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Discussion Starter #1
A small guide, to check/adjust your valve clearence.

This is needed if you either upgrade your cams, ore replace a valve ect.

One thing thats super important, is that you dont swap around with anything.
keep everything numbered and seperated.

I use an old box i had from some wireplugs to keep the lifters in.

Also remember to lube everything, oil oil oil!

To lift the head from the bench, i made 2 pieces of wood, with a cuple of old headbolts from buttom and up in the head to keep them in place


The clearence is set by the thinkness of a shim, thats located underneath the lifter.



All my lifters/shims all numberd up.


Start by measure all the shims, and write it down.


Put in the shim, and lay it down as it was before, dont swap them upside down, its easy to see witch side thats sitting on the valve.


Afterwards, put in the lifter, oil thease up on the sides, and make sure they turn freely around in the head. multiply above 11 more times :)


When installing the cam, its important, that the cam goes straight in the head! find a neutral position were theres lift in eatch in, and tighten it down so it goes straight in! very important!
Dont bother about putting in the seal in the end, the first time you put in the cam, because its very likely that the cam is going out again.
And agian! remember to use oil in the "bearings" and on the lifts of the cam.
give the bolts a drop of oil on the threads, and the part were the head of the bolts meets the bearing cap.


Now Tourge the bolts in the correct order, 9-12 nm.




Now that the cam is in place, turn it a few rounds, making sure nothing is out of the ordenary, sounds/stuck and so on!
turn it, so the lifting part of the cam, goes straight up in the air.


And now its time to do the actual measurements!
on the exhaust side, the gab has to be in between 0.35-0.42
Stick in the gaugeblade (is that the correct english word?)
in between the cam, and the lifter, the biggest blade, that suits, will be your clearence. Note this down underneath were you noted the thickness of the shim.



Now to the calculation

An example from my engine.

Shim thickness 2.99 mm
valve clearence 0.20 mm

so ill take 0.15 from my shim, and buy a shim in 2.85 mm for that valve.
mount it, and remember to dubble check your valveclearence with the new shim in place.

Now, my head was ported flowed and all the valves got a new type of cut.
this meaning i got some low clearences. and on Number 1 valve none of the gaugeblades fitted in between! 0 in clearence!

what you do here, is to swap around 2 shims. just take one thats 0.20 lower then what is in it, and measure once again,
that way, you are sure that you can get the right calculation, instead of counting with a 0 clearence.

Remember, this was the exhaust side only! the intake side has a different clearence value.

Ron
 

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Excellent, thanks. :thumbsup:
 

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The angle of entry for a feeler guage is a bit crook due to the design of the head.
Nissan recommends using a thin gauge entered from each side and then add the total to measure your clearances.
I was taught to use a 3-feeler test when checking valve clearances.
(1-thou under size, correct size and 1-thou over size)
So under-size should swim in, correct-size should feel just right and over is a no-go.
Becomes second nature to always have 3-blades out.
 

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nice write up.... shimming my head gave me a headache
this is why i let the machine shop to do it but after he have asked to bring him all of the shims at 3mm i understood that he is using the bad method he will be taking some part from the valves out, i just hope i will not end up when revving at 9000 to have a valve drop on a piston.
gr8 write up.
 

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Discussion Starter #8
a friend of mine did "grind" the valve on his 400 bhp sr20 engine, he had the correct tools to do it, and he never have had any issues.

however, i would ALLWAYS shim it correctly.

Ron
 

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i noticed that after doing a few turns on the cams that they clearances some times changed even if we had all the clearances correct, and i would say that it was down to the wear on the buckets... second hand buckets and also settling .
Now the other hard part i noticed was getting a Fila gauge that had graduations in .001mms the closest we had was 0.05 so that made the the clearances more of an assumption, so would use a .040mm and 0.045mm and 0.050 to get an estimate of the clearance and where it fell and that way we new if it were slightly tight on 0.045mm it was around that mark + or - 0.045mm if it was loose it was on the greater side so more like a 0.0455mm or even a 0.046mm ..
This was more down to keeping clearances in the middle, too tight you risk keeping valves open and burning the valve, and too loose you risk the shim hopping out at high RPM or the Cam slapping the bucket and wearing itself away quickly ...
 

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ps the cam goes in and out alot of times to measure and remeasure to get correct clearances by swaping shims around and also if necessary measuring worn buckets and swapping them around too.
 

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and also make sure you measure from the spark plug center and bend the gauge blade to fit under easily our first set of measurements came out wrong because we measured from the outside in intake facing side and exhaust facing sides and this gave us wrong readings, its better from the inner with a L shape bent Blade...
 

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ps never even think about grinding the valve tip, this is not a good practise, it removes the hardend tip of the valve, and also makes it softer, also makes the tip surface rough, not ideal, you want to leave the valve stem and tip alone and deal with shims and buckets only for clearance.
 

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Discussion Starter #15
Adam did you read post number 8 ?

I allways have my buckets/shims/valves in numbers, so every item goes back in the same hole look at the 2´ pictures, and notice the numbers...
i would never swap around buckets, only for new ones.

If people cant use a gaugeblade correctly, they shoulden even start on a enginebuild.
its ok to think when dooing this.

Ron
 

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Discussion Starter #16
Excellent write up Ron thanks for sharing & taking the time to do this.:thumbsup:
Np, if it helps people im happy to do it,

I just forgot to do the guide on how to dial the cam when dooing so :/
i guess there must be some other good guides out there on that

Ron
 

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The way you do it is the way I was also taught to do it instead on motorbikes. Our work benchs was like a operating table plus was told never to swap parts always putting everything back where it came from as swapping parts around can strain & accelerate the deterioration of other parts plus once you start swapping parts you will never get it back the way you had it LOL.

A shame you never got to do the cam dialing in as it would of been a nice finish to this thread.:thumbsup::thumbsup::clap:

Again thanks for your time & effort buddy
 

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i recon that even if ron cant put it in will have to find someone who is doing cams and can put some pics and explainations up, it isnt easy and requires some knowledge of valve opening and closing times and piston to valve clearance .... requires some thought and some calculations intake openining time and closing time ... and same for exhaust tricky stuff really. I know this much you need a Timing wheel to put on the crank to get all this set correctly and a DTI on the cam intake or exhaust etc.
 

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I watched all them videos on here before as someone put the link up before, probably yourself lol. Yeah they make good veiwing buddy thanks for sharing it.:thumbsup:
 
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