Milwaukee Midget

[Geo]

Nope, I have not seen you about these parts.

Looking forward to "mo data"

Keep up the good work Fordboy!

Geo 

[Milwaukee Midget]

Nope, I have not seen you about these parts.

Looking forward to "mo data"

Keep up the good work Fordboy!

Geo 

Wish I were there today, Geo - 70 degree weather - I'd warm up a couple of ales in the Lucas fridge, and lend you some elbow grease on the cat.

How's your build coming?

If you see Toto, just put him in the picinic basket and drop him off with Auntie Em.

[Milwaukee Midget]

Well, this doesn’t happen often – at least not in my experience building a rather odd duck.

An advertised race part for an MG, ON SALE, IN STOCK, and SHIPPED ON THE DAY THE ORDER WAS PLACED.

It's almost like ordering a Chevy part from Summit.

Cheers to Mini Mania and UPS – my straight cut, close ratio gear set will be here on Thursday.

Now all I have to do is hope they’re sending the right parts . . .

Fordboy, I think you still have my transmission case – I’ll need to make arrangements to come and get it this week.

Been poring over the BL service manual, the Chilton manual and the Moss Motors exploded view of the tranny, and while I’ve got some gaskets to order, I think I can start putting it back together next weekend.

Never shifted a car with straight cuts – this may prove to be interesting.

[fordboy628]

Fordboy, I think you still have my transmission case – I’ll need to make arrangements to come and get it this week.

Never shifted a car with straight cuts – this may prove to be interesting.

Midget,

1/  Confirming location of your extra ribcase trans case is: South of the cheddar curtain, where wrist-slashing & ledge-walking is the order of the day.

2/  If those gears are the BMC close ratio setup I'm familiar with, shifting is NO PROBLEM.  Only the gears are straight cut.  2nd, 3rd & 4th gears still have synchros, so it will shift as a stock gearbox, just more noise from the box, and more power out the tailshaft.

It is the dog-ring gearboxes that are more touchy to shift, because they do not have any synchros, and therefore rpm's between the gearbox shafts needs to be better matched.   A synchro is actually a mechanical "speed brake" which helps the loose nut behind the steering wheel to match the shaft speeds for easier shifting.   The lack of a first gear synchro on many "Briddish" "sports cars" explains the designer's intent.   First gear is only meant to be engaged whilst at a full stop, not so much fun.............and not the fast way around slow, twisty race courses.........

3/  And on another happy & fortuitous note, later this week, Toto, (your cyl. head) will be ready to smuggle back across the cheddar curtain.  I suggest a moonless night run, (ala Junior Johnson) better for the "moonshine" and there are fewer flying monkee patrols.

4/  May need you to bring the rocker arm assembly.   I want to check for r/a center of mass/gravity.
 
Fordboy

[fordboy628]

Midget,

More info:

Inlet valves (old)                 55gr.
Inlet valves (new)               50gr.
Exhaust valves                    42gr.
Tappet                                44gr.
Valve springs                      48gr.
Spring retainers & keepers   15gr.

And, just for yucks:
"lightened" tappet                40gr. (!!!! illustrating why "lightening" BMC tappets is a waste of time.......)
New 'Kent' tappet                 48gr.

And just for having everything in one place:
Tubular Pushrod                   69gr.
Stock pushrod                      53gr.
Rocker arm                          92gr.  (Is this a complete rocker arm assembly?)
APT tappet weight                43gr.

I'll make & post a spreadsheet of valve train component masses and their "equivalent masses" later today or later this week.  I'm going to include columns for: "equivalent mass in pounds" and also for "% of total valve train mass".   That will provide some interesting numbers for advocates of "lightening" components or lightweight components.  (Such as Titanium components...)  For racers who have not considered this analysis before, there may be some surprises.   My advice has always been and continues to be:   "Be smart and spend your time and/or money to the best advantage"...................

Perhaps you can bring me some stock rocker-arms?  I want to calculate weight & moment of inertia of stock ones for comparison.   I want to show why roller-tip rockers have a higher moment of inertia and therefore require higher valve spring pressures.
 
Fordboy

[fordboy628]

Midget, et all,

As I threatened, more info, PRELIMINARY SPEADSHEETS for equivalent mass:



Almost all the information is correct, BUT, I used an arbitrary correction factor for the rocker arm's moment of inertia, for this preliminary version. I WILL NEED TO SUBSTITUTE THE CORRECT VALUE ONCE IT IS KNOWN, FOR THIS INFO TO BE CORRECT.

What is interesting is:

1/  The valve is the component with the highest % of the total mass, no big surprise to me.  Titanium valves, @ a 40% weight reduction, can significally benefit rocker arm valve trains............   40% of 32.4% is a net of 12.96% overall reduction................

2/  Lightening lifters (as recommended in various BMC books) for a net reduction of 4gr. seems to be a waste of time.  Although I will not argue that less weight/mass is not better, (because empirically it is), this example is a net reduction of 9% of 11.1% for a net total reduction of .999% (1% o/all).   Not much of a payback for a LOT of work.  Better to put the effort and/or money into a part that will give a higher % payback, such as the parts on the valve side of the rocker arm.............

Just some food for thought, careful selection of valve train parts can give large benefits.   Especially in larger, heavier, rocker arm valve trains.......
(BTW, I am not recommending Ti parts for your jewel, just a convenient example.)
 
Fordboy

[Dean Los Angeles]

Question me this . . .

12.96% always sounds like a good number. Reducing the mass of the valve train is always good.

But how good? If you made no other change to the engine, what horsepower difference between stock weight and modified weight valve train?

Race engine calculations always have a 1:1 correlation between cubic inches and cubic dollars. And that's for the first 95%.
That last 5% that gets you out of 2nd place costs double cubic dollars.

[Milwaukee Midget]

Dean -

We're thinking along the same lines.

While weight reduction is almost always good, at this point, provided the valvetrain is stable, all I think I could reasonably achieve by lightening the valve train further would be additional revs, which I don't think I need.

For a ball park comparison, everything here likely weighs half of comparable SBC components.  So the overall mass in motion is significantly less, although proportionally more per HP than would be the case on a SBC.  As the scale of a build goes down, so retreat the achievable advantages from weight reduction in the valve train.

In short, it still has to be "X" strong.
 
We are at the point of diminishing returns.

Dyno Day Approaches.

As to cubic dollars per horsepower, I'm in denial, but it's safe to say I could have built a pretty darned strong Mopar street engine for what I've sunk into this thing.  

[USFRAMONTE]

Chris, just remember that old adage....If it was easy, anybody could do it!

[JustaRacer]

Not an expert, but:

The goal is to get the spring rate down.  Do everything you can to run the lightest spring rate that will stop the engine from playing piston-tag.

Keep the springs cool when running, release them in storage, and check/replace on routine basis.

Gains in HP, lower oil temps, better guide life, valve life, lifter life, cam life, cam drive, bearings, etc.

How much HP it's worth is part of the equation, not the whole enchilada.  Some of the costs can be recovered by longer life of related items.

But I could be wrong.  It's worked for me, but I'm not hardcore.

[fordboy628]

Midget, et all,

Some thoughts, in order:

Question me this . . .

12.96% always sounds like a good number. Reducing the mass of the valve train is always good.

But how good? If you made no other change to the engine, what horsepower difference between stock weight and modified weight valve train?

Race engine calculations always have a 1:1 correlation between cubic inches and cubic dollars. And that's for the first 95%.
That last 5% that gets you out of 2nd place costs double cubic dollars.

Good question.  The honest answer is: "It depends."  Valve train weight (mass) reductions provide benefit more along the lines of reliability, lowered spring requirements, higher rev limits, etc, etc.  Lower valve spring pressure requirements (for a given max. rpm) can 'free up'  bhp otherwise lost to friction losses.   Higher, reliable, rev limits can produce more h/power, if the torque curve can be extended to the new rpm range.   Needless to say, extending the rpm range is dependent on inlet tract flow adequacy, which varies among engine types.

I think your cost/hp estimates are low, especially for 'unique' engines.........

Dean -

We're thinking along the same lines.

While weight reduction is almost always good, at this point, provided the valvetrain is stable, all I think I could reasonably achieve by lightening the valve train further would be additional revs, which I don't think I need.

For a ball park comparison, everything here likely weighs half of comparable SBC components.  So the overall mass in motion is significantly less, although proportionally more per HP than would be the case on a SBC.  As the scale of a build goes down, so retreat the achievable advantages from weight reduction in the valve train.

In short, it still has to be "X" strong.
 
We are at the point of diminishing returns.

Dyno Day Approaches.

As to cubic dollars per horsepower, I'm in denial, but it's safe to say I could have built a pretty darned strong Mopar street engine for what I've sunk into this thing.

Yes, half the weight, AND, half the cyl. head ports!!   So Amen to all of the above & a prayer (& a Heffeweisen 'offering') to St. Augustine of Hippo.

Not an expert, but:

The goal is to get the spring rate down.  Do everything you can to run the lightest spring rate that will stop the engine from playing piston-tag.

Keep the springs cool when running, release them in storage, and check/replace on routine basis.

Gains in HP, lower oil temps, better guide life, valve life, lifter life, cam life, cam drive, bearings, etc.

How much HP it's worth is part of the equation, not the whole enchilada.  Some of the costs can be recovered by longer life of related items.

But I could be wrong.  It's worked for me, but I'm not hardcore.

Apparently though, you are hardcore enough, because your comments are right on.  Amen again, AND, another 'offering'!!!
 
Fordboy

[fordboy628]

REPAIRS TO "TOTO"

1/  Installed replacement inlet guide for #1 cylinder to proper height.
2/  Counterbored Valve spring pockets to 1.28"/1.29" O.D. to fit hardened spring bases.     NO increase in pocket depth.
3/  Honed valve guide I.D.'s for additional clearance,  inlet .0012"/.0020"    exhaust .0018"/.0025"   Unable to remove all "bellmouthing".
4/  Check new valve guide for concentricity to previously machined seat  TIR = .002" max,   able to lap-in seat to valve.   (Thank you, St.
     Mowog!..........)
5/  Lap-in all valves & seats.
6/  Pre-clean for assembly & checking.
7/  Check valve spring installed height for replacement valve. (New valve .050" longer stem length.)
8/  Check installed hts & select spring shims for all valves.   (Shims selected to equalize at 1.400")
9/  Check distance: Valve face to cyl. head surface, front to back, 1E-1I-2I-2E-3E-3I-4I-4E
     1] .201"
     2] .209" (Praise be St. Mowog!!)
     3] .210"
     4] .201"
     5] .201"
     6] .208"
     7] .208"
     8] .202"
10/ CC chamber #1 with new valve to check compression ratio:  17.2cc       (previous value: 17.3cc  From reply #1351 on page 91.  All
      Hail St. Mowog!!!)
11/ Assemble boxes of bits to be smuggled across the "cheddar curtain" to "Beerhaven" by overjoyed owner & Chrysler driver.

Evidentiary photos:


12/  Rewarding owner & self with a celebratory serving of "Hobgoblin Ale"!!!!!!!!!!!!!!!!!!!  (All hail St. Augustine of Hippo!!!!!!!!   and the absence of "Flying Monkees" and their buttocks......................)
13/  Onward & upward to dyno adapting.............................     Has anyone perchance seen my pet flying squirrel?
 
Fordboy

[fordboy628]

VALVE-TRAIN COMPONENT WEIGHING

This is all you need to "get started" for most applications:



600 gram capacity x 0.1gr    $14.95
500g  Calibration wt.            $  8.95
100g  Calibration wt.            $  5.95
  50g  Calibration wt.            $  3.00
+ shipping, handling, etc

http://www.americanweigh.com/product_info.php?cPath=102&products_id=254
http://www.americanweigh.com/index.php?cPath=113

Other scales of other capacities available from the same/other companies.   Just knowing the weight of various choices for valve train components itself can be useful...................

If you have a "direct attack" valve train (non-rocker ohc, various flatheads, etc), the scale, a 'good' calculator, ability to use a spreadsheet and a "detailed" cam analysis printout gets you started.   If you have an ohv, rocker arm sytem, you will also need to measure the moment of inertia of your rocker arms.   If you are lucky, (pray to St. Mowog, or the patron Saint of your project!!), the manufacturer of your rocker arms may be able to provide you with this tidbit of information..............

Be aware that these calculations require a significant & intense understanding of higher math & physics......................AND, they only get you from point 'A' to point 'B'.  You may need to get to point 'C' or 'D' or 'E', etc..............
 
Fordboy

[Interested Observer]

Fordboy,

Re: Preliminary spreadsheet, reply #1865

It is generally accepted that the effective mass of a spring is 1/3 the total mass.  Is your 1/2 factor “preliminary” or just a measure of conservatism?

[fordboy628]

Fordboy,

Re: Preliminary spreadsheet, reply #1865

It is generally accepted that the effective mass of a spring is 1/3 the total mass.  Is your 1/2 factor “preliminary” or just a measure of conservatism?

Interested Observer,

I usually start at 1/2 the spring mass as a preliminary factor just to be conservative.   Since I use a spreadsheet, it is easy to add pages with alternate scenarios and/or "What if?" scenarios to explore possibilities.   Once I have exact weights for all the components, moi, etc, I want to be more precise.   Precision is relative here because the formula predicts a "best case scenario", 'presumes' (??) a rigid valve-train and ignores valve spring resonant frequency.

And so I end up doing some additional analysis, such as:
1/  Some 'margin of safety' has to be built in at some point.
2/  The resonant frequency of the spring(s) selected need(s) to be evaluated Vs. engine operating rpm range.  The typical result here is
     that a possibile selection has to be discarded because of poor harmonics.
3/  I usually check the full open pressure of the spring Vs. the nose radius of the cam against the tappet for sane 'contact pressure'.
4/  I might also check spring pressure at the juncture of the closing flank & the closing ramp, IF, I have a complete cam profile.

If this is starting to sound to you like an analysis of kinematic forces, I also do that from time to time.  I also fall back quite a bit on my practical experience with 4 cyl. race engines of various types.  No smoke and mirrors, just good (?) engineering coupled with good (?) judgement.

I have used this type of valve spring on BMC race engines previously, with good results.  So I am not too concerned, just doing the math.

Thanks for your interest & comments,
 
Fordboy

edit:  The steel rocker pillars that replaced the original alloy pillars were fabricated to increase valve-train stiffness & improve head gasket clamp load.