Valve Train Noise and Miss ? - Team Camaro Tech
Engine General Engine Discussion.

 
LinkBack Thread Tools Display Modes
post #1 of 10 (permalink) Old Nov 20th, 05, 01:26 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Valve Train Noise and Miss ?

I have a newly rebuilt 355 engine in my 69. It has a valve train noise on one side of the engine that I can't get rid of. It sounds like a loose rocker, but it won't adjust out. It's not too loud but I can hear it.It has a Comp Cams 275 DEH hydraulic Camshaft. Could it be a bad rocker? It has stock rockers. I pulled the valve covers and all rockers are moving and valves opening and closing.

The engine also has a miss to it. I haven't been able to drive the car because it is all apart. I am having a carb rebuilt for it but am running an old carb I have just so I can move the car. The carb is not much but I don't know if it would make it miss like it is. It has new plugs, and the same wires, dist, and cap it had before rebuild and it didn't miss then.

I can pull of one wire at a time and it seems to make a difference on all eight cylinders. It just won't smooth out. I know it's hard to diagnose a problem like this without being there but I'm looking for suggestions.

If the car was together I would drive it and see if it smoothes out but it's not.
Could my whole problem be my carb?
ck 2 is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old Nov 20th, 05, 02:59 PM
Gold Lifetime Member
Harry
 
dawg's Avatar
 
Join Date: Mar 2004
Location: Colebrook CT.
Posts: 4,029
Re: Valve Train Noise and Miss ?

did you use assembly lube on the lifter bores?
and cam lobes when you installed cam?
if its a hydraulic cam and lifters I would pull the lifter that the rocker goes to and see if it is collapsed.
also check the surface of the lifter that contacts the cam lobe to see if it is worn. (should not be flat .slight dome on the contact surface).
if that looks good then I would think you dropped a lobe on the camshaft.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

434 stroker
US Navy retired

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
dawg is offline  
post #3 of 10 (permalink) Old Nov 20th, 05, 08:03 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Re: Valve Train Noise and Miss ?

Yes I used assembly lube on the lifters and cam lobes. All the rocker arms are moving. How could I have a wiped lobe if all the valves seem to be opening and closing?

It's not that loud, it's hard to even tell which one it is.
ck 2 is offline  
 
post #4 of 10 (permalink) Old Nov 21st, 05, 08:07 AM
Gold Lifetime Member
Jim
 
Join Date: Dec 1999
Location: Yorkville, Illinois USA
Posts: 22,121
Re: Valve Train Noise and Miss ?

easiest way to tell which one it is is to press on each rocker while the engine is running, see which one makes it go away. Another check is "how fast does the pushrod spin?" If you have a collapsing lifter, tightening the rocker will slow the spin, but it will spoeed back up after a few minutes.
If you're losing a lobe, it should be possible to tighten the rocker enough to make it quiet, for a while. A collapsing lifter noise will come back pretty quick.
A failing lobe doesn't just go flat all at once. It simply wears away gradually. Once you know which one it is, it could be helpful to use a dial indicator to check the lift, and compare it to one that doesn't make noise.





To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
New website for my vert is coming together. Do ya like the slide show on the home page?
JimM is offline  
post #5 of 10 (permalink) Old Nov 21st, 05, 04:49 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Re: Valve Train Noise and Miss ?

Okay I went out this evening and checked one side of my engine. The side I could hear some noise. First off most people probably wouldn't have even heard what I'm hearing, it isn't clacking like a really loose valve. I cranked the engine over by bumping the starter while watching each valve. I couldn't visually see any difference in the travel of the valves. ?

So I take an old valve cover and cut out the center section to try and keep from making a mess. I let the engine warm-up and hear some ticking but not alot of noise for the valve cover being open IMO.

I loosen one valve at a time until it starts ticking and then tighten until it quits then add 1/4 turn. Things were pretty quiet. I don't think you will hear anything once the covers are back on. The other side has never made any noise.

I still have a miss though. The carb I have on it is running extremely rich. The plugs are black. It doesn't pop, crack, or backfire. I guess tomorrow I will move to the other side. I changed the oil right after breaking the cam in and even strained the oil through a clean rag. I didn't notice any metal. I don't see any sparkles in the oil now either. If my miss is coming from a wiped lobe shouldn't I be able to see the lack of valve movement?

Last edited by ck 2; Nov 21st, 05 at 05:10 PM.
ck 2 is offline  
post #6 of 10 (permalink) Old Nov 21st, 05, 05:42 PM
Gold Lifetime Member
Jim
 
Join Date: Dec 1999
Location: Yorkville, Illinois USA
Posts: 22,121
Re: Valve Train Noise and Miss ?

It really depends... the lobe is point 3 inch and change... if you lost less than a tenth (so far), you won't see it, but could easlity measure it. What did your pushrod spin look like? could you identify which valve(s) were the noisy ones?





To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
New website for my vert is coming together. Do ya like the slide show on the home page?
JimM is offline  
post #7 of 10 (permalink) Old Nov 21st, 05, 06:50 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Re: Valve Train Noise and Miss ?

Say I lost a tenth that would measure but not see, would this cause a miss or just a noisy rocker?

I didn't get to check the pushrod spin because after I adjusted the valves they really started squirting oil. Even with just a small section cut out of the center of the valve cover they were really pumping. I may try tomorrow to check them. What will the spin tell me?

Could I check the lift at the pushrod instead of at the lifter? If so, how and where could I get a cheap dial indicator to use? Would a 1 inch indicator work?

Thanks again.

Last edited by ck 2; Nov 21st, 05 at 08:06 PM.
ck 2 is offline  
post #8 of 10 (permalink) Old Nov 22nd, 05, 03:31 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Re: Valve Train Noise and Miss ?

Can anyone tell me if I can check for a worn lobe at the pushrod with a dial indicator? If so how ?

Again, if I can't see any difference when visually watching the rockers move could a lobe be worn enough to cause a miss in the engine?

Thanks.
ck 2 is offline  
post #9 of 10 (permalink) Old Nov 22nd, 05, 04:39 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Re: Valve Train Noise and Miss ?

Update!
I have been out in the garage again. I removed the valve cover on the right side of engine(the side I had heard the tick). I cranked engine over and could hear a tick, tick, tick. Sounds just like spark jumping. I noticed it was coming from one certian valve (the intake valve on #2 cylinder). So I checked the rocker and it wasn't loose, I tightened it a little and it ticks every time the valve opens. This is just with the starter, not the engine running.

So I remove rocker and switch it out with another, it does the same thing.No change, noise is still on same valve. But I can remove that rocker and crank the engine and the noise is gone.
What do you think is causing the noise, a spring, retainer, or valve ?

I know this still won't fix my miss, but this is where the tick was coming from for sure. I would still like to check the lift and compare each lobe to the other without removing the intake if possible.

Thanks again.
ck 2 is offline  
post #10 of 10 (permalink) Old Nov 22nd, 05, 09:16 PM Thread Starter
Senior Tech
Chris
 
Join Date: May 2004
Location: kentucky
Posts: 889
Re: Valve Train Noise and Miss ?

Anyone have any ideas ?
ck 2 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome