New/Modified Header Design?

[spl310]

What happened with the expensive one you had made?

[Daryl Smith]

It had some small leaks which could not be fixed without taking it apart which
1) the guy that did it did not want to do
2) I would not trust the guy to do properly anyway.
Sooo........It has been sitting here waiting for me to take a welding class or find someone to fix it properly.....and I think I've found someone, but I'm going to test out the modified aftermarket header first.

This "while I'm here" disease is taking it's toll..................I hope I get to drive the car for a while.........

Mike,
Thanks, it turned out better than I thought it would and With luck will work as good as it looks. and it wasn't that expensive. About $200 - $250 for all the parts and welding, header excluded. Then about another $100 - $150 to get it ceramic coated, I think.

[project_timemachine]

Hi Daryl, any updates on the new modifications to your headers? Here's some photos of the headers I had installed in my roadster for your reference while you're revising the design. It's a 4-1 design though. The rightmost piping is designed to give as much space as possible from the starter motor to keep it from being fried especially during track days. I think it helps a lot. Anyways, I'm looking forward to your updates.

[Daryl Smith]

Well, What the H E double hockey sticks!!

Here I am trying my damndest to develop the exhaust system for better efficiency/power when, really, it all starts, and in the R head finishes, in the exhaust port. I was told by several people that the exhaust port was bad, really bad, but they wouldn’t explain what was so bad about it……Guess I just didn’t push hard enough.

I’ve recently taken a stock head to a local head porter to get it flowed and get the stock flow #’s to compare with a head which has been worked on and I was going to change a few things on (#’s to follow). When I come back to pick up the head a couple weeks later, he tells me that the intake port is really good, and flows more than enough, as is, for the power level that I am looking for…….(Great!).

He then tells me the exhaust ports are bad (I knew that, why?). The exhaust ports are lazy. (Huh? ) They‘re lazy. Too BIG. They don’t get the gasses to a sufficient speed when exhausting the cylinder to keep flowing and pull the intake air in. They allow reversion of exhaust gasses back into the cylinder diluting the intake charge, costing horsepower and torque. ……..(Bugger!)
Can that be fixed?

It may be possible to weld it, How much do you want to spend? On your engine you are only going to get maybe another 15 horsepower. ……..

SO…I started to search again. How big should the exhaust port be? I spent a couple evenings searching the internet and couldn’t find anything. Then on a different search I got my first lead….Wikipedia – on the ‘flowbench’ writeup states “ ….common to see exhaust port sizes roughly 60% of the intake…”

Okay, the stock exhaust port is 1.1 in x 1.25 in = 1.375 square inches.
The stock intake port is about 1.375 in diameter, which is 1.485 square inches
1.485 x 60% = 0.891 square inches….. 35% smaller than the stock exhaust ports.

That would make the exhaust port about 1.1”x .813”, like adding a chunk of metal almost .440” to the floor of the port…..

So, I’m stumped. This is the only info I can find. It compares port sizes only and has nothing to do with the engine displacement or power levels.

A week or so later I am looking over the info from a header modeling program called Pipe Max, and damn if there isn’t a breakdown of “recommended exhaust port area”!! And the #’s are close enough to be identical!! Are 2 sources enough for confirmation?

Now that I know what the problem is with the exhaust, I don’t know if there is a ‘work-around’, and if there is, if the cost would justify the gain.

Looking back now, I would say that the currently available header was built to fit the exhaust ports. I don’t know if going from the 1 ½” port to 1 3/8” pipe (as I did on the header which Garm bought) would help or not. …..(Sorry Garm). It makes sense to me now that the stock exhaust manifold and the available header perform about the same.

At this point I am considering my options. Make the port smaller or run what I got. See if there is a different way to work the header (shorter runners like ProjectTimeMachine)?……….

Has anybody tried making the port smaller??

[eastmedia]

If you were to hog out the intake to 1.708 inches in diameter, the exhaust would then be 60% of the intake. Don't know if there's that much room.

Project time machines one piece header looks good, but wouldn't you be heating the intake mixture in that setup?

[jamesw]

If it's aluminum it can be welded up and then ported. If your weld ever breaks loose at least it will be traveling in the right direction.

James

[Linda]

One thing to do is get the measurements on the work done by some of the gurus and see if it fits the 60% rule ( Rebello etc)
James could measure the work done for him by Premo perhaps


Linda

[Gregs672000]

I'm not sure I even want to post on this topic for a variety of reasons, not the least of which is that I'm no expert... But I do know one, and he is the only guy I trust. His response I'm sure would be 1) there is A LOT of garbage info on the Internet... Because someone has written something and posted it here and there does not make it correct or universally applicable, and often times poor info gets repeated as gospel over and over; 2) airflow is not just about size, bigger or smaller, but about WHERE you do your grinding, and while numbers are helpful here it is as much about understanding how a port works and how air flows under different circumstances; 3) port work is part of an overall system, and if you don't address ALL parts of that system (which I know you have been Daryl) you won't get as good a result as you hope and in fact can go backwards. When doing development on a head and system he has not done before, Steve asks that ALL components be in hand so that they can be evaluated as a system, along with cams, springs rates, valve size and shape, compression ratio, desired power profile (i where the engine makes power and over what range)

[fj20spl311]

I am no expert, but I do remember that anti reversion cones helped sometimes on cars that the "trick" set-up was to weld up the exhaust to a "D" port.......but that was years ago.

Maybe a plate welded in the exhaust flange that insets into the exhaust port at the bottom to convert it to a "D" port might help....LOL.....

It might not be a big deal to weld the bottom of the port........

Remember I am no expert........

[Daryl Smith]

If you were to hog out the intake to 1.708 inches in diameter, the exhaust would then be 60% of the intake.
True, but it would kill intake velocity, and power in the process.

Project time machines one piece header looks good, but wouldn't you be heating the intake mixture in that setup?
I meant the header portion. I don't know what to conclude about the one piece intake/exhaust setup.......

not the least of which is that I'm no expert...
Me neither, but I'm learning, and in the process trying to answer a few questions for others on here.........
I wonder about how much of what I've written previously is garbage because I didn't have all the info..... Still not going to shut me up or keep me from asking questions...
I do welcome any corrections to what I might write, or have written....I want the correct info in these threads.......

1) there is A LOT of garbage info on the Internet...
Yes, I've come across a lot of crap in seemingly respectable sites. Which is why I always try to verify info in as many places as possible. Having the port size info from ONLY 2 sources is unusual for me, but it's all I can find, and coincides with what the head porter was saying, so... I guess that's three sources!? I have several engine building books also and NONE mention anything about exhaust port size.......

2) airflow is not just about size, bigger or smaller, but about WHERE you do your grinding, and while numbers are helpful here it is as much about understanding how a port works and how air flows under different circumstances;
EXACTLY!! However, and remember I'm no expert, a combination of CFM and Velocity numbers should give you a pretty good picture.

3) port work is part of an overall system, and if you don't address ALL parts of that system (which I know you have been Daryl) you won't get as good a result as you hope and in fact can go backwards.
In the case of the R head, it seems, there is very little for a head porter to do. A little bit of grinding the ridges in the intake port, around the valve seat (a reasonably easy job for the competent DIYer, apparently), and a decent valve job, at the most I am told, for a good street engine, and it won't gain you much. UNLESS you want to drop some BIG $$$ for exhaust port and combustion chamber modifications....

When doing development on a head and system he has not done before, Steve asks that ALL components be in hand so that they can be evaluated as a system, along with cams, springs rates, valve size and shape, compression ratio, desired power profile (i where the engine makes power and over what range)
As it should be, however, development information on building a stronger R engine is a little tough to find, as are the parts, there are no "build guides" for 120 - 130 - 140+ hp R based engines. The Stroker Poll thread is a good start, but basically just lists what people have done without a lot of results of the build (tho there are some dyno #'s). What should be done is decide what power level you want, then start asking the professionals what you need to build that into your engine. They should be able to tell you whether it's possible (scale back your expectations?), and or help you put the parts together to do it. Lou Mondello in Oz seems to be the only one doing any kind of development work on the R engine tho.....

[Daryl Smith]

Linda,
I would be happily surprised if exhaust port size has been addressed at all by any of the builders. If it has, nobody has said anything......

[Garm]

I don’t know if going from the 1 ½” port to 1 3/8” pipe (as I did on the header which Garm bought) would help or not. …..(Sorry Garm).

I was happy to try that header, and the car sounded GREAT. It is possible this further discussion helps explain my 70 whp on the dyno though!

[project_timemachine]

Ron, so far the one piece stainless steel header/intake set-up is doing well for everyday driving and occasional vintage racing. Temperature hovers at around 190F (middle of the temp gauge) during racing with prolonged revs at 3000 to 6000rpm. I tried putting high temp wraps on the headers and the tune got nasty...engine was really rough so I decided to take it out. The engine has been running smooth ever since with a nice tan color on the plugs after driving around town.

[Daryl Smith]

Garm,
The header may help, problem is we don't know without a before - after test. The 1 1/2 - 1 3/8 transition was well done, I have to say that for them. 70 whp @ what rpm? Considering ~ 20% for drivetrain losses that would be about 84 crank horses which is what many people think would be closer to the actual stock hp rating at 6000 rpm.........

Steve,
I'm not a fan of the one piece design, but if it ain't broke don't fix it! Althugh I would be tempted to try a ceramic coating on the outside of the whole thing, as well as the inside of the intake. ...... But , if it's working well as is.........
It has been suggested that a shorter header like yours might be the way to go. I'm currently trying to find some info on the best way to deal with "lazy ports"....

[Daryl Smith]

Just pulled the 4-2-1 header I built on the previous page off the engine.
The three areas which were not ceramic coated radiated so much heat that it has burnt the paint off the engine in those places, and also I believe, fried the oil pan gasket (the header rested right against the engine). No paint peeling in those ares at all, for years, with the ceramic coated headers....

Since the header is oversized anyway, I dented it in a bit where it would meet the oilpan for about 1/4" clearance (hardly noticeable really), and it is off to get ceramic coated.......