Head work

[biggy238]

I have done a novice port job on my cylinder head and have seen this relief cut in another thread.

Is it intended to promote scavenging and is it safe for a stock head?

Monkey Fist Rage

 

[WUnderwood]

I believe it's to prevent cracking between the valves.

 

[DirtyMaxx03]

I believe it's to prevent cracking between the valves.

This

 

[murphy41]

It won't have much of a performance affect at all. They say it is to prevent cracking. When a 12v head cracks, thats where everyone Ive seen cracks at. Is between the valves.

 

[biggy238]

Thanks gents. Any tips or tricks to throw at mine while I can still work on it?

Monkey Fist Rage

 

[murphy41]

Is that picture of your head? If not post up a picture of yours with the porting you've done.

 

[Ghostman]

I cut my 12v head down there as well to help prevent cracking.

 

[biggy238]

I have some terrible pictures. I meant to get some better ones. I followed what piers had a photo of and one of the threads on here. I have to get some stones to smooth it with.

I will get more tomorrow.

Monkey Fist Rage

 

[biggy238]

This is what I used for a basis


I'm curious about these also. More stress relief?

Monkey Fist Rage

 

[WUnderwood]

Increases flow in lower cam lift, supposedly

 

[Ghostman]

My discussion with a few engine builders; unshrouding the valves helps low lift flow a lot. Enough to be well worth doing.


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[biggy238]

My discussion with a few engine builders; unshrouding the valves helps low lift flow a lot. Enough to be well worth doing.


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Well, I had read mention on unshrouding, but none with enough definition of what was meant for me to attempt it. Is what's in the picture above sufficient?

Monkey Fist Rage

 

[biggy238]

Also, this thing has been decked
~.020" so it is somewhat unshrouded from that process

Monkey Fist Rage

 

[Ghostman]

Make sure you have enough PTV clearance.


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[biggy238]

Make sure you have enough PTV clearance.


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Over sized gasket was the plan

Monkey Fist Rage

 

[Ghostman]

Over sized gasket was the plan

Monkey Fist Rage

That might lower your compression a bit. Have you got a valve job done? Usually pretty cheap to set the valve face depth.

 

[murphy41]

Biggy, did you paint your head white !? I wanted to do mine white, but Im not that brave.

 

[biggy238]

That might lower your compression a bit. Have you got a valve job done? Usually pretty cheap to set the valve face depth.

A 3 angle? No. No valve work. (yet) That goes beyond the free or near free initiative.

And yes, I'm aware of the compression drop. I'm curious about the shims needed and the appropriate timing for this now that the head has been decked. I just hadn't gotten around to asking yet.

Monkey Fist Rage

 

[jakerc69]

My local injector guy told me there was only 3 thicknesses of injector washer shims. Thin..stock thickness..and thick.

 

[Ghostman]

My local injector guy told me there was only 3 thicknesses of injector washer shims. Thin..stock thickness..and thick.

I got these same three in the top end gasket kit.