Porting and polishing the heads?

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loud00ls

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i just got a good deal on some factory heads off an 02 v8 ls with only 43,000 miles on it for 50 bucks :D ...so im now wondering if it would be worth it to get them ported and polished and maybe get the cams reground. Or maybe i should just sell the heads and throw on some nitrous and call it a day. I would love to have my car all motor with no power adders. But i know i could put more money in building the heads, and still not have the power of a turbo or nitrous kit that would likely cost cheaper. Anyone have any sugestions on what route i should take?
 
I think you already know what I will say. I will restate it for anyone else following in your shoes or future reference though.

Porting your stock heads will give some benefit, but that benefit depends on how it was cast from the factory. I would see this as a good following step after already having gone nitrous, s/c, turbo unless you plan to stay N/A forever...

The best bang for the buck is nitrous oxide, hands down. It is the cheapest and easiest power a person can get. The downside, and a big one at that, is that a bottle of nitrous does run out. Another not so great thing is that it usually costs about $40.00 per bottle refill which adds up over time. If you spray enough it will even eclipse the total cost for a turbo system eventually.

Turbo will be the best overall power. It will give you much more power when compared to a supercharger and has constant power on tap at any time; unlike nitrous oxide.
 
Im with you loud but I dont think it would make to much a difference all on its own. I am one that is allways against Nitrous oxide anyway.
 
The old rule of thumb was a port and polish job would get you a few percent power, something like 5%. Usually there are other modifications that will get you more bang for the buck. But a port and polish job on top of other mods is icing on the cake and if done properly will help the car breathe a little better.

I did my own port and polish many years ago by myself and it was a slow time consuming process. If you have time and the proper tools it might be worth doing yourself. The key will be if any one has the port profiles that work for this engine.

Back long ago, you could buy profiles or they would be in hot rod books, they were essentially the shape of the ports cut out of cardboard and glued to a stick with a marker showing how far in that profile was supposed to fit. You would grind a little and see if the profile fit down in the port at the depth it was supposed to be and grind a little more til you got there. The risk of winging it is that especially with aluminum heads you could cut too deep and hit water or air.

An easy safer way if you don't know the profiles is to take an intake or exhaust gasket and scribe the outlines of the port using the gasket as a template. You can grind the heads to fit the outline and go in just an inch or two which is relatively safe. Deeper requires you knowing what you are doing or luck. On the intake side you don't want to polish too much, you want a little turbulence on the surface.

Not sure if there are many people who work on the LS engine who would know what profiles would be correct for this engine.

Like the guys said other mods will most likely do more for you than porting and polishing.

Just old opinion and experience with old Dodge engines that have almost nothing in common with the LS engine so don't trust what I say.

Jim Henderson
 
i actually know a guy at a well known local machine shop that will do a 5 angle valve job and a mild port and polish for 600. That to me is a pretty good deal considering the power gains should be more then even the sct computer at 400 dollars. I was also talking about regrinding the cams which would be expensive im sure, but im sure there are some pretty decent gains to be had when ground for an all motor setup. I just like the idea of having to run no power adders, to run simmilar times to a turbo ls ;) ..And this isn't my everyday driver either so i dont mind it being unpractical
 
Jim Henderson alluded to a process I always knew as "Port Matching".
I did that on a 390 once, and it helped it open up some. I have no idea how much, if any, gain you would get from that, on the LS.
You can also help combustion chamber flame propagation by rounding off any sharp edges on the piston tops, and this helps with air flow, as well.
Correct me if I am wrong, but the gasoline engine is basically a big air pump, and the more air that can flow thru the engine, the more gas is used, and you get more power. So, mods that help the air movement, and mods that help the engine spin faster, reliably, are good to the point where you cant get more gas into it.
The amount of gas will be controlled by the computer, and that may be our biggest limitation...that, and the cubic dollars to do some of this...:D
 
So you port the heads and leave the intake and exhaust manifolds alone? A lotta work for minimal gains. Now if you were to get a better flowing intake manifold/TB set-up along with headers of some sort, then it's worthwhile. I personally don't think you're gonna feel as big an improvement that you think you will. But hey, ya never know until you try, right?
 
From what i see there is alot of room for porting on these heads, judging by the carbon build-up around the gaskets. The runners also have a really rough texture, so im allmost positive there is a good amount to be had just by porting and polishing. That is also a good point with the headers, i really didn't take those into consideration, im sure those will limit what-ever work i put into the heads . If need be i'll try and fab up some headers.
 
You might have better luck than me and NickT on here with finding someone to fabricate some header flanges since you have the heads off the block already. Everyone we tried was throwing out ridiculous numbers. Kooks came back with 2500 or so to make one off headers. Yeah, ok! :lol:
 
Kooks would be nice NYC, but you can look in the phone book and find a shop that might do it for a reasonable price. I found a few places and I think Jet Hot Coatings was willing to find some for me, or make them,... I forget. I found people that make custom hoods based on OEM's, sometimes you could find anything out there.
 
Oh, we found stuff. The prices they were dishing out made it not all that worthwhile. I'd rather spend the money on other non-car related stuff for just a tiny increase in HP/TQ numbers.
 
Hard to say how these heads would respond to it, most modern day heads are designed so much better than the old cast stuff from the past. I doubt headers would do much either...just a opinion. Either would likely be to small a gain to justify doing.
 
For some people every single bit counts and these are things that can help when in conjunction with others not?

Either way I would not be interested in it, I would use the cash for other things myself like you NYC.
 
i have a couple freinds that are welders so i was thinkn about taking the flange of the old manifolds and cuting it flush and weld new tubes on the old flange, and bending new tubes . Should also be pretty easy since its a pretty straight path down and back.
 
loud00ls said:
I just like the idea of having to run no power adders, to run simmilar times to a turbo ls ;) ..And this isn't my everyday driver either so i dont mind it being unpractical
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Hehehe I would pay to see that. ;) Unless you are talking about totally custom cams, badass port job and a custom stroker motor then you will not be getting close to what a turbo will make on these cars. You can try though. ;) It is not a simple job to hit 360rwhp even with a 4.6 4v Cobra engine and the 4.6's actually have mods available for them. More power to you in your endeavor, however misplaced it will be.
 
I agree with the every little bit counts here. But it has to be weighed out with just being way to much effort for to little gain.

Thats why I'm gearing...I know that that will absolutely make this car launch and in general haul azz.
 
Garbone said:
Correct me if I am wrong, but the gasoline engine is basically a big air pump, and the more air that can flow thru the engine, the more gas is used, and you get more power. So, mods that help the air movement, and mods that help the engine spin faster, reliably, are good to the point where you cant get more gas into it.
The amount of gas will be controlled by the computer, and that may be our biggest limitation...that, and the cubic dollars to do some of this...:D
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It is not that simple. What matters just as much as flow is ensuring that you have a combustion friendly cumbustion chamber. Flow is not everything if the cumbustion is only 85% complete. For example, the GT-40P heads you find in the later 5.0 Ford Explorer's benefit greatly from a port job, but benefit even more from unshrouding the spark plug and giving it a more direct line to the a/f charge coming in. That results in more complete combustion which makes more power. I have seen heads that flowed higher numbers but made less power due to this.

Also adding more fuel is a non-issue also as all you have to do is command your fueling in the base fuel table and calibrate the MAF transfer function to allow the vehicle to see that commanded lambda and you are fine. Fueling is tunable and easy to do so in the tune. You can also swap injectors just fine also; especially in the Gen2 LS's where you have a simple EV6 injector and not the retarded air entrainment rails like in the Gen1. Even the Gen 1 isn't very hard to swap injectors on but it is a little more difficult.
 
Louud00ls the only proper way to make it worthwhile to port your heads and do it properly is to get a used Gen1 head that is junk. Take it on a metal bandsaw and cut it right down the middle of the combustion chamber. Then take a mic to it at the different thicknesses of metal surrounding your intake and exhaust ports. That will be the ONLY way to get the info you need so you do not port too deeply and punch into the water jacket. It is either this option, fly blind and hope not to screw up, or fly blind while remaining supersafe and just do more of a polish job and more or less waste your time for very very minimal gain.

Keep in mind that porting is an art. Allot of people, even "professional" porters claim to be porters when all they are is metal hoggers. Porting is based upon flow dynamics which are governed by much more than larger port size.
 
ILLS said:
Louud00ls the only proper way to make it worthwhile to port your heads and do it properly is to get a used Gen1 head that is junk. Take it on a metal bandsaw and cut it right down the middle of the combustion chamber. Then take a mic to it at the different thicknesses of metal surrounding your intake and exhaust ports. That will be the ONLY way to get the info you need so you do not port too deeply and punch into the water jacket. It is either this option, fly blind and hope not to screw up, or fly blind while remaining supersafe and just do more of a polish job and more or less waste your time for very very minimal gain.

Keep in mind that porting is an art. Allot of people, even "professional" porters claim to be porters when all they are is metal hoggers. Porting is based upon flow dynamics which are governed by much more than larger port size.
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Very much true.
 
loud00ls said:
i have a couple freinds that are welders so i was thinkn about taking the flange of the old manifolds and cuting it flush and weld new tubes on the old flange, and bending new tubes . Should also be pretty easy since its a pretty straight path down and back.
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Welding cast iron to regular steel is a baaaad idea. It can be done, but it usually cracks real easily. If yyou want to do it properly then take a stock manifold as a measurement example (or even a exhaust gasket) to a water jet cutter or CNC machininst (water cutter will be cheaper) and have them cut you some new flanges out of steel. Then have your welder friends make you some headers from there on back.
 
loud00ls said:
i just got a good deal on some factory heads off an 02 v8 ls with only 43,000 miles on it for 50 bucks :D ...so im now wondering if it would be worth it to get them ported and polished and maybe get the cams reground. Or maybe i should just sell the heads and throw on some nitrous and call it a day. I would love to have my car all motor with no power adders. But i know i could put more money in building the heads, and still not have the power of a turbo or nitrous kit that would likely cost cheaper. Anyone have any sugestions on what route i should take?
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I have to agree with a few folks on here that porting and polishing some heads may not be the best investment for horsepower when there are other low cost adders to consider. I know if you are building an engine from the ground up then it might make sense to port and polished the heads as well as putting an new high lift cam and such.

When we raced VW Beetles (yes, VW Beetles!) in the late 80's we would tear down the motor after each race and start all over with a new crank, cam, pistons, heads and the whole bit. The cost associated with those parts are peanuts compared to the high cost of engine parts for today's cars. Of course, taking out a VW engine, tearing it down and rebuilding it was a 2-3 hour job. Engines today are "supposedly" engineered at a higher tolerance so you may not get the same results as you would in an old school big block.

I never ran nitrous in my LS so I can't say what it would do. However, I'm sure between Lou, aka QuikLS and Robert they can be the best gauge if that is the best bang for the buck when comes to "quick" horsepower. It is unfortunate that there are not any companies out there that will invest in really high performance engine parts the LS but I understand why. So, we are left to beg, borrow and steal from other cars to make it work. Ain't that right Lou?!? :D
 
Yes - is was a lot of work for hp. Pulling the heads was not a chore I want to do too many times.

The founder of the LLSOC was the first to try this many years ago - they ended up cutting too close to one of the water jackets and ended up having to tear it all out after it sucked all the anti-freeze out the tailpipe.

The guys that came over for the Austin garage day saw the set of heads on the floor that have been ported&poished I did together with a guy that owns a performance shop here in town. He has all the right equipment and measuring devices. I am no expert but the shop owner is. I did exactly what Rocket stated - we cut up a junk head to see where the water channels are and where the overall strength of the material is (I wish I would have kept the cut up one – would have made a great garage decoration…).

It’s been a couple of years – but my LS made an addition 29rwhp and 22lb/ft of torque with those heads. I see if I can find the dyno sheet and post it up. I pulled them when I started getting more serious in SCCA – and pulled the heads and N2O off the car. I also purchased 3 sets of cams and started on those…… This was all before the SCT software was available to us - show the only tuning was what the car could adjust within itself.

The heads are like any other car – but it was such a royal pain working on the car. I also ended up messing with head gasket leaks a few times after swapping - my own issues there....
 
wow a 29 rwhp gain . Quick was that including the cams u mentioned or just the heads themselves. Who did the 3 sets of cams your speaking of, and how much did they charge? I allready know someone to port and polish the heads but i need to find someone to do the cams.
 
Quik LS said:
Yes - is was a lot of work for hp. Pulling the heads was not a chore I want to do too many times.

The founder of the LLSOC was the first to try this many years ago - they ended up cutting too close to one of the water jackets and ended up having to tear it all out after it sucked all the anti-freeze out the tailpipe.

The guys that came over for the Austin garage day saw the set of heads on the floor that have been ported&poished I did together with a guy that owns a performance shop here in town. He has all the right equipment and measuring devices. I am no expert but the shop owner is. I did exactly what Rocket stated - we cut up a junk head to see where the water channels are and where the overall strength of the material is (I wish I would have kept the cut up one – would have made a great garage decoration…).

It’s been a couple of years – but my LS made an addition 29rwhp and 22lb/ft of torque with those heads. I see if I can find the dyno sheet and post it up. I pulled them when I started getting more serious in SCCA – and pulled the heads and N2O off the car. I also purchased 3 sets of cams and started on those…… This was all before the SCT software was available to us - show the only tuning was what the car could adjust within itself.

The heads are like any other car – but it was such a royal pain working on the car. I also ended up messing with head gasket leaks a few times after swapping - my own issues there....
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Any possibility that your guy who did the P&P on those heads could use them as something of a template for doing another set of heads? I'd be interested, provided I can locate a set of used heads, or a trashed engine with salvageable heads. I can only imagine what a Gen 2 would produce, with a solid tune and perhaps reground cams if you got 29RWHP from a gen 1 with no tune... If it could pull 40RWHP, it might be a worth-while expenditure. Hell, I dropped about $2300 on CNC'd PI heads and crane cams for my truck; and that's only worth about 60HP on a 4.6L.
 
NateRW21 said:
Hell, I dropped about $2300 on CNC'd PI heads and crane cams for my truck; and that's only worth about 60HP on a 4.6L.
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That may be the gains while N/A but when blown you would see much higher gains. That is where ported heads really come into their own and start paying for themselves.
 
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