i just got my head back from the shop the other day, had the valve seats redone and had the shims checked. after bolting the head to the block and set the timing i spun the motor by hand and im not geting any compresion. i could feel it sucking and blowing from the runners. i shined a flash light in the spark plug hole and i could see light shining past all the valves they were all fine with the cams off but bolted down its pushing them open when they are suposed to be closed. im at a loss why it is doing this now ? any one runn in to this befor ? :confused:

When the valves are 'redone' They remove material from the head which causes the valves to get closer to the cams. All the shims need to be replaced with thinner ones to compensate.

It takes a special tool to determine the spacer thickness. It is a plate which bolts to the head and is a reference point for a dial indicater to measure the height of the end of the valve stem. It is Kent-Moore tool J38957-N.

http://www.websorcerer.com/images/shimtool.gif

If they charged you for checking the shims, ask them how they did it, and ask to see the tool.

Lew

What do you mean by "had the shims checked", are you talking about the lash caps or is your motor a GA.
Did you change the cams?

At first guess I'd say the shop over cut the seats or over faced the valves, and now the valves are farther recessed into the head, hence the stems are farther up and with the cams installed the rockers are loaded.

A little more information would be good?
All valve open?
Inlet and Exhaust open?

all the valves are open all at diffrent hights . the shims are the ones siting on top of the valve stem one is a rocker arm retainer and the other one is used to match the hight with the retainer shim to level out the rocker arm.

lshadoff that tool is used when the cams are off im not sure how you would check the valve hight when the cams are installed.

lshadoff that tool is used when the cams are off im not sure how you would check the valve hight when the cams are installed.
What I meant was, that they had to use that tool to check the valve heights. They obviously did not do it. Did they charge you for doing it?

You need to find a shop (or a list member) that has the tool (it is expensive) to determine the correct shim thicknesses. Then you'll have to find a friendly Nissan dealership that will allow you to swap your shims for the correct ones.

Lew

Dang. I had some headwork done and I am pretty sure they put it together without measuring. The owner of the shop even told me "if I did everything I charged for, I wouldnt make any money" I am hoping I dont run into problems liek this

lshadoff that tool is used when the cams are off im not sure how you would check the valve hight when the cams are installed.

You need to remove the cams to check it.

Dang. I had some headwork done and I am pretty sure they put it together without measuring. The owner of the shop even told me "if I did everything I charged for, I wouldnt make any money" I am hoping I dont run into problems liek this
It sounds to me like he just admitted he cheated you. Do you have an itemized bill? If so, threaten to sue him unless he returns your money.

Lew