<VV> Engine noise question - sorry, long

ChiefTAM@aol.com ChiefTAM@aol.com
Fri, 18 Jun 2004 12:12:53 EDT


-  I originally sent this to Matt offline, but got to thinking he might not 
check his mail for a while, and I need to decide a course of action by later 
this afternoon, so I am sending it out to VV for a bit of advice on how to 
proceed. -   


I am sending this off list, as many others are at the convention.  I have a 
question I wonder if you might give me some insight into.

You have responded to my reply's on fixing my 69 110 Convert. after it broke 
two piston rings on the #4 cylinder while driving it from Iowa to Texas.  I 
went in with the help of a NTCA member and pulled the engine apart, replaced the 
rod bearing on #4 and put in new rings on that piston, honed the cylinder 
(everything still standard, under 50,000 on engine) and put it back together.

After starting it back up, I had one lifter that made noise, needed to get 
pumped up I guess, and after 5 minutes or so of idle, it did.  I drive the car a 
few miles around town last week, and it just purred.  I drove it last night 
as well about 10 miles, getting it fully warmed up, making sure everything was 
OK to drive the thing to work today.  It ran well again.  

This morning, I started out for work, 42 miles away.  The car ran 
beautifully, until I came into town.  I stopped at a stop light, and as I pulled away, I 
didn't give it enough revs (4-speed) and it rattled like detonation twice and 
then took off.  A couple blocks down, just before work, I noticed it didn't 
sound quite right, louder than normal.  I pulled into the parking lot at work 
and as I reved the engine above idle, I could hear a knocking, sounding like it 
was coming from the center of the engine. 

I let the car sit for an hour and a half and went out to start it again.  At 
idle, it sounded pretty normal, certainly like it is hitting on all cylinders. 
 As I would flip the throttle, raising it above idle, it would make the 
knocking sound again, coming from the center of the engine, I believe.  The 
knocking would get louder the higher the revs, and disappear, or almost disappear at 
idle.

Now my problem.  I don't know what it is.  I don't think the detonation had 
anything to do with it, as that sometimes happen if I don't rev it up enough 
when taking off.  I certainly don't think it is a piston ring again, as it is 
making noise, and it really didn't before, just sounded a little off.  I don't 
think it is a rod either.  I would think that if it is a rod bearing, that 
would make noise all the time.  We only replace one rod bearing, and I believe we 
got it torqued right, so I don't think it would loosen up.  

The only thing that I can think of left is valve train.  Coming from the 
center of the engine, I am inclined to think lifter.  I am wondering if the 
problem might be a valve that is too tight, and after it got warm, it started to 
make a knocking or hammering noise.  Is that what they do or sound like?  It is 
hot here in Texas today, and so I know that the engine got warmer today then it 
has been since I put it back together.  I would think if a lifter is loose, 
you would get more clacking of the rocker arms than sounding like it was coming 
from the center of the engine.  As an engine fully warms, the metal expands 
and the valve would get tighter wouldn't it?

So, any ideas?  I am trying to decide if I should get a trailer and haul it 
back home.  I didn't bring my sockets, but I could probably get some and take 
off the valve cover to see if one of the valves is too tight and loosen it up.  
I don't want to hurt anything further, especially if it is something simple 
like a lifter.  

I suppose there could have been some junk in the engine that got into a 
lifter and plugged it up.  I did warm the engine up with new oil and filter, and 
then changed it again, so the oil should be good and clean now.  Don't 
know......what do you think?

Todd Miller
Dallas