Weird knock/tap.
Thread Starter
Le Mans Master
Joined: Nov 2002
Posts: 8,339
Likes: 75
From: Tampa Bay
St. Jude Donor '06
Weird knock/tap.
I am still troubleshooting my rebuild. I haven't been able to isolate a tap in the right side. I pulled a valve cover off and found a loose rocker. I tightened it up, but it didn't "feel" like the others. This is where I am afraid I my mind may be playing tricks on me. I have no tap when in neutral even under high revs. The minute I put it under a load, the tap shows up even under the slightest accelerator input. The power is not near where it should be. Could this be a simple timing problem? I am having nightmares of a wiped cam lobe.
Thread Starter
Le Mans Master
Joined: Nov 2002
Posts: 8,339
Likes: 75
From: Tampa Bay
St. Jude Donor '06
Originally Posted by big_G
It sounds like an exhaust leak, probably at the exhaust manifold.
Thread Starter
Le Mans Master
Joined: Nov 2002
Posts: 8,339
Likes: 75
From: Tampa Bay
St. Jude Donor '06
Originally Posted by big_G
Check timing (both mechanical and vacuum advances), carb. for full throttle operation. If a Q-jet, make sure the choke secondary lock-out is off when the choke is open.
Man, I hope you are right. Both scenarios have crossed my mind. An exhaust leak could cause the tap, and the setup I rigged for the demon carb could not be opening it up completely. I guess I need to spend the time to troubleshoot the obvious before I start chasing ghosts.
It does reassure me to hear the same hypothesis from someone else.
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Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Adjust the vlvs and double nut/backup the lock nuts.
Going thruogh this myself after my brand new Comp Cams self-locking rocker nuts loosened on cam break-in. Makes things confusing as i didn't know what would do that to brand new lock nuts on brand-new screw-in studs.
Anyways i recommend going to the Crane Cams w/s and printing thier vlv adjust proceedure. Also stop by the local hardware store and buy 16 thin buckup nuts (3/8"x18 i think but maybe x16). Once u get the preload adjusted, set the backup nut - ensure u don't move the bottom nut while tightning the top onto it.
BTW what kind/brand of lock nuts are on ur rockers? Comp Cams?
cardo0
Anyways i recommend going to the Crane Cams w/s and printing thier vlv adjust proceedure. Also stop by the local hardware store and buy 16 thin buckup nuts (3/8"x18 i think but maybe x16). Once u get the preload adjusted, set the backup nut - ensure u don't move the bottom nut while tightning the top onto it.
BTW what kind/brand of lock nuts are on ur rockers? Comp Cams?
cardo0