need some clarification on pistons and valve shims

[NISSAN240SX12]

ok, i have been blogging my issue with my car for sometime now. I think I'm getting close to what my issue is. here's the link to the blog zerothread?id=354633. originally I had taken my cylinder head to the machine shop to have it cleaned and resurfaced. but when i got it back all the valve shim with the caps were taken out. not knowing that it mattered where there are suppose to go i put it all back together and I have been having an issue with a noise from the head with a bad valve leak. This one auto tech told me that since that i have had the block bored out .020 over and i used the original pistons with oversized rings that i need to get oversized pistons also. is that true? I though you could use oversized rings and use the original pistons. as far as the valve shims go has anyone ever successfully put there valve shims back into place not knowing where they sat originally? I was thinking maybe it might be possible to go to the junk yard and pull the shims from a ka24de engine and mark where they sit and use them. think that might work? any help would be great! thanks

[preludesamsivtec]

no the junkyard thing will not work. you need to have the service manual and the spec for the clearance for the caps. take a piece of paper and a couple feeler gauges and measure each cap to camshaft. Write down each measurment for each cap in order. Write down the number that they acutaully are not what they are supposed to be. Then then remove cams and add or subract shims to get the correct tolerance. like if one was supposed to be .030 thousands and it was actullay .045 thousands you would take a .015 shim out of the cap. Each valve sits at a different height in the head so taking them out another head and putting them in your car would not help you. As for the pistons i work at honda and we have different pistons for the oversized rings but for nissan i cant say for sure. The best thing is to call any dealer and ask them if they have oversized replacments if they do then i would say yes you should use the matched pistons and rings

[preludesamsivtec]

i forgot to add checking the clearance is a process that must be followed to the T. Use the manual, it is your best friend anything you want to know is in that manaul. Make sure torque each bolt for the camshaft caps in order( there is an order) and to the proper spec.

[Vegascorbin]

#1. Yes you need to use BOTH over size pistons and rings when your engine is bored out. Not a big deal aslong as it was bored to a standard size. The shop that did the work shoul dbe able to tell you what size you need.

#2. I would ask the machine shop that took things apart to put it back together. We had our SOHC head checked and surfaced and we took it to the shop with everything in place and got it back the same way. I don't even know if they took it apart. If the shop had to take it apart then they should put it back the correct way. You paid for a complete job and it sounds like they only did a half job.