Cam timing after head is milled Ideas?

[Chuckcruzin1986]

Hello,
I milled my head .05" and have an adjustable pulley bolted to the cam.
I don't want to set-up my cam with an indicator etc (the right way) at the moment, just want to get the engine going and running fairly normally.

It is a stock camshaft.

So, it looks like I should Retard the cam to compensate for the head moving down the .05" but how much?

Thanks,
Chuck

[rcfanatic]

If you milled it .05" then you definitely need to check the valve clearance, more than likely it will be too close.

On the other hand if you meant to say that you milled it .005" then you are fine and no adjustment is needed. You won't notice a difference.

[Chuckcruzin1986]

Head was milled .050"

If you milled it .05" then you definitely need to check the valve clearance, more than likely it will be too close.

On the other hand if you meant to say that you milled it .005" then you are fine and no adjustment is needed. You won't notice a difference.

I have check the valve clearance using the stock cam and gear. My question is what would be a good starting point for the adjustable gear?
Thanks

[StereoInstaller1]

The question I have is how are you gonna tune it in the end?

[Dj Buttchug]

. are you positive its not 5 ten thousands of a inch. 5 thousands seems like to much

[payney8]

5 thousands of an inch is a huge cut I don't think they would have cut that much

[ForcedFirebird]

5 thousands of an inch is a huge cut I don't think they would have cut that much

Most machine shops start at .0015" (one and a half thousandths), if that doesn't clean it up, they go another pass. Some shops start at .003" and if that doesn't clean it (usually does), they will go another .002".

Just for reference, .003" is the thickness of a hair or piece of typing paper (I have 3yrs experience in a CNC machine shop).

It really depends on the condition of the head, and the more cylinders on a head, the tighter the tolerance needs to be since they are longer (.001" per cyl)...

[payney8]

hahah i know bud. I am a mining/marine diesel mechanic i rebuild engines bigger then your car and more expensive then most houses. Maximum machine tolerance on most of them is 0.01" after that you have to run over sized head gaskets and that has its own issues.

[rcfanatic]

I have check the valve clearance using the stock cam and gear. My question is what would be a good starting point for the adjustable gear?
Thanks

It depends on if it was really .050" or .005". For .005" just leave it at stock. For .050" you'll want to retard it 3-4 degrees I believe but even then you might not feel a difference compared with stock

[whodwho]

I believe you need to advance it. If the cam and crank are on their marks and then you move them closer together from milling, the cam would rotate CCW (retarding) to tighten the non tensioner side of the belt back up so you would need to advance to bring it back to marks.

[rcfanatic]

I believe you need to advance it. If the cam and crank are on their marks and then you move them closer together from milling, the cam would rotate CCW (retarding) to tighten the non tensioner side of the belt back up so you would need to advance to bring it back to marks.

whoops yeah I was thinking about the head instead of the gear. good call