Milwaukee Midget

[wheelrdealer]

MM:

I paid my $1 per HP. I am happy to send the extra when you get the 100HP tune-up.

Good luck,

BR

[lsrjunkie]

I to, am all paid up! Looking forward to seeing what this little engine finally puts out! 

[Milwaukee Midget]

You guys are the best - Thanks!

CONFIRMED - May 28, for those of you who wanted to wait.

I intend to extract HORSES and DOLLARS. 

[fordboy628]

Midget,

I'm busy with the list for the Queen, (that would be the RED Queen), but as soon as I am finished, (probably when I'm dead), I'll work on a a condensed format of the hard output data, including some specs & analysis.   I will forward this to you, for perusal at your leisure.   (Whilst you are enjoying a brew, for instance. . . . .)   Then, if there are any other requests for the hard data, you can send it off straightaway, at a reduced file size.

I also still intend to post up some spreadsheets/graphs with analysis, as I threatened before, with your prior permission of course.
 
thoroughly thrashed out Jesterboy. . . . . . .

[Milwaukee Midget]

Thanks, Mark - I am still struggling with reading the files.  I removed the Superflow reader and all the files, and will attempt to re-install and start from scratch.

[Seldom Seen Slim]

Okay, Chris -- here's a partial list of those folks that were kind enough to cough up a few bucks in response to your Dynothon Challenge.  I remind one and all that this is a partial list -- 'cause there are a few checks that have arrived - and the list of those is at the store (and I'm not right now).  I'll add those names in a day or two.  Also -- some of these donors may not have sent in $$ in response to your engine - but I didn't take the time to try and sort out the stuff right now.  If you didn't send money in Chris's motor's honor -- let me know if you'd like to do so.

Anyway, from 10 - 17 May I got these Paypal notices:

Luke Kohler,  Bill Reilly,  Chris and his Mommy and Daddy,  Joseph Christian,  J-P Trzebiatowski,  Graham Hatfield,  Dean Lanborn,  Joe Daly,  Jon Bennett,  David Hosley,  Denis Carroll, and Jorge Holland.  Oh, and LSR Junkie, too.

I'll be putting your names -- and the other folks that have donated since mid-March - on the home page list of donors.  Thanks one and all.  I'll do my best to reward you for your remunerative kindnesses.

Edit to add one name -- thanks, LSRJunkie.

Edit to correct a Paypal-addled misspelling.

[fordboy628]

Kemo Sabe,

Whilst out on the range, set fer a spell at T&T.   Observed & measured the following cold valve lash dimensions:

1E   .024"
1I   .022"
2I   .025"
2E   .023"
3E   .023"
3I   .022"
4I   .022"
4E   .023"     These numbers certainly seem to be acceptable given the higher spring pressure and the number of pulls.   Glad to know this now . . . . . . The cam/lifters/springs/valve train seem to be getting acquainted nicely, just for a change of pace . . . . . . . .

I think a cursory inspection combined with a relash gets you more pulls/info/bhp, on the way to Dodge City or maybe SLC/Bendover . . . . . . .  

Also: took some manifold measurements from the cylinder head.   Going to try to come up with a better head/manifold match.
Inlet port @ head face, 37mm dia.,  134.5mm C/C spacing.
Steel manifold @ head face, 34mm dia.
Aluminum manifold @ head face, 32mm dia.    There are some issues @ the carb face on both manifolds as well.

Picked up alternative fasteners for throttle plates.   Rebuilding/modifying your 45DCOE & the 48DCO I've loaned you.

Found the problem with the 45's accelerator pump circuit, you took a silver (solder) bullet in the foot . . . . .  you need some practice with that shootin' (soldering) iron. . . .
Will post pics later for a Weber on-line build diary tutorial . . . . . .    These changes should solve the problem with the 45DCOE carb.
 
Tonto

P.S. STILL searching for the jug of the better "Firewater". . . . . .

[lsrjunkie]

Wow Slim! I feel like Batman! I got my real name and my alias mentioned!  So much for keeping my secret!!

[Koncretekid]

Kemo Sabe,

Whilst out on the range, set fer a spell at T&T.   Observed & measured the following cold valve lash dimensions:

1E   .024"
1I   .022"
2I   .025"
2E   .023"
3E   .023"
3I   .022"
4I   .022"
4E   .023"     These numbers certainly seem to be acceptable given the higher spring pressure and the number of pulls.   
 
Tonto

P.S. STILL searching for the jug of the better "Firewater". . . . . .

Mark,
I find those lash settings high. My BSA 500 single specifies .010" even with the race cam.  Seems like there would be a whole lot of clacking and banging going on.  But then, it is British!
Tom

[Milwaukee Midget]

1E   .024"
1I   .022"
2I   .025"
2E   .023"
3E   .023"
3I   .022"
4I   .022"
4E   .023"     
P.S. STILL searching for the jug of the better "Firewater". . . . . .

Mark,
I find those lash settings high. My BSA 500 single specifies .010" even with the race cam.  Seems like there would be a whole lot of clacking and banging going on.  But then, it is British!
Tom

Tom, yes, those do seem wide, but they are the specs Dema set forth, and toward the high side recommended by David Vizard.  Stock is .012, but that is with a 1.25:1 rocker ratio.  We're at 1.5:1, so that accounts for some of the increase.  .022 and .024 permits an adequate amount of oil to build up on the lobe and the bottom of the lifter, which is pretty critical when you realize that the tappet is only .812.  We're also trying to ride the crest between a very gentle clearance ramp rate and a lash that winds up being too much of a shock to the system.  Break-in and 15-16 pulls with no appreciable change in clearance tells me we're probably just about where we need to be.

Last time, my cam got chewed.  Of course, there were other issues at play . . .   

If unattended, this cam is likely to be hard on lifters.

Fordboy - aka Tonto - Firewater forthcoming.   

[Crackerman]

Unless you are using some super duper oil i haven't heard of, .025 still sounds a bit loose and can definitely hammer the valvetrain way up there in the rpm range. I can see that clearance on exhaust due to heat expansion, but taking them to .015-.017 ought to help all around the power band.

[38flattie]

Those clearances look more like big roller cam lash settings!

I'd be reluctant at the least, and hesitant at best, to second guess Dema's recommendation, though!

Great job, Chris and Mark!

[38flattie]

Also: took some manifold measurements from the cylinder head.   Going to try to come up with a better head/manifold match.
Inlet port @ head face, 37mm dia.,  134.5mm C/C spacing.
Steel manifold @ head face, 34mm dia.
Aluminum manifold @ head face, 32mm dia.    There are some issues @ the carb face on both manifolds as well.

Custom match ported intake an option? I wouldn't think it would be too hard to get some flanges made, and tubing cut....  

[fordboy628]

Kemo Sabe, et all,

Lash settings are determined by:

1/  Height of the clearance ramp ground into the cam blank, ie, the portion of the cam grind between the base circle and the opening/closing ramp . . . .
2/  The rocker ratio, where larger/higher ratios permit more clearance . . . . . (OH cams with direct action and therefore a ratio of 1/1, REQUIRE LESS clearance for proper
     operation . . . .
3/  Valve stem/pushrod growth (in length) due to the heat of operation, which in efffect reduces the working clearance . . . .
     (heat one of your exhaust valves & measure the length HOT Vs. cold.  You might be surprised . . . . )
4/  The "stiffness" of the valve train for OHV (pushrod) engines . . . .
5/  Etc, etc . . . . .
6/  This is one area where the customer should follow the clearance specs set forth by their (reputable) cam grinder, since he/she knows how much "ramp" is ground/designed in.

Although I don't have the ramp specs for the custom "Midget" cam, I typically find that I can't get myself in too much trouble by following St. Dema's instructions.   He has designed/supplied me with dozens of specialty cams for "weirdball" applications over the last 30+ years.    I have NEVER been disappointed by his product/work.   It is why I continue to use & recommend his products . . . . . .

By now it should be clear to everybody why you just can not use any dimension for the camshaft clearances, OR, compare between OHV (pushrod) & Direct Action (OHC or Flathead!!) valve trains.  (Yes, I know I left out the exceedingly complex OHC with rocker followers, please don't PM me about it . . . .)   The purpose of the clearance ramp is to gently take up the lash & PREVENT an excessive instantaneous load to the valve train.    If the follower is exposed to the flank without a ramp, the loads are very high and almost instant, quite possibly exceeding the strength the the materials in question with extreme contact pressures . . . . .  (this also includes roller followers . . . . .)

Some numbers for cold lash:

A/  Let's say we have a cam with a .016" ramp height, and an OHV engine with a 1.5/1 rocker ratio.   So then:

     .016" ramp on cam * 1.5/1 R/Ratio = .024" MAX permissible valve lash.   I would probably run .021"/.022" Ex. and .019"/.020" Int. for starters, UNLESS the cam mfg. 
     suggested otherwise . . . .

B/  Let's say we have a cam with a .010" ramp height, and an OHC engine.   So then:
     .010" ramp height * 1/1 Ratio = .010" MAX permissible valve lash.   I would probably run .009"/.010" Ex. and .007"/.008" Int for starters, again UNLESS the cam mfg.
     suggested otherwise . . . .

Some advice from experience:

AA/ For a typical OHV engine, (.020"/.025" recommended lash), you can typically run .004"/.006" tighter than the cam mfg. states.   If your engine picks up power with less
      lash, you probably need more cam.

BB/ For a typical OHC engine, (.008"/.012" recommended lash), you can typically run .002"/.003" tighter than the cam mfg. states.   Comment as per above.

CC/ For either engine type, if your engine picks up power with a lash setting that exceeds the mfg's recommendation, you probably need less cam.

DD/ Running with excessive lash will typically beat your valve train to death from the high loads imposed . . . . . .

EE/ Take the time to ask your cam grinder how much clearance ramp is ground into your cam, so you can calculate intelligent choices . . . . .

If you are not familiar with camshaft terminology refer to this site:  http://www.camtechniques.com/Pages/term.html
 
Fordboy

[Milwaukee Midget]

Unless you are using some super duper oil i haven't heard of, .025 still sounds a bit loose and can definitely hammer the valvetrain way up there in the rpm range. I can see that clearance on exhaust due to heat expansion, but taking them to .015-.017 ought to help all around the power band.

It sounds logical - but it doesn't work that way on this . . . , well, can I really call it a design?

Here's what happens when you run at .018 - This is a SPVP-5 grind after two runs at Maxton and two pulls on a chassis dyno - and granted, there were other issues involved -



There were a couple of grinds that APT and Crane used to make for this set-up that let you run a tighter lash with a 1.5:1 rocker ratio.  They had almost no ramp, but the experience of racers was that is was harder on the valvetrain, and the cams tended to scuff and snap.

It's the heat at the lobes and the lifters that kills this combination.  The extra oil, at the base circle of the cam and the bottom of the tappet, helps dissipate it.

Here is my understanding of the logic of this -

With the wider lash, the lifter rides higher on the oil film of the base circle because the lifter doesn't skim as much oil from the cam.  This better prepares the lifter with more lubricant when the lobe actuates it.  Both the lobes and lifters run cooler because of the extra oil.

Example -

A stock cam with 1.25:1 ratio rockers set at .012 provides clearance of .0096 between the tappet and the base circle of the cam.  So the oil film at the lifter's loosest point in the cam rotation is .0096, which is probably fine if you're running 50lb's of seat pressure x 1.25 (Rocker Ratio) through a .5 inch wide lobe over a .812 tappet.

With the special grind set at .023 and a 1.5:1 rocker ratio, the potential oil available to lubricate and extract heat from the lobe and lifter at the base circle increases to a thickness of .0153.

The effect is

A. Cooler lobes and lifters, because almost twice as much oil is dissipating the heat from the lifter while running on the base circle of the cam.

B. A better lubricated tappet, because more oil is being deposited consistently onto the face of the lifter as the lobe approaches it.

Dema Elgin put a real soft ramp on this that takes up the slack pretty easily.  Given that early in his racing career he campaigned a Spridget, I'm inclined to bow to both his and David Vizard's experience and recommendations regarding the lash.