seems to verify this. I tried pushing down on the rocker arms but none of them moved down at all so the lifters are solid. Tried picking up and twisting the pushrods but none of them had any play in them.
Decided to take off 6 cyl intake and exhaust rockers and pushrods, held the lifters up with magnets, disconnected spark plug wire and fuel injector, then started the engine. The loud tapping noise was not there anymore, but once it settle there was a light chatter. Might have been a tool or something rattling so not sure for certain but it sound damn near normal again.
Took off the whole upper valve train to inspect it. None of the pushrods were bent, none of the rockers were cracked or had bad wear, none of the valve springs were cracked or were stuck shut. I figured maybe there was an unruly lifter so I pulled the head to take a look. Pulled all the lifters to inspect them, none of them seemed too bad. Most still had a very clean bottom and a few had a very light surface wear but nothing crazy. Didn't see any dirt or gunk but I replaced the lifters on 5th and 6th cylinder just to be sure.
I scrubbed the pistons clean and looked at the head but nothing stuck out at me. Replaced the intake and exhaust gasket because I had a very small exhaust leak from the ebay header I got. It seems to have warped and bowed out a tad from the heat and you could see the carbon traces on 1 and 6. Tightened it all down with a new Victor Reinz gasket and put the head back on.
Started it up and still have the exact same noise. Bummer. Waited a bit for the new lifters to pump up and cover the rockers with oil but the noise still remained. No play in the rockers still. Took some of the parts to my engine guy and he thought maybe the rocker bridge was bent and the rockers were hitting it because there was a small mark on either side of the bridge. Took it home, straightened it but still no luck. After looking carefully though it doesn't look like the rockers could hit where the marks were because the bearing mount would hit before anything and there were no marks at all between bearing foot and rocker bottom. Even marked the max rock points and ran the engine and the rockers don't go that far.
Tried moving that rocker set and pushrods to the front, and the front to the back but the noise still remained in the back. I am absolutely stumped at this point. What on earth could it possibly be?! It is killing me because I've exhausted every possible thing I could think of so maybe someone on here know's something more on the subject then I.
Youtube Video Here:
Link if that doesn't work: https://www.youtube.com/watch?v=gzslg8owJ5s