38 replies to this topic

[Gianni]

Any possibility it could be to do with valve springs. I read that of u put in a different grade cam you should change valve springs ect, or else they kinda flap against the new cam because the compress rate of the spring is different.

And with the cat thing, you gotta use one of those skinless cats, less padding so it makes a more vibrant rattle, not a muffled one

[rowlys_evo3]

the upside to using a kitten would be that it will be easier to get through the hole in the top of the can....


on a serious note....you can still get nice even compression results from slightly bent valves as it is a spike pressure you are measuring....not a constant.

but lets hope for bad lifter oiling first.

now back to cats..........did you know that you can play music with a cat?

a live cat wailing does bear some semblance to the sound of a violin which once has their strings made from cat gut

what should i do??
pull them out and bleed them in diesel then put them back in??
just something i read

[jack be nimble]

How should the tin be agitated in order to replicate the noise?

[BMGTZ]

what should i do??
pull them out and bleed them in diesel then put them back in??
just something i read

yes mate that would be a good start....hopefully they will clack for a few seconds after start up then go silent

[BMGTZ]

How should the tin be agitated in order to replicate the noise?

I find a salsa rhythm to be closest to the sound of a dud lifter. the cat adds the metallic tick as the flea collars hits the tin...but a live small cat replicates the inconsistent tick of of there being only one or two dud lifters by writhing around as it rides the the salsa wave.. A bent valve can be replicated by removal of the flea collar :P:P

[BMGTZ]

Any possibility it could be to do with valve springs. I read that of u put in a different grade cam you should change valve springs ect, or else they kinda flap against the new cam because the compress rate of the spring is different.

And with the cat thing, you gotta use one of those skinless cats, less padding so it makes a more vibrant rattle, not a muffled one

yes I agree .....skinless are good but the noise is more akin to a bottom end knock than valve train.


and a good point on the springs....have you checked for coil bind?

[jack be nimble]

I find a salsa rhythm to be closest to the sound of a dud lifter. the cat adds the metallic tick as the flea collars hits the tin...but a live small cat replicates the inconsistent tick of of there being only one or two dud lifters by writhing around as it rides the the salsa wave.. A bent valve can be replicated by removal of the flea collar :P:P

I thought a mechanical aid might be required, eg a cement mixer or clothes dryer, or maybe kicking the tin down a rocky incline.
Was it suggested the paint tin should be empty of paint?

Coilbind should be ok with aftermarket springs? But I would still check,
With older cars, we isolate ticky lifters by holding pressure on the lifter side of the rocker arm and listening for a change in the ticking, be careful of the moving bits though, and do your JHA and take 5

[mymidlifecrisis]

Couple of things - First 2 questions for everyone coz I can't remember, can a lifter be put in upside down? - do the rocker arms have lash caps - can they go in upside down. Seen it before with falcons - similar noise.

Is the base circle diameter the same between cams?

I also thought the valves could be hitting the pistons but I'd seriously doubt you'd get a compression reading.

Rocker arms the right way.

Not taking the piss mate ....just trying to figure it out too.

Cheers

[rowlys_evo3]

How do you check for coil bind???
Lifters can only go in 1 way same as the rocker arms
The base circle looks to be the same have to get a vernier on it
I'll pull the lifters out again and bleed them in diesel see how it goes

[Gianni]

Well the valves. Oils be hitting the pistons if the timing belt is out, specially now with the lumpier cams,

As for checking the valve springs I don't know because I've never had to do it, but one day soon hopefully I will I wanna rebuild my head

[Gianni]

Someones got it in for me giving me negative feedback for everything I suggest.

[jack be nimble]

Stolen from lunati power webpage, I think they make mainly chebby cams, they suggest 60-100 thou between the coils.
We used to say 10 thou for every 1000 rpm, but overhead cam engines can run tighter as they have a lighter valvetrain. Ok as a guide, or ask your spring manufacturer.


Items: 0 Home : Tech : Valve Spring Tech
Valve Spring Tech
Valve Spring Pocket Clearance

Valve spring pocket clearance is the gap between the inside diameter of the valve spring pocket (or cup, if used) and the outside diameter of the valve spring.
Too much clearance will result in the spring "dancing" around in the head, which "beats up" the spring mounting surface and the spring itself. If this is the case, a spring cup may be used. Additional machining of the spring pocket may be required to accept the spring cup.
Not enough clearance will bind the spring in the pocket, overstressing the bottom coil by limiting its movement and not allowing the spring to "grow". This will cause the bottom coil to wear against the head and/or prematurely fail. Machine the valve pocket using a Spring Seat Cutter if not enough clearance exists.

Valve Spring Retainer Fit

The valve spring retainer should fit the valve spring being used. A slightly snug fit is acceptable, however a fit that is too tight can overstress the top coil, and cause it to fail. A fit that is too loose can lead to spring "dancing."
Valve Spring Installed Height

The installed height of the valve spring is the distance between the valve pocket (or cup, or shims) and the outer edge of the spring retainer (which is the height of the valve spring) when the valve is closed. To check installed height, follow the following procedure:
Install the valve in the guide.
Install the retainer and valve locks.
Install all spring cups and/or valve spring shims (basically, everything except the valve spring).
Hold the valve closed by pulling the retainer up tightly against the valve locks.
Measure the distance between the outside edge of the valve spring retainer and the spring seat. A snap gage or a height micrometer should be used.
Check the distance against what is recommended on the camshaft specification card. An installed height of +/- 0.020" is acceptable.
If the installed height is not within 0.020", either machining of the valve pocket, or removal/installation of valve spring shims is necessary.
Repeat this procedure for the rest of the valves.

Valve Spring Retainer to Valve Seal Clearance

The distance between the innermost step on the valve spring retainer and the valve guide must be 0.090" larger than the maximum valve lift of the camshaft. Measure the distance between the top of the valve seal to the bottom of the valve spring retainer. After adding 0.090" to your measurement, it should still be larger than the maximum valve lift of the camshaft. If not, machining of the valve guide in necessary for adequate clearance.
Valve Spring Coil Clearance

Coil clearance is the distance between the valve spring coils when the valve is it maximum lift (fully open). A minimum of 0.060" must exist between the coils at maximum lift. Coil bind is when the valve spring is compressed fully-to the point that all of the coils are "stacked up" on top of each other. For high RPM applications, .100" is recommended . Coil bind is a catastrophic condition that will result in valve train failure. Disassemble each spring (if multiple springs are employed at each valve). Check all the springs (both inner, and outer springs) If there is not 0.060" - 0.100" minimum of clearance between the coils, the solutions are: the valve retainer, the valve locks, the valve, or the spring must be changed; the spring pocket must be machined. Keep in mind that these modifications will change the valve spring installed height

Valve Spring Retainer to Rocker Arm Clearance

When installing the rocker arms, check to see that the inside of the rocker arms clear the spring retainers. Many rocker arms have a "relief" to accommodate large valve spring retainers.
Valve Spring Run-In

Each set of Lunati valve springs are hand-selected to keep load variations below +/- 10% of the next. However, it is important to "run in" your new valve springs at low RPM using the following procedure:
Start the engine and run the engine between 1500 and 2000 RPM until the engine reaches operating temperature.
Shut off the engine and allow the springs to cool.
After initial run-in, most springs will lose a slight amount of pressure. Re-check and shim up the valve springs if necessary. After the springs are "run in", spring pressure should remain constant until the point of replacement.

[mymidlifecrisis]

For coil bind I'd assume it would be quite difficult to turn the engine over by hand as the spring is essentially bottoming out on it's seat before full lift x 16.
You can compare between a stock spring and after market by measuring the spring thickness x how many coils etc.
Btw, I've never heard of bleeding lifters in diesel but it's been awhile since I've been in the engine game. We used to clamp them in a vice between soft jaws and gradually apply pressure etc.

Cheers

[rowlys_evo3]

ahhhhhhh... after all that it was a loose cam gear.... thanks everyone for their help

[jack be nimble]

Good one. Congrats on finding that. Should be a good ride now with bigger cams and all

[BMGTZ]

no cats have been harmed during the investigation.....although some were worried

[EV0300]

^ abit disappoonted in the fact that none were

[rowlys_evo3]

thanks again to every one with the cat... i mean noise investigation.... i hope it goes better... im going to take it to meek to see if he can pull any more killa wasps out of her

[Evo-00x]

Loose cam gear? Make sure you check the timing belt for any wear marks now also check the thread of the bolt that holds the camgear onto the cam for any damage!!
Also look on the backside of the camgear for any wear too. If the bolt or the timing belt shows evidence of damage change them!