Intro to a port job

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gliderider06 said:
Pardon my ignorance, or just plainly missing something here, but... what is the purpose of putting in larger valves in a head,(other than having new valves) if nothing is done leading up to that valve? I just don't see any gain at all in doing so.
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My whole purpose was to take the Edelbrock aluminum cylinder head parts and put them in a cast-iron head. Then to have them ported and slap them on my 340.
The Machinist? that I had to put the guides and the valves in told me what a wonderful job he had done and that he had done some Bowl work on them also. It was all bs. But I did not know that until Moparofficial checked them out.
 
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All on a set of 308s? Take the valves and other parts and get a core set for $100. No need to all new seats or dealing with trying to put back material someone else took away, unless there's a class mandate for those specific heads. Advice should be to replace IMO. Assume guides, exh seats, and then port.
 
MOPAROFFICIAL said:
Its 2.020...and there is a well around all valves with a sharp edge that could about cut your finger open , 2.05 vs is +.030 ÷2=.015...so no imo, because the well is roughly .020 larger.
I'll have my guy look them over and see about a throat and chamber side.
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I run 2.05s when the seat doesn't support 2.02s. It doesn't leave sharp edges unless it's sunk, plus you're porting. Throw the castings out and start fresh.
 
moper said:
All on a set of 308s? Take the valves and other parts and get a core set for $100. No need to all new seats or dealing with trying to put back material someone else took away, unless there's a class mandate for those specific heads. Advice should be to replace IMO. Assume guides, exh seats, and then port.
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A fresh set sounds nice but.

Cost of heads
Shipping
Instaling 11/32 guides
Machine work for installing 2.02
Valve job

I'm ahead I think sticking with fixing the heads I have don't you think?
 
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sell those to someone building a stocker .
Salvage the valve gear and replace with some stock stuff.
 
If the work shown is questionable - makes total sense to me to throw them out. I'd bet if they went to my head guy he'd be redoing the guides too because I'd bet they are not done well enough for him. So IMO it's just not worth it. Not that "me" matters here, just sayin'.

I guess I misread the post intent. I thought it was about porting - so I looked at it. This is about resurrecting a wreck a shop created. In that instance - I would throw them out and move on using whatever small parts I could.
 
All the bowl and port work in the world is meaningless if the seat geometry is jacked up. I'm with Moper, for the cost of 16 insert seats and a correct valve job you should be able to find a set of better castings to build on.
 
If MOPAROFFICIAL can work the heads, let him, I will await the results. could turn out to be a silk purse.
 
If your going with a max porting, and i don't think you are, then yes throw then out and start from the start..............

I don't think your are.

I would keep what you have, if you have the cash, hardened seats are alway a good idea, and would get u back to a ah start. but i think attention to details will get what you want.

I so badly want to go into low lift and how it can be a negative............but,.............. what has help low lift has help high lift from becoming turbulent. win win.:thumbsup:
 
Cudafever said:
If your going with a max porting, and i don't think you are, then yes throw then out and start from the start..............

I don't think your are.

I would keep what you have, if you have the cash, hardened seats are alway a good idea, and would get u back to a ah start. but i think attention to details will get what you want.

I so badly want to go into low lift and how it can be a negative............but,.............. what has help low lift has help high lift from becoming turbulent. win win.:thumbsup:
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Lipstick on a pig.
 
MOPAROFFICIAL said:
I went ahead and did a mild bowl blend, which basically removed 1/8 from the I.D of the bowl and mild short side blend.

Now the numbers and a lesson for you...
.100 .... 36
.200 92
.300 145.9
.400 196
.500 219
Low lift is in the toilet.
Back to that pocket the intake sits in, shrouded and choked.... I took a very small bit and blended that lip all the way around the chamber side and re tested.

.100 59.6
.200 116.7
.300 170
.400 209
.500 224
Notice the low lift jump , not great, but it's there now.
I say it all time, dont sink the valves...it kills the low lift flow like you cant even imagine.
These heads need a good valve job.
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I had not followed this thread but IMHO this is a pretty darned significant thing to know.....

This got me to wondering how much time the valve spends at under .300" lift, and found this 'fast' cam profile (for an SBF) cam online....
http://performancetrends.com/ca20.htm

Looks like the .075-.300" valve lift range for a 1.5 ratio (.050 to .200" lifter lift) is around 84 degrees total out of 227@.050".... that is over 1/3 of the .050" duration time.

Getting this flow up is like going from a 'fast' ramp camp to a 'fast-fast' ramp cam LOL. Thanks for making this point so clear!
 
C130 Chief said:
All the bowl and port work in the world is meaningless if the seat geometry is jacked up. I'm with Moper, for the cost of 16 insert seats and a correct valve job you should be able to find a set of better castings to build on.
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moper said:
If the work shown is questionable - makes total sense to me to throw them out. I'd bet if they went to my head guy he'd be redoing the guides too because I'd bet they are not done well enough for him. So IMO it's just not worth it. Not that "me" matters here, just sayin'.

I guess I misread the post intent. I thought it was about porting - so I looked at it. This is about resurrecting a wreck a shop created. In that instance - I would throw them out and move on using whatever small parts I could.
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I'm in one port so far.
At the point you end up having three or four hundred bucks into a set of heads and then find out how the machinist got the installed height spec of the eddy springs "these are in @1.805" was to sink the valves 'creating more work' to reverse the negative effect it had on flow and at that do a lawnmower seat grind 'creating even more work'... it takes the wind out of your sail. We will explore the cheapest, practical route and realistic potential of what's to work with and decide.

To all of you... if you have work done at a machine shop, look into what you're asking them to do and ways to do it before you just hand it over and say "make this work".
Many ways to skin a cat isnt always good.
 
I had this very situation on my last build.
 
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I wish the op had run the head before having them ported.....Then he could truly see the improvement being made.

Not sure there would have been any HP improvement with the 2.02 installed over the stock 1.9x valve.............
 
That's why I titled the thread "intro to a port job"... what you find out when they show up.
I could start another and call it "resurrection of the dead" or "how to bandaid a flow killing valve job"...

Its paying twice for a valve job that should have been right the first time... that really sucks for him. Should have used + .050 pop up retainers or +.050 locks to get the inst spring height
 
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Cudafever said:
I wish the op had run the head before having them ported.....Then he could truly see the improvement being made.

Not sure there would have been any HP improvement with the 2.02 installed over the stock 1.9x valve.............
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Was 1.88 stock.
So I really thought that a 11/32 valve stem and a 202 valve would definitely flow better with a mild Port job than a 3/8 stem 1.88 valve without any porting.
 
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Jadaharabi said:
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Was 1.88 stock.
So I really thought that a 15/16 valve stem and a 202 valve would definitely flow better with a mild Port job than a 3/8 stem 1.88 valve without any porting.
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I keep forgetting that part, makes it even worse. 2.02 should have sat proud in the chamber
 
nm9stheham said:
I had not followed this thread but IMHO this is a pretty darned significant thing to know.....

This got me to wondering how much time the valve spends at under .300" lift, and found this 'fast' cam profile (for an SBF) cam online....
http://performancetrends.com/ca20.htm

Looks like the .075-.300" valve lift range for a 1.5 ratio (.050 to .200" lifter lift) is around 84 degrees total out of 227@.050".... that is over 1/3 of the .050" duration time.

Getting this flow up is like going from a 'fast' ramp camp to a 'fast-fast' ramp cam LOL. Thanks for making this point so clear!
Click to expand...

It would have run like it had a 1920 holley on it and a banna in the tail pipe.
 
MOPAROFFICIAL said:
I missed the last 2 posts.

Yes, I do a before flow test... though it's very predictable..;)

The valves are sunk and that is killing low lift flow because there is a pocket around the valve.... .100 lift is shrouded by the chamber .060 deep from the sunk valve job , if they just did a top chamber side cut that would help BIG TIME. In this scenario .100 becomes. 040 if that.

At .100 lift the valve is shrouded so bad the pressure was too high.

Cfm as sent to me...

.100 35
.200 90.5
.300 145.9
.400 187.7
.500 207
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Good Lord, where is the scrap pile icon? Probably pretty good flow for a K car head...
 
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