Valves In Dodge CR Head

B

blownsmoke2

Trying to make a hook
Joined
May 11, 2008
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243
Is it worth changing them? How big can you go? How about changing the intakes to a 45 degree cut? If this is the case why can't you use a set of exhaust valves?

Any input would be appreciated.
 
stock intake valves are lower grade metal and can't stand up to as much heat as the exhaust side. Stock Cummins exhaust valves are Inconel so yes, you can benefit by going with exhaust valves in all. Whether their angle makes a difference or not... don't know
 
I believe a 45 degree angle lets the air in faster and forces it straighter down the cylinder.
 
The Cummins exhaust valve is good quality inconel. The 45 degree seat goes along with porting, and aids in air flow at above .250 lift.
The biggest valve that will go in a Cummins 5.9 block is a 1.340 or .040 bigger than the stock valves. In a 6.7 block we go with a 1.450 valve, or .150 larger. The addition of a bigger valve alone is not worth it if you don’t do the corresponding port work.
Airflow is the most important part of any build.
 
blownsmoke2 said:
Is it worth changing them? How big can you go? How about changing the intakes to a 45 degree cut? If this is the case why can't you use a set of exhaust valves?

Any input would be appreciated.
Click to expand...

i have heard of guys going with ss valves in the intake and the inconel in the exhaust... also heard of some going all the way up to a 2.?? size valve dont know how true that is though. I would just talk to a reputable company that does heads frequently and they should be able to help you. just my .02
 
I don't believe they are different sizes just more conical and different cut. I took alot of metal out of head just didn't cut off intake. Maybe this winter I can due the intake side. I just figured with the new cam being quite a bit healthier than the old Scheid cam it would help it breath better. Hell just gasket matching opens it up quite a bit.
 
COMP461 said:
The Cummins exhaust valve is good quality inconel. The 45 degree seat goes along with porting, and aids in air flow at above .250 lift.
The biggest valve that will go in a Cummins 5.9 block is a 1.340 or .040 bigger than the stock valves. In a 6.7 block we go with a 1.450 valve, or .150 larger. The addition of a bigger valve alone is not worth it if you don’t do the corresponding port work.
Airflow is the most important part of any build.
Click to expand...

This is the winter project to go along with a standalone if the ever get it figured out and on the market. I've definatly built the bottom end for it just working on the top end.
 
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