Rattling from Valves near CPS

[bowsercake]

I get a rattling sound from 1500rpm to 2200 rpm. It is most noticeable when the engine is cold and it starts to go away and is barely noticeable when the engine is at operating temp. The sound completely goes away after 2200 rpm. I thought it was something in my engine bay rattling until I spent some time searching around. Could it be that my valve shims need to be replaced/adjusted? Or could my CPS gear be making this noise?

I am pretty sure that it's not rod knock because I've had that before and it was harsh. I can tell that this noise is coming from the top of the engine in the front so that's why I am guessing valves. Has this happened to anyone else? Thanks guys.

 

[rtrdpenguin]

Yep, I had it pretty bad. After adjusting the valve shims it got a lot better, but the valves still make a bit more noise than I'd like. The shims are all well within spec too =( I guess our valves just make lots of noise.

 

[bowsercake]

Is it better to have the shims make the clearances smaller or larger? I believe my shims were all within spec at one point though.

 

[jdub]

How about looking in the TRSM and adjust to spec?

 

[bowsercake]

They were adjusted to TSRM spec 3 months ago. And were fine until recently.

 

[jdub]

Is this on a rebuilt motor?
(i.e. rebuilt head and pistons..if so, what kind of pistons?)

 

[92TealSupra]

I am guessing you had the motor rebuilt? Not to many people can say they were 3 months ago and only did the shims on there valves..

Check the spec, and I would check them over again and make sure you did it correctly and make sure they're still in spec, hope your valve guides are not shot.

 

[Mr. Y]

side note: my CPS rattles. Yes, it's CPS itself. I can feel it when put arm on CPS cover. And valve clearances are in spec.

 

[bowsercake]

Is this on a rebuilt motor?
(i.e. rebuilt head and pistons..if so, what kind of pistons?)

Yes. The original pistons were looked at and reused with just the rings and bearings replaced, the Rods had some machine work done to them.

Head had a valve job with new seals.

 

[jdub]

I was thinking perhaps it's piston slap, not likely with stock pistons unless the piston-to-wall clearance was opened up quite a bit.

I'd check valve clearances, especially if you are taking the machine shop's word on the spec. I would check the cam caps and journal clearance too...there's a specific torque order in the TSRM.

 

[trydrew]

Mine does this too, and from what I can conclude my CPS gear has too much backlash. The gear itself appears to be fine while the gear on the cam appears worn. Since my CPS seal (inner) is showing age, I was going to replace the CPS gear and see what happens. I have other EX cams but they all appear to have the same wear.

I'm going to check my journal clearences just to see how they look.