Hi,

Any home porting experts, I've got a question.

I'm currently home porting a set of LT4 castings. Following the standard abrasives instruction booklet, I did the gasket matching first. I found it know exactly the way the gasket is supposed to go on since it wiggled around a bit, even with the little plastic guides in place.

I'm worried that I might have taken off too much material on the floor of the intake ports. There is now a very slight dip after the gasket to the floor, when the gasket is about in the middle of its play. Two questions (a) is this a problem, and (b) is there anything that can be done about it...I don't want to pay to have metal welded back in but will if I have to, however I was thinking maybe I could trim the gasket a little on the bottom of the runner so it would match up better.

Any thoughts? Thanks in advance.

 

Yeah, I'll tell ya.. Standard Abrasives is really putting out some killer cylinder heads this year...

; )


A. It's not BAD bad, but it's not good (of course it depends on how "slight" it really is). Of course being a DIY job, especially using things like the SA stuff, you aren't going to get much anyway, so IMO it doesn't matter much at this point.

B. Add material, have someone that knows what they're doing fix the shape.

Free advice: Wanna see a crappy port? Click Me.

LT4 castings are nice, be careful. :)

 

Yeah I'll take your word...I think I'm going to hand these off to Lloyd instead of ruining...er, doing them myself. Hopefully he can fix whatever I've screwed up...

 

Let me see if I understand this correctly. That pik is part of the SA site? So, they are marketers, not head porters. Is that so bad? Look what marketers did for Fram filters.

 

please, be more specific why this is a crappy port. keeping in mind that that pic cam from an article about polishing, not porting (they say porting, really the only thing they say about porting is to gasket match).

so, as a straight polish, what EXACTLY is wrong with it? they didn't change the shape of the port too much. if you read the caption from the pic, it says "With this cutaway, we polished the whole port to better illustrate the rough-to-touch finish.
Note the smoothed valve guides and short side radius."

tell us WHY this is a bad job?

 

To be philosophical about it, I 'spose a person could say 'not too much', cuz, it is still resembles a port. That port has had more than a polish job. There has been material removal. An oem port isn't shaped like that. A comparo with an oem port pik would be worth a 'few' words. An engineer involved in the oem port shape would cringe seein' that one.

It's unfortunate the link below is no longer active.
http://home.tir.com/~steveher/lt4.html
Anyone know another address for those pics or similar?

 

LOL, yeah I just find it funny that people think something like cylinder head work is so painfully simple and just take the first advice they run across to heart, not really taking into consideration the source oftentimes. I guess it's good though, if they gave people real carbide burrs so they were actually doing alot, they'd probably have alot of angry people with swiss cheesed castings :D

What's wrong? Do some reasearch, ya wont learn anythin' if people just tell ya :D. Straight polish? Polishing isnt worth much.. sure makes things look pretty though :D.

 

I actually got a bunch of carbide burrs to go with the standard abrasives kit. And with aluminum it certainly is easy to "swiss cheese" your heads! See my other thread...I already think I need to have someone add a little aluminum to the floor of the ports.

Otherwise I'm not just following the "first advice" I have come along. I've done my homework, read some books, thought about it a lot. My biggest problem right now is not so much the theory of head porting as the practice of it, as I'm still new to using a grinder. But I know which areas to avoid (short side radius, valve seats, exhaust port floors). I'm still not sure what you find so wrong the the SA demo port.

 

Well I wasn't really talking about YOU in particular.. just the general public.

That's the problem, seewhutimean

It takes a long time to figure the stuff out.. keep working at it if it seriously interests you.

 

The only thing I can see is too much flare at the port entry, would reduce air velocity, and then it is also odd how it flares again after tightening up a bit, right before it hits the throat area.


But I'm shooting in the dark with my limited knowledge. Straightup, now, what *is* wrong with it...if you've time I demand (beg?) a detailed explanation .

 

Sorta like 'knowing is one thing, but applying that knowledge and getting anticipated results is quite another. That is why some, and aspiring young guys like Phil get a decent price for their work, and have chosen to do headwork as an occupation.

You read/study the books, then follow thru. Check the results, come to realize the books must have omitted/forgotten a couple of things.

But I know which areas to avoid (short side radius, valve seats, exhaust port floors)....intake port floors.

It's kinda ironic. The pros use the flow bench on a regular basis, yet they also know from experience, what areas need the attention, and which areas to leave alone. The average enthusiast is not that familiar/experienced with what areas to alter and which not to, yet as much as they could/would learn what affect their work is having, they don't use the flow bench.

 

that is what i/we are trying to do. yet everytime i have ever asked a head porting question, i get answeres like "that sucks" without any REAL input into what sucks. so far the only real answer has been from kuma about the flare. quite a few people are quick to criticize, but very slow to show how "they could do it better."

i want to have my heads ported properly, but am really too poor to pay one of you guys to do it for me. besides i take quite a lot of pride in saying that my car was done totally by myself. (i.e. any idiot can BUY a fast car, it takes skill to MAKE a fast car.) but very often i cannot get concrete answers to my questions about the more esoteric aspects of power. i understand that some of this is more art than science. but you guys can at least throw out the basics of what to do.


does anyone have any real input into the problems with the s.a. heads?

 

I consider it the other way around. It's not like guys are guessing at the results they get on the flow bench.

.....does anyone have any real input into the problems with the s.a. heads?

Personally, don't know what to make of the dip in the roof. Lighting? Lighting looks bad, but if you want to promote someone, why take a pic of an actress with her bad side facing the camera? Doesn't that floor shape look odd to you?

The more an individual studies cutout sections (yes, like the section on the SA site) of various head ports (the more the better), say an older gen 1 head and a raised port 'bow tie' head, and notes what is diff, one can get an idea what changes were stressed to improve the heads. Without good bench experience, don't try to 'reengineer' the port shape.

No, books won't get the job done, but it will 'steer' you in the right direction, (usually). The more you study/read, the more you realize some books are better than others regarding info you can use and/or is accurate. I know, I know, you're just doing one set of heads. In this climate of quick fixes, it is not good news to read the more time/effort you put into this (or anything), the more proficient you will become.

Another tip: When Lloyd or Phil post, listen, er read and take notes. Wanna be a fanatic? I know the archives are short lived here, but check out ANY head related posts by either guy. It can be like pieces of a puzzle. Geez, talk about rambling.

 

The more an individual studies cutout sections (yes, like the section on the SA site) of various head ports (the more the better), say an older gen 1 head and a raised port 'bow tie' head, and notes what is diff, one can get an idea what changes were stressed to improve the heads. Without good bench experience, don't try to 'reengineer' the port shape.

No one is trying to reengineer the port shape. I think what we are asking for are some concrete examples and advice other than "do a search," (which I've done, numerous times,) "do more research," (which I've also done, ad nauseum), and other rhetoric, like "listen to your father, Luke." What I am looking for is specific information. What makes the port in the picture so bad? Why is this question so hard to answer?

No, books won't get the job done, but it will 'steer' you in the right direction, (usually). The more you study/read, the more you realize some books are better than others regarding info you can use and/or is accurate. I know, I know, you're just doing one set of heads. In this climate of quick fixes, it is not good news to read the more time/effort you put into this (or anything), the more proficient you will become.

Well that's *slightly *annoying. I'm not asking for a quick fix, I'm asking for specific information. Obviously if I'm going to spend loads of time reading books and perusing this board, I'm not just interested in a "quick fix." If that was the case I would have paid someone to do this for me, but I want to be able to say, "I built this." And built it well. I've put many,many hours into this before even picking up a grinder--or even ordering my parts!
Another tip: When Lloyd or Phil post, listen, er read and take notes. Wanna be a fanatic? I know the archives are short lived here, but check out ANY head related posts by either guy. It can be like pieces of a puzzle. Geez, talk about rambling.

Rambling is alright. However, ponitication without substantiation is not. Let's pretend we're a vector of air flowing through the pictured port. What is that like and why?

 

Ok WHO is lloyd and how can one get in contact with him/have work done?