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A few more repetitious /6 head questions...
https://slantsix.org/forum/viewtopic.php?t=30811		 Page 2 of 2
Author:  THOR [ Wed Sep 03, 2008 4:36 am ]
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Quote:
I have been wanting to try porting my own heads, but do not know the first thing about it.
It has alway been something I wanted to try, but I cant afford to mess up a good set of my big block 915 heads, small block X heads, or the MP R/Ts such.
On the other hand I hate to start with a plain old 318 2-bbl. head and sink all that time in it just to end up with something that still isn't as good as the R/T's. I guess thats why cylinder head guys get paid the big bucks.

I have quite a large selection of quality tools I have purchased the past few yearsand I guess the only way to learn is to do it.

If only I had 100's of hours of spare time and a flowbench...
Don't we all :twisted:

I am not that familiar with porting myself, but I have been taught well by Mr. Dutra, and take that information to heart, so when I do my head (sometime in the next 5k years) I will be able to pick it up, an git 'r done.


Not trying to thread-jack here:
Quote:
How much does the finish matter when you get a head planed? The local machinist doesnt do engines but he does everything else. I know he could plane some off but can it be too smooth? And to clarify, .100 off is safe for a stock motor?
.100 is safe, although you may notice a bit of oil burning from your rings if the engine has alot of miles on it, due to the increased CR (Compression Ratio). The surface finish is really important when it comes to gasket choice. Certain types of gaskets require certain levels of roughness, called the RA, or Roughness Average. Most places who are just planing the head so they can slap it back on utilize a belt sander, which works better on Cast Iron than Aluminum. The problem with belt sanders is that it is impossible to tell how much material you take off the head while sanding.

If the machinist uses a CBN cutting head, then the surface finish produced will be just fine (around 20 RA, which produces an almost mirror like finish) The CBN has a dial of sorts, so that the machinist can run the head down exactly .100 from its starting point.

A CBN cutting head produces among the most smooth surface finishes available by todays machinists, so you need not worry about it being "too smooth."

~THOR~
Author:  slantfin [ Wed Sep 03, 2008 4:36 am ]
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I found this article about porting very helpful. http://www.sa-motorsports.com/diyport.aspx
Author:  Doc [ Wed Sep 03, 2008 10:33 am ]
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For your engine build, you will not need "100 hours" of porting time.
All the SL6 heads I rebuild get at least 1 hour of porting work, just to get all the sharp edges and casting "bumps" blended. Just a little time spent helps a SL6 head a lot.
DD
Author:  rock [ Wed Sep 03, 2008 12:15 pm ]
Post subject:  Daniel and Dart, I advise this kind of burr
Daniel and Dart,

I found the long stem burr to work best (about 6 inches long) and a christmas tree shape burr is very useful indeed. I bought a high quality set of 4 shapes for about $100 from a welding place but you don't that many or that good a burr. Check out an old post of mine from last summer where I had a head all done to match a big aussie manifold gasket, after about 5 Saturday mornings. I thought I would do one more hit.....and went through an exhaust water jacket. Tears indeed. If you have a junker head bust it up with a hammer to see how the jackets go and how much meat you have in places.

It is relatively easy, its fun and you will not believe how fast a burr cuts cast iron (wear eye protection!). This is not like working steel with a file.

rock
'64d100
Author:  runvs_826 [ Wed Sep 03, 2008 10:11 pm ]
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I think your putting to much thought into what Doug is saying and what the words "Port and Polishing" mean. For what Doug is trying to say you don't need a flowbench or a 100 hours but one Saturday. Just take an intake/exhaust gasket and bolt it up to the head. Take your grinder and "match" it, I gurantee this will help and not hurt your flow. This "gasket matching" is the easiest and best bang and home builder can do. I've done it on my in progress slant and a couple 302's it's very nice and consistant.
"Porting" on the other hand is cutting into the actualy head and making your own rectangle, oval, whatever. This can hurt your velocity and flow if you take to much, to little, or are not consistant between the cylinders.
Author:  Hyper72Valiant [ Wed Sep 03, 2008 11:20 pm ]
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I remember a person that if you sent him your head he could port, polish, bigger valves, etc.. and do all that stuff for ya for $$$ I don't remember his/her name
Author:  daniel_depetro [ Thu Sep 04, 2008 2:27 pm ]
Post subject: 
Quote:
For your engine build, you will not need "100 hours" of porting time.
All the SL6 heads I rebuild get at least 1 hour of porting work, just to get all the sharp edges and casting "bumps" blended. DD
Quote:
I think your putting to much thought into what Doug is saying and what the words "Port and Polishing" mean. For what Doug is trying to say you don't need a flowbench or a 100 hours but one Saturday.
I understand exactly what he meant and that not every head has to be fully ported an polished.
What I meant by having 100's of hours to do the work would be my learning curve for each different type of head plus doing the actual heads on all of my engines. I may not have the largest or most valuable collection but I do have a lot of mopars and mopar engines on stands.
I talked a few times with some head guys and they talked like it was nothing to sink 15 hours into a head! :shock: (and they know what they are doing.)

That flowbench may pay for itself after a few engines.... :lol:
I wonder how much they are? It sure would be nice to have a way to gauge ones progress after all that work.

On the other hand I have tried to contact Shady Dell Speed Shop several times (left phone messages, PM's, and posts) and all went unanswered. Their knowledge on mopar small block seems second to none and the work I have seen on Moparts (sorry everyone) was outstanding. Anyone have a way to get ahold of them? I wanted them to do some work on my MP R/T's...

Does anyone have any photos of their slant head that they have done (pics of the during process would be extremely benificial to me)?
How much metal are you guys removing with the pocket porting? Hardly any? Quite a bit?

Thanks for all the thoughts, help, and links (which was very easy to read and useful). Any further tips or thoughts (good or bad) are always welcome.
Author:  Aggressive Ted [ Thu Sep 04, 2008 3:51 pm ]
Post subject: 
I had mine bowl ported and gasket matched by our local drag strip engine shop, however I went back in and cleaned up (smoothed out) the intakes even more. We didn't do as much to the exhaust. Instead, we spent alot of time on the intake. We did open up and smooth out the exhaust manifold allot.
Author:  65Dodge100 [ Thu Sep 04, 2008 3:56 pm ]
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Here is a good head porting thread with instructions and pictures from Doctor Dodge.

Danny
Author:  CARS [ Fri Sep 05, 2008 8:44 am ]
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Quote:

That flowbench may pay for itself after a few engines.... :lol:
I wonder how much they are? It sure would be nice to have a way to gauge ones progress after all that work.

Years ago (probably late 80's early 90's) the car mags all built there own and published the articles. It involved hair dryer type of technology but it would show the before and after difference.
I don't know if anyone would remember where to find this info.
This was before all of the mags where under one roof(when HOT ROD and Car Craft hated each other). And way before the car mag empire had their own dyno's and flow benches.
Author:  CARS [ Fri Sep 05, 2008 8:48 am ]
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http://www.ag.auburn.edu/users/parmega/ ... lowbench2/

Amazing what you can find on the net! Do a search and start building!!!
Author:  daniel_depetro [ Fri Sep 05, 2008 9:48 am ]
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Awesome, That may work well for a bit.

As stated at least you get a before and after change. It may not be super sensitive to small changes or very accurate, however you can tell if you are increasing performance or ruining your head(s).


I love this line from the above article:

"What is this for, what does that do, why did you make it this way, what kind of motors did you use and how did you calibrate it?"
Clark and MSD graciously answered any questions we posed, and offered suggestions and encouragement along the way.

I was talking with a fellow the other day about his 650+ engine he was running and I asked him a few questions. He told me about most of it but said he definately had some secrets he would never tell anyone.
I also was told by a person that they could tell if my car was a real A12 by a photo of the driver side firwall area. He too would not tell the his secret and I have seen lots of Bees and even A12 bees but I have yet to notice any difference that would be in that area.

I am definately going to try to reproduce this flowbench. I wonder how much it'll cost in the present times...$1,700.00?
Author:  cavisco [ Sat Sep 06, 2008 8:01 pm ]
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The world of surplus or ebay may be your friend. Ten of these would max out a 20 amp 115 vac circuit.
http://surpluscenter.com/item.asp?UID=2 ... tname=misc
Author:  slantzilla [ Sat Sep 06, 2008 11:06 pm ]
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One thing you have to remember about porting a Slant head, what you leave alone is way more important than just grinding away anything you can. Slant ports are pretty easy to get into reversion.

Same thing with too big of valves. Too much valve gets you into shrouding by the cylinder wall, especially on a stock or light overbore.

1.88" intakes fit and work like crazy on a flow bench, but will not flow much better than a stock valve once the head is on the motor.
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