318 head porting for the average joe

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Thanks.. yes , will be smoothing everything out.. Plan to do some more work next week, during the holidays.. I have done most of the rough work on one complete head. Just have to open up the bowls to match the first one.

Happy Holidays !
 
That push rod pinch or bump in the port is NOT as big of restriction as it LOOKS.

3 angle Valve job, Then bowl blending, Then guide trimming, Then inlarging bowl area..............At this point you have got the air flow though the head high enough that the push rod pinch is now the choke point.(smallest area or size...aka RESTRICTION)

If you figure the "area" in each section of the port. you will find that the prp (push rod pinch)is one of the larges area of the port is stock form.

My opinion is from playing with the 340/360 heads. The 318 heads my be different!.?
 
Thanks to all you teachers, and sharers of great and valuable knowledge, this has become my fav thread. Hats off to those who know and don't mind sharing. you guys are rare, and classy.
Now for some questions. Being new to this type of hop ups, and clean ups, modifications, how far can we newbies go and not get into water or oil jackets and ruin a good head? that worries me most is not knowing how far we can go for certain, and how to know how far not to go. ALSO.. whats the chances of maybe doing an at home three angle valve job, for us guys who really like saying, well ya see, I did it all at home in my shop( garage)?
 
Here is some more work on one of the open chamber 318 heads. I posted some pics a few pages back, and I've been looking at some of the work others have posted, and it was clear that I was safe to remove some more material from the guide boss area. I hope I didn't hack it too badly. For you guys who know what you're doing, please give me some feedback. I'll take any advise and constructive criticism you've got.

318 Head Porting 129-1.JPG


318 Head Porting 129-2.JPG
 
Once the rough work is done with the carbides, where do I go from there? Do I go with blue stones and then sandpaper rolls? These are the bits I used for the rough work. Will you experienced guys post some pics of the bits you use please? Thanks.

318 Head Porting 130-1.JPG
 
I have very little experience, learning porting myself this winter, but those appear to be the same kind of bits I used for all the cutting work.

I used 80 grit rolls from Eastwood for the next and final steps. I worked it little harder on the exhaust side to smooth more than the intake.

my 2 cents
 
4spdcuda66 said:
Once the rough work is done with the carbides, where do I go from there? Do I go with blue stones and then sandpaper rolls? These are the bits I used for the rough work. Will you experienced guys post some pics of the bits you use please? Thanks.
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Running gas on a street driven engine, polishing the intake port can be counter-productive.

A slightly rough surface creates a boundery layer of turbulance & prevents gas from adhering/pooling to the port surfaces.

Polishing the exhaust ports does have benefits.
 
VIOLENT\6 said:
Running gas on a street driven engine, polishing the intake port can be counter-productive.

A slightly rough surface creates a boundery layer of turbulance & prevents gas from adhering/pooling to the port surfaces.

Polishing the exhaust ports does have benefits.
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Yes, street engine. I have read that the intakes should not be polished smooth for the reasons you mentioned. Probably no smoother than 80 grit? I have also read that the exhaust side can be polished to a mirror finish for optimum evacuation and less chance of carbon build up. This is my first port job, so any advice will be much appreciated. Thanks.
 
"I" personally don't like to see the valve guide area thinned out to the point that the edges are razor sharp. Who knows? A small piece could break off and fall into the cylinder. That would suck. Also.....regarding the finish of the ports. I was once a proponent of the "rough" intake finish myself, but after consulting those who do it for a living and reading their experience, it's NOT the finish, but the port size and shape that makes the determination in flow. The carburetor (or injectors) have the job to atomize fuel. Once it's atomized, it's atomized. It ain't gettin no better. lol
 
RustyRatRod said:
"I" personally don't like to see the valve guide area thinned out to the point that the edges are razor sharp. Who knows? A small piece could break off and fall into the cylinder. That would suck. Also.....regarding the finish of the ports. I was once a proponent of the "rough" intake finish myself, but after consulting those who do it for a living and reading their experience, it's NOT the finish, but the port size and shape that makes the determination in flow. The carburetor (or injectors) have the job to atomize fuel. Once it's atomized, it's atomized. It ain't gettin no better. lol
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I disagree.
No matter how good of a atomization you get. There will still be Fuel Drop out. A Rough texture and sharp seat angles will help to put it back into suspension.

the port size and shape that makes the determination in flow.
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I agree BUT, the texture will help out a port that is not perfect. A first time porter will still be learning how to hold and cut and will benefit from this.

With that all said, Pro Stock has been using this concept for many a Years.
 
Ask IQ52. He seems to say the same thing I do. That it's not the finish. It's the port size and shape. I take his word for it, especially since he's a professional porter and engine builder.
 
When you have shaped your port the best you can, still need more, and you can't port any more due to water risk or roof thickness. .............You go looking for other ideas to make your goal.

I have personally had a port, were the air was so close to jumping of the ssr. You could wave your hand in front of the port. And the flow (cfm) would drop and come back at high lift.

I highly polished that port and lost 20 cfm.

Did nothing to the port but hand sand the ssr with 80 grit sand paper. Got the air to hold back on to the ssr, and go my 20 cfm back. There was NO port shaping just texturing and only on the floor at the ssr and, on the ssr


I'm no Pro Porter just a average joe! sharing my experience:cheers:
 
....and neither am I. I just gave an opinion on the flippin valve guide and you pick one mutha flippin sentence out and wanna argue it. Get lost.
 
I cleaned up those thin guide bosses. Rustyratrod had a good point about possibly losing a piece of metal down the cylinder. Going back and looking at some of 1wildandcrazyguy's work, it looks like I can go even further whittling those bosses down. I think I'll cool it for now. I'm getting a good feel for the die grinder, I just need to step back a bit. I appreciate the feedback you guys are providing. Hey wildandcrazy, you out there? I'd really like to get your opinion as well. Thanks.

318 Head Porting 141-1.JPG
 
I cut the roof down on the exhaust ports and cleaned up the bowls a little. I pretty much avoided taking anything off the floor. As far as the crazy crossover port, I guess just blend it as good as I can? That last photo is the crossover.

318 Head Porting 142-1.JPG


318 Head Porting 142-2.JPG


318 Head Porting 142-3.JPG
 
One thing you could do to "fix" your razor thin chunks of metal would be to install new bronze guides and just dull out the thin spots around them. Just a thought. From what I gather, you're doing this to practice and if they turn out well, use them?
 
txstang84 said:
One thing you could do to "fix" your razor thin chunks of metal would be to install new bronze guides and just dull out the thin spots around them. Just a thought. From what I gather, you're doing this to practice and if they turn out well, use them?
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You said it. I do plan on the guide inserts, but thought cleaning those up a little made good sense.
 
That's lookin good! I think you gotta knack for it.
 
RustyRatRod said:
....and neither am I. I just gave an opinion on the flippin valve guide and you pick one mutha flippin sentence out and wanna argue it. Get lost.
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I simply said i disagreed with you, and gave reason why.
chill out :D

Carry on every on. Sorry for the Pissing match. :wink:
 
Back at you. You don't have coin.Make what you have work.. That's real hot ridding.
 
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