Tight valve clearances + valve noise

[grimreaper]

My exhaust side camshaft is noisy, as in diesel sounding and loud. Just checked the clearances of the shims. A few were at .007 " and the greatest clearance was .009, would this cause the racket im hearing? This is border line per tsrm specs, is it worth it to get the shims closer to the middle of the specs?

sounds like valve tick but quite deep and loud. no exhaust leaks, manifold has 7/16 studs and all are tight as well as the rest of the turbo flange bolts. Cam saddles tq'ed where they should be, no movement from camshaft up and down or left and right.

thoughts? suggestions?

to add, noise is at idle and is NOT 1:1 with rpms, oil psi is normal and well above tsrm range... it increases .5:1 with rpms until the motor noise drowns it out...

 

[jdub]

The 7M valve train tends to be noisy. Tight clearances don't tend to make it worse though, but it can lead to a burned valve.
Did you check your cam journal oil clearances?

BTW - The cams won't move...the valve springs are pushing on them

 

[grimreaper]

good point jdub, never considered that. The shims will be "dropped" so they are in the .011-.012 range. Ij informed they will burn the valve seats. lucky me compressions is still the same and i rarely beat on the car... ive been informed tight clearances burn valve seats, bit loose with more noise is better then tight and burnt valves

i will check the oil journals when i re shim this week and post back if there is an issue.

 

[grimreaper]

whoops, i measured with the big end of the cam lobe at an angle to the lifte/shim instead of directly across from it.... most of them are in the .018 inch range


im confused. do i need to shim between the cam and the head when i plasitgauge? or is removing the lifters and measuring after that going to be enough?

 

[3p141592654]

This has been covered before, so I won't repost here.

http://www.supramania.com/forums/showpost.php?p=474041&postcount=7

 

[grimreaper]

read it and plan on using it. However if removing material from the cam saddles, wouldnt that increase the clearances? im just not understanding how you can decrease clearances with removing material.:1zhelp:

is it how the cam cap wears? does it wear out of round and by lapping your shaving the sides down creating a rounder bore?

 

[IJ.]

If you remove material from the caps parting surface it will close down the bearing clearence (will also be slightly out of round)

This will in turn pull the cams closer to the Shims and close down their clearences as well.

 

[grimreaper]

i think i see the light, shave the cap ENDS (where they meet with the head), not the actual bore it self?

got it now, that could have been very bad....

 

[IJ.]

Refer to your #1 Sig quote

 

[grimreaper]

man if that isnt the biggest understatement of the night! i dont know why, i just overlooked the simple and BAM it became complex in my head...