Been trying to figure out a ticking noise in my 340. It just started a few weeks ago and seems to be getting worse. Motor has 2 k on it but not sure on the build from the previous owner. Thought it was a exhaust leak but after some checking I believe it is in valve train. It gets worse when the engine is at operating temp and it will come and go as the rpm changes. Changed to straight 30 wt oil and it did change but is still there. They are stamped rockers and all seem tight. I pulled the lifters through the head with a magnet and they all look good also. a few of the push rods have this wear on the rocker side of them and I'm not sure if it could be the problem or if they need attention either way. Have tried to pin point it with stethoscope, rubber hose and the long screw driver to the ear it but really can't narrow it down. I did smoke test the exhaust and there were not leaks. I also swapped the fuel pump and it made no difference either.
Ticking noise/push rod wear
- Thread starter dgibby
- Start date
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OldmanRick
Well-Known Member
Since it seems to be there at operating temp, what's your oil pressure look like....cold and hot? On the surface, it looks like it could be the lifters or a minimal preload setting (pushrod length). The fact that it just started makes me curious though.
Check the rocker surface where it contacts the push rod. Long ago, I had one rocker get wallowed out and the rod would move around from side to side under load. I changed out the rocker and the ticking went away.
MRL Performance
Well-Known Member
What do the rockers look like? It may have gotten dis-formed. Its pretty common with stock rockers
They look good to me but unless it obvious not sure what to look for. They are smooth and look consistent compared to each other. I will check them again tomorrow. Do I need to replace the rods with the wear on them or is it to be expected?
Nope. Didn't know there is a certain way they go. What am I looking for to make sure they are correct?
Stock shaft has a notch on one end. Driver side the notch needs to be toward the front and down. Passenger side the notch needs to be toward the firewall and down.
OldmanRick
Well-Known Member
Keep this in mind guys.^^^^^^^ Seems to me a misassembled rocker shaft would have had this issue right from the git go.
Whilst I agree Rick, it doesn't hurt to check everything out.
To the OP, make sure the hold down spacers are in the correct position as well as the rockers themselves. By the looks of that rod it seems like it had side pressure, not lined up correctly, I would double check all of that too. The rockers are left/right specific in regards to position on the head/cylinder.
I stole this pic from James in his for sale ad.
So I check all the rocker arms for wear and confirmed that the shafts were on the correct way as well as the rockers. All was correct. I switched the complete rocker/shaft assemblies passenger to drivers side and fired it up. The noise was still on the pass side and after some checking found one of the rockers seems loose on the shaft. All seem to be very tight but this on rocks on the shaft except when it is pushing the valve down. It also is the same one that the push rod has the most wear on. I guessing a bad lifter?? since the noise didn't move when I switched the rockers. Going to replace the lifter and see what happens but still wondering if those push rods with wear need to be replaced also?
Subscribed. Might be my problem too.
cudavert
DARTAHOLIC
If you swapped shafts/rockers from side to side and you've still got noise on the passenger side, maybe you should've also swapped the push rods too. I'm thinking flattened out cam lobe or somehow one of the push rods is a bit too short. They DO sell them in increased lengths I believe. As long as you've checked all the wear surfaces for galling/damage first, you know, inside the rocker arm and shafts.....
Well I replaced the lifter and push rod on the loose rocker, it is tight now but I still have the noise. So I pulled the intake to check out the cam. Really not sure what it should look like but to me it seems to have some premature wear on it. The surfaces are all smooth to the touch but look scraped up to me. Here are a few photos and a bunch more on this link. Give the link a minute to focus then you should be able to zoom in. Thanks.. https://www.icloud.com/photostream/#AC5n8hH4GkP9fL
UOP
Well-Known Member
Can you see any scratches on the lifter? Do you see something like this? This is a lifter out of a buddy's 383 that we were trying to diagnose a tick and discovered a lobe had started to wipe. Very few miles on this engine too.
cudavert
DARTAHOLIC
Is that a cam lobe or the fuel pump eccentric? LOL How do they feel to the touch and the "fingernail test"?
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