Oval port or rectangular port intake???
#21
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Charter Member
Re: Oval port or rectangular port intake???
More good information gentlemen.
Checkmate,
I will get those numbers to you tonight via e-mail.
I am now wondering what an intake change would do to my engine's behavior. Not trying to hijack Checkmate's thread but this all seems to be related one way or another.
Russ
Checkmate,
I will get those numbers to you tonight via e-mail.
I am now wondering what an intake change would do to my engine's behavior. Not trying to hijack Checkmate's thread but this all seems to be related one way or another.
Russ
#22
Registered
Re: Oval port or rectangular port intake???
Originally Posted by cstraub69@comcast
Actually you don't want the intake to line up with the head perfectly. You want the head to be above the floor of the intake about .100". A little step there to promote better "mixing".
Chris
Chris
Roby
#24
Registered
Re: Oval port or rectangular port intake???
But why not maintain a swirl texture on the intake & head port to keep the fuel suspended. I have always had the best results by finishing an intake port (intake and heads) semi-smooth then going over it with a rather coarse brake hone. My method for doing this was a clockwise push and a counter-clockwise pull on the front cylinder ports. and the opposite on the back cylinder ports. When I swore off carburetors I only finished the heads intake ports. However perfect port matching was essential.
#26
Guest
Posts: n/a
Re: Oval port or rectangular port intake???
I don't know how rough you leave your stuff, I like nothing less then a 40 grit finish on the intake. Better yet the texture of a golf ball. People get into the the "tumble debate" which I don't know if you are pro or anti, but I can say this by leaving the step shows gains on the dyno. I feel it picks up the "stragglers" and gets them mixed in with the others.
I know Roby some of the cup teams have experiment with a " valve seat" area on the intake face of the head. This area is cut with multiple angles then blended with a flapper wheel. These angles protrude into the path of the intake runner.
Chris
I know Roby some of the cup teams have experiment with a " valve seat" area on the intake face of the head. This area is cut with multiple angles then blended with a flapper wheel. These angles protrude into the path of the intake runner.
Chris
#27
Registered
Re: Oval port or rectangular port intake???
Originally Posted by cstraub69@comcast
I know Roby some of the cup teams have experiment with a " valve seat" area on the intake face of the head. This area is cut with multiple angles then blended with a flapper wheel. These angles protrude into the path of the intake runner.
Chris
Chris
Roby
#28
Registered
Re: Oval port or rectangular port intake???
Originally Posted by WETTE VETTE
The Merlin rect port manifold is perfect for a 540 low RPM motor!!
Roby
#30
I hate the winter!!
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Re: Oval port or rectangular port intake???
I am not claiming to be an expert at porting. I am just going to report what my AFR cnc'ed ports look like. They have a numerous ridges or steps going down into the port both the intake and exhaust. I called them to ask why they left them like they, they said it was so the fuel / air mixture tumbles down the port. They claim it works well. I will try to post a picture later today.