PORTING where-how-why

[440dart]

the engine in my spirit #2 is bad did a leakdown test and it was horrible on 3,4 cylinders with scoring in #3 cylinder, safe to say i cant wait to see what it feels like with a GOOD engine if this is how it runs with 2 good cylinders.


so is what iam doing is going to ring and bearing my spirit #1 engine because the cylinders are in good shape and since my other engine will need to be bored to clean it up thats what i will put my 20over pistons in when iam ready to build that engine. reason why i tore out the spirit #1 because i blew the head gasket and it the rings were shot "lots of blow by" sorry for the long post


Anyway i will continue to drive spirit #2 around till i get this engine done my questions are for porting

1 what can i do to enhance the flow of my head i have little porting exsperience i can do clean up well the easy stuff
2 what can i port on the manifolds
3 please post pics of your porting
4 please exsplain where to take material off so i dont screw it up lol

I saw some post about taking the ears off the center of the exhaust manifold but some say not just wondering if this issue ever got resolved????


my setup

precision sc61s
+40s
FMIC
stg3 cal
3in exhaust
soon to have meth

[mpgmike]

I don't have massive pics on file, but here are a couple I did for my TIII.


Intake ports were "funneled" a little better, and a little better transition from the intake manifold to the ports.




I did a bit of radiusing on the combustion chamber squish pads, and cleaned up the bowls some.



The exhaust port looks wierd, because each port is matched to the manifold; there are 4 differently shaped exhaust ports. I removed the ridge in the middle myself.

Unfortunately, I don't have any more pics on my computer. I still have the parts (not installed yet) so I could take more if there is interest.

Mike

[Millerman340]

Alright everyone with pic's post them up!

[440dart]

how do you do the funneling looks time consuming lol

on the radiuseing of the combustion chamber what are you grinding on and whats the thearoy on this and what are you trying to acomplish? just trying to get a better understanding

[puppet]

So ... who has done porting with flow numbers ... at least showing some improvement over the stock port geometry?

It's nice to see port work pic's ... I love looking at them as much as the next guy but that doesn't really tell much in the end. There's a lot more to porting a head than just looking at the various sections and trying to think what would be a restriction without really knowing for sure if it is. That and the thinking that we can make the air flow where we want it ... while doing so usually kills flow.

I remember a few years ago the talk about the T3 heads and the dividers needing some sort of advanced attention ... like being sharpened or laid back. Have noticed lately that other heads with similar port configuration .. and similar attention paid to the dividers .. have actually flowed worse as a result. It would seem that messing around with the dividers can hurt a guy pretty quick.

Not singling out any body in particular ... just trying to see if we can quantify the port work with some factual comparisons.

[Directconnection]

There's a lot more to porting a head than just looking at the various sections and trying to think what would be a restriction without really knowing for sure if it is. That and the thinking that we can make the air flow where we want it ... while doing so usually kills flow.

I totally agree.... and have experienced this many times myself on the flowbench.

I have yet to do any T-III porting myself, but will be tackling a quick bowl port job on my T-III in the coming month, or two (along with a little flowbench verification)

I am certain that Mike has some before and after #s, too.

[puppet]

Frankly, a guy could use something a simple as a shop vac and a manometer to gauge progress on a port job ... lacking access to a flow bench. While such a rig wouldn't do much for comparing numbers it would tell a guy if he's doing the right things.

I'm gathering parts to make a flow bench myself ... just for home use. Plans are all over the net and once a guy gets the orifices calibrated against a bench like a SF he can actually compare the numbers he gets with others with some degree of accuracy.

Biggest hurtle I see with the T3 heads is having one that you can "mess around with and test" before you carve the good one. 8v's are nice like this. You can saw one up in four pieces and have at it without too much trouble ($$$).

[440dart]

iam just looking for some bad spots something that i can do my self like casting flaws things of that nature since the head is off and will be off til i rering the engine. i will leave the hard stuff for the pros

i did the exhaust mani today not sure if i hurt flow or increased, i tried to take most of the sharp bends out of the runner and try to make it as straight as shot possible to the collector, i actually ground through on 2 different spots going to have my uncle braze it then re do it so it will flow good. where the mani bolts to the head i gasket matched but i didnt take the little humps completely out i just lower it about as much of the material i took out to match the gasket, or should i just grind it smooth.

[mpgmike]

how do you do the funneling looks time consuming lol

You don't want a "straight" port. The flow gets lazy the farther it travels down a consistent conduit. You want large progressively getting smaller, up to the "choke point". In a cylinder head, this is typically where the port transitions from the port into the bowl. Measuring the TIII runners in the head with a bore gauge indicates that there is a funnel ram effect from the factory. Considering the cross sectional surface area (CSSA) of the ports and the "curtain area" with the valves open, opening up the ports is probably going to cost power without also installing larger valves. Keep the velocities consistent.

on the radiuseing of the combustion chamber what are you grinding on and whats the thearoy on this and what are you trying to acomplish? just trying to get a better understanding

Take a square milk carton, place a mirror so you can see behind it as you face it, light a match and place it behind the carton about 1" from the far wall. Now blow and watch the flame. Take a soda bottle, or something about the same diameter as the milk carton is square and repeat the test. With the sharp edge milk carton, you have to blow your lungs out to quench the flame, but with the round soda bottle, a little puff douses the match. Rounding the sharp edges in the combustion chamber allows for the air/fuel charge to travel around the cylinder better, and when the spark plug fires, allows the pressure and flame front to reach more of the AF mix quicker. Plus, it invariably puts more of the pressure over more of the surface of the piston. Force = pressure X surface area. Increase the available surface area on the piston and make more power.

I wanted to try to keep it brief, but thorough.

Mike

[mpgmike]

I totally agree.... and have experienced this many times myself on the flowbench.

I have yet to do any T-III porting myself, but will be tackling a quick bowl port job on my T-III in the coming month, or two (along with a little flowbench verification)

I am certain that Mike has some before and after #s, too.

I could take it beyond the flow bench. I recently ported a Hyundai Sonata head for a car competing in the $10M 100mpg X-Prize race. On the exhaust I increased flow by 12 cfm (@ valve lift @28" WC) while I actually reduced flow by 2.8 cfm on the intake. The car makes approximately 40% more power WHERE IT IS INTENDED TO BE DRIVEN.


Hyundai exhaust port


Intake port

The flow bench isn't always the last word. Sometimes peak power numbers aren't necessarily the last word either. Sometimes improving things where needed has an adverse affect on something else.......that doesn't matter to the driver.

Mike

[mpgmike]

I went and dug out the manifolds and shot some pics.


Opened up the throttle body opening to 60 mm to comfortably house a 58 mm TB.




Opened up the intake to just under gasket size and smoothed over the injector bump somewhat.


I squared up the turbo inlet and radiused from there back into the ports.


Shaped and generally smoothed over for better flow.

Mike

[440dart]

mike did i screw up my manifold, i did alot more grinding on it then you did i just made it so some of the necked down areas are more open and not as sharp of turns. was hopeing for an easier passage to the collector, where i did most of my grinding was on one of the outer ports where its its own single runner then it meets up with the other 3cyls at the collector well where it meets at the collector there a large bump it sorta squeezes down then it opens up and meets with the other 3cyl makes a turn then gos out the collecter well i tried to take as much of that bump as a could i took as much out is my tool would let me there is actually alot of meet there so i could of ground out alot more

[Directconnection]

If you broke through it, then yes.... it's trashed.

Get another and have someone else do it for you, especially the cylinder head.

[440dart]

If you broke through it, then yes.... it's trashed.

Get another and have someone else do it for you, especially the cylinder head.

just going to have it brazed should be alright, well i knew i am not the best for porting, thats why i did the mani cuz its easy to replace a cylinder head is not


mike how do you do the funneling iam just curious and how long does it take you to do one port

[440dart]

mike i still have questions about my mani i did because i took alot out "besides where i went through" did i ruin it by ruining the velocity

[t3rse]

Replace it. You will blow the hole open sooner or later.

[Directconnection]

This is a TURBO exhaust manifold, not just a typical turbo manifold.... brazing I wouldn't think would be suffice.

Don't worry about funneling, tapering, re-shaping, or grooving anything. I am not ridiculing you, at all... ok? But being that you are new to the porting thing, you will be better off leaving it alone, or better yet.... sending it to someone that does have experience.

[puppet]

It's probably wrong to completely discourage you from doing anything with your top end. Doing a little blending and smoothing would go a long way. I'd stay away from anything radical just because of the reasons Steve pointed out.

On the other hand, if a guy could find some "dime a dozen" four valve head(s) similar to the prized Lotus, some experimentation with flow improvement could take place. Then apply that knowledge to the Lotus.

[440dart]

lol iam not going to touch my head other then smoothing some minor things up, iam just curious about the funneling just looks really really rough

[440dart]

2.4 neon heads are simular arnt they? is there a good site that exsplains porting