Cylinder Head Work Port and Polish - Page 4
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  1. #61
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    Quote Originally Posted by gustafson View Post
    Huh what?


    Computerized fuel injection is more cost effective than playing with porting

    That is my point.

    Flow is important, but what flow. when?

    On a carbureted car large ports cause low velocity and poor fuel distribution at idle. Fuel injection and be programmed to eliminate that.

    You can add more horsepower with a good fuel injection tune than all the porting you want.

    Not saying porting is 'bad'[although as mentioned, much of it is done badly]

    Full emission cars are running much higher horsepower per cubic inch than the fanciest ported an polished carbureted cars ever did, and they idle, start from cold and don't stink.

    And they aint polished.
    I'm sure the "full emission cars" part pretty much excludes any modifications under the watchful eyes of the California Air Resources Board.

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    Someone once told me that if you don't have enough information on the head to do a proper port job then a good polishing never hurt performance. Yes its stock, but it will perform way better than if just left alone.

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    Quote Originally Posted by gustafson View Post
    Huh what?


    Computerized fuel injection is more cost effective than playing with porting

    That is my point.

    Flow is important, but what flow. when?

    On a carbureted car large ports cause low velocity and poor fuel distribution at idle. Fuel injection and be programmed to eliminate that.

    You can add more horsepower with a good fuel injection tune than all the porting you want.

    Not saying porting is 'bad'[although as mentioned, much of it is done badly]

    Full emission cars are running much higher horsepower per cubic inch than the fanciest ported an polished carbureted cars ever did, and they idle, start from cold and don't stink.

    And they aint polished.
    In red ^^^^^ Bullshit! WRONG WRONG WRONG
    Yes newer engines make gobs of power in comparison to yesteryear.
    But, it is NOT because of the fuel injection. It is 100% because of engine architecture, including ports!
    You slap the newest whizz-bang FI system on a ZZ302 chebby, and guess what? It ain't gonna make any more power to speak of.
    Your point is not valid. You will never increase the air-flow potential with the fuel delivery system.
    And you will never increase max potential power choosing FI over a properly tuned carb/s. Period.
    I don't understand what you are trying to say? But it is making zero sense in the context of this thread.
    And it is painfully obvious you do not know how to tune a carburetor.

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  5. #64
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    Quote Originally Posted by stevensm581 View Post
    Someone once told me that if you don't have enough information on the head to do a proper port job then a good polishing never hurt performance. Yes its stock, but it will perform way better than if just left alone.
    Never "polish" intake ports. You can not make the exhaust ports too smooth. But the intakes need to remain rough.

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    Quote Originally Posted by standardparts View Post
    Ah, the 426 wedge. Long, long time ago I played with one. A real Max Wedge. Crossram and Max Wedge heads, and not that they needed help, they were ported. Hemi 8 bolt flange crank, lots 'o compression, Milodon swing pickup--4 speed car
    -all the Super Stock stuff. Heavy engine--scary fast top end. Big dollar collector parts now-a-days. Am surprised that there would be enough demand for CNC ported "B/RB" motor heads. Anyone ever do Max wedge head castings?

    EDIT---"snowshooze"....Went down the "B" motor rabbithole...gonna have to broaden my horizons beyond SB Chev....The "B" motors are still a "thang".... Man, them "B" motor heads can flow...Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software
    Damn straight B/RB motors are still a thing! Some of the best muscle-car era heads ever. Basically the big-brother version of a SBC head.
    Max Wedge heads were pretty damn serious power makers. None of the Big Mopar heads were "bad". 452 castings are probably most desirable these days for the induction hardened exhaust seats. But the 915's and 906's are still very relevant. I play with the 516's for the closed chamber, and squish properties.
    Better have your tune on point though or you will rattle the pistons right to death, LOL.

    Anymore most everybody runs to one of the excellent aluminum offerings. With Trick-Flow's probably being king of the hill. Many benefits to running ally heads.
    But, some of us still like to play with old-school iron.

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    Quote Originally Posted by wheelieking71 View Post
    In red ^^^^^ Bullshit! WRONG WRONG WRONG
    Yes newer engines make gobs of power in comparison to yesteryear..
    May depend on where in the stream you inject the fuel.
    Sitting where the carb was is just a fancy carb.
    Also here with the inflow wet a mirror polish maybe not so good as one needs to keep the gasoline in suspension.
    Tuning a carb is also an art that few have enough time into to do.
    Bikes.. jets, slide cuts, needle tapers and more. Cars.. squirters, front and back jets, power valves, linkage, plate edges, rod thinning. None of this easy or what the books say.

    Those who do flow rates do not understand.
    I ran oval port BBC heads and made money off others running rectangular. Sure they had a higher CFM flow rate. Yet I made more power where needed and had the faster car.
    Bob

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    Quote Originally Posted by wheelieking71 View Post
    Never "polish" intake ports. You can not make the exhaust ports too smooth. But the intakes need to remain rough.
    For more turbulence? Mix the air and fuel?

    Wonder what the diesel and DI guys do, since it's just air coming in the port.

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    Quote Originally Posted by CarbideBob View Post
    May depend on where in the stream you inject the fuel.
    Sitting where the carb was is just a fancy carb.
    Also here with the inflow wet a mirror polish maybe not so good as one needs to keep the gasoline in suspension.
    Tuning a carb is also an art that few have enough time into to do.
    Bikes.. jets, slide cuts, needle tapers and more. Cars.. squirters, front and back jets, power valves, linkage, plate edges, rod thinning. None of this easy or what the books say.

    Those who do flow rates do not understand.
    I ran oval port BBC heads and made money off others running rectangular. Sure they had a higher CFM flow rate. Yet I made more power where needed and had the faster car.
    Bob
    In these times the info is out there. This guy knows his shit! Holley Carb Secrets... Get the most out of your Holley! - YouTube
    He also happens to work with David Vizard a lot. And he (David) is the grand-master of head porting.
    I have read most of David's books. Including this one: David Vizard's How to Super Tune and Modify Holley Carburetors (Performance How-To): Vizard, David: 9781934709658: Amazon.com: Books
    In the last couple years, a lot of these old-timers are showing up on youtube. And it is AWESOME!

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    Quote Originally Posted by 52 Ford View Post
    For more turbulence? Mix the air and fuel?
    -
    Yes, you do not want to wet the surfaces.

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    Quote Originally Posted by CarbideBob View Post
    Yes, you do not want to wet the surfaces.
    Exactly. My G'pa used to go after the ports with a needle-scaler before he cut for new seats.

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    Quote Originally Posted by CarbideBob View Post
    Yes, you do not want to wet the surfaces.
    Ah, that makes sense. I've never tried porting anything, myself. I have an extra GX390 that I'm thinking about putting in a little boat and I think I'm going to play with that. I figure on a little boat I aught to really be able to notice small improvements in power. Plus it's cheap if I screw it up.

    I'm thinking about building a... UTV? Big go-kart thing? Not sure, yet. Figure the boat would be good practice. I haven't decided on an engine, but I almost bought a wrecked Kawasaki Ninja 1000. Engine was fine. Exhaust was FUBAR from sliding on the road.

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    Modern EFI tuning is way beyond carb level capabilities.

    You can make the same power with a carb, but EFI can do things carbs never dreamed of.

    Port injection with full timing control is much superior to a carb for engines that operate over a wide powerband (street driven stuff).

    I don't think porting is dead at all, but a lot of builds can skip that step because EFI tuning can make plenty of power without messing with the internals.

    I've only ported a couple sets of V8 heads- Ford FE and SBC. I have ported a shitload of B series Cummins heads though and can say with a 100% confidence less is often more and it isn't obvious what makes more power where you want it for the build at hand until you test a bunch of stuff.

    It's more about the port/bowl shape than the size IMO.

    I will say I was just involved in the build of a BBC with some old OE square port heads that were hogged out to the point you could put your fist in the intakes. I thought it would fall on it's face and not make power until 7000+, but that thing fucking screams from 4000+. Budget 496 made a half dozen $30k 632's look slow.

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    Quote Originally Posted by Garwood View Post
    Modern EFI tuning is way beyond carb level capabilities.

    You can make the same power with a carb, but EFI can do things carbs never dreamed of.

    Port injection with full timing control is much superior to a carb for engines that operate over a wide powerband (street driven stuff).

    I don't think porting is dead at all, but a lot of builds can skip that step because EFI tuning can make plenty of power without messing with the internals.
    I can not, will not, argue the powerful virtues of EFI. It is my opinion that ignition control is even more powerful than fuel metering.
    But the fact remains, EFI does not "make" power. It just doesn't.

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  20. #74
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    Quote Originally Posted by wheelieking71 View Post
    I can not, will not, argue the powerful virtues of EFI. It is my opinion that ignition control is even more powerful than fuel metering.
    But the fact remains, EFI does not "make" power. It just doesn't.
    Nope, doesnt "make" power. Just gives more control/options to the tuner.

    As far as I know modern EFI systems like what Holley is making all give you control over spark, too. Can't imagine why they wouldn't. Gotta have a crank position sensor, anyway.

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    Quote Originally Posted by Garwood View Post
    Modern EFI tuning is way beyond carb level capabilities.

    You can make the same power with a carb, but EFI can do things carbs never dreamed of.

    Port injection with full timing control is much superior to a carb for engines that operate over a wide powerband (street driven stuff).

    I don't think porting is dead at all, but a lot of builds can skip that step because EFI tuning can make plenty of power without messing with the internals.

    I've only ported a couple sets of V8 heads- Ford FE and SBC. I have ported a shitload of B series Cummins heads though and can say with a 100% confidence less is often more and it isn't obvious what makes more power where you want it for the build at hand until you test a bunch of stuff.

    It's more about the port/bowl shape than the size IMO.

    I will say I was just involved in the build of a BBC with some old OE square port heads that were hogged out to the point you could put your fist in the intakes. I thought it would fall on it's face and not make power until 7000+, but that thing fucking screams from 4000+. Budget 496 made a half dozen $30k 632's look slow.
    How about some details about the budget 496 versus the half dozen $30K motors? Must be some details that should prove interesting.

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    Regarding the polished vs rough intake port... I'm rebuilding the carb on a Stihl 2 stroke for some one right now (literally right now) and noticed the intake port is... serrated? Sorta interesting.

    Sent by telegraph using - .- .--. .- - .- .-.. -.-

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    Quote Originally Posted by standardparts View Post
    ... half dozen $30K motors?
    $ 30,000 isn't so much ... a competitive engine for a midget will run 40. Half as many cylinders, too.

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    I don’t think 40 k is going to go very far these days
    Don


    Sent from my iPhone using Tapatalk Pro

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    Quote Originally Posted by standardparts View Post
    How about some details about the budget 496 versus the half dozen $30K motors? Must be some details that should prove interesting.
    Not my engine. I know there's like $12k in the engine from the carb to the pan. Built in a dirty shop with a Harbor Freight torque wrench. I was pessimistic it was going to be a turd in the racing class it's in, but second time out after some bugs were worked out it packed some lunches and neither I nor anyone else involved has any idea why it runs so darn good.

    My point was only to illustrate that even when you think you know a tiny bit about engines something comes along and surprises you. I recommended oval port heads, but he found this heavily modified square port setup for a sweet deal with some questionable, unverifiable back story/provenance and the heads flat work.

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    Quote Originally Posted by D Nelson View Post
    I don’t think 40 k is going to go very far these days
    Them things aren't allowed on dirt But prices ... could be. I haven't been around it for a while. Took a quick look at gaerte, no prices, surprise surprise


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