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  porting, polishing, gasket matching

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Author Topic:   porting, polishing, gasket matching
indyphil
Gearhead

Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002

posted 09-12-2002 10:48 AM     Click Here to See the Profile for indyphil   Click Here to Email indyphil     Edit/Delete Message   Reply w/Quote
This is a call to all those racers that have been there and done that.

If i buy a new or rebuilt 4 barrel carb, and a nice new intake for my 289 2V engine. And lets say it has some other mild upgrades, headers and a mild cam. What do the following cost, how much bang do i get for the buck, and which ones can i do myself with a dremel or a drill:

basic intake and head porting (gasket matching)

intake and head full port and polishing job

above plus 3 angle valve job.

Alex has suggested before that new heads is cheaper than porting. but I was wondering if i could match the ports on the new intake to the heads with a simple gasket match, and do it myself? How much horsepower might I gain by doing these things?

Polishing sounds like a lot of effort for little gain? One guy even told me that polishing can hurt combustion and you should leave the intake ports dull.

Any opinions and experiences are always welcomed.

------------------
'68 coupe 289 2V
CAT engine performance engineer

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mstngjoe
Journeyman

Posts: 64
From: Oregon
Registered: Aug 2002

posted 09-12-2002 11:06 AM     Click Here to See the Profile for mstngjoe   Click Here to Email mstngjoe     Edit/Delete Message   Reply w/Quote
Take a look at this link for some basic info on home porting:

http://www.sa-motorsports.com/diyport.htm

------------------
My Mustang
My engine

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Moneymaker
Administrator

Posts: 19751
From: Lyons, IL, USA
Registered: May 99

posted 09-12-2002 11:23 AM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Skip the polishing. You can do the match porting yourself. You only need to go 1/2 inch into the ports. Try and clean up the bowl area around the guide a bit. Have the valve job professionaly done.

------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

NHRA/IHRA/SRA/MCA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
Professional Manwhore
The Barry of BarrysGrrl

Quote: "I never met a magazine mechanic I liked."

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[email protected]
Gearhead

Posts: 440
From: Lakewood, CO, USA
Registered: Jun 2001

posted 09-12-2002 12:57 PM     Click Here to See the Profile for JCQuinn@work   Click Here to Email JCQuinn@work     Edit/Delete Message   Reply w/Quote
Narrow the guide as much as you are comfortable with. I have gone down to 1/16" on each side with no problem. Feel the short turn radius with your finger and you will feel a sharp ridge where the cutters that Ford used in the bowl area (under the valve) met the cast port. Smooth this ridge until it feels like a constant radius. Then remove all of the ridge left in the rest of the bowl. These heads also respond well to slightly larger valves.

On the exhaust side, try to remove as much of the exhaust guide in order to eliminate the flat spot in the port roof that the guide area makes. If you have the thermactor hump, remove it to the level of the port roof. These exhaust ports like to have the roof raised but the floor makes little difference. If you try raising the roof be sure not to exceed your header or manifold size. You can "D" shape the roof slightly, this shape flows best with these heads.

I used to do a lot of work on these heads trying to make a competitive modified small block. Now I would just buy a better head. These heads will work very well for a hot street car if you are willing to do your own grinding. If you are going to pay somebody, buy aftermarket heads.

Like Alex said, skip the polishing. It is only useful in the combustion chamber. A polished surface reflects more heat back into the combustion chamber but you wont see the difference on a street motor.

John

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skips69
Gearhead

Posts: 274
From: Catlin, IL USA
Registered: Mar 2001

posted 09-12-2002 11:31 PM     Click Here to See the Profile for skips69   Click Here to Email skips69     Edit/Delete Message   Reply w/Quote
You're in Lafeyette? Go see (Woody) @ Woody's machine shop in Thorntown (near Crawfordsville). He ported, polished, gasket matched, added heavy duty valve springs, completed a 3 angle valve job, etc on my 351W 4V heads a few years ago. Did awesome work, and very reasonable. He knows Fords, expecially the CJ's, but does work to everything that comes in. Even if just for some tips or to see his shop, it will be worth the short drive for you.

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deadhead
Gearhead

Posts: 153
From:
Registered: Sep 2002

posted 09-12-2002 11:36 PM     Click Here to See the Profile for deadhead   Click Here to Email deadhead     Edit/Delete Message   Reply w/Quote
JCQuinn,

I'm currently doing port matching and a little bowl cleanup on my vintage '66 289 heads. Is the "thermactor hump" you mentioned the bump in the upper left corner of each exhaust port?

Thanks,

deadhead

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deadhead
Gearhead

Posts: 153
From:
Registered: Sep 2002

posted 09-12-2002 11:43 PM     Click Here to See the Profile for deadhead   Click Here to Email deadhead     Edit/Delete Message   Reply w/Quote
JC,

Yet another question (excellent, to-the-point-no-bull post, by the way. Thanks).

When you say to try to "remove as much of the exhaust guide to eliminate the flat spot in the port roof", are you telling me (us) to make the exhaust guide area look like that of the intake--kinda scooped out?

deadhead, again

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indyphil
Gearhead

Posts: 877
From: Lafayette, IN, USA
Registered: Jul 2002

posted 09-13-2002 10:57 AM     Click Here to See the Profile for indyphil   Click Here to Email indyphil     Edit/Delete Message   Reply w/Quote
This is a great post,
If you do the work yourself this is free power with the exception of the tools.

does a '68 289 have thermactor humps?
(save me from having to look myself!)

Thanks guys

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[email protected]
Gearhead

Posts: 440
From: Lakewood, CO, USA
Registered: Jun 2001

posted 09-13-2002 11:53 AM     Click Here to See the Profile for JCQuinn@work   Click Here to Email JCQuinn@work     Edit/Delete Message   Reply w/Quote
Deadhead - Yes the hump in the exhaust port is what I am talking about. Grind it to be even with the port roof. Be sure to make it on the same radius as the entire roof line. There will be a small depression left behind the flat spot you have just created. Don't worry about the depression, if you grind into it you will do more harm than good. What you are trying to accomplish is a constant radius port roof.

Keeping the constant radius in mind, that is what you are trying to accomplish at the exhaust guide also. Remove the guide support on the headder side as much as possible. You are trying to minimize any projection into the constant radius.

There is a ridge where the factory machining meets the cast port floor. Just like I described on the intake. Take this ridge away also.

Indyphil - You probably have the hump, I think all the heads after mid 67 had the hump cast into them.

Just to expand on the larger valve idea. I don't remember which valves interchange but I know you can use stock replacement valves with a larger diameter such as Chevy valves. Just make sure the stem length is close to the same as stock. I don't know what machine shops charge to put in larger valves but as long as the size change isn't too dramatic it is fairly easy to do and shouldn't cost too much. These heads really like a slightly larger valve.

In case you are wondering, Yes I did all this work and tested it on a flow bench.

John

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deadhead
Gearhead

Posts: 153
From:
Registered: Sep 2002

posted 09-13-2002 01:29 PM     Click Here to See the Profile for deadhead   Click Here to Email deadhead     Edit/Delete Message   Reply w/Quote
JC,

Just to make sure I don't screw anything up... I can grind off the entire thermactor hump, both on the left side of the port and up to the current port roof?

deadhead

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[email protected]
Gearhead

Posts: 440
From: Lakewood, CO, USA
Registered: Jun 2001

posted 09-13-2002 01:47 PM     Click Here to See the Profile for JCQuinn@work   Click Here to Email JCQuinn@work     Edit/Delete Message   Reply w/Quote
Yes, you won't hit water. Just be sure to grind straight back into the port, don't angle up to meet that little depression behind the bump.

John

[This message has been edited by [email protected] (edited 09-13-2002).]

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deadhead
Gearhead

Posts: 153
From:
Registered: Sep 2002

posted 09-13-2002 07:06 PM     Click Here to See the Profile for deadhead   Click Here to Email deadhead     Edit/Delete Message   Reply w/Quote
JC,

I'm all ready to do the intake port matching but I'm having a helluva time placing the intake gasket. It seems it could go up or down an 1/8" or more and still function. Give me a hint as to where to place the gasket vertically. Horizontal doesn't seem to be a problem.

Thanks,

deadhead

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deadhead
Gearhead

Posts: 153
From:
Registered: Sep 2002

posted 09-13-2002 07:26 PM     Click Here to See the Profile for deadhead   Click Here to Email deadhead     Edit/Delete Message   Reply w/Quote
Here's another question. My headers AND THEIR GASKETS have not yet arrived, but I would like to start on the exhaust port side. I measured a Fel-Pro and a Mr. Gasket set today. They were identical in port width, but the Mr.Gs had a taller opening by maybe an eighth inch. Hedman says the header opening at the flange is oval. I know I should wait for the Hedman gasket, but I keep thinking the bolt holes don't move, so why couldn't I match the ports to another gasket. Any thoughts would be greatly appreciated.

deadhead

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deadhead
Gearhead

Posts: 153
From:
Registered: Sep 2002

posted 09-16-2002 07:21 PM     Click Here to See the Profile for deadhead   Click Here to Email deadhead     Edit/Delete Message   Reply w/Quote
JCQuinn,

OK. I've removed the thermactor hump--even with the roof and even with the side of a standard exhaust gasket. I can feel the depression you spoke of left behind the thermactor hump, but what should I do about the ramp-like depression remaining on the same side coming up from the floor where the casting halves meet?

deadhead

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mustangguy
Journeyman

Posts: 2
From: San Francisco, ca
Registered: Sep 2002

posted 09-18-2002 01:16 AM     Click Here to See the Profile for mustangguy   Click Here to Email mustangguy     Edit/Delete Message   Reply w/Quote
Heres the exhoust of some 66 heads my friend did. These are CA smog heads.

http://www.289mustang.com/images/shaun4.jpg

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