11 Bravo

iTrader: (3)

Might as well add this post while I'm at it. Is there a good book or website to learn? I'd like to get a set of junk heads to practice on to see if I could do it myself. Someday in the far, far future I will build up a budget stroker LS1, doing almost everthing myself. So this seems like a good place to start, as far as things I'm ignorant on.

SNW Vette

Hi,
I have never seen a "How-To" on porting LS heads. I have seen pictures of modified heads on the web and in magazines but these were without a write-up from a professional source.

David Vizard's book "How to Build and Modify Chevrolet Small-Block V-8 Cylinder Heads" (Motorbooks) gives some background on his porting techniques that were developed for SB's. Much of the theory should be applicable to the LS family.

John Dalton's book "Practical Gas Flow" (Motorbooks) takes you through building a basic flow bench that can be used to compare mods to a baseline port. He also has several interesting techniques to figure out where to mod a port.

John Lingenfelter's book "John Lingenfelter on Modifying Small-Block Chevy Engines" (HpBooks) has a good discussion on pocket porting.
These books are available at www.Amazon.com

Good luck and please post any new info you come up with,
Steve

Nine Ball

iTrader: (38)

Here is one awesome site for you: Standard Abrasives Do-It-Yourself Porting

Very informative, and lists all the tools you will need for the job. Have fun!

Tony

Crazyquik

Lingenfelter's book is at most all the Barnes & Nobles and Border's bookstores I've ever been too. Never seen Practical Gas Flow, I'll have to check that one out.

11 Bravo

iTrader: (3)

Thanks, Nine Ball, that is an excellent site. 2 questions. Since it says you can't use a dremel tool, who knows of a good brand electric die grinder? And, if I did a basic port/polish job on a set of LS1 heads would that be equal to aftermarket stage 1 heads? Doesn't seem to be too hard to accomplish. I can see me saving alot of money. And, I already know of a set of junk heads to practice on. They're out in the woods <img src="gr_stretch.gif" border="0">

Brother J

I looked at as many ported head pics on the internet as I could find to get a basic idea of what areas need attention. Basically, the bowl area and the valve guide need the most attention. Vizard's book was a big help, also. Be conservative, preserve velocity and swirl and resist the urge to "hog em out." "First do no harm." I used an air-powered die grinder with 6" long carbide non-ferrous cutters. Like a hot knife through butter, so ya gotta be real careful. Netted me .2 in the 1/4, gonna dyno soon. Feels smoother and has better breathing on the top end. It also contributed to the demise of my 10-bolt. <img src="gr_grin.gif" border="0">

Here's a diary I posted on our local board:

Day 1:
Back cut the intake valves, polished up the faces on in/ex, radiused the outer edges of the exhaust valves.

Ported the area around the intake valve guides, smoothing out the fin area, maintaining the shape and direction of the fin to avoid changing the swirl pattern. (Note: An air-powered die grinder with a non-ferrous cutter removes material real easy. This is fun stuff!)

Blended valve seats to the port bowls. Plenty of extra valve seat material to remove. Using a stone, slower going with the hardened valve seat material.


Day 2:

Streamlined area around exhaust valve guide. Enlarged exhaust runners slightly, leaving the port exits unchanged. Cleaned up intake runners, removing casting flash and leaving the walls slightly rough. Smoothed and polished port bowls under the valve seats using cartridge rolls.

Day 3:

Cleaned up combustion chamber area with cartridge rolls. (Real rough casting, tore up lots of rolls.) Smoothed out transition from valve seats to combustion chamber, hand sanding very carefully. Lapped valves to seats. Cleaned heads. Installed new LS6 valve stem seals. Installed valves. Ready to install!!

P.S. Just keep in mind that I am NOT an expert on head porting. I was just willing to experiment and take a chance to see what I could do on my own.

[ December 24, 2001: Message edited by: Brother J ]</p>

ls1 joe

iTrader: (37)

Hey there is always SAMRacing.com

Terry Burger

iTrader: (4)

Porting is very easy to do, it just takes a LONG TIME and is REALLY BORING. It's also easy to mess things up. If you have the money pay someone else to do it.

SNW Vette

Hi,
I forgot to add earlier that Joe Mondello wrote an article on porting LS1 heads. It is in the current issue of "Engine Rebuilders" magazine which is a trade magazine published by Babcox. Do any of you work at a shop that may have a copy and could get a summary of this info on the web?

Thanks,
Steve

faster67

I'm not a porting guru, but I've ported tons of small block Chevy, big block Chevy, small block Ford castings, stock and aftermarket. Pretty much any cylinder head needs a great short side radius and a nice straight valve pocket to lay down the numbers. When I started tinkering with a friend's '98 SS, I decided to try my hand at getting some decent numbers out of some '98 castings. I had heard that out of the box these heads were flowing close to the 250cfm mark, these weren't even close. I think they flowed ~222cfms on the best intake runner in stock configuration. I just happen to have a buddy with a new Superflow bench and after probing, porting, probing, porting, etc., etc., I found a pretty easy 15cfm in the short side and pocket on the intake and exaust side, but after that it took a good amount of work to pick up from there. Granted, that was with the stock valve angles and there is definately a little more to be had with not a bunch of work. If you don't know someone with a bench, there's not really any way to know if you're helping or hurting the airflow characteristics. For me, the time invested wouldn't add up to tarketed horsepower level I was looking for so I ditched the project. Most people's Stage 1 heads are flowing ~270+ and that's not something you stumble across. These heads are very nice just right off of the showroom floor. As far as actually porting the heads, you can use an air die grinder, an electric grinder or whatever you prefer. If you don't already own a large compressor and you don't plan on porting tons of heads in the future, I'd start looking for some electric die grinders. I buy my porting supplies from some of the local tool supply stores. They usually have all the sanding rolls I want, stones, carbide cutters and all kinds of neat little abrasives and I can order just the stuff I'm low on. If you plan on working on your own car on a regular basis, I strongly suggest buying an air compressor and some air tools if your work area provides. I can't imagine working on things without using air tools. <img src="gr_grin.gif" border="0"> I use a cheap die grinder, large compressor, die grinder mounted guage/regulator setup to control speed and lots of carbide cutters. Depending on your goals, it might be worth it to invest a little money on some good porting tools and go for it!

-Bernie

jblazy18

iTrader: (4)

so overall faster67, would u recommend getting aftermarket heads or just port n polishing the stock heads.. i have a 98 z28 stock lookin to upgrade on parts.. if u recommend getting aftermarket heads, which ones would u recommend for a street/strip application.. n i also plan on getting a supercharger/ intercooler n NOS dry 150 shot system.. im still learnin at all this.. thanks

GuitsBoy

iTrader: (4)

Holy crap this is an old thread!

Im sure it still pays to get a set of professionally ported heads, but if you want some info:

https://ls1tech.com/forums/showthrea...e+ported+heads
https://ls1tech.com/forums/showthrea...e+ported+heads
https://ls1tech.com/forums/generation-iii-internal-engine/316041-pics-my-bo-white-ported-241-s.html
https://ls1tech.com/forums/generation-iii-internal-engine/316237-just-starting-head-porting-project.html
https://ls1tech.com/forums/showthrea...e+ported+heads
https://ls1tech.com/forums/generation-iii-internal-engine/346464-pics-ported-heads-help-me-port-mine.html

Incidently, looks like "faster67" hasnt posted since jan 2002, so you might not get an answer...