Decision time...If i pull the head.

CobraSix

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Well, I tried drilling out the the heat riser tubes, but the screws won't come out. So I think I'm going to give up and just pull the head back off and take it to get welded right. Should have done that first. If you don't know what my problem is...my port divider has come loose and is rattling up a storm.

here is my decision. the reason I'm hesitant about pulling the head, is that I had a thin head gasket on.

If I remove the head, I'm going to put roller tipped rockers on. Think the extra lift will give me some of the power I lose by dropping half a point on compression? I'll be at 9.0:1, which I guess I can at least run mid-grade vice high grade.

I love this car...I really do...

Slade
 
Slade,

Either that or take another .020 off the head to get back to 9.5:1 CR. If you have to remove the valves for the welder you might as well visit the machine shop too. Then you can add the roller rockers at your leisure since you wont need to remove the head again. Or you could just put a shout out for a steel shim head gasket. Anyone? Anyone?
 
the head was just done, enlarged valves, etc.

The real reason I want to convert now to the roller tips is that if the head is off, I can check my clearances to make sure i have room for the extra lift since I'm running a cam with .440 lift now. I'm less concerned with the gasket, as my head has been shaved before.

Slade
 
Slade - it won't hurt to check, but valve to piston interferrance is not a problem on these engines. All the chambers I've measured have about .600" clearance or better from head surface to valve surface. The valve would have to drop down that far just to reach the deck of the block & at peak valve lift, the piston is no-where near the top of the stroke. This is mostly a concern of certain V-motors where the chamber is very shallow on one side and deep on the other putting the valve deep into the deck of the block. At the top of the exhaust stroke you have the EXH closing and the INT oppening, but even with the most radical of cams, the valve would be nowhere near the piston with these engines.
 
If given a choice between 1.6 rockers and a half point of compression, I would opt for better breathing. At best, the CR loss might account for 4-5 hp (2-2.5%). But more airflow more than makes up for it. And as you pointd out, operating costs will be lower.
 
Howdy Slade and All:

This brings to mind Porker Principle #4, which says, "Given a choice between a fattening food item and a none fattening food item, a Porker will always eat BOTH!"

If you don't have to make a choice why not choose both? It you can have compression and flow that sounds like the best deal to me.

Adios, David
 
I think he means that he will lose compression if he pulls the head because he woun't be able to find a thin(metal) head gasket again, so he will have to use the thicker composite head gasket.
 
Doug...thanks.

Now I can have my cake and eat it too.

Kstang hit the nail on the head. I had conceded that if I pulled the head to fix the port divider, I would end up with a thicker head gasket and drop my CR.

Now I don't have to worry about it.

Slade
 
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