ported irons
- Thread starter shawnz
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Its not necessary but definitely helps. Every 10 degrees added duration pushes the powerband up 300-500rpm, so make sure that the valve springs are up to the task of the added rpm and be sure to break it in properly and use a good oil with plenty of zinc and phosphorous...there are plenty of posts on here about that subject if you do a search. Be careful who you have port the heads because theres alot of people out there who do really bad work and charge alot of money. Its best to go with a proven head porter.
changing the head to a set of champions would be good. you dont have to change the cam but with a different cam you can take more advatage of the high flow heads. Also a champion ported intake to match would be nice as well.
ported iron heads
seems to me that you would be wasting money to bolt on an expensive set of heads without upgrading the cam to get the air in & out more effectively. there's gotta be "better bang for the buck" elsewhere. i could be wrong, but i believe you'd be rather disappointed with your investment.
bw jones
seems to me that you would be wasting money to bolt on an expensive set of heads without upgrading the cam to get the air in & out more effectively. there's gotta be "better bang for the buck" elsewhere. i could be wrong, but i believe you'd be rather disappointed with your investment.
bw jones
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Never had anyone disappointed by installing upgraded heads.
It is absolutely the "best bang for the buck" on a turbo car. The stock cam will do fine even in a 10 sec. car.
Even alum heads on a stock block will give very satisifying performance, more than most can used safely on the street.
To answer the original question, yes, in my experience, a stock cam WILL be sufficient.!
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It is not so much the very slight increase in size of a 1.77" intake valve that makes a big difference in air flow, but the aftermarket is made to flow much better than a stock valve.
To maximize the cost and effectiveness of new valves, more port and bowl work should be done to optimize and increase air flow.
Comes down to the more $$$ you spend, the better product you end up with!
oops
my mistake ....... it was late when i posted and i should have reviewed SHAWNZ mods in his signature. i made the assumption that he was asking about heads as an initial mod. and for the money, there are several less expensive mods that would be beneficial and more cost effective.
my experience has not reflected that of Nick M, but his experience is MUCH more extensive than mine and i would fully trust in his advice
.
an interesting observation, however, is that i've seen many cars with ported heads running little or no quicker than other cars with a stock longblock and the same mods.
bw jones
my mistake ....... it was late when i posted and i should have reviewed SHAWNZ mods in his signature. i made the assumption that he was asking about heads as an initial mod. and for the money, there are several less expensive mods that would be beneficial and more cost effective.
my experience has not reflected that of Nick M, but his experience is MUCH more extensive than mine and i would fully trust in his advice
.an interesting observation, however, is that i've seen many cars with ported heads running little or no quicker than other cars with a stock longblock and the same mods.
bw jones
84BuickGNYorkPA
Daily Driving Buick V-6 Turbo's 1979 - Present
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This is just my view on the subject, why go through the trouble of replacing the heads and not the cam? Since the car is already down and all the parts are already off the car. The heads will flow better and a good mild cam will help the new heads flow more for very little extra $$ spent, considering the labor factor of where you will be at just for the heads. But to answer your question I agree that the stock cam will work, just for a couple extra bucks you will get more out of them.
For instance, I just port and polished a set of stock heads last winter $25 for the used heads(Im a machinist), back cut the exhaust valves, took this all to NAPA for a 4angle/radius valve job and to skim the heads flat, match the valves to there new seats($150 approx.). I found a new 208/208 Erson cam for $75 on this board, bought some new lifters and repaired the front cover with plate aluminum and a tig welder(cam button was rubbing about .05 deep into the casting). The car was down for 12 days, with me doing all the labor during my spare time.
Chuck
For instance, I just port and polished a set of stock heads last winter $25 for the used heads(Im a machinist), back cut the exhaust valves, took this all to NAPA for a 4angle/radius valve job and to skim the heads flat, match the valves to there new seats($150 approx.). I found a new 208/208 Erson cam for $75 on this board, bought some new lifters and repaired the front cover with plate aluminum and a tig welder(cam button was rubbing about .05 deep into the casting). The car was down for 12 days, with me doing all the labor during my spare time.
Chuck
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You are correct bw, you need more than a stock turbo, intercooler, injectors, etc. to take advantage of ported heads.
Cann't tell you the many times I have been red-faced by posting w/o reading the proper info!
Coming from an automotive machinist of 7 years and a CNC programmer and general/prototype machinist for 10 years-
If you're a machinist, why did you take it to NAPA to get them machined?
Im not trying to be a smartass, Im just wondering if its because you're a general machinist and not an automotive one, and dont have the engine machining equipment on hand.
What were the final port volumes and flow numbers at 28" water?
4 angle/radius valve job? Whats that? Why didnt you back cut the intakes? Thats where alot of the low lift benefits come from. That and the throat work.
A cam is a good thing, but not necessary to get to where you want to be on a turbo motor. The factory cam was ground with forced induction in mind, so the overlap is kept to a minimum and the exhaust event is a little delayed to trap exhaust pressure. Its not perfect and could use more lift, but it does really well.
84BuickGNYorkPA
Daily Driving Buick V-6 Turbo's 1979 - Present
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1st off, I don't want to hijack this thread, but I will answer your questions,
Here is a link to where I work, American Hydro Corporation : Home . I have my papers from the state of PA after completing a 8000 hr apprentiship, way back in 1984. Yea, we do our own CNC programing also, except for the 3 diminsional profiles. My machine has a 100 ton rotary table capacity, 30 feet of X travel, 15 feet of Y travel and 89" of Z (The 4' square ram), the head has 270 deg. of travel (swivels from a typical HBM to +/- 135 deg.) So no, I don't have access to automotive machines, and the guys at my NAPA are good at what they do. The showed me the cutter that they used to do the seats on the heads, where carbide with 4 small angles and the end of the cutter has a radius(there really wasn't any part of the head that got hit with that, since it was ported). I do not have a flow bench and they offered to flow the heads for me, I declined. I'm not a pro racer, just a weekend warrior...
As far as back cutting the intake valves, not sure where you are comming from(I honestly don't know what you mean), as the valve opens the intake valve is already angled to direct the flow into the head. Here is a link to some pictures of the project Picasa Web Albums - Chuck - 8445 Buick V-...
The exhaust valve on the other hand as it opens, the valve body right under the seal is a huge restriction and of course got back cut. I would like to take this time to thank "turbofabricator" for his guidance on my maiden voyage!!
Chuck
turbofabricator
Well-Known Member
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The beauty of running a turbocharger is that it WILL cover a TON of mistakes. If you talk with serious head porters they will always tell you to port a head for normally asparated and the turbo will help even more. I found that port volume is key in a good turbo head. Flowing a head at 28" of depression is a good way to see results of workmanship. But, it is no where near the flow of your heads at 25 psi boost. We don't race a flow bench. BUT, a good flowing head on a bench, "usually" works better than a poor flowing head. A flow bench will also not show the results of some modifications that the car will at 25psi boost. Rarely, can you completely screw up a head if you systematically approach porting. Even just bowl work will help a Buick V6 head. Nothing like giving it a try. (though you will soon learn why ported heads cost so much.
:biggrin: ) Anyone that has the tools and the patience should give porting a try. You will learn alot if you read up on it and start grinding. I've seen some pretty ugly ports in my day that mysteriously made decent power.
The most expensive professionally ported cylinder heads that I have had my hands on (Ferrari, NHRA Pro Stock, Comp, ect.) had VERY smooth intake ports. I'm not quite sure how to create a golf ball finish in an intake port, though? Even all the aircraft I have worked on do not have "dimples" on thier wings. Nor do props. Just make it .005" wider
:biggrin: ) Anyone that has the tools and the patience should give porting a try. You will learn alot if you read up on it and start grinding. I've seen some pretty ugly ports in my day that mysteriously made decent power.The most expensive professionally ported cylinder heads that I have had my hands on (Ferrari, NHRA Pro Stock, Comp, ect.) had VERY smooth intake ports. I'm not quite sure how to create a golf ball finish in an intake port, though? Even all the aircraft I have worked on do not have "dimples" on thier wings. Nor do props. Just make it .005" wider
You mention the machine you run. Do you run 1 machine all day? I absolutely mean you no offense...your apprenticeship speaks for itself and Im sure this doesnt apply to you..just a basic rant...but something that has always bothered me is how some machine shop company owner will stick a guy behind 1 machine and make him do the same repetitive job all day, day in, day out...totally de-skilled mindless work and then he tells his employee "Yeah, you're a machinist". Like the movie "the machinist", the guy stands behind a drill press all day drilling a hole in the same part, day in, day out, then he goes totally insane. And then the world thinks that this is what a machinist is. A machinist can design, engineer, create parts (to sometimes extreme tolerances and most of the time within .001") using blueprints, he knows trig, geometry, algebra, etc. This kid I hired here had a really big head. Always a pain in my ass and had a big attitude. He was convinced he was a machinist because he was a CNC machine operator. At his old job he would read a program's tool list and load all the tools, set the heights and run the program, then pullt he part out and replace it and start over. His old boss never told him he wasnt a real machinist or a CNC programmer. He was a mill operator. He made 14 bucks an hour at that job and was convinced he should be making alot more so he quit that job. 14 bucks an hour is alot of money for a machine operator. I eventually canned him because his attitude didnt come anywhere near his capability. When I interviewed him, he wasnt answering my questions, so to cut to the chase, I handed him a print I made and said "if I hand you this print, can you make this part?" He said no, he's never done that before, but insisted he's a machinist.
Sorry. Rant over.
As far as back cutting the intake valves- Its always a good idea to start with a new valve so you have as much metal to work with as possible. Stick the valve in the grinder, set it to 30 degrees, and grind away most of the factory 45. Then grind the 45 and then add a 15. You'll get an easy 20 CFM below .400 lift out of this. The same goes for exhaust valves. But the leading outer edge of the exhaust valve should be radiused.
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