|11-24-2004 09:34 PM|
Raising the roof of your port is easy. The trick is just to not grind out too much. I could be a little better helping you if I knew what engine you are working on.
The most beneficial thing is blending the bowl area under the valve, and making it flow out as well as in.
When you look inside your valve bowl, you will notice that the short side radius will often form a "shelf". Recontouring that into a smooth curved radius, and depending on the head design, cleaning out what would be obstructions, like the valve guide part that sticks down into the port, stuff like that are more critical than raising the port roof. Its the bowl area where you get the most gains. If you are working on a Small block Ford Winsor or Cleveland, I have a lot more time working on them, I can give you better direction on what to do. However, there are certain givens in all porting jobs, what you should and should not do. Its more important to obtain a good smooth flow passage than to make it bigger.
Rule 1. You dont want to increase the angle of the bend going from the valve seat to the head port on either the intake or exhaust. The idea is to do what can be done to straighten out the curve.
Rule 2. ( You dont want to polish the intake ports mirror smooth. Give them a florentine finish, as a fine polished intake port tends to allow the fuel/ air mixture become unsuspended, allowing the fuel to reconstitute as a fluid.
Rule 3. You cant get the intake side shiny enough. Since you are pushing burnt fuel air mixture out the exhaust, theres no need to keep anything suspended, so the slicker the surface the better. Polishing the exhaust port also aids in preventing deposit buildups as its difficult for them to attatch to a smooth surface.
The only method of porting out an engine is with a die grinder and rotory files, grinding stones, and fine emery cloth darts and wheels.
There is the alternative method that is used with a machine that pushes a mud like stuff through the port to do the job, but that is extremely expensive.
There is also CNC machining and that can get pricy as well.
You have to be ware of raising the roof on the port as there is usually a water passage somewhere nearby and if you get into that, you have ruined the head.
If you want to send me a PM, I will take the time to describe the types of stones, rotory files, sanding points and wheels that I use. With the stones that I use, I can get very close to a CNC machine job.
|11-24-2004 08:49 PM|
|Mad Maggot||If using this compound is not a good idea, what would be a good way to go about enlarging the ports? I want to raise the roof of the runner into the rocker arm valley a bit so it directs the air over the short side radius better instead of choking it off. If this area will not affect structural integrity too much, will this compound still work?|
|11-24-2004 06:59 PM|
I have known of people using aluminum based epoxies in aluminum heads to reshape ports etc, but not in steel heads. The only way to build up any part of a steel head is to use nickel welding rod or wire, then reshape it. I would be very leary of using such a thing in a daily driven vehicle. It is doubtful that most compounds would adhere to the steel with the radical temp changes that go in inside an internal combustion engine. Exhaust temps can easily get up over 1000 degrees, causing for a lot of expansion and contraction of materials. I dont know of any compounds that would have the same elasticity, growth, and shrinkage rates of cast steel. It would be a terrible thing to have a chunk come off in your intake port and get sucked into a cylinder.
As mentioned with the aluminum stuff, the only guys I know doing that are drag racers.
Unless the manufacturer of this elixor can show me serious lab tests under the conditions I have mentioned, I would stear clear of it.
|11-23-2004 11:27 PM|
I need an opinion...
I need some opinions or advice on Goodson's port reshaping kit (PRK-99) for heads. It's a two part epoxy that acts like a filler for reshaping the port or adding material to thin spots. I need to know if this works for aluminum as well. I have not seen a product like this before, and I emailed Goodson for some more specifics but they were not very informative. If anyone has used this product or has heard anything about it, I would appreciate some feedback. I'm not advertising, I just need to know if this stuff really works. They say it can be sanded, drilled, tapped, and machined.