Camshaft Installation

[twilightprotege]

Hey Guys,

I'm getting my nice custom ground cams on tuesday next week (yay for me).....now the question

who has installed the cams themselves and what did you do about the valve clearance and shims?

Now the workshop manual says to replace the shim, a friend of mine (who i trust) said the easiest way is to have the original shims machined to the correct height.

I dont like the idea of machining the original shims, so i guess replacing them is the way togo, but are they costly? do you like buy a pack of 32 or something and they have 2 different heights in them or something?

also, the measuring the clearence, that very difficult?

thanks

 

[twilightprotege]

i should add also to the above, when i ask is measuring the clearence diffucult, how difficult is it to be sure that the clearence is 0.26mm or 0.26mm...etc - i have one of those cleanance testers so i'm fine there, just never used it and dont want to be pushing to hard to make it fit when it's supposed to be able to slide in and out without issues

another thing, when you installed them, what was the cleanace like straight off? were most of them the right clearence etc?

 

[twilightprotege]

or....am i just reading too much into all of this - ie, the clearance on a just under 30000miles engine wouldnt be an issue?

 

[Kooldino]

I assume you can't just buy new valves and shims that are already matched to the correct clearances?

 

[twizyours]

I just measured min with a feeler guage. I thought that was the way you measured them. If it you keep putting the different sizes through until one doesnt fit then the size below should be the clearence. They all are speccified sizes. Thats how I did it. I thought that was the way to measure it. Also I didnt change my shims and the clearence was good.

 

[chooch]

There's no way to get the reground cams to have the exact same base circle radius as your original cams unless your cam grinder has your original cams as a reference. Even then it would still be difficult to do. You will definately have to check all the clearances.

I'm suprised there hasn't been a discussion about this before. I've swapped my cams 3 times now and not once did I ever get proper valve clearance on all the valves.

Don't bother machining the original shims... It's pretty difficult to machine 0.001-0.002 to accuracy. Besides, the labor of the machine shop will cost as much as new shims. Shims from the dealer run about $8-10US.

Recommended clearance is .010" +/- 0.001 intake and exhaust. And I'll tell you now, the engine runs a alot smoother with the clearances set between 0.009-0.010". Although 0.009 might be a little on the tight side for the exhaust if you like to work your engine hard.

It's a pain to set the valve lash because without the special tool (which saves you from removing the cams to get the shims in/out), you have to measure, remove the cams, reshim, reinstall the cams, remeasure... etc.... until you get the proper clearance. Too tight you risk burning a valve, too loose you get valvetrain noise. And 0.0005" does make a difference so don't think "It's only a 0.0005 of an inch". 0.0115" and you'll get a little bit of ticking when the engine is cold but does go away when it's hot.

It would be a good idea to invest in a quality digital micrometer also. You'll get a headache reading a standard micrometer.

Don't forget to go your dealer to get a list of available shims.

 

[twilightprotege]

kooldino, you can buy new valve shims, but you have to install the new cam first and measure the clearences (pain in the butt)

twizyours, that's what i was planning on doing. i have a feeler gauge and that's what i was planning on using, so fingers crossed i'll be right. good to know how you did it, that's what i thought i needed to do.

chooch, you're wrong about the cams. our cams have a base circle of 1.38". i bought blank cams from mitch at protege5online.com and had them ground to the specs i want. they could fit the base circle on them no worries. when you changed cams, how out was the clearence? i'm certainly going to try and make the clearence 0.009" because that's gives the cams more lift (yay). what i was planning on doing is installing the cam, measuring all the clearences and if i need to get new shims, i'll buy the ones i need and go from there. i'm definately going to buy a decent micrometer that's for sure. now for the funny thing. i rang a dealer here today..."we dont have a listing for available shims...if a car needs them we get them machined up"....weird. anyway, i then spoke to a head specialist near me who said that with an engine with my amount of k's, and if i use the same base circle, there should be no clearence issues at all...a straight sap basically...he said the only real issues i'll come across is valve spring bind if the lift i got made was too much.....

now, twiz and chooch, are you guys using jspec/mazdaspeed cams or custom? the cams i'm getting are custom, they'll have 0.365" of lift. i'm sure that'll still be safe considering that's only 0.021" (0.5334mm) more lift. surely i wouldnt have any issues with that.

dont get me wrong, i'm confident with engine work etc, but i dont do it everyday for a living and i want to be as close to 100% certain on what i'm doing and the problems that might occur before i do anything.

edit : another thing i forgot to ask, did you guys get a new cam oil seal or were you able to reuse the original one?

 

[twilightprotege]

another thing with using the feeler gauge, how easily should a measurement go in and out before it's the right size? i mean i dont want to be forcing in 0.26mm and it eventually gets in there where in fact the clearence is 0.25mm etc...

 

[twizyours]

I have jspec cams. The feeler guage should slide in or it wont go in at all/ You will see when you are doing it. Thumbs up for doing research before your project. The fact that you are doing your research and the way you write you will have no problem. Soon as you stick the feeler guage in you will know what guage the clearence is, youll see. Also I used new cams seels as cheap as they are I thought why not just change them. If you have low miles on your car you would probally be fine, but it is like 8 9 dollars for one cam seel so I would just change them.

 

[chooch]

Yes the base circles are 1.38", but we are talking about variances of 0.001" on each lobe, which there will be. If the cores can be ground to 1.38X" with the X variable being exactly as your original cams, then you will not need to reshim anything.

I'm not very good at explaining things...

The feeler guage should only have a slight drag, you should not have to jam the feeler guage in.

 

[twilightprotege]

fingers cross my original cams are as close to 1.38" as possible...

i'll let you know how i go next weekend.

thanks for your help guys, i feel very confident now.