68 Engine Question
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
68 Engine Question
What are the possible causes for a loud tapping noise coming from my 327 engine in the vicinity of # 6 or # 8 cylinder?
I removed the valve cover and see no broken springs or push rods or rocker arms out of place. I heard it a day or two ago after the engine was running for a few minutes and then it went away. Today approximately 30-60 seconds after starting the engine the noise appeared and grew louder so I immediately shut down the engine. Oil pressure is good, engine is completely new with all new internals assembled by a machine shop and has been run a total of less than 5 hours since it was built and installed a few weeks ago.
Any thoughts?
Thank you,
Kurt :confused: :cry :(
I removed the valve cover and see no broken springs or push rods or rocker arms out of place. I heard it a day or two ago after the engine was running for a few minutes and then it went away. Today approximately 30-60 seconds after starting the engine the noise appeared and grew louder so I immediately shut down the engine. Oil pressure is good, engine is completely new with all new internals assembled by a machine shop and has been run a total of less than 5 hours since it was built and installed a few weeks ago.
Any thoughts?
Thank you,
Kurt :confused: :cry :(
Heel & Toe
Joined: Jul 2002
Posts: 16
Likes: 0
From: Austin Texas
Re: 68 Engine Question (ksbunting)
On a hydraulic engine, a stuck lifter?
On a solid engine, excessive lifter/valve clearance? (readjust)
On either, a sticking valve?
How does it run? Does the noise increase with increasing RPM? Any hesitation/missing?
On a solid engine, excessive lifter/valve clearance? (readjust)
On either, a sticking valve?
How does it run? Does the noise increase with increasing RPM? Any hesitation/missing?
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Re: 68 Engine Question (Brons2)
It's a hydraulic lifter engine.
Seems to run OK but shut it down as soon as I heard the npoise to avoid damage as engine is new.
What are the signs of a sticking valve, what should I look for and what causes it to stick?
Noise increased with engine rpm.
Thank you for any suggestions,
Kurt
Seems to run OK but shut it down as soon as I heard the npoise to avoid damage as engine is new.
What are the signs of a sticking valve, what should I look for and what causes it to stick?
Noise increased with engine rpm.
Thank you for any suggestions,
Kurt
Racer
Joined: Aug 2002
Posts: 384
Likes: 6
From: Brockville Ont
Re: 68 Engine Question (ksbunting)
try starting the motor and immediatly remove the spart plug wire on the cylinders one at a time (near the knock) if the noise disappears it is likely a rod bearing (if the oil pressure is down) or a wrist pin seized up or loose, if it were a valve she would either back fire through the carb for an intake or out the exhaust for exhaust valve, if it were a blocked or collapsed lifter it would show up as a loose push rod.
good luck
Bill
good luck
Bill
Melting Slicks
Joined: Jul 2000
Posts: 2,107
Likes: 14
From: Lancaster PA
Re: 68 Engine Question (mxzx turbine)
Since it was assembled by a machine shop I would contact them immediately and let them decide what you should do next. I sure can appreciate the frustration you must be going through. I hope it is nothing serious. Good Luck, Craig :chevy
Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Re: 68 Engine Question (GDaina)
If it is a rod bearing, that means a complete teardown.
After spending $3200.00 to have it assembled and now that the engine and engine compartment is detailed to look like original, it really stinks to start all over again. It's been 7 long years and now it just got longer. I'm not young and I had hopes of driving this thing before I die. I'm sure as hell not going to let my kids have it and drag race around in it. Still need a paint job and reinstall the interior. Thought the engine part of the restoration was finally done and behind me.
Sad day in Mudsville.
Kurt
After spending $3200.00 to have it assembled and now that the engine and engine compartment is detailed to look like original, it really stinks to start all over again. It's been 7 long years and now it just got longer. I'm not young and I had hopes of driving this thing before I die. I'm sure as hell not going to let my kids have it and drag race around in it. Still need a paint job and reinstall the interior. Thought the engine part of the restoration was finally done and behind me.
Sad day in Mudsville.
Kurt
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Thread Starter
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
Re: 68 Engine Question (GDaina)
George,
Would you venture to guess if the crankshaft has sustained any damage?
It took me almost 2 years to locate the proper crankshaft that was in new condition and they stopped making them in 1969 whihc is why I ask.
Rods can be replaced but this was the correct factory crank.
Thanks,
Kurt
Would you venture to guess if the crankshaft has sustained any damage?
It took me almost 2 years to locate the proper crankshaft that was in new condition and they stopped making them in 1969 whihc is why I ask.
Rods can be replaced but this was the correct factory crank.
Thanks,
Kurt
Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
Re: 68 Engine Question (ksbunting)
If the bearing material wore through to the steel backing the crank, at a minimum it will need turned undersize. If the wear on the bearing is not through the copper you may not have to do anything but you do need to check things out thoroughly. Check your crank's journal diameter and the diameter of the rod's big end. Make sure that the cap was not reversed. Also look for defects in the surface finish of the crank. Just to be sure, it wouldn't hurt to polish the journal surface with a strip of fine emery cloth and clean, clean, clean. No dirt or metal pieces anywhere!! If everything looks good, make sure you check the rod bearing clearances when putting things back together. If you had a shop build the motor you may want to see if they will warranty their work and eat some of the repair cost.
You want to make sure that if you put the motor back together that it doesn't happen again!
You want to make sure that if you put the motor back together that it doesn't happen again!
