oldeskewltoy does some discovery on an SR20DE - SR20 Forum
 2Likes
  • 1 Post By oldeskewltoy
  • 1 Post By oldeskewltoy
 
Thread Tools
post #1 of 16 (permalink) Old 10-03-2014, 04:12 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
oldeskewltoy does some discovery on an SR20DE

As I alluded too in my introduction....

Quote:
Originally Posted by oldeskewltoy View Post

More recently (past 5 years) I've been learning the "black art" of cylinder head porting

One of my earliest clients (owner of OST-005) has moved on from his 4AGE powered MG, he is now racing a P10 Primera/G20, and he asked me to look @ an SR20DE head.......

More to come.......
I've been porting, massaging cylinder head castings for about 5 years. Often times I record these porting jobs.

This is my first chance @ an SR20DE head... a highport model This is the condition that I got it in....





NOT a good looking head... and as can easily be seen, this head has spent a fair amount of time wet, and not the good kind either... look at the rust all around #3 intake bowls/seats....



but a "bath" goes a looong way sometimes...



and sometimes the bath reveals more extensive issues... as in this head, look at the #1 and #5 exhaust cam journals. The "rust" you see is embedded into the aluminum, to clean this area up and make it proper again would be a pricey endeavor... so, instead of fixing, lets do a bit of discovery instead...


Initial impressions.... the casting itself is a bit rough, more deburring could be done to the castings, especially the top of the head which holds the cams and valvetrain. The chambers on the other hand appear to be well placed, with very little evidence of edges that would promote detonation (ping). The intake paths are bow legged shaped to allow for the HLA, the intake seat/bowl could use blending to better take advantage of the angled port, and mild short radius. The exhaust bowl/seat is far worse, significantly too small, the port provides little or no room for an adequate short radius, while the splitter, port roof, and narrowing walls are far too intrusive, and appear to truly restrict airflow.


More to come.......
aztecred92 likes this.
oldeskewltoy is offline  
Sponsored Links
Advertisement
 
post #2 of 16 (permalink) Old 10-05-2014, 05:01 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Too begin with... this head is one for discovery.... and as such I'll be performing different porting on 2 of the 4 cylinders, leaving 1 cylinder to use as a control. What do I mean when I say "control", I'll be using my flowbench to monitor any gains, or losses do to my porting work. I'll be leaving #2 cylinder and its ports completely untouched. I'm leaving #4 untouched for the time being, but may use it to "assemble" the knowledge I learn from porting #1 - within the lines, and #3 - outside the lines.

My flowbench... checking a Toyota 7MGTE head


Quote:
Originally Posted by oldeskewltoy


Initial impressions....

1) the casting itself is a bit rough, more deburring could be done to the castings, especially the top of the head which holds the cams and valvetrain.
2) The chambers on the other hand appear to be well placed, with very little evidence of edges that would promote detonation (ping).
3) The intake paths are bow legged shaped to allow for the HLA, the intake seat/bowl could use blending to better take advantage of the angled port, and mild short radius.
4) The exhaust bowl/seat is far worse, significantly too small, the port provides little or no room for an adequate short radius, while the splitter, port roof, and narrowing walls are far too intrusive, and appear to truly restrict airflow.
1 - as I mentioned, the casting is a bit rough leaving many areas containing sharp edges. From my experience, often times poor casting areas lead to sludge build up because the oil and debris sits in these areas "cooking" into place as the miles go by. Making these areas less prone to holding the oil and debris, helps keep the engine cleaner, and easier to shed oil back into the oil pan. A second, and purely selfish purpose is with me constantly changing its position on my porting bench, the roughness really hurts my hands.....

2 - below is a view of the Chambers #3 and #4 , I've blacked out the valve openings to avoid distraction....

As you can note, other then doing a tiny bit of blending around the seats, putting a ~.020" radius on both "squish" pads, and polishing the chambers I've had to do very little.




As a comparison here is a small gif showing a 4AGE combustion chamber as it goes from stock, to finished






More to come.....
oldeskewltoy is offline  
post #3 of 16 (permalink) Old 10-05-2014, 08:16 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Often times during my work, I will ask my readers questions... kind of to see if their awake


So... for the SR20 crowd...




what on earth is this????? And what does it have to do with porting an SR20???
oldeskewltoy is offline  
 
post #4 of 16 (permalink) Old 10-06-2014, 01:31 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Quote:
Originally Posted by oldeskewltoy View Post
Often times during my work, I will ask my readers questions... kind of to see if their awake


So... for the SR20 crowd...




what on earth is this????? And what does it have to do with porting an SR20???
No guesses... really? Not even a shot in the dark? This is audience participation time.....


How about a few hints.......

The lexan sheet you see is just a template...., the final version will be in steel



Does that make it easier??? How about if I add that the "14 1/2" you see written on the steel plate refers to degrees, does that help at all???
oldeskewltoy is offline  
post #5 of 16 (permalink) Old 10-06-2014, 06:00 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Quote:
Originally Posted by from another forum
I really have no clue so here's a shot in the dark: template for cutting valve seats??
First... thanks for getting involved... it does make these more fun...

it isn't a template for cutting valve seats... It does have to do with the valves

when finished, it will be a tool, absolutely required for learning if I'm just hogging this out, or actually improving the air flow.

Let me drop a few more hints....



halve 29....









Knowing it will be a tool.... Did that make it easier... or harder???


More to come......
oldeskewltoy is offline  
post #6 of 16 (permalink) Old 10-06-2014, 09:31 PM
Original Owner
 
aztecred92's Avatar
 
Join Date: Jun 2001
Location: San Antonio, TX
Posts: 1,045
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Garage
Feedback Score: 9 reviews
A template for your flow bench?
aztecred92 is offline  
post #7 of 16 (permalink) Old 10-06-2014, 11:18 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Quote:
Originally Posted by aztecred92 View Post
A template for your flow bench?
Quote:
Originally Posted by from another forum
OK. Looks like it's used to hold the valves open? So you can perform the flow test right?
bingo... it is the tool I'll be using to set the valve openings....

Here is a sample of it in use... the use is to show the viewers that I can set this tool at any height... note the tool on the bottom of the photo... and note the valves @ the top of the photo





Now being able to set the valves is important... just as important is knowing exactly how much... so I plan for the plate to accept a dial guage to read the amount of lift

[img]http://ost.ebeans.ch/albums/userpics/10005/SR20_valve_setting_plate_steel_nearly_finished_*** t_needs_wedges_for_gauge1.jpg[/img]

(mod, or admin, something keeps messing up the above photo posting... the letters with asterisks are "j u s")


and the finished tool......



The dial gauge will "read" from the edge of the spring retainer



more to come.......
oldeskewltoy is offline  
post #8 of 16 (permalink) Old 10-06-2014, 11:35 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
the view as mounted to the head...




Now that the valve setting tool is finished, its time to re-configure my flowbench to measure the SR20 head. Earlier this past summer I had a new bore adapter "machined" to 86mm



so that I can then place an SR20 headgasket on the bench to determine where the alignment dowels will be drilled into the flowbench table to properly align the head over the 86mm bore adapter.



Here is the "view" the flowbench will see...






More to come.......
oldeskewltoy is offline  
post #9 of 16 (permalink) Old 10-07-2014, 04:34 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Now... where was I before I got us side tracked on tool development....



Oh yes...

Quote:
Originally Posted by oldeskewltoy
1 - as I mentioned, the casting is a bit rough leaving many areas containing sharp edges. From my experience, often times poor casting areas lead to sludge build up because the oil and debris sits in these areas "cooking" into place as the miles go by. Making these areas less prone to holding the oil and debris, helps keep the engine cleaner, and easier to shed oil back into the oil pan. A second, and purely selfish purpose is with me constantly changing its position on my porting bench, the roughness really hurts my hands..... :cry:

2 - below is a view of the Chambers #3 and #4 , I've blacked out the valve openings to avoid distraction....

As you can note, other then doing a tiny bit of blending around the seats, putting a ~.020" radius on both "squish" pads, and polishing the chambers I've had to do very little.
A small addition , as for the roughness/sharp edges, you can see preliminary deburring in the photo above that shows the tool mounted to the head. You can see where I ran the carbide cutter along some of the edges.

As far as chamber shapes - and, in fact, all the work I'm performing is "on a budget". So.... I will not be welding and re-shaping combustion chambers, that is prohibitively expensive (Thousands$$$) because for the most part less than .5% of you would ever consider paying for that kind of modification. Typically I delivery a finished product for well under $1000.


So we have discussed the casting and its requirements, and the combustion chambers. Now we come on the difficult part trying to increase the cylinders breathing capability. Note I said increase, because I'm NOT looking to discard(swap) low speed performance, in favor of high speed performance. The best goal is to provide a W I D E powerband.



Borrowing Martins dyno, I've made a few alterations



The dotted red lines I see as air flow problems(or how they will respond once corrected), the green lines is the desire for MartinS engine once we put this heads development into practice, along with his camshaft choice and appropriate compression bump.




A few different views of the intake port passages....






Now compare those views with a few others.....



Same similarities... while there are other differences....

Two of the views above seems to show the SR20 intake ports to have a similar shape to a Formula One design :bigthumbup: but hold on... the F1 design doesn't have an HLA to avoid :angry:, the top view showing the port layout is our issue here. The port opening is marginally 50mm (do to costs, the port opening varies at the seam from 49 to 50),


the intake valves are less than 9mm apart from each other,


and the HLA makes the port splitter somewhere close to 23-24mm at its widest point.... and so you get a bow legged intake port.....


More can be done here ... mostly because this is a production automobile head, and as such typically there is enough casting material available to better shape, not only the intake port... but often the entire head.




More to come.......
aztecred92 likes this.
oldeskewltoy is offline  
post #10 of 16 (permalink) Old 10-07-2014, 09:49 PM
SE-R Newbie
 
Join Date: Sep 2014
Location: Orlando
Posts: 13
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Nice work. Can't wait to see more
98backbell is offline  
post #11 of 16 (permalink) Old 10-08-2014, 12:33 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Quote:
Originally Posted by from another forum
Dan - I disagree on the the part between 3k - 4.5k. In my opinion it is an ECU thing.


I did a few pulls and got the same result all the time! As I was in a hurry, I could not log ignition and AFR together.
The AFR values for them self explain my thesis quite well...


btw. the engine on this one is BONE stock! no exhaust, intake, etc!

Actually, it also happens @ 5500, and the torque falls like a stone! I can therefore assume that the standard ECU isn't going to be used? The head may also be part of the problem as air speed changes as the rpms climb.


I ALWAYS begin @ the seats and bowls.... ALWAYS. Other porters may, or may not begin this way, I've found that beginning at the seats and bowls will determine the rest of the porting on that cylinder. To begin @ the seats and bowls... one must begin at the valve.... The SR20DE has a 34.25mm intake valve




Our valve seat ID measures...



doing the math... the seat bore is almost 86% of the valves diameter. This percentage is very good for a stock set up, typically I try to get the bowl to 85%-90% of the valves diameter to equal the seats bore. So since the seat is in the range, only minimal work will be performed on the seat.

As I begin to work cyl #1 (staying within the lines). The very first things I look at is the seat and bowl alignment. This SR20 is far better than a few of the 4AG heads I've worked, SOOOO the focus on the SR20 intake seat/bowl is the short radius....

Quote:
Originally Posted by from another forum
A few quotes from his(oldeskewltoy's) side:
Quote:
Intake:
  • Short Radius - the short radius is the only place to easily increase the overall valves draw on the port. A un corrected short radius that interferes can have little or no air flow at lower lift points. This will hurt overall filling of the cylinder, and lower power

#1 cylinder - Note the protrusion on the bowl on the right(#1 valve), it doesn't have to be a lot, that protrusion you see makes the low lift airflow stagnant because at the valve the air/fuel charge has to navigate a sharp angle. The #2 seat/bowl shows the initial reshaping of the short radius.







A bit more work in this view, the #2 bowl is showing mild re-shaping to allow more volume. I'm careful to port areas that will "straighten" the angles, or in this case do my best to minimize the bow legged effect. With that in mind note I worked the outside of #2 bowl(far left of bowl on left). This minimizes the angle, that the air/fuel charge has to navigate. A similar, yet not quite as significant amount of material was removed from the inside(right) of the bowl on the left.

A slightly different perspective... showing the overall shape of the bowl and seat transition - the key areas to note in this view are the 3 and 9 positions inside each bowl




Lets get back to our control... #2 intake bowls, and seats



So what I've done is increased the area around the bowl for the opening valve to draw upon.



More to come........

Last edited by oldeskewltoy; 10-08-2014 at 12:41 PM.
oldeskewltoy is offline  
post #12 of 16 (permalink) Old 10-09-2014, 08:30 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
needed to make another tool.......




A stock intake port is approximately 27mm (+ or - .25mm) and 100mm long @ that diameter




A stock intake splitter is approximately 24.5(+ or - .25mm) wide....






Today's question - So... how much "extra" material is around the HLA?





More to come.........

Last edited by oldeskewltoy; 10-09-2014 at 08:44 PM.
oldeskewltoy is offline  
post #13 of 16 (permalink) Old 10-12-2014, 06:11 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
The HLA is 17 mm in diameter, making the HLA hole 17.0something in diameter, but surely under 17.1mm... so subtracting 17.1 from 24.5, that leaves us about 7.3mm of unnecessary splitter width. What we don't know is how evenly set the HLA bore is in relation to the two bow-legged intake ports.

Exact HLA placement inside the splitter is as yet not fully determined by me, or a photo or some other evidence I've been able to find. The cut away shown a number of posts above doesn't include the HLA The view below kind of shows it, and yet it isn't specific. What you can tell in the view below is the HLA does interfere on the intake side, while it appears to not be an issue on the exhaust side.




So, by mathematics there is SOME room along the splitter for removing some material to help "straighten" the port, and remove some of the bow-leg the ports follow. This will help, but my little home made calipers found another problem....

no guessing on this one.... we know the valve is 34mm, the bowl/seat @ 29mm, and now....

Quote:
Originally Posted by ost
A stock intake port is approximately 27mm (+ or - .25mm) and 100mm long @ that diameter
Think about that for a moment... the port = the throat for nearly 4" of length. The "throat" in an intake port is the narrowest point inside the port, it is designed to help speed up airflow a short distance from the valve. This narrowing also limits reversion(the air/fuel charge "bouncing" off the closing valve and moving back up the manifold). Often times, especially in performance engines, the throat is preceded by a gradually tapering section that goes out to the flange, and it either connects to an intake plenum, or an ITB. The tapering section is similar in principle to a velocity stack. The SR20, having a "throat" 4" long only chokes down the air volume by having a set diameter through this part instead of a tapered diameter. So if, along with straightening out the air passage we can add a taper to each port, in theory, we should be able to see noticeable gains in volume, with minimal loss in velocity.


So lets move on to what all this means.... Intake port - 4 panel as it transitions from stock to "within the lines" = inside "stock" openings - note I have not increased the opening size, I've worked within the original casting, and at no time have worked beyond that. The outermost green dotted crescent highlights that the area just inside the ports edge got the majority of the work, and not the edge itself




Look carefully... in the 2nd view down I diagram what I'm doing. Note the orange dotted line, it shows where I worked the splitter at its widest point. It shows I changed the shape, that I removed a bit more material from the roof and floor of the splitter while taken only a minimal amount from the splitter wall. Remember our measurement of 24,4mm, that is at the narrowest point at the center of the splitter, but do to the extreme arc of the port, the splitter at the roof and floor are closer to 40mm, and with care offer up a LOT of material that can be removed if done carefully... as shown by the time you get to the bottom view.



The other green dotted line/arc show additional areas of material removal. They also begin to highlight the narrowing, and shaping of the splitters leading edge.


So... why did I leave a large section the port walls untouched?


more to come......



PS - over the next couple of weeks I'll be trying to keep up here, but I have a family issue I need to pay the most attention too... so if I'm not on for a day... 2 or gosh darn even 3... I'm just handling family issues.... I'll be back shortly

Last edited by oldeskewltoy; 10-12-2014 at 06:33 PM.
oldeskewltoy is offline  
post #14 of 16 (permalink) Old 10-13-2014, 04:57 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Quote:
Originally Posted by from another forum"
Here is a thread from a few years ago with numbers obtained from a flowbench. Maybe they can be used to compare? http://www.sr20-forum.com/all-motor/...flow-data.html Posts 1 and 3.
very interesting information... although the intake side tends to vary... the exhaust side.... is, "pretty crappy"
Quote:
Originally Posted by from another forum
The exhaust flowed the same as all the other DET's out there... pretty crappy.

Exhaust only flows 170 @ .500"
I have some thoughts on the exhaust side as well........... .... but for now I'll stick to the intake side.....



A unique view... 3 slightly different angles on my port work. Cylinder #2 , my control, on the left, cylinder #1 (within the lines) on the right...



... these views help to show how I've worked the top and bottom of the splitter, it also shows how I've shaped the bowls to blend into the seats. The top view shows the splitter roof, the center view shows the center work, and the bottom has more of a focus on the splitter floor. Also the short radius blending is plainly visible.


This photo also shows I left a large portion of the port walls untouched... so I ask again... Why did I leave sections of the port wall untouched?







more to come......



PS -
Quote:
Originally Posted by from another forum
The intake port on the VE looks superb!
So it seams, that we just need to develop the right cam-package for road racing - and it would be a killer combo!

@Dan: smallport 4age .
I was thinking the same thing....

oldeskewltoy is offline  
post #15 of 16 (permalink) Old 10-14-2014, 04:35 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
Quote:
Originally Posted by oldeskewltoy
So... why did I leave a large section of the port walls untouched?
Quote:
Originally Posted by from another forum
...to discourage fuel puddling on the runner walls?
it isn't likely that the fuel would puddle on the port walls, **IF* it were to puddle, it would likely be on the floor... but... because of this "aero" port, if the fuel is going to puddle, it'll puddle on the back side of the valve, or possibly just before the valve on the port floor


Quote:
Originally Posted by from another forum
To try not to increase the area too much and thereby change the air speed in the port?
this is correct... although "change", should be "lower"... For to be truthful, if we can port this head AND increase the velocity (air speed), then I'm better than I think I am...

I'm not saying I can't do that.... but finding that unicorn/unobtainium spot that both increases volume and increases velocity is VERY tough to find....


speaking about increasing both volume... and velocity.....




I now have, or will have once it has been cleaned(on loan), a low port SR20 head to get some measurements and photos from.... Even before cleaning... I can EASILY tell why/how this head makes more power... 2 less than obvious changes. The obvious change is the port is low, and it is much shorter... but although both of those help... the 2 less than obvious changes are inside the port/bowl areas themselves.... 1) the stock port ID is a lot closer to 28mm (remember the highport is only 27mm), and, 2) the short radius is much better. Sometime next week I'll get this head back, and take some better photos...

until then.... a dirty head... but you should be able to see the 2 less obvious changes....





more to come.......

Last edited by oldeskewltoy; 10-14-2014 at 04:36 PM.
oldeskewltoy is offline  
post #16 of 16 (permalink) Old 10-17-2014, 01:58 PM Thread Starter
SE-R Newbie
 
Join Date: Sep 2014
Location: Portland, Oregon
Posts: 15
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
(Thread Starter)
MODS: over the past few days I keep getting warnings from my virus protection....

to audience: because of the frequent alarms, and the infrequent responses on SR20forum, if youd like to continue to follow this thread - http://www.sr20-forum.com/all-motor/...tainement.html
oldeskewltoy is offline  
Sponsored Links
Advertisement
 
Reply

  SR20 Forum > Main Forums > All Motor


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome