Kacyc3

For those that have wiped a cam lobe what are the slightest symptoms to look for? Obviously there can be metal in the oil,running poorly but were there anything before posted above?

riverracer au

i wiped #7 exhaust lobe couple years ago.
seamed to be running fine before it went sour.
previous oil change showed no sings of anything amiss.
felt like a couple of potatos had been stuffed up my exhaust pipes.
had no power under load.
here's the posts i made about it back then, https://www.corvetteforum.com/forums...r-in-72-a.html

CanadaGrant

If you adjusted your lifters and now one isn't like the others, beware....
Below is a factory 45 year old cam with nylon timing gear out of my 69 427. A couple of lobes are almost a quarter inch smaller than the other worn ones but it still ran pretty good....

Kacyc3

Engine was rebuilt like 1k mi ago and changed the oil about a month ago and put about 70 ish miles since with new oil brand. I noticed a different sound in exhaust after extended idle at a light tonight and slight bog at the same time. Clears up by 1500 rpm and revs with no problems, and sounds correct.

gjohnson

I wiped an intake on my original motor and it quickly turned into a V-7

jb78L-82

Had a 73 Nova SS that wiped one lope…engine felt flat, developed a miss at idle, kept fouling the plug on the cylinder with the wiped lope…but it ran decent under power.

Kacyc3

It runs and sounds normal while cruising also.

Tampa Jerry

Put a vacuum gauge on the engine to get manifold vacuum. If you have a wiped lobe, the gauge will show an erratic reading. Google engine vacuum and you will get examples on how to interpret the readings. You should be able to get a vacuum gauge kit at most auto stores for less than $20. Good luck. Jerry

CanadaGrant

"kept fouling the plug on the cylinder with the wiped lobe"
Check your plugs.
Tampa Jerry has a nice piece of advice.
"Put a vacuum gauge on the engine to get manifold vacuum."
If you have any sort of fluctuation, start looking at the valve train.

tonak

Car was "chugging" when reved from idle in my garage. I just happened to pull the spark plug from the wiped lobe's cylinder and it was very fouled, oil was black and it was being used. Motor ran pretty well on 7 cylinders after some tuning, but the exhaust lobe on 7 was FLAT.

Bobs69BB

Kacyc3,

Was engine rebuilt with flat tappet lifters? Did you use high zinc oil? Did you follow start-up and break-in procedures (well documented on this forum)? How did the oil look that you changed at 1k?

I'd do it in this order 1) compare plugs 2) check manifold vac if you are comfortable with interpreting result 3) check lifter clearance. Loose lifters are a giveaway.

If any of the above look fishy, it is way easier to pull the intake and inspect cam/lifters than to worry for more miles and have to rebuild the whole engine.

And yes, at the time I wasn't smart enough to see the symptoms and had to do a complete $$$ rebuild. So you are asking the right questions ....

Robert

Kacyc3

Yes it has hyd. Flat tappet lifters. Yes it was broke in correctly. Oil was brown from normal use not black no alarming metal on magnetic plug. Was using valvonline vr1 racing 20 50 but made over 60.psi at idle. Couldn't find 10w30 or 40 locally so I went with another brand that is reported having 1k ppm zinc.