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Ron Earp
11-07-2004, 11:03 AM
Before I do something bad I just want to check it here.

I have my head off my motor so that I can re-ring the pistons. I've got new gaskets and the new gaskets, like the old ones, are larger than the intake and exhaust ports of the motor. Figures, Lotus is not known for quality castings, that is for sure.

Now, I read the rules that I can port match these things so that they match the gaskets and that I can do so for 1" into the head. I intend to do this and it would appear that it would help flow out quite a bit. But, porting and polishing are dis-allowed.

I do not want to run afoul of the rules or get in trouble if protested. So, if I port match these things and blend them in for one inch that is legal, correct? I'm just concerned that if someone looks at it they'll say "porting, illegal!".

------------------
Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

Bill Miller
11-07-2004, 12:17 PM
Ron,

You've got a pretty good handle on the rule. What you are considering is legal.

------------------
MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

Renaultfool
11-08-2004, 06:13 PM
Ron, that is not what the rule says.

There is a difference in "port matching" and "opening a port up to the size of the gasket"

D,1,I allows for port matching only. Gaskets are free therefore it doesn't make logical sense to allow you to open the port to "any" gasket. All you would have to do is buy a bigger gasket.

To legally port match, the port on one side of the gasket surface would be untouched assuming one port was smaller than the other, or some area of both ports would be untouched if the ports are offset.

Hogging the ports out the the size of the gasket hole 1" each way from the manifold surface would not be legal according to the rule book in my opinion.

ITANorm
11-08-2004, 06:49 PM
Originally posted by Renaultfool:
Hogging the ports out the the size of the gasket hole 1" each way from the manifold surface would not be legal according to the rule book in my opinion.

Not to mention that it would be counterproductive in most modern engines.

Banzai240
11-08-2004, 07:11 PM
Just a point from a previous discussion, but since Gaskets are free, you are allowed to use ANY intake gasket.

It has been successfully argued that because of this, there is no requirement to have to port match to a FACTORY sized gasket, so in essence, you can open up the ports at this point (up to 1" in on either side), to ANY gasket you choose to use, including one with much larger port openings...

I wrote a letter on this, thinking it was a loophole that needed to be either closed or better clarified, but the rule was deemed adequate as written...

So, read your ITCS carefully before taking this to heart, but the way the current rules are written, there is really no limiting factor as to how much you can "match" your ports... You can pretty much pick a gasket, and open the ports up to whatever point you deem appropriate...

Like some others have said, however, on a more modern engine, you are likely to go backwards if you play too much with this... They are pretty well cast from the Factory (speaking of Nissans, Toyotas, Hondas, etc.. mostly... Others may vary...)

Good Luck,


------------------
Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
http://home.comcast.net/~djjordan/Web/DJ_AV1.jpg

[This message has been edited by Banzai240 (edited November 08, 2004).]

Geo
11-09-2004, 01:45 AM
Darin is quite correct on this one. Match the ports to any size you like.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

Ron Earp
11-09-2004, 02:39 AM
Originally posted by Renaultfool:
Ron, that is not what the rule says.
There is a difference in "port matching" and "opening a port up to the size of the gasket" D,1,I allows for port matching only. Gaskets are free therefore it doesn't make logical sense to allow you to open the port to "any" gasket. All you would have to do is buy a bigger gasket. To legally port match, the port on one side of the gasket surface would be untouched assuming one port was smaller than the other, or some area of both ports would be untouched if the ports are offset. Hogging the ports out the the size of the gasket hole 1" each way from the manifold surface would not be legal according to the rule book in my opinion.

After reading the rule over I disagree. The rule indicates that I can match the ports to the gasket and that is fairly simple. My gaskets, as delivered and it is what is available from Delta Motorsports, the only Jensen place around, are about 1/8" larger than the ports all the way around. It is clear looking at the intake maniold size, and the head size, that the head opening is smaller than the gasket and the intake manifold.

Now, if I take a tool and grind away some of the head to match the gasket that is port matching. But, you can't simply grind the head out to the opening leaving a 90 degree step just like you had in the first place. Therefore, you need to blend that ramp up a bit to make a smooth transision into the intake passage. Hence, the allowance for distance.

I'm not working the bowls, altering the intake exhaust floor, or anything like that, just trying to make a relatively free path for air to enter the engine and I think this rule allows for that. I imagine you fellows with late model stuff this is a moot point. I was in a machine shop a few weeks ago that had a BMW 24 valve head on the floor and I was amazed at the size of the ports and the quality of the castings. Mine looks like someone cast the heads in a sandbox.

I suppose one could go crazy with huge gaskets, but, I don't have that option. I'm lucky to get A gasket, much less have a pick of a litter. I think that Darin has the rule right, whether or not that was intended is a different story.

Ron



------------------
Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

Geo
11-09-2004, 02:49 AM
Originally posted by rlearp:
After reading the rule over I disagree. The rule indicates that I can match the ports to the gasket and that is fairly simple.

Actually, the gasket has nothing to do with this rule. You can port match up to 1" from the mounting surface. Hog it out if you like.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

lateapex911
11-09-2004, 02:55 AM
remember Ron, gasketsare free...in a pinch I have made my own...sooooo, it really opens up the rule to more of a "do whatever you want as long as you go no further than an inch".

That said, it is proabably unwise to get carried away here, unless you have a flow bench!

Also, the discussion of how you measure that inch has arisen here before...you can imagine that arriving at a consensus was impossible!



------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

Mark LaBarre
11-09-2004, 08:04 AM
Originally posted by rlearp:
...., are about 1/8" larger than the ports all the way around. ...



That's no different than any VW out there. Grind away.

Mark LaBarre
11-09-2004, 08:05 AM
Originally posted by rlearp:
...., are about 1/8" larger than the ports all the way around. ...



That's no different than any VW out there. Grind away.

Renaultfool
11-09-2004, 11:01 AM
As technical and picky as some of the discussions on this site get, I am amazed that this one seems to fly. What happened to the "if it doesn't say you can, you can't" philosophy? How does the rule indicate that you can "match the port to the gasket"? I can't find the word "Gasket" in D,1,I, the section that allows port matching, therefore to me it seems a pretty liberal interpretation to assume that you can match the port to the gasket or make the port at that point any size you want. The rule as printed allows you to match the port in the intake manifold to the port in the head, which is a little more difficult to accomplish than just hogging the port out to the gasket hole, but that is what the rule says in my book.
I would think that raising the roof of the port 1/4" through "matching" for instance, allowing the air flow a better angle to the valve head, (if your head happens to have a short port length due to the 1" limitation), would be much more of a performance advantage than the improper sized windshield washer bottle, an argument I have seen on this site before.
If it "has been successfully argued" print it in the book. If it doesn't say you can, you can't, right?

Geo
11-09-2004, 12:09 PM
Originally posted by Renaultfool:
As technical and picky as some of the discussions on this site get, I am amazed that this one seems to fly. What happened to the "if it doesn't say you can, you can't" philosophy?

Nice idea. But if it says you can, you bloody well can.

Here is what the rule says:

"Manifold and cylinder head port matching is permitted. No material may be removed further than (1) one inch in from the manifold to cylinder head mounting face(s)."


Originally posted by Renaultfool:
How does the rule indicate that you can "match the port to the gasket"? I can't find the word "Gasket" in D,1,I, the section that allows port matching...

It doesn't.


Originally posted by Renaultfool:
...therefore to me it seems a pretty liberal interpretation to assume that you can match the port to the gasket or make the port at that point any size you want. The rule as printed allows you to match the port in the intake manifold to the port in the head, which is a little more difficult to accomplish than just hogging the port out to the gasket hole, but that is what the rule says in my book.
I would think that raising the roof of the port 1/4" through "matching" for instance, allowing the air flow a better angle to the valve head, (if your head happens to have a short port length due to the 1" limitation), would be much more of a performance advantage than the improper sized windshield washer bottle, an argument I have seen on this site before.

Ah yes, but now you are adding your own words to suit your own sensibilities.

The rule says you may port match. The only limitation placed upon this is the 1" rule. There is no limitation that say only one side may be machined, therefore both sides may be machined and to whatever size your heart desires.

If it says you can you bloody well can.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

lateapex911
11-09-2004, 02:33 PM
Right..........

And the limiting factor would be the gasket....except gaskets are free....soooo, therefor, ergo, and all that, there is no pactical limitation....except what helps and what hurts flow.

Banzai240
11-09-2004, 03:45 PM
Originally posted by lateapex911:
...except gaskets are free....

You know, I must be doing something wrong, because everyone keeps talking about "free gaskets", but I keep having to pay for mine... http://Forum.ImprovedTouring.com/it/biggrin.gif

http://Forum.ImprovedTouring.com/it/wink.gif



------------------
Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
http://home.comcast.net/~djjordan/Web/DJ_AV1.jpg

ddewhurst
11-09-2004, 06:14 PM
Port matching....... Hmmmmmmm

What is the meaning of port matching & where is the definition ? Can I weld some material to either piece or both pieces within the 1 inch & reblend to match ?

Have Fun http://Forum.ImprovedTouring.com/it/wink.gif
David

ps: I may have missed the definition of port mactching.

Banzai240
11-09-2004, 06:41 PM
Originally posted by ddewhurst:
Port matching....... Hmmmmmmm

What is the meaning of port matching & where is the definition ? Can I weld some material to either piece or both pieces within the 1 inch & reblend to match ?


Isn't there something in the ITCS pertaining to adding materials being a no-no?? I'll have to go check...

DJ

Renaultfool
11-09-2004, 06:48 PM
Ah, yes, but my Webster's defines "match" as "to make fit", not hog out. The word "match" itself defines the limits of what you can do, blended 1" each way from the manifold surface. The blending 1" was to limit how far you could go into the port to discourage porting. "Match" would be the definition I gave in my first post. You can line them up and blend the small amount of material removed lining them up into the port wall to a maximim of 1" from the manifold face, but I do not think that means you can remove more material than necessary to line them up. That does not make any sense given the strict interpretations used in most other posts on this site. Show me a definition where "match" is equal to "enlarge" and I will buy it, otherwise I am curious as to how you come to your conclusion from the wording in this section.

That may differ from current practice, especially according to the feelings expressed here, but that does not change the definition. Using common english definitions I do not see where it says "you can hog it out."

"If it says you can, you bloody well can" but if it doesn't, you can't.

Sorry boys, we have to live with what the book says, not what we want it to say, at least until we change the book.

ITANorm
11-09-2004, 07:28 PM
From Norm's Unpublished Dictionary of Automotive Terms in Common Use:

Port matching: (verb clause or noun clause) The act of (or an item that has been) altering the size of head or manifold ports to more closely resemble each other in a cross-sectional plane; usually consisting of removing material from one or both sides to attain symmetry. (Note: The ports in the head are usually left somewhat smaller on the exhaust side, and made slightly larger on the intake side than the port in the mating surface to provide an "anti-reversion step".
__________

So, you could add material, but I think the "no material may be added" may trip you up.

http://Forum.ImprovedTouring.com/it/wink.gif

Geo
11-09-2004, 07:42 PM
Once again you're adding wording. Match means make both sides the same size. There is no limitation placed on this other than tehe 1" in rule.

If it doesn't say you can, you can't. However, if it says you can, you bloody well can. Now, if it says you can and places limits on it, you have to work within those limits. There are no limitations placed upon the size of the ports. Have at it. Probably make things much worse anyway.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

ddewhurst
11-10-2004, 10:54 AM
Guys, asking the meaning of port matching was only a question because I didn't see a definition in the glossary or any meaning other places.

But reading rule 17.1.4.D.l. has it covered.

and external dimensions of the cylinder head or intake manifold MAY NOT BE REDUCED to facilitate internal porting.

Have Fun http://Forum.ImprovedTouring.com/it/wink.gif
David

Banzai240
11-10-2004, 11:11 AM
Originally posted by ddewhurst:
But reading rule 17.1.4.D.l. has it covered.

and external dimensions of the cylinder head or intake manifold MAY NOT BE REDUCED to facilitate internal porting.

Again, you've lost me with your "reasoning"...

What do the "external dimensions of the cylinder head or intake manifold", have to do with the INTERNAL dimensions of the ports??



------------------
Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
http://home.comcast.net/~djjordan/Web/DJ_AV1.jpg

Greg Amy
11-10-2004, 12:03 PM
The "external dimensions" refers to the outline (external dimentsions) of the head.manifold. The purpose of this is to eliminate, for instance, milling back the face head .250 so you could, in effect, match-port 1.250" in...

Tom Donnelly
11-10-2004, 01:31 PM
Ron,

Just pay someone with a flow bench to port match, otherwise you might do irrepairable damage to the head or make things worse. Without testing flow, you're just guessing about modifications to a critical part of the 'air pump'.

Tom

Festus E. Simkins
11-10-2004, 04:12 PM
IMHO, I read the rules a little different than you do. I don't think they say you are matching the engine and maniford to the gasket. You are matching the two engine parts. Therefore, you would have to determine where the two surfaces don't match up and remove only the material necessary for each to mirror the other. This may mean that you remove material on one side of a port on the manifold and on the other side of the same port on engine block. I don't think it just allowes you to hog out the ports on both sides to equal the size of the gasket. You could however enlarge the gasket to fit the ports since gasket's are free.

However, I am probably wrong in this interpertation or maybe its something that has just gotten out-of-hand. Anyway, FWIW, the port matching situation like the ECU situation don't mean squat to me because I run a carb. 12A rotary. We can't do nothing to nothing. http://Forum.ImprovedTouring.com/it/frown.gif

Drive well.

Geo
11-10-2004, 04:35 PM
Originally posted by Festus E. Simkins:
IMHO, I read the rules a little different than you do. I don't think they say you are matching the engine and maniford to the gasket. You are matching the two engine parts. Therefore, you would have to determine where the two surfaces don't match up and remove only the material necessary for each to mirror the other. This may mean that you remove material on one side of a port on the manifold and on the other side of the same port on engine block. I don't think it just allowes you to hog out the ports on both sides to equal the size of the gasket. You could however enlarge the gasket to fit the ports since gasket's are free.

The gasket is irrelevant. The rule places absolutely zero limitation on the matching process besides the 1" rule. You're adding words to the rule that do not exist.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

Quickshoe
11-10-2004, 05:37 PM
Festus,

I would agree that your interpretation is probably what the original rule writers "envisioned" and perhaps that was their "intent" but it is not what the rule says. And we don't know what their intent was, so we have to interpret the rule literally.

Besides, without knowing what the unmodified parts looked like how would one enforce your interpretation even if that is what was meant?

--edit can't spell worth a sheet http://Forum.ImprovedTouring.com/it/mad.gif



[This message has been edited by Quickshoe (edited November 10, 2004).]

ddewhurst
11-10-2004, 09:31 PM
Mr. Jordan, please except my humble apologize for screwing up with my previous post. http://Forum.ImprovedTouring.com/it/redface.gif

***and external dimensions of the cylinder head or intake manifold MAY NOT BE REDUCED to facilitate internal porting.***

Have Fun http://Forum.ImprovedTouring.com/it/wink.gif
David

Renaultfool
11-11-2004, 02:36 AM
Well at least Festus can read english. Glad to have you on my team! Let me try and explain myself more clearly.

"Match" is the defining word that limits the modification in my opinion, and it can be looked up in the dictionary for those of you who do not know what it means.
From the Websters Seventh New Collegiate, the definitions that pertain are, as a noun, (1,a) a person or thing equal or similar to to another, (1,c) an exact counterpart, (3,a) a process of matching, and as a verb, (3,a,2) to cause to correspond, and (4) to fit together.

Quickshoe,it would be very easy to tell if someone had gone too far. If you "match" them as Festus and I think it says, you would just remove the material necessary to line them up, remove the overlaps. This would mean that if one port is bigger than the other one all the way around, only the smaller mating port would be altered up to 1" from the manifold face to match the larger port. The originally larger port would be as cast and look like the rest of the unmodified port. If one port was offset from the other one, one port would be gound on one side and the mating port would be ground on the other side. The two unmodified halves would be as cast, look the same as the rest of the unmodified port. It would not even take any specilized tools, a visual inspection would tell, the same check that would be done for any other illegal porting.

17.1.4.D states that "no permitted componant/modification shall additionally perform a prohibited funtion". I would argue that raising the top of the port beyond that necessary to eliminate any overlap areas, the matching allowed by this rule, would be an illegal modification because it could effect the air flow to the valve due to the change in the angle of approach of the column of intake air to the valve head. I have a 2.0 Ford racing modification manual from Dave Vizard that shows how to raise the port roof at the manifold face for that exact reason. That possibility eliminates the interpretation that it is "free" within 1". "Match" defines what you can do and sets the limit.

ITANorm mentioned adding an "anti-reversion step" at the intake manifold. Sorry Norm, 17,1,4,D, illegal function, unless the intake ports had this funtion from the factory.

Oh, yes, "match" as a verb, (1,a) "to encounter successfully as an antagonist". A truly fitting definition of what we are doing here in the off season.

ITANorm
11-11-2004, 11:10 AM
Originally posted by Renaultfool:
Sorry Norm, 17,1,4,D, illegal function, unless the intake ports had this funtion from the factory.

I disagree. You may "gasket match" - to a free gasket - and you are not required to do it to both sides. For my particular car, it is irrelevant anyway. The factory 4AG engine has the "TVIS" (variable induction butterflies) plate between the head and the intake. It has been decreed by the tech department that it is not legal to modify or remove it (since it's neither part of the head nor the manifold), so doing anything other than cleaning up the (few and minute) casting dags to 1" in is pointless. Not to mention that the intake runners in a 4AG are too big in the first place.

erlrich
11-11-2004, 02:03 PM
Originally posted by ITANorm:
You may "gasket match" - to a free gasket - and you are not required to do it to both sides.

Could someone please point out the section of the GCR that says you can "gasket match"? Not picking on you Norm, but I've seen this reference several times, and for the life of me I can't find it in my GCR.


<font face=\"Verdana, Arial\" size=\"2\">It has been decreed by the tech department that it is not legal to modify or remove it (since it's neither part of the head nor the manifold)</font>

Not trying to be argumentative Norm, but can you be more specific as to when/how this was determined. The reason I'm asking is that I've heard from several 240SX owners who said the butterflies could be removed as part of the matching process.


<font face=\"Verdana, Arial\" size=\"2\">Match means make both sides the same size.</font>

George, I have to disagree with your definition. In this context I believe match means to make both sides the same size as the other. I know it's a fine point, but I think the second you remove more material than necessary to make the ports "match", you have gone beyond what the rule allows. JMHO

Earl

Banzai240
11-11-2004, 02:12 PM
Originally posted by erlrich:
...In this context I believe match means to make both sides the same size as the other.

How do you know which side to start with?? What if you slip and make one side bigger than the other... then can you "match" the the other side to fit??

The fact of the matter here is that there IS no clear definition of what the limits are, other than IN THE END RESULT, the ports should "match". Gaskets are free, so there is no limit there, and otherwise, the ports just need to be made to "match"...

Take that as you will..

Also, concerning the 240SX butterfies... which years are we talking about? Over the series of '91-94 and '95-'98, those butterflies were NOT installed in the factor on some years. The '96 intake that's on my car doesn't have them, but the '93 manifold that's on the shelf does, so I'm assuming that at some point in-between they were no longer being used by Nissan (if it happened to be in '94, then the '91-'94 would NOT be required to use them if you could get your hands on the'94 manifold...)

Remember also that, if these are part of the emmission control system, they can be removed legally as part of that system. Not quite sure what would be required to prove that, but I believe the rules allow for removal of all emmission control (EC) compenents. I haven't looked in my early shop manual to see, but there may be something in there that indicates if these were considered EC or not... It's worth a look...



------------------
Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
http://home.comcast.net/~djjordan/Web/DJ_AV1.jpg

erlrich
11-11-2004, 02:31 PM
Originally posted by Banzai240:
How do you know which side to start with?? What if you slip and make one side bigger than the other... then can you "match" the the other side to fit??


Aw, c'mon Darin, this isn't Bill, you don't have to argue just for the sake of argument http://Forum.ImprovedTouring.com/it/wink.gif

I agree 100% that the rule is ambiguous, and open to several interpretations, but your arguments don't hold much water IMHO. Common sense says you start with the port that is smaller. And as far as what happens if you slip - well what happens if you slip and grind further than 1" into either port? Or for that matter, what if you slip and mill .010" too much off the head, and it is now under factory spec?

I think we'll just have to file this under "agree to disagree". Btw, has anyone ever heard of a protest being filed on the basis of "improper matching"?

Cheers
Earl

ITANorm
11-11-2004, 03:32 PM
Sadly, the butterflies in the Toyota have nothing to do with emissions. They are there to increase intake velocity at lower RPM. There was no version of the 4AG the was offered in the MR2, AE86 or AE89 Corolla that did not have them. The determination was made in response to a query I posed to the SCCA Technical department about 3 years ago. According to them (Eric, I think is the one who actually commented), it also has to remain in the (LP)FP cars.

The good news is, according to dyno tests, they actually do some good - and removing them has, at best, a negligible effect on high RPM torque.

Banzai240
11-11-2004, 05:04 PM
Originally posted by erlrich:
Aw, c'mon Darin, this isn't Bill, you don't have to argue just for the sake of argument http://Forum.ImprovedTouring.com/it/wink.gif

VERY FUNNY! http://Forum.ImprovedTouring.com/it/mad.gif

http://Forum.ImprovedTouring.com/it/biggrin.gif



Common sense says...

Say no more... That is where you lose this arguement! http://Forum.ImprovedTouring.com/it/wink.gif



I think we'll just have to file this under "agree to disagree". Btw, has anyone ever heard of a protest being filed on the basis of "improper matching"?


I've never heard of a protest, but I can say with near certainty that the rule is as George and I have described... I personally wrote a letter to the CRB a couple of months ago asking this to be looked at for precisely this loophole/ambiguity in the rules, and the decision was returned that the rules were adequate as written, even given the issue we've been discussing. There is simply no way to make a ruling on this after the fact, because there isn't a clear limitation or definition on what a "port match" is...

I can tell you right now... those guys that are beating you and I are reading the rule the same way that I do... http://Forum.ImprovedTouring.com/it/wink.gif


------------------
Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
http://home.comcast.net/~djjordan/Web/DJ_AV1.jpg

[This message has been edited by Banzai240 (edited November 11, 2004).]

Geo
11-11-2004, 05:10 PM
Originally posted by erlrich:
George, I have to disagree with your definition. In this context I believe match means to make both sides the same size as the other. I know it's a fine point, but I think the second you remove more material than necessary to make the ports "match", you have gone beyond what the rule allows. JMHO

Knock yourself out. I wish all my competitors read the rules the same way you are doing. There is no, none, nada, zip wording in the ITCS to limit how you match the ports. No wording saying you must leave one side untouched or even that you could only do minimal material removal.

I'll say it one last time (and if you still disagree, all the better for your competitors) that you're adding wording that does not exist.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

John Herman
11-11-2004, 06:08 PM
BTW, everyone seems to be focussing on the intake side. Don't forget about the exhaust side. Free gaskets AND free manifolds. So in that light, do what you want up to 1" into the head. Even if you wanted to use the "strick" interpretation, you could make your own header flange that would match anything you did to the head.

Ron Earp
11-11-2004, 06:36 PM
Well, I would have written and responded to the thread I started but I've just been too dang busy hogging the ports out on my head to take the time! ;-0

Interesting interpretation of the rule and not what I expected, but, I think it is correct in that it is very open the way it is written. No matter, I'm just matching up my larger gaskets and I'll call it quits.

Ron

------------------
Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

lateapex911
11-11-2004, 07:48 PM
And without a real flow bench, thats the SMART thing to do!

Norm, you mentioned that the butterflies were there to increase intake flow velocity...which is to better atomize the fuel for a cleaner burn, right??? See where I'm going? Sounds like emission control to me! Of course, as you mentioned, they aren't hurting, so it's a moot point!

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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

Ron Earp
11-11-2004, 07:56 PM
Originally posted by lateapex911:
And without a real flow bench, thats the SMART thing to do!


Clearly, you missed the sarcasim in my post. And, if so, plently of people can port well for good results WITHOUT a flow bench. And, I happen to be not so bad with cetain heads, this just isn't one of them

Anyhow, it is moot as all I'm doing is matching my gaskets. I've seen first hand on a flow bench what happens with bad work.

Ron

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Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

[This message has been edited by rlearp (edited November 11, 2004).]

Ron Earp
11-11-2004, 08:02 PM
Post dup

[This message has been edited by rlearp (edited November 11, 2004).]

Ron Earp
11-11-2004, 08:03 PM
Post dup.

[This message has been edited by rlearp (edited November 11, 2004).]

Joe Harlan
11-15-2004, 12:02 AM
Ron, Do yourself a favor here. Only do what is needed to clean the ports to each other. I would tend to lean this way no matter what the rules people want to say. Port matching is a bit different that actual Porting. I would look at the head and the intake and decide what needs the most work within the 1" rule. Keep it very clean and dont create any large bumps in the port. then clean the other component to match. creating a big as cobra neck to fit a gasket will cost you more HP than gain you. Same goes for the exhaust. I know what the rule says but sometimes being cute with a rule will cost you more than it gets you.

Joe

ShelbyRacer
11-15-2004, 10:38 PM
<font face=\"Verdana, Arial\" size=\"2\">you mentioned that the butterflies were there to increase intake flow velocity...which is to better atomize the fuel for a cleaner burn, right??? See where I'm going? Sounds like emission control to me! </font>

Nope.

It's actually done to make a variable-tuned runner. Higher velocity increases some of the "stack effect". It also does help promote swirl and tumble, which contributes to clean-burn (as you're saying). The combined effect was more torque, and actually done for more drivability. I've seen a white-paper on it somewhere, but I can't track it down right now.


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Matt Green
"Ain't nothin' improved about Improved Touring..."

RacerBill
11-16-2004, 01:41 AM
How do you tell which side is smaller between the port in the head and in the manifold?

apr67
11-16-2004, 10:42 AM
Racer bill.

Usually we mock up the gasket to the head, and dykum the area to be removed, and then mockup the gasket to the intake, and repeat.

This is something I would generally leave to a porting pro, as they know how to make the most of this job and not muck things up.

My 2 cents.

Ron Earp
11-16-2004, 12:22 PM
This is preceisely what I did. The studs make sure it will align properly and the gasket was used as a template for the dye. I blended and removed material to match the gasket, therefore, both ports should match correctly - hence port matching. I've done a bunch of these before and it is not hard, just takes a bunch of time and a bunch of cartridge rolls and a good die grinder.

Increase in flow? I wouldn't expect much, just whatever you get from not having the ports 1/8" off as they were on mine in addition to the centers not aligning. I don't think it will hurt flow either since I could not touch the runners or bowls.

------------------
Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

[This message has been edited by rlearp (edited November 16, 2004).]

stevel
11-16-2004, 06:38 PM
Originally posted by Renaultfool:

"Match" is the defining word that limits the modification in my opinion, and it can be looked up in the dictionary for those of you who do not know what it means.
From the Websters Seventh New Collegiate, the definitions that pertain are, as a noun, (1,a) a person or thing equal or similar to to another, (1,c) an exact counterpart, (3,a) a process of matching, and as a verb, (3,a,2) to cause to correspond, and (4) to fit together.



this argument can be torn apart too. "thing equal or similar to to another" What's the exact definition of what similar can be? What's the specification of how close you have to make it similar? There isn't one. So if you took off 0.005" too much and it isn't a match i'm illegal? You can't expect exact tolerances so you have to have some variance allowance. But that isn't in the rule and shouldn't be cause it will make it ridiculous. This leads to my next disagreement with your interpretation.


Originally posted by Renaultfool:



Quickshoe,it would be very easy to tell if someone had gone too far. If you "match" them as Festus and I think it says, you would just remove the material necessary to line them up, remove the overlaps. This would mean that if one port is bigger than the other one all the way around, only the smaller mating port would be altered up to 1" from the manifold face to match the larger port. The originally larger port would be as cast and look like the rest of the unmodified port. If one port was offset from the other one, one port would be gound on one side and the mating port would be ground on the other side. The two unmodified halves would be as cast, look the same as the rest of the unmodified port. It would not even take any specilized tools, a visual inspection would tell, the same check that would be done for any other illegal porting.



The other thing you're missing is that not always is it a certain half of the port needs matching. Sometimes and a lot of the times there's flaws all the way around the ports on both the manifold and head that can't be matched to the other. Sometimes there's a slight curve on the floor, roof, wall of the port that you can't make identical to the other side without adding material, which you specifically can't do. And that's when you need to remove material from both sides to get them to match, which this rule allows for. And no one knows what your exact casting looked like before so it's not that easy to see visually if it's illegal. That's where the difference lies and the rule allows for. It's not always possible to "match" one side to the other and you can't even see that after the work has been done, so how do you tell someone they're illegal for that.

And 1" into the port isn't going to do anything performance wise.

And to the person that says you shouldn't do anything without a flow bench. Flow bench's are just as inaccurate and should be taken with a grain of salt as a dyno chart is. I can make a head flow 10% more than it did before at all valve lifts, doesn't mean it's going to make the car faster at all. It's just a means of comparison. You can make a head flow as much CFM as you want, it doesn't make it useful. Each head responds differently, and you can't see that in flow bench numbers.

One of the best quotes I heard from a well know head porter who has been doing them for a long time. A relative newb was talking to him about techniques and flow bench numbers of various heads, and the guy says "oh, you're a flow bench numbers guy. Yeah, well I'm a track times guy. That's how I build heads." Great quote and should always be remembered. A flow bench is a tool, but only one tool and usually doesn't tell the whole story.

s



[This message has been edited by stevel (edited November 16, 2004).]

Victor Penner
12-13-2004, 08:35 PM
I have been researching Port Matching recently as I am considering a Limited Prep EP car that follows the IT head prep rules.

I was under the impression as mentioned many times in this post that one would use dyekem and trace the gasket, etc, etc.

I recently bought a Mustang magazine that has a n article on head porting by a guy that has done heads only since the 50's.

One of the first things the article says is that people mistake GASKET matching with Port matching. Two different animals according to this head guru. Port matching,is taking your best port , transferring those dimensions to the rest of the ports and matching them up. Gasket matching is as has posted above.

Hmmm???

Victor Penner

Ron Earp
12-13-2004, 08:44 PM
Might be one of those things that needs clarification in the rulebook, your explination is logical.

But, if so then there will be a lot of illegal cars out there!

R

------------------
Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

Renaultfool
12-13-2004, 10:27 PM
Now you are getting it!

It is not what we want it to say, but what it says. Even if it does make a lot of cars illegal. That has been my point all along.

In most cases matching to the gasket will make them lose power instead of gain power anyway. This is because it will make your port look like a snake that swallowed a mouse. The fuel/air mixture will slow down in the fat place. Unless the intake ports are short and you open the top of the port way up to allow for a better angle to the intake valve. That won't work on long intake ports though.

Ron Earp
12-13-2004, 10:59 PM
Originally posted by Renaultfool:

In most cases matching to the gasket will make them lose power instead of gain power anyway. This is because it will make your port look like a snake that swallowed a mouse.

In some cases, yes. But, in my personal case there is no way I'll do anything but gain. They are only a tiny bit larger, it won't kill velocity, but there are real gains to be had on crappy British parts from 1970s. Hell, the bolt holes that align the parts hardly line up well, the ports damn sure don't.



------------------
Ron
http://www.gt40s.com
Lotus Turbo Esprit
Ford Lightning
RF GT40 Replica
Jensen-Healey: IT prep progressing!

Victor Penner
12-13-2004, 11:14 PM
I just spent a little time on GOOGLE and came up with quite a few Port Matching results. Mainly "how to" and mainly V8 but helpful none the less. Some of the articles are actually titled "Port/Gasket Matching" so, as on this board, there is MANY interpretations. I am personally favorable to the "gasket match".

Victor Penner

ddewhurst
12-14-2004, 10:49 AM
***I have been researching Port Matching recently as I am considering a Limited Prep EP car that follows the IT head prep rules.***

Victor, have you searched the Production site for the thread on IT head prep ?

Interesting http://Forum.ImprovedTouring.com/it/wink.gif
David

Tom Donnelly
12-14-2004, 12:16 PM
David,
Which thread in particular? I searched on "IT head prep" and got 6 pages of stuff.

Tom

Victor Penner
12-14-2004, 12:34 PM
David,

Yes I have. I didn't participate in that one but I do believe that in Limited Prep Production the GCR is talking about the Head only(as far as IT prep) because the valvetrain is addressed seperately.

Victor Penner

ddewhurst
12-14-2004, 08:38 PM
Tom, Victor rooted out the issue I was refering to. The PCS spec line IT head prep is relating to the IT bare head prep. Not the assembled head with all the components.

Have Fun http://Forum.ImprovedTouring.com/it/wink.gif
David