cam.. valve info???

[dgms240]

my ka has started making a loud rattling sound coming from the head, around the #3 cylinder. NO ITS NOT THE TIMING CHAIN OR GUIDES. does anybody know what the clearances are supposed to be between the cam lobes and the valve shims (i think thats what theyre called, the little cup shaped things that the cams push down on.)??? i think it needs to be shimmed, but i need the factory specs on the clearances and i cant seem to find them, and i have searched. thanks for any help!

[480sx]

Its in the fsm dude. You need a feeler gage to check them.

That being out of spec usually causes a RPM dependent ticking noise. Idk if it can cause a loud rattling noise, but it just doesnt sound feasible.

You are talking about the lifter buckets. The shims are the pieces on top of those buckets.

[Speckid14]

Valve Clearence (HOT)Intake: 0.31 - 0.39mm (0.012 - 0.015in)Exhaust: 0.33 - 0.41mm (0.013 - 0.016in)

REMEMBER: Metal expands when it gets hotter, so compensate a little under when making cold adjustments.

Formula to Follow:

-Using a micrometer determine thickness of removed shim.-Calculate thickness of new adjusting shim so valve clearence comes with specified values.R= thickness of removed shimN= thickness of new shimM= Measured valve clearence

Intake: N= R+M (M- 0.0138in)Exhaust: N= R+M (M - 0.0146in)

Shims are available in 37 sizes from 0.0772in to 0.1055in, in increments of 0.0008in.

I know alot of this is useless, but just trying to elaborate as much as possible on the criteria.Hope this helps!!!

Dont forget to double check measurements!!!Speckid, GL

[480sx]

Dont stress the cold/hot thing. Its been checked, there is no measurable difference.

If the clearances are to tight, you can also take a dremel or something to the tops of the valve stem and take a little metal off. That will increase the clearances. I say this because the shims are very expensive.

[Speckid14]

I'm not a fan of metal shavings around that area, but I can tend to be a tad anal when it comes to that stuff. Whatever is comfortable for the owner. Your wisdom amazes me, lol I would have never thought of that. Speckid

[WDRacing]

Yeah, I'd recommend peel shims before I ground the top of the valves. But that's just my .02, you can always check out ACE or something to see what they have that could fit the bill.

Also, unless the cams were swapped, it wouldn't be the shims. It would be something worn really badly and you'd be shimming to compensate for the real issue.

Like 480 said, does the noise fluctuate with rpm or is it constant? Rod knock?

WD

[480sx]

Ill agree with you both about grinding the valve stem while its in the head, prly not the best idea but it works. Theres ways to deal with the metal shavings like using double sided tape or grease to catch the metal but its still a risk.

[dgms240]

thanks for the replys guys. i already checked the clearances and they vary a little from .203mm to .356mm (.008" to .014"). all were checked with each piston at tdc. i don't think its rod knock, believe me iv'e heard that before, lol. its coming from the head. and it starts around 2500rpm and gets louder as the rpms go up. any other suggestions? the motor was rebuilt before i got the car and has roughly 15k on it. the head looked new under the valve cover. i dont know what would be causing this on a relatively fresh motor.

[480sx]

Your clearances are def to tight, however i just cant see it making the noise your describing. I have had experience with this very thing. Idk though, the head of a Ka is a very simple thing. Theres really not much else that can cause this without being shortly followed by a catastrophe.

What kind of head work did you have done to the fresh motor?

I would go over your head and fix those clearances. At the very least it will get your head breathing right and should be done anyway.

[dgms240]

Valve Clearence (HOT)Intake: 0.31 - 0.39mm (0.012 - 0.015in)Exhaust: 0.33 - 0.41mm (0.013 - 0.016in)

REMEMBER: Metal expands when it gets hotter, so compensate a little under when making cold adjustments.

Formula to Follow:

-Using a micrometer determine thickness of removed shim.-Calculate thickness of new adjusting shim so valve clearence comes with specified values.R= thickness of removed shimN= thickness of new shimM= Measured valve clearence

Intake: N= R+M (M- 0.0138in)Exhaust: N= R+M (M - 0.0146in)

Shims are available in 37 sizes from 0.0772in to 0.1055in, in increments of 0.0008in.

I know alot of this is useless, but just trying to elaborate as much as possible on the criteria.Hope this helps!!!

Dont forget to double check measurements!!!Speckid, GL

are these specs for the s14 (232/232) cams or the s13 (240/248) cams?

[dgms240]

from what i was told when i bought the car, it has a stock head with upgraded springs/ retainers. haven't pulled the cams to check though.

[480sx]

Those are the specs for any cam in any 240. Its the distance between the bottom of the cam lobe and the lifter bucket.