Head shim on boosted 08 nytro

[tylerearl88]

Just wondering if it is necessary to do the valve timing on a nytro when installing a head shim and running ten pounds of boost? This is running pump fuel at sea level.

 

[nate007]

You'll have to re-set everything anyway when you install the shim since you'll have the head off.
Not sure, but even with 10psi @ SL, you may not get away with 100% pump gas without detonation issues.
Sounds risky to me, but it may depend more on what you have for piggyback equipment?

 

[kinger]

Yes a slight adjustment to valve timing will be needed. How thick of a shim are you going to add? .070"+ will allow you to run 91.

 

[rxrider]

I think you guys are talking about cam timing.
And yes you should follow the instructions and set the cams back to stock position after adding the shim.

While you're in there make sure you measure valve clearance and adjust valve clearences if needed. You will be very angry on your slef when you find your motor is not running right after the work is done.

 

[TWIN TURBO]

Adding a .060 or so head shim will only advance the cams a couple of degree's. That's OK for the exhaust on a turbo sled, helps spool the turbo up quicker and reduces overlap. The intake should be retarded the same 2 degree's and maybe even a couple more. Again, retarding the intake cam will reduce overlap which is beneficial on turbo applications. The rule is Advance exhaust cams , Retard intake cams, which reduces overlap helping to stop the loss of charge out the exhaust valve when both valves are open. Retarding intake cam will also reduce cylinder pressure.
I can get thicker head gaskets, thus no need for shims and can get them made in a variety of sizes. Need a couple weeks lead time don't stock Nitro gaskets, maybe in the future.