Maybe a wiped cam lobe?
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Maybe a wiped cam lobe?
I think I may have a wiped cam lobe but I'm am not entirely sure, I haven't removed the valve cover to check the rocker travel yet. There is definitely a ticking noise coming from valve train. The exhaust is popping more than usual, I have true dual exhaust so it pops and crackles when downshifting but it does it more now when I depress the clutch to shift and when revving the the motor just mildly. What would you guys check first. The CAm and lifters are not new. Thanks-Justin
JF74chevelle- G3GM Member
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Re: Maybe a wiped cam lobe?
I believe you have an exhaust manifold (or header) leak. The increased popping/gurgling might be the oxygen getting let in thru the leak and helping re-ignite some of the unburnt fuel. I had this same scenario on my old buick and that's what it turned out to be. It was hard to diagnose until I saw that one of the exhaust manifold bolts had broken.
Some say you can take a tissue and hold it around the areas (carefully! use gloves) of the exhaust ports to tell if you have a leak, but of course you'd have to first remove the cooling fan and run the engine without it to try to isolate any leaking exhaust pulses.
Some say you can take a tissue and hold it around the areas (carefully! use gloves) of the exhaust ports to tell if you have a leak, but of course you'd have to first remove the cooling fan and run the engine without it to try to isolate any leaking exhaust pulses.
clanceman427- G3GM Enthusiast
- Street Cred : 16
Re: Maybe a wiped cam lobe?
that was the first thing I checked but I'll definitely give it another look.clanceman427 wrote:I believe you have an exhaust manifold (or header) leak. The increased popping/gurgling might be the oxygen getting let in thru the leak and helping re-ignite some of the unburnt fuel. I had this same scenario on my old buick and that's what it turned out to be. It was hard to diagnose until I saw that one of the exhaust manifold bolts had broken.
Some say you can take a tissue and hold it around the areas (carefully! use gloves) of the exhaust ports to tell if you have a leak, but of course you'd have to first remove the cooling fan and run the engine without it to try to isolate any leaking exhaust pulses.
JF74chevelle- G3GM Member
- Street Cred : 0
Re: Maybe a wiped cam lobe?
Turned out to be a gnarly exhaust leak, some how the very back bolt backed way out, tightened it up and no more noise
JF74chevelle- G3GM Member
- Street Cred : 0
Re: Maybe a wiped cam lobe?
In case you want to know...My big block lost a cam lobe/lifter a few years back. Car had an intermittent knock, backfire through exhaust from time to time and was down on power..
wbaker01- G3GM Member
- Street Cred : 0
Re: Maybe a wiped cam lobe?
I'll use this at reference because I checked the valvetrain and everything was fine
JF74chevelle- G3GM Member
- Street Cred : 0
Re: Maybe a wiped cam lobe?
When I suspect a cam lobe going South, I remove & Cut the oil filter apart first. If there's any metal, it may be bad, but no metal..
pila- Donating Member
- Street Cred : 43
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