Milwaukee Midget

[Stan Back]

The problem with making A-B runs at El Mirage is the extreme differences you're liable to find in course conditions, wind direction and velocity along with temperature variations from month to month.

[Milwaukee Midget]

The problem with making A-B runs at El Mirage is the extreme differences you're liable to find in course conditions, wind direction and velocity along with temperature variations from month to month.

I agree.

Same goes for just about any track - be it a 1/3 mile clay oval, a drag strip or a road course.

On the other hand, I completely understand the sheer joy of driving one's creation.  And there are folks who have the experience to make changes that will make a car respond better trackside. 

But I know I'm not there yet.

I'm guessing I spent about as much money on the dyno as I did for a room and gas out to Bonneville.  I could have made 2 trips (well, not in 2013 - but you get my point) and maybe have gotten it tweaked to run a little faster.  But I'm at the point where I intend to lead with my trump cards - and be as close to ready as humanly possible before it even goes on the trailer. 

You can learn a lot from the dyno - and it's just not as much fun as thrashing a car!  But you can also become pretty frustrated with a car that simply won't perform, and the flats are not the place I want to be making decisions that require a re-think.

So yeah, it's not likely you'll ever see a "bathtub rebuild at the Super 8" story from me - I'm a romantic, but I'm not THAT romantic.

[fordboy628]

MM, I know you and FB are familiar with these guys as you mention flowing one of their heads somewhere in here. And that FB designed your cam ( I think) but they are talking well over 100hp/L in their engines with the bigger cams (bigger cam in small engine not always correct) but anyway just wondering if you have played with any other profiles. Dynothon showed 95hp? Have you ever run your engine through Pipemax to look at the header specs?

http://www.swiftune.com/Page/2/About-Us.aspx

Hi Jacksoni,

I have recently had the opportunity to inspect and flow test several BMC "A" series cylinder heads during the last few months.   Some have been professionally prepped by name companies like "Swiftune".    Some are professionally done by local machine/"speed shops" and others have been done by owner, ie, SCCA/Midwest Council racers.   I'm going to post up results periodically as I go along with the testing & inspection.

But, I can state some general observations and some non-specific results at this point in time, ie, tonight:

A/   If you have paid the going rate to a "specialist" such as Swiftune/MED, you have most likely gotten your money's worth.    Older heads from say Longman, might have
      been state of the art at one time, but are probably a "bit" less developed today.    Heads done locally may be worthwhile, BUT, you would have to flow-test to be certain.
      I would stay away from a head prepped by an "owner", unless you can have someone experienced flow-test it first, and compare it to a know database of "good" heads.
2/   You CAN NOT tell much of anything visually.    Except, whether the person had a steady hand and/or cared about the quality of their work.   It goes without saying that
      any "prepped and ready to install" head assembly, should be scrupulously clean.    A head carelessly prepped, cleaned and assembled is just that . . . . . .
d/   Think carefully before attempting to "modify/improve" a specialist's cylinder head.    My recent and oft quoted example is that of a very good specialist head ($2500
      USD) that was "improved" by a Midwestern specialist shop familiar with racing BMC's for the pittance of $2000 USD.   This "improvement" removed 8%/13% of the head's
      intake flow, and the bhp fell from 140 peak bhp to 132 peak bhp on the shop's dyno.    Unless you have a flowbench and a dyno, you'll be hard pressed to exceed what a
      specialist professional can deliver.
z/   The current best flowing BMC heads I've tested are from: Swiftune and a head I prepped back in 1992 for one of my clients going to the "Runoffs".    I post graphs of the
      results at another time.

On Midget's cam:
I calculated the space available at TDC overlap for net valve lift.    This (and the tappet dia.) dictated the "flank acceleration" that could be accommodated.     I then prevailed on Dema Elgin of Elgin Camshafts (and if you race an "A" series engine you should know Dema) to take my numbers and grind a cam to fit the space available.    Dema produced an item which fits the space available and produced the desired torque curve.    The idea that a cam grinder would "know" what you need is simplistic.     If you have a popular application that "might" be possible.    But if you have anything "out of the ordinary", the cam guy is going to need some help.    FROM YOU.    Or your engine builder.

On "PipeMax"  (Tm):
I did some simulations with PipeMax for this engine.    For the torque peak & bhp peak desired, the program predicted a smaller pipe than what ran best on dyno test.   The length calculations were useable though.    The "Grenade" has responded with more bhp everytime changes were made to enhance flow capability, both on the inlet tract, AND the exhaust.

On 95.1 bhp:
My previous best for a "big bore/short stoke" BMC 1000 was 98 bhp on the PHP dyno back in '92/'93.    That engine used 2 HS2 SU carbs.    (98bhp/liter)
My previous best for a "big bore/short stoke" BMC 1100 was 106 bhp on the PHP dyno, year ??      That engine had a Weber 45DCOE.          (96.3bhp/liter)
My previous best for a "big bore/long stoke" BMC 1309  was 135 bhp on the PHP dyno back in '92.    2 x HS4 "thrubore" SU's.                     (103bhp/liter)

Based on the bmep numbers from these examples, there is more to obtain from these engines.    I left PHP, (the company I founded) before the "real" BMC development program began in earnest.

Since the V/E on BMC's is so low, C/R is the key to "good" bmep & bhp.    That is much easier to achieve on 1309cc and larger engines.    Much more difficult on 999cc's.    I think 103/105 bhp/liter can be achieved, IF, the C/R can be bumped up.   Most pro builders I know are at about 98/100 bhp/liter with engines of 13/13.5 to 1 C/R or less.

I think there is going to be a Dynothon, Part Deux; but that's not my call.
 
Fordboy
    

[fordboy628]

Mark is - as I write - flowing my head with the complete intake - including the carb - and stubs for exhaust.  There are 5 other racing heads he has flowed this last month.  One is a relatively untouched Swiftune head, the other Swiftune was butchered by a nameless shop, one was cut by my guys at C&S in Milwaukee, one is a Longman of unknown origin, and I'm not sure of the other one.  He's also testing my head with anti reversion exhaust valves.  So a raft of information will be coming our way probably by next Monday, and will help us chart engine development for this year.

Midget,

I was gonna post up some of the flow-test results tonight, but after the long day and the errand running and the previous posting, I'm just too d*mn tired.    Suffice it to say that the head is pretty good.     Not as good as the best Swiftune, but in the second tier.     Improvement to the first tier MAY be possible.    Don't know just yet.

Too tired even for a beer . . . . .

Fordboy

[jacksoni]

Too tired even for a beer . . . . .
cry
Fordboy

WOW!

Don't know a lot but what little I have gleaned over the past few years messing with my current engine tells me that 1) CFM is not the be all end all (port velocities, the valve job, and so many other things have an impact on how the engine performs) and 2) a perfectly good head can be really screwed up by someone (local expert) "tinkering with it", hogging it out or many other things and 3) dyno helps a lot but does not say for sure how it is going to go down the track. For instance, a very respected engine builder/head guy whom I have alluded to previously says, in essence, a connecting rod is to attach the piston to the crank and it's length is of no real significance along with the rod/stroke ratio. He has shown on many dyno tests changing only the rod ratio that there is no power advantage high or low ratio. (there may be some minor friction differences due to thrust effects). There are innumerable people who say rod ratio is important including folks who design camshafts, for instance , and drivers looking at how a car comes off a corner or accelerates. The difference, (my understanding here) is a static vs a dynamic one. Steady state HP on a dyno may be far different than how an engine behaves throughout an RPM range going down or around a track. (mostly drag here and circle track). Bonneville fits more in steady state realm of things. And the MM engine, like mine, has certain physical characteristics that cannot readily be changed. Number of years back while I was trying to dyno a prior engine, a couple had one of your BMC engines on the same dyno trying to find that hp or two you are looking for. They were at 100 + or - and played and played, maybe out of my sight got a few more but I understand what you are up against. Mr FB, I agree with all you have said and think is great you and Mr Midget are able to work together on this. I will continue to follow and occasionally pipe up as the mood strikes. 
 

 
 
 

[fordboy628]

Too tired even for a beer . . . . .
cry
Fordboy

WOW!     YES!!  PREPARE YOURSELF, FOR THE END OF THE WORLD MUST BE NEAR!!   (and I'm not a Mayan . . . . .)

Don't know a lot but what little I have gleaned over the past few years messing with my current engine tells me that
1) CFM is not the be all end all (port velocities,   Yes.    Usually, someone who thinks he has too much flow, merely has parts sized improperly.
the valve job,   Yes. I am constantly amazed by the guys who think valve seat shape/valve shape does not matter!!   I've done some back to back flow testing on MM's head, testing valve shape only.   The results are an eye opener for those in the throes of evolution denial.
and so many other things    Yes
have an impact on how the engine performs)   Yes.   As I'm fond of saying: "It's complicated."

and 2) a perfectly good head can be really screwed up by someone (local expert) "tinkering with it", hogging it out or many other things   Yes, I see this all the time!!   Racers are just too "optimisty" and the folks doing the "work" are glib.    Most of the time, as in my example, the shops doing the "improvements" do not have a dyno or flow bench.    They convince their clients that they somehow, "know", what is needed.    Call me a skeptic/non-believer/infidel, BUT, I want to see NUMBERS.    BEFORE & AFTER . . . .

and 3) dyno helps a lot but does not say for sure how it is going to go down the track.   Well, it depends on how the "dyno testing" is done.   You are correct in saying that "steady state" and/or "step" testing is not representative of how an engine runs on the track.    But, there are programmable dynos that control both load & throttle opening.    These can be used to accurately simulate "laps" of a particular track.    The results from these dynos are representative of how your engine will perform on that track.    Must guys do not have access to one of these . . . . . and so have to use a more "basic" method.     This, in and of itself, isn't such a bad thing.    BUT, it will probably require some "track tuning" to get everything working properly.

For instance, a very respected engine builder/head guy whom I have alluded to previously says, in essence, a connecting rod is to attach the piston to the crank and it's length is of no real significance along with the rod/stroke ratio.    This is not my experience.    The differences in engine geometry created by changing the rod length/stroke ratio impact several significant engine variables.    (BTW, not trying to be negative about this engine guy.    I'm sure that he (like me) has definite opinions about a lot of things.)

He has shown on many dyno tests changing only the rod ratio that there is no power advantage high or low ratio. (there may be some minor friction differences due to thrust effects).    Again, not my experience.    If all he did was change the rod length/pistons, and did not change/optimize other engine "events", I would not expect to see much difference in bhp.    Maybe +/- 1%.    And if the dyno is not accurate, AND repeatable, it becomes very difficult to find/validate 1%.    The peak bhp may NOT be much different "short" rod Vs "long" rod, but the shapes of the torque/bhp curves will definitely be different.    The guy with the larger "area under the curve" is typically the guy who wins.    And we are not yet discussing whether or not the "shape of the curve", is in the rpm range where it is needed . . . . .

There are innumerable people who say rod ratio is important including folks who design camshafts, for instance , and drivers looking at how a car comes off a corner or accelerates.    Both true.

The difference, (my understanding here) is a static vs a dynamic one. Steady state HP on a dyno may be far different than how an engine behaves throughout an RPM range going down or around a track. (mostly drag here and circle track).    The rate of acceleration required for the type of racing is extremely important.   If steady state bhp was the only important factor, nobody would care about component mass (weight).

Bonneville fits more in steady state realm of things.   I would characterize B'ville as a low rate of acceleration, [in the top gear(s)], maybe 50/100 rpm/second or less.    If you are steady state, you are "topped out".     Let's face it, at B'ville, eventually everything goes "steady state", although I do not think that is the goal.

And the MM engine, like mine, has certain physical characteristics that cannot readily be changed.    And that's why "It's complicated".    Sorry, not trying to be a jerk.   Dealing within the constraints of the original "packaging" of the components can be quite the challenge.    Most engine guys are NOT very good at it.

Number of years back while I was trying to dyno a prior engine, a couple had one of your BMC engines on the same dyno trying to find that hp or two you are looking for. They were at 100 + or - and played and played, maybe out of my sight got a few more but I understand what you are up against.    It would be interesting to know more about the engine specs or perhaps the PHP engine #, if it was prior to 1995.

Mr FB, I agree with all you have said and think is great you and Mr Midget are able to work together on this. I will continue to follow and occasionally pipe up as the mood strikes.  cheers    Thanks!   BTW, I know MM invites all comments.     Look at the cr*p he puts up with from me!

Also:  It was my dad who was Mr.    I'm just Mark/Fordboy/the dumbas* making a racket with the flow bench.   As my mood suits me . . . .  

Hi Jack,

I put some comments/thoughts into your text, sorry.    Still a slow & crappy typist . . . . .

And I also feel that it is important to note:    There is some "professional disagreement" within the racing industry, about what is, or is not important.    My opinion is: just that, MY opinion.    I reserve the right to change it, at any time, without notice.    Smart, competent, professional engine guys, just let their results do the talking . . . . .

Take note: "There is nothing permanent except change."     And there is always a new way to "skin a cat" . . . . .
 
Fordboy

[fordboy628]

So yeah, it's not likely you'll ever see a "bathtub rebuild at the Super 8" story from me - I'm a romantic, but I'm not THAT romantic.

Midget,

It should be just that, a story.    Count me out on the bathtub rebuilds.    I need somewhere to sleep.
 
F/B

[jacksoni]

OK Mr Dumbas* (sorry couldn't resist- don't mean it at all as clearly you are not) I do not disagree or have any issue with your comments. The engine builder I was referring to I think was trying to make a specific point with his statement (sort of like Smokey saying put the longest rod in it you can fit). I think he meant there are many variables- to coin a phrase- "its complicated" and rod ratio is down the list. Indeed I think in his testing he did not go back and optimize other variables that might have shown a difference. Piston weight, for instance, and pin height as a secondary factor is important. When I was putting my engine together I had a pin height of about 1.4" or so and he said is that as low as you can get it? I had at that time a 6.25"rod and a 2.4rod ratio and despite his statement "is that all" I was reluctant to make the rod longer. I know on his pro stock motors he likes a ratio in the 1.7 range. Anyway, its complicated and rod ratio is just part of it and he knows it well so don't take the statement that it makes no difference too much to heart.

The  dyno session I was referring to was in the range of 20 years ago. Though that shop is closed the owner still does some machine work from shop in the back of his house. He may remember and if you really want to know I will ask him. He still does machining for me. Whats a PHP#?

Again, I agree with all you have said and the additions to my incomplete comments.

By the way, the engine/head guy I refer to works for Reher-Morrison, in charge of cylinder head development. He does know something about it.

Jack

[fordboy628]

The  dyno session I was referring to was in the range of 20 years ago. Though that shop is closed the owner still does some machine work from shop in the back of his house. He may remember and if you really want to know I will ask him. He still does machining for me. Whats a PHP#?

Jack

When I owned PHP Racengines, Inc.  every engine built up in shop and dyno tested was stamped, on the head/block/various other castings, with an ID # to identify the engine positively.

For instance:   PHP 92-150

Decoded it stands for: Engine built by PHP in 1992 and the 150th complete engine assembled and dyno tested.    Other records @ PHP would indicate engine type, size, client, etc.    The engine # would not be changed during subsequent rebuilds, but the records would be updated.

Although PHP is still in existence, I have no idea whether that engine numbering system is still company policy.
 
Fordboy

[fordboy628]

Warning Will Robinson!!   Warning!!    Impending data dump . . . . .

Ahhh, the cure for information constipation . . . . . . .

and I need my beanie 'copter cap!  (for the additional brain cooling airflow. . . . . .)

OK, the key to understanding all these comparison graphs is the file ID's.    They are:

A/  Chris Conrad 03     The Longman head, as used at B'ville.    9/32 REC style valves.    Tested with 38mm radiused inlet adaptors, pvc exhaust stub pipes, 2.82" bore adator.
B/  Longman BMC 1     Another client's head assembly.             9/32 REC style valves.    Tested as above.
C/  Swiftune BMC 5      Another client's head assembly.             6mm MED valves.           Tested as above.
D/  Swiftune BMC 51    Another client's head assembly.             9/32 REC style valves.    Tested as above.    Same casting as "C" after valve replacement.
E/  Swiftune BMC 1a     Another client's head assembly.             9/32 REC style valves.    Tested as above.    Another sample from Swiftune.
F/  Longman BMC 2      Chris's Longman head as tested by C&S in Wisconsin.  same valves.    No inlet adaptor, no exhaust stub pipe, 4.03" bore adaptor.

Also:  All testing was done @ 28" test pressure, in steps of .050", from .05" to .55"/.60"   except the testing @ C&S.   They used differing steps.
         Graphs are:  the average flow for all 4 intake or 4 exhaust ports, except the C&S test is one cylinder only.    Average flow is a good way to compare one head to another.

   
       Chris's head, my test procedure Vs C&S test procedure.   A vs F                             Chris's head Vs another Longman head.   A vs B

   
                 Chris's head Vs Swiftune w/6mm valves.   A vs C                       Chris's head Vs. same Swiftune head, with 9/32 Swiftune/REC valves.   A vs D

   
                Chris's head Vs the best Swiftune example.   A vs E                                            All 6 samples on a single graph chart at once.

Some random thoughts:

A/  The upper LH graph shows why you want to have a consistent test procedure, with proper adaptors, if you want to compare results.
B/  The center pair of graphs illustrates how badly you can affect flow by "improving" things, and not bothering to test your work.   Also compare the center Left graph with
     the lower Left graph, the difference between the 2 Swiftunes.    Lower left as from Swiftune, center left "improved"  . . . . .
C/  Lower Right graph just illustrates how the forest can make it hard to see an individual tree . . . . . .
D/  Increasing your page magnification level will make the graphs larger and perhaps easier to read, but it will undoubtedly jumble the captions.

OK, now you have something to think about all weekend.    
 
Fordboy

[Milwaukee Midget]

Mark, THANK YOU FOR THIS.

Let me throw out some thoughts, too.

I took the info from the graphs and charted my numbers against the numbers for a stock 12G1316 head - a middling head in stock form – the info is from APT – with a couple of caveats – I don’t know at what pressure the APT head was flowed at – looking through most of their online graphs, they seem to use 25” as their bench mark - and I don’t know if they used a proper adapter -



If we compare ANY of these heads to the stock unit, we see dramatic increases in flow.  Let’s assume that the stock head was flowed at 25”, the comparator would be about 5% more, we’re still looking at about 30% more CFM across the range.  Even the sarcastically “new and improved” Swiftune head is a 25% increase over stock.

So it’s fair to say that all of these prepped heads are okay to decent, despite being maximized to different standards with different techniques.

What’s also important is to remember that the air requirements of the engine, due to its diminished capacity, are much less than would be the case if I were running a 1275/1310.

What I’m seeing that I like is that in virtually every comparison, I’m a bit ahead of the others in all but one case in low lift flow up to ~.300 lift.

By the time I bought a Swiftune head, shaved it to the point that it had small enough chambers to be of any help, I think I’d be hard pressed to justify the cost or demonstrate an advantage on the dyno.

[fordboy628]

So it’s fair to say that all of these prepped heads are okay to decent, despite being maximized to different standards with different techniques.

What’s also important is to remember that the air requirements of the engine, due to its diminished capacity, are much less than would be the case if I were running a 1275/1310.

What I’m seeing that I like is that in virtually every comparison, I’m a bit ahead of the others in all but one case in low lift flow up to ~.300 lift.

By the time I bought a Swiftune head, shaved it to the point that it had small enough chambers to be of any help, I think I’d be hard pressed to justify the cost or demonstrate an advantage on the dyno.

Midget,

I agree.

One other aspect of the Swiftune head(s) is:

They utilize the latest 12G940 casting, which is thinner in the deck area, and therefore, CAN NOT BE SUCCESSFULLY MILLED AS MUCH AS YOUR CURRENT LONGMAN cylinder head.

I'm only interested in a few more things about the head/induction system:

1/    Total flow of the head with the inlet manifold installed.    Radius adaptors on the inlet of the manifold.   All 4 cylinders.
2/    Total flow of the complete inlet tract, with Weber carb installed at WOT.  All 4 cylinders.
3/    Exhaust flow with "RimFlow" exhaust valves.    All 4 cylinders.    The one cylinder I did test was comparable to the previous "RimFlow" tests, but I want full results.
4/    Examining the head for differences in the intake ports.   Cylinder #3 is the best individual port so far, of any head tested!    It would be nice to be able to duplicate that
       result with the other 3 ports . . . . . . .

I'll be in the woodshop today making the manifold radius adaptors I need to perform #1 above.    I'll post up more graphs later, your head Vs one more; plus graphs of all 4 cylinders, intake & exhaust, etc.

If we compare ANY of these heads to the stock unit, we see dramatic increases in flow.  Let’s assume that the stock head was flowed at 25”, the comparator would be about 5% more, we’re still looking at about 30% more CFM across the range.  Even the sarcastically “new and improved” Swiftune head is a 25% increase over stock.

Yes, of course this is true, and I won't argue the point.    ("This is abuse.  Argument is two doors down the hall.")

BUT, 

My points are thus:

A/  When you pay top dollar, you should get top performance.
2/  When you pay top dollar to "improve" performance, you should get "IMPROVEMENT" . . . . . and the documentation to prove it . . . . . . .
d/  There are many purveyors out there who advertise "modest" improvements over "stock" and at "modest" cost.    And while they would be good choices for street/modest
     output racing engines, they are probably not the "best choice" for "all out" race engines.

BTW, since you nicknamed your engine "Grenade", I was thinking it was "all out", right?

A client should get what they pay for.    Now we are all big boys here, and we are all also schooled in the "real world".    So we all know "S**t happens" and that everyone in this business isn't honest.     I simply dislike seeing the honest businesses slog along on the edge of profitability, while "others" profit handsomely exchanging BS for dollars . . . . . . .
 
Consumeradvocateboy, er, Committedtoscienceboy, well, hopefully you get the idea . . . . . . . .   

[Milwaukee Midget]

We're on the same page, brother.

I put up the chart with the APT info to do two things -

1 To set up a baseline to demonstrate what kind of turd we're trying to polish.

2 To also show that, as you are fond of saying, "We're trying to slice the cheese really thin" at this point.  What I'm seeing here is that with numerous attempts by reputable head cutters and even questionable techniques by a nameless "guru", ANY additional gains in flow are going to be very tough to come by, and in fact, one must move forward with extreme caution in order to prevent destroying any gains we've already achieved.

By the way, my 5% adjustment was not charted on the graph, but I found the formula for converting flow bench data of differing baselines.   

We're comparing at 28".  If you have a head that was flowed at 25", the formula would be

28/25  =  1.12

Find the square root of the quotient (1.12) = 1.058.

Multiply that times the flow at 25".

So actually, at 28", it's closer to a 6% increase on the 12G1316 head.

But again, I'm assuming APT tested at 25".

[fordboy628]

Turd polishing, part Deux . . . . . . . .

midget,

OK.   Here are some graphs of your cylinder head's average flow Vs. some additional samples from the database.

Again the key to understanding all these comparison graphs is the file ID's.    They are:

A/  Chris Conrad 03     The Longman head, as used at B'ville.    9/32 REC style valves.    Tested with 38mm radiused inlet adaptors, pvc exhaust stub pipes, 2.82" bore adator.
B/  Swiftune BMC 1a    Another client's head assembly.             9/32 REC style valves.    Tested as above.    Another sample from Swiftune.
C/  Joe R. RimFlow       Another client's head assembly.             9/32 RimFlow valves.      Tested as above, except one cylinder only.  12G1316 casting.  O/size F/P valve sizes.
D/  Joe R. PHP 92-150  Another client's head assembly.             9/32 REC style valves.    Tested as above.   Base head for test 'C'.     12G1316 casting.
E/  Chris Conrad 04     The Longman head, as used at B'ville.     9/32 RimFlow valves.     Tested as above, except for one cylinder only.
F/  Stock 12G1316       Stock casting, no porting.                      9/32 stock valves           Tested by APT        Adaptors unknown.
G/ Joe R. PHP 92-148  Another client's head assembly.              9/32 REC style valves.    Tested as above.   F/Production valve sizes, 12G1316 casting.

The output graphs are also color coded to the brief description on the right hand side of the graphs

Also:  All testing was done @ 28" test pressure, in steps of .050", from .05" to .55"/.60",   except the testing @ APT.   They used differing steps and 25" of test pressure.
         The APT tests have been corrected to 28" of test pressure.
         Graphs are:  the average flow for all 4 intake or 4 exhaust ports, unless noted.    Average flow is a good way to compare one head to another.

The program I use only allows 6 heads to be compared on one screen shot, so some of the information is doubled up in the graphs.    I separately graphed out intake flow and exhaust flow this time because the stock flow for intake would have been mixed in with the modified exhaust graphs, creating some confusion.

And this time I inserted the graphs one at a time, so that they can be enlarged (use your screen zoom %) and not jumble the captions.


#1  Average intake flow Vs. several other very good heads and a stock 12G1316 casting.


#2  Average intake flow Vs. several other very good heads, an OK head and the stock 12G1316 casting.


#3  Average exhaust flow Vs. several other very good heads.   The counterpart to graph #1.


#4  Average exhaust flow Vs. several other very good heads and a stock 12G1316 casting.   The counterpart to graph #2.

Some thoughts:

A/  It is apparent that the prevailing notion that the 12G1316 casting is not a suitable selection for a "racing head" is erroneous . . . . . .
2/  Producing good flow numbers appears easier to achieve on exhaust rather than inlet,  (and this does not consider the much higher cylinder pressures when the exhaust
     valve opens . . . . .)
d/  As noted previously, the very best exhaust flows in these test results, utilize RimFlow valves from Race Engine Components, by a large margin . . . . . . .   Note the flow of
     your head with the RimFlow exhaust valve.    Both heads tested with RimFlow valves responded very positively at low & mid lifts . . . . . .
 
Fordboy

[Milwaukee Midget]

Just stumbled across this one.  Syd Enever was the driving force behind the MGA and the MGB, and involved with the racing program with MG for years.

Either his son or his grandson came across this 8mm home movie of the 1957 Bonneville trip.  You'll see George Eyston, and I think that's Phil Hill's ice blue MGA pulling into the parking lot of the motel.


http://www.youtube.com/watch?v=P2BHtqKuRe0