Impalas.net banner

1 - 6 of 6 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
Upon getting home last night I noticed I had a kind of rattling tap noise coming from under the hood. I couldn't do much last night at 10pm due to noise and neighbors, but got out this morning before work to see if I could isolate where it was coming from.

It sounds like it is coming from under the driver side valve cover area, or just below. The noise seems to lessen and go away with more rpms, returning when you let off the throttle and return to an idle. The engine is a 283 in a 67 impala, the previous owner said it was bored 30 over, and it has a little heavier cam than stock (not sure on cam specs).

I tried to get a short video clip myself to let y'all hear it, and apologize for the shaking camera-work.

http://static.photobucket.com/player.swf?file=http://vid709.photobucket.com/albums/ww95/Super_Kinkade_Bros/2011-02-07_09-58-40_809.mp4

Taking the valve cover off on that side, I didn't see anything broken or floating around. The oil level was a little under full when checked.

Under the valve cover, each had a very slight bit of wiggle to them except for the right hand valve of the front two pairs.

http://i709.photobucket.com/albums/ww95/Super_Kinkade_Bros/2011-02-07_09-49-38_836-1.jpg

I won't pretend to be any kind of mechanically inclined, but was hoping I could get the knowledgeable opinion of the forum.
 

·
Super Moderator
Joined
·
13,041 Posts
Old 283 engines had pressed in rocker arm studs. If you installed a healthy cam, the vibration of the valve train will pull the studs out of the head (which loosens the valve lash so that it clicks). In the good old days you used to pin the studs to the cast iron bosses in the head. Today you take the head to a machine shop to have the bosses cut down drilled and tapped for screw in studs.

Another issue is the fact that the oil refiners ditched all of the additives that used to be in motor oil prior to January 2008 (prior to that it was about half of what was in the motor oil when these cars where new). They removed these additive metals that used to protect flat tappet cams from wear because there hasn't been a flat tappet engine made in over twenty five years and the metals where contaminating catalytic converters from blow by in cars with roller tappet cams.

Either way it sounds as if your valve lash has loosened whether due to wear or a stud pulling out.

Big Dave
 

·
Registered
Joined
·
19 Posts
Discussion Starter #3
Excellent! Your posts and advice have been nothing but educational since I joined this forum, so I appreciate your feedback. I lack the garage space of my own to get messy, so might need to have the work done in a shop but I prefer going in with a rough idea at least instead of as a 100% naive target for a ripoff, so definitely thank you for the input.

Out of curiousity, how do I know if my engine uses solid or hydraulic lifters?
Also, since I did not put the heavier cam in myself I don't know the specs on it. What advice would y'all have as far as clearance/gap using feeler gauges if that route is required? I'm going to try and get in touch with the previous owner, but he is a couple states over and may not have the information anyhow.

I wish I had the garage to do this by ear with the engine running. I don't mind making or cleaning up a mess, but these apartment owners probably wouldn't care for it too much. I may just try too get an extra set of valve covers with the cutout area on top and head to the far end of the property here if the local shops try and take me for a ride.
 

·
Super Moderator
Joined
·
13,041 Posts
I doubt if you have a solid lifter cam. If you did you would need to find out what the cam grinder wants the lash to be as every cam has different valve lash setings. Older cams (from the muscel car era) where set fairly wide at 0.028 to 0.030" inch of lash, today's cams are about half of that amount.

You most likely have a flat tappet hydraulic cam as they are about $400 cheaper than a solid or hydraulic roller cam kit. Unfortunately you have to buy DZZP additive to make up for what is missing in your motor oil to run a flat tappet cam (which adds about $30 bucks to an oil change) so you will eventually end up paying more for the cheaper flat tappet cam than buying what you need up front.

Big Dave
 

·
Registered
Joined
·
12 Posts
I doubt if you have a solid lifter cam. If you did you would need to find out what the cam grinder wants the lash to be as every cam has different valve lash setings. Older cams (from the muscel car era) where set fairly wide at 0.028 to 0.030" inch of lash, today's cams are about half of that amount.

You most likely have a flat tappet hydraulic cam as they are about $400 cheaper than a solid or hydraulic roller cam kit. Unfortunately you have to buy DZZP additive to make up for what is missing in your motor oil to run a flat tappet cam (which adds about $30 bucks to an oil change) so you will eventually end up paying more for the cheaper flat tappet cam than buying what you need up front.

Big Dave

Or you could buy a quart of comp. cams break in oil @ five or so bucks and use about 12oz. per oil change.

:beers:
 

·
Registered
Joined
·
19 Posts
Discussion Starter #6
Awesomely enough for my wallet, this ended up being loose bolts down around the torque converter area, one of which had actually come off and was rattling around. I was thankful it didn't end up being something much more severe and costly, and also thankful for the lessons on valve lash, etc through these boards and the worried research over the course of a few weeks there.

Loving these boards and loving the learning experience this whole journey is turning out to be.
 
1 - 6 of 6 Posts
Top