Valve shims...

[bmxer882x]

Ok so I'm replacing my head gasket. Took the head off and took it to the machine shop to get checked over. Upon arriving he said he didn't want any of the loose stuff to fall of so he would remove it. He pulled off my rockers and marked where each one goes, no big deal. Then he started grabbing the shims/guides. I didn't know anything about it so I grabbed the bag of stuff he just removed and went on my way.
I'm now seeing things talking about the guides are all 3mm tall and the shims are different. I measured all my shims and they came up to 2.93,2.94,2.95,2.97 x2,and 3.0 x3. Do these need to go into a specific spot? I've seen a guide on measuring and placing them in a certain spot, but I've also seen people saying it doesn't matter.
Just a bit of info, my head is stock valve train with tomei poncam's going in.

[TheRealSy90]

They should have went back in each spot that they were removed from. And the guides are all the same size.


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[bmxer882x]

Since I don't have the tools to check this. What should I do? I've been looking at the double guide guide. I may end up doing that if I won't be fine just placing them whereever. They are so close in measurements. I also noticed my dial caliper is a little out of spec.

[AzS13hatch]

The only tools you should need to check valve clearance is a set of feeler gauges. The are extremely cheap and available. I suggest getting some and when you put your poncams in, check the clearance and adjust accordingly. You may have to purchase a few new shims and that is where having a properly calibrated caliper is going to come in very handy or you will be ordering the wrong size shims. If the shop knew you were changing the cams, that is likely why they didn't mark your shims, as you would have had to go through the process of checking and adjusting anyway.

[bmxer882x]

Just got to work on this because I've been prepping my head/block for install. With the cam installed I can not fit my .152mm feeler gauge under any cam lobe pointed up. I don't know where to go from here.

[AzS13hatch]

If you have tested every valve, its time to see what the biggest feeler gauge you can fit under each, take notes of which one is what measurement. Then take the shims out and use your caliper to measure the thickness of each shim and where it was before you took it out. Then with the difference you will have to do math to figure out what size shims go on each valve and then order the correct shims.

[bmxer882x]

That's just it. I can't fit a feeler gauge under any of them. With my smallest shim in. Im going to make the tool and see how that goes. Im looking for a lifter now. Which makes me wonder if my valves have always been left open a tad. (Always had a very slight misfire I could never diagnose)

[AzS13hatch]

If you are worried that the valves are open, do a compression test. What is the smallest feeler gauge you have tried to fit?

[bmxer882x]

Head is still off the block. Can't do a compression test. Smallest feeler I have is .152mm which is right in the middle of spec .13-.17mm

[AzS13hatch]

Other than buying a new set of feeler gauges and seeing how big the one that can fit is and doing math, I can't see another way, but I'm definitely not all knowing haha. Regardless how you sort it out, it sounds like you will be buying new shims.

[StuckeyOG]

Also, a machine shop should be able to tip the shims a few thousandths of an inch for you to get it into spec. I took my head to a machinist to have it pressure tested, checked for cracks, milled, 3 valves replaced and a 3-angle valve job. All this cost me $180.

My machinist offered to tip the valves and I declined, have regretted it since, as they have been a big headache.
Purchased my first set of 10 shims from Nissan at ~ $13.50 a shim. Forgot to torque the cams to spec, just nipped them down with a ratchet everything was wrong.

Second time, I needed 7 shims, two of which were smaller than anything Nissan makes. I had some old ones machined to the "proper" clearances I needed.
Found out the old BC cams I purchased were mislabeled on inlet and exhaust and had to have 3 more machined.

It was only 3 more because at that point because I had so many damn shims lol!

TL;DR: I suggest getting your valves tipped and having a competent machine shop handling it. Some may disagree and say DIY and save the money, which is respectable.

Personally, I would prefer next time to skip dicking around with the shims and will be having the valves tipped and head built to spec in a machine shop, while I do assemble the block, manifolds and everything else.

[omgosh]

derp

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