Porting with no fear

[lilwhirlwind]

Hey guys. Just wondering if someone could possibly post some before and after pictures of port jobs to demonstrate the basics of porting.
Maybe someone could explain porting basics along with the pics?

A few of my friends wanted me to post this thread to see what kind of responses I got!

Thanks! !:D

[smittythewelder]

Spend an hour or so on the couch, getting high, and you should be able to go out to the garage and do your porting with no fear . . . .

[Bill Van Steenwyk]

Spend an hour or so on the couch, getting high, and you should be able to go out to the garage and do your porting with no fear . . . .



Smitty:

And if he does not want to do it himself after the hour on the couch, we both know, or have heard of someone, who might take on the job, if they have any stash left.

Bill

[champ20B]

Hey guys. Just wondering if someone could possibly post some before and after pictures of port jobs to demonstrate the basics of porting.
Maybe someone could explain porting basics along with the pics?

A few of my friends wanted me to post this thread to see what kind of responses I got!

Thanks! !:D

Man, your hungry for knowledge! Well, here is a few good words for start. I have souped up some motors in my time (10-30+hp ). Now here are a few basic things to keep in mind....porting is pretty simple as long as you don't deviate into uncharted territory. What I mean, is by starting without changing the port height (timing). FYI, you don't want anything over 160-170 degrees if you want it not to be too peaky and need chambers. You want about 140-155 psi compression for a hot rod job. Ignition timing might need to be readjusted by feel after then.
Anyway, if your ports are rounded, then just note how tall they are and wide. Keeping these dimensions the same, make the round holes square. For your intake ports, do the same just equal to the area of the carburator venturie +5 or 10%. The intake port posts can be given a sharp knife edge in their centers on the trans passage side (I call it funneling). Polish and round any edges into the transfer passage for good flow. Get some boysen double reed valves. Get some slightly bigger carberators. Extend your exuast port covers farther from the exhaust ports for more free flow without added noise, with a spacer. You will just need to take a gasket for a pattern to a local machine shop and have them cut you a spacer as thick as you want. Its an old trick of mine.

Remember, that if you ever want to raise ports height, never take off material on the bottom edge. Only take off from the top edge toward the head. Sometimes you can cut out a port post or two as long as the piston rings don't pop out. Another good idea is to get an old worn out racing powerhead that someone raced as modified, pretty cheap. You can measure it out all through and use its dimensions as a learning guide to do to a motor you want to build. Other than that, there is so much one can do, you could write a book 2 inches thick about it! Have a good one!

[Powerabout]

If someone supplied me with unlimited blocks and a dyno , I guess I'd call it porting with no fear

[Fast Fred]

experience gives you the no fear , you would need to know, what the end use is to be, what kind(merc ,omc,,,,,,,,,,,,,,,

[A/B Speedliner]

Squared ports still need an minimum 1/8" radius in the corners on exhaust ports. This improves flow and helps control heat build up which will distort the cylinder roundness. Per Harry Brinkman.

[lilwhirlwind]

Man, your hungry for knowledge! Well, here is a few good words for start. I have souped up some motors in my time (10-30+hp ). Now here are a few basic things to keep in mind....porting is pretty simple as long as you don't deviate into uncharted territory. What I mean, is by starting without changing the port height (timing). FYI, you don't want anything over 160-170 degrees if you want it not to be too peaky and need chambers. You want about 140-155 psi compression for a hot rod job. Ignition timing might need to be readjusted by feel after then.
Anyway, if your ports are rounded, then just note how tall they are and wide. Keeping these dimensions the same, make the round holes square. For your intake ports, do the same just equal to the area of the carburator venturie +5 or 10%. The intake port posts can be given a sharp knife edge in their centers on the trans passage side (I call it funneling). Polish and round any edges into the transfer passage for good flow. Get some boysen double reed valves. Get some slightly bigger carberators. Extend your exuast port covers farther from the exhaust ports for more free flow without added noise, with a spacer. You will just need to take a gasket for a pattern to a local machine shop and have them cut you a spacer as thick as you want. Its an old trick of mine.

Remember, that if you ever want to raise ports height, never take off material on the bottom edge. Only take off from the top edge toward the head. Sometimes you can cut out a port post or two as long as the piston rings don't pop out. Another good idea is to get an old worn out racing powerhead that someone raced as modified, pretty cheap. You can measure it out all through and use its dimensions as a learning guide to do to a motor you want to build. Other than that, there is so much one can do, you could write a book 2 inches thick about it! Have a good one!


Thanks

[champ20B]

Thanks

Your welcome! But what A/B speedliner said about having a 1/8 radius rounded corner in a square exaust port is absolutely right on. That was something I forgot to mention, but is important to know and would be a must.

[lilwhirlwind]

Your welcome! But what A/B speedliner said about having a 1/8 radius rounded corner in a square exaust port is absolutely right on. That was something I forgot to mention, but is important to know and would be a must.


I am hungry for knowledge, I read everything I can.

Thanks for all of the info. I really appreciate it

[Powerabout]

I am hungry for knowledge, I read everything I can.

Thanks for all of the info. I really appreciate it
Confucius says;
he with the the biggest pile of scrap aluminum knows the most.

[LittleCharger]

Confucius says;
he with the the biggest pile of scrap aluminum knows the most.

Ain't that the truth! Lol

[Lil' Blue Rude]

Gordon Jennings two stroke tuning handbook is a pretty good place to start for info on porting. You'll have to keep in mind that a lot of what he is talking about is high rpm motorcycle engines with gear boxes so the power bands on those motors are peaky vs a outboard motor that needs a broader power band. But it has a lot of good info on 2 stroke porting.

[zul8tr]

Some reading for you:

http://www.vintagesleds.com/library/manuals/misc/Two-stroke%20Tuner's%20Handbook.pdf


http://iheartstella.com/resources/manuals/tuning/Graham-Bell-Two-Stroke-Performance-Tuning.pdf

Scroll the list for mods to Merc
http://www.boatsport.org/

[Aeroliner]

http://www.ebay.com/itm/Mercury-Outboard-Racing-How-to-Modify-Your-Mercury-Outboard-Harry-Brinkman-/291221559578?pt=Motors_Manuals_Literature&hash=item43ce28591a&vxp=mtr

Here is a good manual.

Alan

[Revengable]

I slipped with my tool then had 8 ports to mirror.

Be very afraid.