Milwaukee Midget

[Milwaukee Midget]

Do they coincide with the valve guides that looked like they copped the worst pounding?

jon

No, not really - good thought, though.  The one in the picture is the worst of the three, and it is on an intake, but the other two are on an exhaust and an intake.

The adjusters are out of what's called an "A+" block for the MG Metro/Mini, and they are stock replacements from Minispares.  As to who manufactured them, when, where, or to what standard, in this day and age, who knows?  I'm putting a lot of valve pressure on this valve train, with lift at the valve of almost 1/2 inch.  It's not a fun environment, but I think they were just improperly hardened.

You know, I just sat here and stared at the picture for a couple of minutes.  When I get home, I'm going to grab my micrometer and check the diameter of my balls.

Yes, and then I'll measure the adjusters . . .

[Captthundarr]

He,he, he.
Chris, just curious to know, how much spring pressure are you running in that little screamer?

[grumm441]

So the pushrod is straight isn't it?
I guess you also have to look at the angle that it is working over. It looks like it is moving to a point where it is going past the the radiused (is that a word) area of the ball and socket. I would like to see the movement of that rocker thru a whole rotation of the cam
Oh and http://www.writeupsidedown.com/
G

[Captthundarr]

˙ƃuıɥʇ pɐq ɐ ǝq pןnoɔ sıɥʇ uɐɯ ʍɐ

[Ron Gibson]

MM
  IMHO   Jesel says to not have over 1 1/2 turns out from seated on your adjusters as a starting place. The one on the right appears to be way more than that. Do all of the scored ones have the adjustment out like that? If they are out too much your rocker geometry is way off (needs longer push rods) and imposes too much load when trying to start to open the valve.
 
Just my $.02 and worth what you paid.

Ron

[Milwaukee Midget]

Frank, Grummy, Ron, thanks for checking my work -

Ron - The adjusters are where they are right now so I could relieve the pressure on the rockers and remove the shaft and head.  This is from two years ago with a reground cam with a smaller base circle.  The cam in it now was ground from a new billet and sets the pushrods a bit higher into the socket.



When the head comes back, I'll need to mock it all up again and determine my pushrod length.

Grummy - Pushrods are straight, but your point on the radiused end of the pushrod is a good one.  Let’s see what the new adjusters look like.  By the way, if we continue the use the word "radiused", we can MAKE it a word - Funk & Wagnalls be damned.


Frank, the Crane springs should be delivering about 75-80 lbs to the seats.

[grumm441]

The rocker geometry is also a big question mark
I didn't pay proper attention to the geometry on the spigot of sunshine motor and had some problems
The rocker was running out of slot at full lift
However they showed up pretty quickly on the dyno
Although looking at that picture, is it possible the pushrod is running into the body of the rocker at full lift
G

[Milwaukee Midget]

Although looking at that picture, is it possible the pushrod is running into the body of the rocker at full lift.
G

Thanks, Grummy - I'm not seeing any indication of that on the rockers - they're aluminum, and there's no nibbling there.

I'm not a big fan of shims, but I don't have a problem with machining down the pedestals or pushrods.

Everything is going to change a bit when the head comes back, but any thoughts I can get ahead of time - hey - forewarned is forearmed.

[Milwaukee Midget]

Still waiting on the head – seems between the time I sent it in and the time that APT received it, a few other racers beat me to the queue – it is that time of year. 

Dick Luening has a sign up in his MG shop, which reads, “We interrupt this marriage for Racing Season.”  While I find Dick’s sign humorous, I know I need to maintain some balance with Mrs. Midget.  She has been an absolute trouper with respect to this goofy endeavor, and I’ve made a point to spend some extra time with her this winter.  We’ve taken in a couple of plays, went down to Chicago to catch Black 47, and we’ll be seeing Nick Lowe next month.  There will no doubt be a few things I’ll need to do around the house this spring before I can beg off completely to the garage with a sixer of Pabst and the Cubs on the radio, but I’m completely fine with that.

I did get my new linkage for the carb today.  The old one was a contrivance I cobbled together out of a piece of angle iron and a drilled out gas fitting.
 


It worked fine, but it only worked on the manifold that I had set it up for, which has an attachment boss.  I want to be able to swap out manifolds during my next dyno session, and maybe even at Bonneville.  Seeing as the new unit attaches to the carb rather than the manifold, it turns that whole operation into an 8 bolt change-out with no adjustments necessary.
 




If I’m careful, I won’t even need to disconnect the fuel line.

I've got my good friend and keyboard virtuoso, Rob Pfeiffer, working on some T-shirt art work.  Promises to be kinda gnarly.

[38flattie]

Chris, you're a smart man! Smart men know when 'Mama ain't happy, ain't nobody happy!

Carbie setop looks nice!

[Milwaukee Midget]

Thanks, Buddy.  It will be very practical, and probably safer in the long run.

Every now and then, you’re scoping out the Flea-Bay, and something comes up you just don’t expect.  You may not wind up buying it, but it might lead to a very enlightening conversation with the seller.
  
http://www.ebay.com/itm/Dry-Sump-Oil-Scavenge-Pump-BMC-XSP-F-Jr-Spridget-Mini-all-displacements-/190651749031?hash=item2c63bad2a7&item=190651749031&pt=Race_Car_Parts&vxp=mtr

A BMC Works dry sump pump?  Cam drive?  Formula Junior?  I didn’t know that they had made such a thing.  

My inner geek got the best of me, so I dropped him a note, and 5 minutes later I was knee deep in a phone conversation with a guy who had extensive knowledge of the short-stroke, factory A-block motor I’m cloning.  One hour and forty minutes, and two pages of notes later, I’ve come away with a few more tricks to finish my tweaks.

So Mike, (I took notes, but did I get his name right?  MARK) if you wind up reading this, thanks for your time today – I am very grateful.

[Tman]

Here it is PBR and the Rockies

[Captthundarr]

Yep Chris, you learn the dangedest thangs from the some stranges sources (eeek-bay)
Frank

[fordboy628]

Hi Midget,

Well, ahem, stayed up until 04:30am CDST reading all 64 pages of your build blog.  My curiosity has been piqued, to say the least.  Several thoughts have occurred to me since our conversation and thence reading the build diary.   In no particular order, here goes:

1)  Stop using the stock clutch slave cylinder immediately.  Use a modified Saab center mount, on the input shaft sleeve of the trans, with a remote bleeder on the firewall.  Plumb this with aeroquip.   A good machinist can fabricate the adaptor.  This setup is now probably available complete through specialty Spridget/Mini folks.  This solves the problem of bleeding the clutch AND gives more clearance to the frame in a tight spot.  I don't know what your clutch finger height is and this is critical for proper setup since the Saab slave cylinder has limited travel.  The length of the adaptor to mount the slave cylinder will need to be very precise.  And do not forget that as the clutch disc wears, the pressure plate fingers MOVE TO THE REAR OF THE CAR.  Not having enough clearance between the throw out bearing face and the fingers results in....potential clutch slippage and crank/thrust washer WEAR.  This needs to be worked out with the engine/trans on the work bench.  (I no longer willing to work on the floor or in the dirt.....ageing is such a pain!)

2)  I am just thinking out loud here and getting ahead of where you are in the car's development.  But I am wondering if you are allowed to run a Spridget trans with Hewland gears inside?  These exist, and although expensive, I am wondering if said item allows overdrive/underdrive top gear ratios?  Does anyone out there know?  My thought is that Hewland gears allow top gear splits on the order of .04 difference.  Your standard trans 4th gear ratio is: 1 to 1.   Your diff ratios options are 4.22/1 & 3.90/1   If you get close to the I/GT (?) record at some point, splits on 4th gear ratio of: .92/1; .96/1; 1.04/1; 1.08/1; etc, MIGHT prove useful in setting a new record.  OR.... is there a 4.10/1 or 4.11/1 diff available for these beasts? 

3)  Have several thoughts on your engine issues, but I want to get my thoughts in order first.   I will say this though, after 35 years of building & dyno tuning racing engines, high speed misfires (even slight ones) are typically 3 things:

A)  Poor/inadequate fuel delivery and/or fuel curve drastically rich/lean.  Putting my Weber thoughts in order before posting.   
 
B)  Ignition timing inadequate (poor spark at/in combustion chamber) or ignition timing significantly off from what is required.   Talking about ignition timing in terms of crank degrees is meaningless here.  My experience is that rod length/stroke ratios have significant impact on "crankshaft degrees of ignition timing".  This is because ultra long rod length/stroke ratios (as you have) cause the piston to "dwell" more BTDC & ATDC.   (Causing decreased valve/piston clearance as well)  Rather than think in crank degrees, think in terms of piston movement in thousanths of an inch, BTDC.  Also, along these same lines regarding ignition timing:  spark plug type (not manufacturer) DRAMATICALLY AFFECTS TOTAL TIMING, HOWEVER YOU MEASURE IT!!!   A retracted gap spark plug requires MORE ignition than a projected nose spark plug!  THINK ABOUT IT..... it is about the total length of the flame path in the combustion chamber.   Shorter flame path = less total ignition timing required.  Longer flame path = more total ignition timing required.  Sometimes the physical requirements of the engine or the heat of combustion (ie: Top Fuel) require using a short nose or retracted gap spark plug.   I have seen more than one engine melted by a change from a retracted gap spark plug to a projected nose spark plug without the needed reduction in total ignition timing.   "Indexing" of spark plugs can also change the ignition timing requirement.  Sorry for getting a little off topic here, pet peeve of mine.   

C)   Inadequate valve spring pressure, both open & seated.  This is a very technical subject, but in general terms: Higher valve train mass/high valve train moment of inertia/higher engine speeds/higher cam flank accelerations, etc., REQUIRE more valve spring pressure to CONTROL valve train motion.   Years ago I did some 1275 engine development for a friend who raced a Sprite in SCCA F/Production.  He was always close to the front of the pack & even won the occasional National race.  One session on the dyno revealed an engine that would not run above 7000rpm with heavy load.  Keep in mind that this was a quasi-competitive car/engine/driver combo.   A valve spring change resulted in an engine that would pull cleanly to 9000rpm.   Some minor tuning of the carbs & ignition timing checking led to:  Race win & NEW F/Production LAP RECORD AT THE JUNE SPRINTS @ ROAD AMERICA!!   

IT'S ABOUT SOLVING THE PROBLEM, NOT THE SYMPTOM.   

I'm sure we will talk/blog some more.  Might be motivated to work for/trade parts for decent microbrew.   Only one request, no more using the P****** word around a lifelong Bears fan!!!!!!!!!!!!

 
MB

[Milwaukee Midget]

Fordboy628, welcome to the forum, and again, thanks for your time and interest.

You're looking for Microbrews, eh?  Ask Tman about my selections for out-of-towners - I'll always trade time/parts/conversation for beer.

If you spend a little more time on these forums, you will see some builds and projects that are so out of the ordinary, so varied, and just so darned interesting, you'll wonder why you haven't been here before.

We take cat skinning to the next level - we actually develop recipes.