Milwaukee Midget

[fordboy628]

midget,

I did not ask about the length of time to delivery . . . . . . . .
 
Fordboy

Good thing you are not trying for 2015

Well, in fairness to everyone who produces "oddball", one off parts for racers.    Every "special" project has a "learning curve", which unfortunately, takes an investment in those commodities which racers don't usually have in excess: TIME & MONEY

When I was working for Pro level efforts, I solved many delivery problems by:  Throwing somebody else's money at it.

Can't do that in this instance.     I'm just glad that there are guys willing to carve this stuff out, one bit at a time.     
 
Fordboy

[jacksoni]

I hear you. My pistons were to be 2 weeks, took 6. Cams are now at 3.5 months and still going strong......

Mr Fordboy, while you are hanging about here, I know you have more experience with pushrod type engines than DOHC stuff with direct tappets or followers but do you have thoughts about breaking in new cams in this setting (direct tappets in this case),. I know regular flat tappet cams take a lot of babying in many situations to avoid wiping the lobes but with DOHC direct, the tappets don't rotate, are flat, but the actual load is much less. Less spring pressure, no rocker arm to multiply load on the lifter etc. Other than assembly lube in general would you do anything special lube/oil wise as is often suggested with pushrod flat tappets? Though way down the road for you and Midget, it does apply.....

[fordboy628]

I hear you. My pistons were to be 2 weeks, took 6. Cams are now at 3.5 months and still going strong......

Mr Fordboy, while you are hanging about here, I know you have more experience with pushrod type engines than DOHC stuff with direct tappets or followers but do you have thoughts about breaking in new cams in this setting (direct tappets in this case),. I know regular flat tappet cams take a lot of babying in many situations to avoid wiping the lobes but with DOHC direct, the tappets don't rotate, are flat, but the actual load is much less. Less spring pressure, no rocker arm to multiply load on the lifter etc. Other than assembly lube in general would you do anything special lube/oil wise as is often suggested with pushrod flat tappets? Though way down the road for you and Midget, it does apply.....

Jack,

As a matter of fact, back in the 80's and early 90's when I founded and owned PHP Racengines, I seem to remember building & dyno'ing about 100 Lotus TwinCams & Cosworth BD & FV variants, all with bucket "flat" tappets.    There can be problems with these types of valve trains.

My thoughts:

1]  Chilled iron cams with steel tappets have better "compatibility" than steel cams with steel tappets.
2]  Contact pressure is also a factor for break-in, I insist on running in on lowered valve spring pressure, NO MATTER HOW MUCH TROUBLE IT IS TO CHANGE VALVE SPRINGS.
     It is worth the effort.    I usually remove the inner spring, minimum, for "break-in".    Break-in rpm needs to be carefully controlled at reduced spring pressures.
3]  If the tappet is dead flat, I request the cam lobes be ground with "extra" lobe taper and/or offset, to spin the lifter.    NO tappet will survive without rotation.
4]  If the cam grinder recommends against a "flat" tappet, inquire as to whether they can spherically grind the tappet to a radius they recommend for "their" lobe taper.   If
     not, Dema Elgin can spherically grind tappets to a variety of radii.    One might inquire whether he has a setup for the tappet diameter you are using if you need this done.
5]  I had steel cams nitrided after grinding.
6]  "Parkerizing" of steel cams lobes and steel tappet surfaces is also a good idea that helps lubrication.    Chilled cast iron cams may not need this process.   DLC coatings
     are now being used to help with some of this, but I do not have any experience with them in this application.    Compatibility is a huge factor with DLC.    And it is
     expensive.
7]  My experience is that the tappets need to be about 54/58 Rc hardness.    Harder is not a problem on the tappet, I've used parts as hard as 65 Rc.
8]  Cams need to be 4/5 Rc hardness points softer than the tappet.    Cams/tappets at the same hardness are usually a problem.
9]  Rc hardness is relative, and can be less if the cam lobe nose "contact pressure" is less or low.    Good cam grinders can advise a user on this.    HIGH contact pressures,
     as in high velocity/acceleration cam lobes, with high valve spring pressures, and high valve train mass, need "harder" parts, and even this might not prevent wear.
10] I always insist on a cam break-in lube with "moly", generously applied during assembly.    Don't go nuts, but thoroughly coat both the lobes & tappets.
11] I always add a ZDDP additive on top of the moly assembly lubed lobes & tappets.    I tend to drown the parts.    This is only for flat tappet cams.
12] I like regular racing oil for "break-in" as opposed to break-in oils.    I worry about bearings too.    I tend to use lighter weight, multi-grade oils.   There is so much new
      information out there, or on the web, I would advise being careful with oil choice.    I tend to go for oils with higher film strength, because I am an advocate of "lower" oil
      pressure in general.

All of this will apply to the new engine for the Milwaukee Midget.    It is going to be interesting . . . . . .
 
Fordboy

[fordboy628]

Got to thinking that I had covered this subject before.     Lo and behold, my previous thoughts on the subject of midget's steel cam.    Not sure what page it was, (way, way back) just copied it here:


Billet steel flat tappet cams with chilled iron or steel tappets is the most difficult & dicey break-in of all cam/tappet combos/types.  The only procedure that would work for me was:

1)   Parkerize cam or Specify Parkerizing to Cam Mfg.   If parkerized tappets are available, use them.   Chrome faced tappets ($$) best.
2)   Assemble engine with cam & tappet faces coated with moly-based assembly grease/lube.   (DON'T GO CRAZY WITH THIS.)
3)   Assemble cyl. head to run-in cam/tappets on outer springs only!   VALVE LASH CANNOT BE "LOOSE", RUN "TIGHT" if necessary.
4)   If possible pre-heat engine oil & coolant prior to firing.
5)   Pressurize oil system BEFORE fire-up, make sure oil gets to rocker shaft & valve stem tips.
6)   The oil you use for run-in matters, DO NOT USE A SYNTHETIC OIL.
7)   You MUST use an oil additive that contains ZDTP.   (zinc dithiophosphate, not sure on spelling, probably Haz/mat now.)
8]   IMMEDIATELY on fire-up run engine to 2500 rpm.  Vary rpm between 2500/4000 for 10 minutes.   No idling or high revs permitted.
      If possible, check tappet faces/cam lobes for scuffing @ 10 minutes.   If scuffing is encountered, or valve lash opens up, STOP.
9)   If OK, continue run-in for 10 more minutes.   Inspect again, and if OK, change to regular valve springs.
10) Run-in for an additional 10 minutes @ full spring pressure, vary rpm 2500 to 6500.   Inspect for final time, if OK, you can evaluate 
      ring seal/ring bed-in.   (Via blow-by meter OR Leak-down checker.)
11) If ring seal is OK, change oil filter.  It will be partially plugged/plugged with moly/greases/etc.  It will probably still be too soon to run
      a synthetic oil.
12) Check valve lash and adjust if required.  Check other aspects of engine that require attention, ie: retorque cyinder head, etc.  Now
      you are ready to dyno-test or run.
13) Above presumes that you are checking everything else you need to check on run-in.  Different engines types need attention in 
      different areas.   Know what yours needs, and use the Cosworth axiom:  IF IN DOUBT, ASK.

Pray if you must, but only in ADDITION to the steps above..................

As you can see, this type of procedure is most easily done on an engine dyno, and yes, I know this procedure is a GIANT PAIN IN THE KEISTER!!  It also works.
 
Fordboy

[jacksoni]

Thanks, Mark- sorry I had forgotten about "life pre-Nascar".

Lots of good thoughts. There are a bunch of ZDDP additives it seems, not to mention huge debate about that plus other additive packages and how important (or not) these things are.
one sample: http://zddplus.com/

[fordboy628]

midget,

Confirming:

Hub height on 1275 "mockup engine":   .998"    from face of crank hub to rear face of 'backplate'.

Flywheel friction face to backplate rear face:    1.973" avg.     (1.966"/1.981" measured)

Steel backplate thickness:    .290"

I dragged out the mockup and checked one dimension.     It matched the drawing from my file, so I'm OK with that.


I do not have a way to double check my sketch of your billet crank hub in the engine with the backplate.    I'll do an overlay drawing with that as the worst case scenario for fit up.    I do however, have a sketch of the BMC trans & input shaft.    I will put that on another overlay sheet to double check.     I can then "ghost in" the hub modifications once we have dimensions for the a$$ end of the Rover.     So I guess I need to schedule a run to "Beerhaven".    We will also need the x/y co-ordinates of the Rover engine mounting bolts, using the crankshaft centerline as the datum point.    So I guess we also need to make a run to "Wiggle pin's" garage to use his digital table on his mill.

So many field trips, so little time.

Also:   Marine Crankshaft e-mailed me an estimate of 14 wks & $3500 for a one off billet for the Rover.   That includes an engineering charge and would be from the time they have a sample & sketch in their hands.    Since it has been a few years since you got your other billet from Rody, and this one will be 5 mains/8 counterweights, it might not be a bad idea to get a quote from Rody.    Just so there are no nasty surprises.     You'd be pissed if it takes a year AND $3500 . . . . . . . .

OK, time for a Zywiec Porter  . . .  dark, malty, 500ml, 9.5% ABV . . . .   mmmmm       2 = naptime . . . . . . .
 
Fordboy

[fordboy628]

OK, first full day of Spring 2015 is over.   ONLY 504 days until Speed Week 2016.   So boys and girls, as promised . . . . . . . . . . . .

ROVERFEST!!!           (like anybody but the 2 of us cares . . . . . .  )

Okay, Fordboy - back to work on the K - which we are now upgrading to an N for political reasons, which I'll explain over the phone.

Specs are looking like this -

56 mm stroke gets us 989 cc, and if we need to overbore by .5, we're at 1003, which is still under the 1015 class limit.

The Honda Acura rods are the best bet as far as size is concerned - 137 mm in a 201 deck height, provided we can get by with a 35mm pin height.  Stock crown height is about 20 on a Rover 1.4 slipper piston.  It's about 36 on an A series non-slipper slug.

This puts us at a 2.43 R/S ratio.

The stock Acura rods, by the way, are rev limited @ 7900 in the factory programming for a 1.8 @ 130 hp and a 89 mm stroke.  Haven't done the math backwards yet, but I'm thinking properly prepped, they might be strong enough?

midget,

I have run some displacement and compression ratio numbers for analysis.    There is some good news and some bad news.     I'll start with the good news:

1)   75mm measured stock bore.   Propose .5mm overbore to utilize existing barrels.   Need to check wear to be sure the barrels will hone up clean.   Bore diameters in
      increments of .5mm provide the best availability for racing ring packages.   If it appears the barrels won't clean up, 76mm bore may be an option.

2)   As you calculated a 56mm stroke, (reduced from 79mm stock) gives a 1003cc displacement, well within the 1015cc limit.    If 76mm bore is required, reducing the stroke
      to 55mm gives a 998cc capacity.   Or 55.25mm  S gives 1003cc's;  55.5mm S gives 1007cc's.

3)   Taking the stock dimensions and calculating the stock deck height results in a dimension of 201.9mm     This is going to need to be verified, as this dimension will no
      doubt remain fixed, within a small tolerance.   This uses a stock piston compression height of 22.5mm, measured off the stock piston.

And that is the end of the good news . . . . . . . . .

4)   Retaining the std deck height and reducing the stroke would increase the rod length to 151.4mm if keeping the std compression height.    If the 137mm con rod length is
      used, that results in a compression height of 36.9mm (1.453").    I'm thinking that a piston forging to fit those dimensions is unlikely, though I could be wrong.    That
      piston would be very heavy though, compromising the plan to use a narrow, low tension ring package.    It would also limit the rpm potential of the piston/pin/rod.

5)   If the piston compression height is increased to 28mm (1.102") the rod length could be reduced to 145.9mm.     30mm (1.181") = 143.9mm rod length.     This is the
      point where a piston mfg needs to be contacted, so the design can actually be produced from an existing forging at reasonable cost.    I've seen guys draw all kinds of
      parts, only to find out that they can only be made in the "Twilight Zone" . . . . . .    Availability of piston forgings will dictate the rod length.

6)   Rod length/stroke ratio is going to be very high with this setup.  No way around it.   Piston dwell at and around TDC, is going to create piston to valve clearance issues,
      and the valve notches in the pistons will need to be pre-planned to be adequate.

7)   Lack of the ability to shorten the deck height is becoming a real "PITA" here.

This is the part where we need to get together and do some serious drinking, er, thinking about the path forward.   You will need some mfg info to make sensible choices.
 
Fordboy

[fordboy628]

midget,

I'm going to start a Comprehensive Engine Build Plan (Tm & copyright) file for the Rover.

It will be 3/4 pages of planning and choices specific to this engine style for Bonneville/LSR in the I/GT class.

Better to have it all laid out on paper first.

Let me know about any decisions you have already made.
 
Fordboy

[fordboy628]

Is it possible that "Roverfest" is part of the wicken spring ritual?

 
F/B

[manta22]

Sounds like some sort of a dog show.....   

Regards, Neil  Tucson, AZ

[SPARKY]

ROTFLMAO   

[4-barrel Mike]

Sounds like some sort of a dog show.....   

Regards, Neil  Tucson, AZ

It has to be, the pony is dead!

Mike

[Milwaukee Midget]

midget,

I'm going to start a Comprehensive Engine Build Plan (Tm & copyright) file for the Rover.

It will be 3/4 pages of planning and choices specific to this engine style for Bonneville/LSR in the I/GT class.

Better to have it all laid out on paper first.

Let me know about any decisions you have already made.
 
Fordboy

Mark, I seem to recall that in my conversation with ARP, there was a little wiggle room on deck height and head thickness.  Maybe a haircut on the block might help.

I'll measure up the belt, do a tooth count and see if Gates has any options on a -2 and -4.

I'd prefer not to, but if we're starting with a clean sheet of paper, let's look at all options. 

The one decision I've made is that I intend to make this work.

Sounds like some sort of a dog show.....   

Regards, Neil  Tucson, AZ

It has to be, the pony is dead!

Mike

I find it uncanny – and possibly unnerving – that people I only see face to face once a year can be so attuned to oblique nuances of my sordid past . . .

In the late 1990s, I worked for the Wisconsin State Fair, and managed a stage between the horse barn and the Purina Pavilion.  It was fun work – 11 days in August in Wisconsin, putting up fiddler contests, political speeches, bluegrass bands, strong man competitions, a radio program coordinated with WGN out of Chicago.  Long days, but one left with a feeling of satisfaction at the end of the run.

Given my stage’s location and the occasional call to the grounds personnel to clean up “shoe polish”, it occurred to me that I was a bit more than a “Stage Manager”.

So I created my own title – one which has stayed with me through my tenure with my Milwaukee Area Music Industry volunteer work, and Summerfest – to wit . . .



Pom Rod update – the vinyl dash appliqué is drying and I got the shifter bent into a position which won’t require me having to shift with my armpit.  Mr. Bettes, thank you again for the killer deal on the torch!

In keeping with the rock-and-roll theme on the Bugeye, I took a broken microphone, filled it with epoxy, and I now have a shift knob that will complement the dash . . .

[Speed Limit 1000]

And the beat, of the dog and pony show, goes on

[fordboy628]

Mark, I seem to recall that in my conversation with ARP, there was a little wiggle room on deck height and head thickness.  Maybe a haircut on the block might help.

I'll measure up the belt, do a tooth count and see if Gates has any options on a -2 and -4.

I'd prefer not to, but if we're starting with a clean sheet of paper, let's look at all options.    Of course.

The one decision I've made is that I intend to make this work.     Yes.   But work well . . . .

midget,

See my notes in your text above . . . . .

Keep in mind, all the info available cautions that the max that can be taken off the head is .75mm (.030")    I would much prefer to just "skim" it straight, only if necessary.
Where I am going with this is that any compression ratio raising will need to be done with a "dome" on the piston.    So we just want to have a comprehensive plan to prevent any "Oh crap!!"  moments . . . . . .

 
Fordboy