Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - First time porting heads
View Single Post
  #24 (permalink)  
Old 01-04-2013, 08:10 AM
Camaro_Nut2001's Avatar
Camaro_Nut2001 Camaro_Nut2001 is offline
Drag Racing Lover
 

Last journal entry: '68 Impala Project
Last photo:
Join Date: May 2009
Location: Mascot, TN.
Age: 46
Posts: 143
Wiki Edits: 0

Thanks: 86
Thanked 2 Times in 2 Posts
First off, Thank you for the great info. I ordered some longer mandrels, for the cartridge rolls, and they should be here today. I didn't get tired I just didn't want to take to much off the guides for fear of exactly what you said, weakening the guide. These are the heads I plan to run and I want them to last alot more than 20K miles. After looking at the pictures on the computer I did see where they are definately not the same. They look different just by lookin at them. I'm gonna get some numbers for FBird in a little bit and post them and i'll do a little "Tweaking" and try to get them as close to the same as possible. I don't have a way of cuttin the valves myself, although I have done it a few times on a schools machine, but I am gonna lap them in good. I "may" talk to my machine shop friend about what you suggested on cuttin the valves. There is a pretty big ridge under the intake seat, do I smooth it out and blend? I've read not to disturb it and also to smooth it out, lol.
Quote:
Originally Posted by hcompton View Post
They are not all the same but an improvement. They should flow well with a little more tweaking. Final cuts are slow and steady. If your tired same them for the next day.

Intakes are probably good for what they are. I would take off the ruff casting maybe even just use sand paper rolls for the intake side. The guide on the intake side are pretty tall. They could be cut but they will probably only be worth a few ponies and could result in bad flow if not done correctly.

Are these your heads your going to run or a set you are using to learn on. If its for learning purposes or all out racing. You can cut the guiide all the way put and leave a flush surface. I would think this should flow the best since these are not swirl port heads and rely on the combustion chamber to turn the air inside the combustion chamber and allow for the final mixing of the air as it flows past the valve and swirls into the port. But this type of short valve guide will crap out the seals and get wobbly real quick unless real guides are put in place first. But it will last 20k miles or a race season. I also thin the valve stems on the lathe to allow for more flow. Just dont do this with sodium filled valves. And back cut the seat area of the valve right down to the seat and allow for better flow over the valve. For bike race engines i will even round the seats with the flapper leaving the valve flat and rpunding the seat in the head and lap the valves in to seat them. Give a lot better flow at low lift levels that will allow the engine to get more air moving sooner in the intake cycle.

Valve size is also usally only at the seat where is touches the head. So moving the seat right out to the edge of valve will increase the effective valve size. And allow more flow at first opening event which allows more air to flow across the entire intake cycle.

Sorry for the short discription it would take hours to go over everything but for your heads a basic clean up should be all that is needed.

Hope this helps.
Reply With Quote