Polished one chamber, anyway... what do you guys think?

First time ever here, too. Also, what's the point of the bump at the bottom? Not the vane in the runner, the bump at the bottom of the chamber...

What do you guys think?

Before:

 

After:

 

the bump is most likely the desing of the chamber. Take a look at Twisted flow heads, they have that "heart" shape to them. just that, a design for the chamber.

Good job on the polish, make it a mirror finish, polish teh runners as much as possible, & get that sheesh thermal coated

 

pretty good chance that's its there to create turbulence or a "swirling" effect in the cc. Be careful when ur polishing that you don't remove metal, or atleast not alot, although i know that ur looking for low compression, we probably don't want it tooo low, unless u have some plans of eh, 24 lbs of boost. Also, look into a 3 angle on those heads with a port job, i wouldn't recommend porting the heads with out the ability to bench flow them, it's been known (very common) for people to make the heads flow worse than they would stock, even with larger ports...but definately think valve job, you'll love the new sealing power.


ps, doesn't look bad polished up either, had a friend who actually "polished" the whole deal here, of a cylinder head. The whole thing didn't have a ridge, bump, or rough spot, after the polishing it was buffed and shined like a piece of mirror, but the thing was so smooth that it was virtually un-usable in any engine, ANY.

 

as for the ports, I'm basically going with a gasket match... don't see any reason for more flow than that .

 

grind away all the metal until you get to the green circle in the picture, try to get as close as possible to the valve seat. after you do this you can tell by just looking at it how much more flow you will get.

 

sorry about the crappy pics, camera sucks

 

Yeah, I'm working over the throat area and all now.

I'm not going to grind down the vane as far as you did - I'm porting to increase velocity first, actual flow second.

Remember - daily driver here. I want max power before 6k rpm.

that's interesting... I didn't take out as much material as you did on the intake valve area, but mine looks smoother?

 

 

*add to favorites*

OK, I have not done this, nor studied any of this port n polish stuff, so be gental on me


Why polish the top of the combustion chamber?

I do understand the intake port cleaning.

I didnt know you could take valves out and grind there, I learn something every day

 

Polishing the chamber helps prevent hot spots, and detonation (turbo, remember? detonation = BAD)

You want the throat about 85% of the diameter of the port. It helps with velocity, and low end power.

First one is completely done! I'll post pics tonight. Now, two more cylinders to go, and I can start on the 2nd head

 

not polished yet, just ported.

 

Lee, are you sure about having more flow, what exactly is going to happen to port velocity once it reaches the cylinders and is rapidly expanding, it's going to slow down. So yes, you'll have the flow, but you're not going to be getting the enough vacuum to pull the air into the cylinder to fill that extra area. Plus, what's going to happen to you'll flow better with a 3 angle being done to the heads, not just take away a bunch of metal. Another thing to think about, although you're removing tons and tons of metal, how will this effect the heat transfer from your valves going through the cylinder heads, one of the most important aspects of the valvs is proper contact with the cylinder head so you're valves don't over heat, burn, crack, bend. etc, don't know how the head will hold up having soo much removed in a "uncalculated" manner, just wondering if the math has been done to back the method.

 

One head done.... jesus talk about taking a long time.

 

the "high speed" section of the port is the turn right before the valve bowl, i barely touched that part. The most restrictive part of the ports are the valve bowls, 2/3's of the airflow gains to be made are done here. I get this information from the August 2003 issue of Popular Hot Rodding.

Im not going to retype the whole article, but if you want to read it go pick it up, it has a very descriptive 7 page article on do's and donts or porting, what will give you the most gains and what a valve profile should look like.

 

alright, just making sure that ya had checked up on things...i've seen waaaay to many guys say "make the holes bigger" and in effect make their cars lose more power than if they had just gone and bought some aftermarket heads for 500 bux....long as ya know what ur doing, and have the equipment to do it, then i don't think you'llh ave any trouble.

 

the vain on my heads is ground down about that much and it does not hurt low speed driveability. i had my heads done professionally done by one of the guy's that used to do them for GM when they used the 60* in off road racing. they also flow more then supersix's heads with less work.

 

Last weekend on one of them TV shows they did a port n polish on set of heads then flow benched them. They were saying that the polished exhaust and combustion chambers keep carbon and deposits from sticking.

They also said something about not going any more than 1 1/2 in into the port.