Milwaukee Midget

[Interested Observer]

MM/Fordboy:
Given:
   Only one liter, NA, 75mm bore,  ~ 150 hp
   Top-hung liners with light diametral interference fit for lateral location
   Steel dowels
   Rubber (Viton/Silicon?) coated thin copper gasket
   11,000 lb preload per bolt (per standard)
Then:
   Are O-rings and O-ring grooves needed?  Why?
   Are liner diameters enlarged to the extent of needing siamesing needed? Why?

It seems to be completely functional and a lot simpler without those two features (and little or no concern about coining the head).

[fordboy628]

MM/Fordboy:
Given:
   Only one liter, NA, 75mm bore,  ~ 150 hp       999 cc, ~61 cubic inches.    Bhp goal for first iteration: 125 bhp  ~2.05 bhp/cu. in.

   Top-hung liners with light diametral interference fit for lateral location      The liners are not "top hung".  Very slight interference/clearance at the base, but the barrels are in compression between the block and the cylinder head/gasket.

   Steel dowels     Yes.

   Rubber (Viton/Silicon?) coated thin copper gasket    Flatout uses a very thin (.001"/.002") clear silicon rubber coating on both sides of the copper material.

   11,000 lb preload per bolt (per standard)    The plan is actually to use as much preload as the parts can tolerate, without undue distortion of said parts.   Easy to say, tougher to accomplish.


Then:
   Are O-rings and O-ring grooves needed?   Yes.   Why?    Because I'm basically conservative and do not wish to damage parts and incur extra costs in the development phase.   The damaged parts might not be able to be "reclaimed".   And since the parts are not readily available and cheap here in the US, why take the risk?    About 2 bhp/cu. in. is where head gaskets start experiencing serious compression loadings and failures.   Since ultimately we are looking for as much bhp as possible (what racer isn't?) it is just simpler to use the best compression sealing from the start.    Note that shim steel and MLS gaskets all use embossing to enhance the compression seal.    The manufacturers don't do it just to add cost.

   Are liner diameters enlarged to the extent of needing siamesing needed?   Yes.   Why?   The small amount of bearing area on the bottom of the cylinder "shoulder" onto the block casting is inadequate.    This is a crucial flaw in the original design, and that is not just my opinion.    Specialty sleeve manufacturers share this thought.   To increase the load carrying area the sleeve's OD must be enlarged.   Block bore diameter ~3.32"/84.3 mm.    3 mm minimum sleeve bearing "width" per side adds: 6 mm + 84.3 mm = 90.3 mm     That is greater than the 88 mm bore spacing, so a small "flat" must be machined on adjacent sleeves, to fit into the block.   Depending on further analysis of the space available inside the water jacket, we might go even larger than 3 mm to increase the bearing area further.

It seems to be completely functional and a lot simpler without those two features (and little or no concern about coining the head).    It would be a lot simpler, that is sure.  But rather than go through the development cycle one step at a time, say the way OEM's do, I would rather use my engineering experience to take a "shotgun approach" from the outset.   It spends some extra money perhaps early on, but usually prevents some expensive, stupid failures that can claim a lot of parts.   If you are an OEM, parts are cheap.    If you are working on something unique or rare, I try to bypass some steps in the development process (based on my engineering and/or experience) because it is cheaper in the long run.

IO,

Some of my thoughts inserted into your text and highlighted.

I'm not coming to the party as a wet liner "virgin".    I have significant previous experience struggling to modify wet linered engines to "reliably" produce more bhp per cu. in.    It is the same old story:  OEM manufacturer designs for a particular bhp output, tuners are unable to extract reliable power at higher output levels because of some designed in "limitation".    OEM designs are driven by cost, and over built parts are heavy and more expensive.   The days of significant "over-design" (such as SBC or Climax FW) are long over.

JMHO and YMMV   

Hope you had a pleasant Christmas.

 
Fordboy

[Milwaukee Midget]

Hi, IO -

Even staring at it, checking my notes, and going over Mark's comments, what we're up to here is as clear as mud.

Just to clarify, go ahead and double-click on this picture - it will take you to the video -



By design, the physical control over barrel movement is the step on the barrel into the crankcase and the clamp load of the head through the block.  There's a couple of thousandths of barrel movement side to side within the crankcase at room temperature.  This is how the engine was designed.  

Mark has explained the dimensions pretty well, but to summarize, the plan is to have Darton whip up some oversized sleeves that will be machined to be a press fit into the block both into the body of the crankcase, and at the top of the block at the bosses where the through bolts pass.  This should be sufficient to stabilize the barrel's side-to-side motion and eliminate fretting of the head face where the barrels meet the head.  O-rings, along with the steel dowels will further stabilize the mating of the top of the block and the head.
  
By making the top of the barrel larger in diameter with a deeper step at the point that it meets the bores in the body of the crankcase, by machining the face of the bores in the crankcase to provide a larger ledge for the new barrel step to sit on, and by machining the bolt bosses concentrically with the crankcase bores to be a press fit with the top of the barrel, we should be able to stabilize the entire assembly.

Given the enlarged diameter of the barrels, I'm thinking turning the outside of the barrels where they're exposed into the water jacket with cooling groves might also be a smart idea, but we haven't discussed that completely.

Another issue this addresses is that in stock applications, honing of the bores is not recommended - replacement of the barrels is the standard procedure.  With the new, larger barrels firmly press fitted into the block and with the use of a deck plate, we'll be able to get the recommended bore finish Total Seal recommends for their gapless rings.  We're fighting for every bit of CR we can get, and wasting it on blow-by is something I want to minimize.
 
As to holding it all together, the ARP studs arrived on Christmas Eve.  Apparently, Santa is no longer shipping directly from the North Pole - these were drop shipped by the factory elves in Ventura, California.  The original "long bolt" is on the top -



Cam wheels arrived as well.  I picked up a pair from Piper that I paid for with PayPal through a parts purveyor in Provence -



And the spare head for flow experimentation arrived from Pork Pie's Part of the planet -



I'm pretty sure I'm the only person in Milwaukee who owns one - I'm dead certain I'm the only Milwaukeean with a spare.



 

[Interested Observer]

MM/Fordboy:
Be assured that none of my ruminating is in any way a criticism, only trying to understand how it is going together and suggest a couple of things that had occurred to me.   I swear I read somewhere (not here) that the liners were top hung.  Your explanations make sense, of course, and I would agree with them.  Belt and suspenders.

[fordboy628]

MM/Fordboy:
Be assured that none of my ruminating is in any way a criticism, only trying to understand how it is going together and suggest a couple of things that had occurred to me.   I swear I read somewhere (not here) that the liners were top hung.  Your explanations make sense, of course, and I would agree with them.  Belt and suspenders.

IO,

No offense taken.  Sorry if my reply seemed a bit harsh or preachy.   Speaking for myself, I'm always glad for any help from any source, including the offering of differing points of view and the resulting discussions.

The whole idea of Chris' Build Diary was to document the whole process, soup to nuts, warts included.    If I was not in agreement with Chris' philosophy on this, I wouldn't be posting.    My idea in contributing to this documentation, is to illustrate out that there are some alternatives to cut and try based methodology or even educated guess based methodology.   My personal experience is that when you take the time to think about things first, and then evaluate information based options, the results are typically better.   My comments and input are focused on the engine/drive train part of the project, and I'm hopeful that perhaps some of the readers might find something useful for their own effort, or perhaps find an interesting, trivial nugget of science or math, with which they can use to avoid paying a bar tab.    

Thank you for all your insight and math help on this project.   Please keep posting.   This thing is going to need all the duct tape we can find, from every source!!

Although, . . . the belt and suspenders comment has left an unfortunate mental picture of my grandfather in my mind . . . . . . .    

 
Fordboy

[fordboy628]

Holy Crap Batman!!

600,000+ views!!      

 
Batsquirrelboy

[SPARKY]

600,000   
 hmmm you two are running the Pied Piper a hard race or--- 

 there are an unusual number of LSR sick lemmings being led to a formerly dried up---- inland sea following this build 

[Seldom Seen Slim]

Interesting - unh, - metaphor (?), Sparky.  I don't think I've heard that one before just now.

[Milwaukee Midget]

600,000  
 hmmm you two are running the Pied Piper a hard race or---  

 there are an unusual number of LSR sick lemmings being led to a formerly dried up---- inland sea following this build  

A couple of thoughts -

I'm aware there are a number of "lurkers" who visit this build, and I'm grateful they're finding entertainment, solace, humor and/or intelligent discussion here.  I'm glad we're reaching people, but there is a number that means more to me than the number of hits on the build diary.

135

1. The first Factory MG to come to Bonneville was the EX135, driven by Goldie Gardner.  It was the factory streamliner that the So-Cal team eyed up for inspiration on body design, and hit over 200 mph before the war on the Autobahn in Germany.

2. My best speed in 2014 was 126.684.  While I don't think a record of 135 is likely, I'm thinking a run that might put the Midget into impound again could touch on that number.

3. 135 hp is also in the ballpark of what Mark and I think we might be able to get out of the K-Series.

I used to be focused on 121.779.  That number was replaced with 122.539, and we did it with 99.1.

So now, I have one number that glues everything together.

I'm waiting for Chuck to publish the numbers that are allocated for this year, and if 135 is not taken, I hope to get it.

Historically significant, a speed goal, and a horsepower goal.

So that's the numerology I'm looking at.
 
As to the "formerly dried up inland sea" . . .

I've read through damned near every document I can find on what's happening at Bonneville.  I've been critical of some observers and observations, and indeed, snide toward some who genuinely want to help.  For all of it's alleged "natural beauty", I accept the fact that it is now, and will likely remain, an engineered environment and landscape.  So yes, despite the very real possibility that the Bonneville Salt Flats my never be raceable again, we're pressing on.  And as I look through these other build diaries, I see others are as well.

Some of my best friends are Lemmings.  

MARK - Check you e-mails!

[tauruck]

We NEVER give up.

[fordboy628]

Some of my best friends are Lemmings.  

Perhaps, just not this particular one . . . . . . . .   

MARK - Check you e-mails!

I had a wonderful 2 hour drive home from Glenview last night in the ice storm, getting in at 7pm.    Since I last checked my e-mail @ 14:30, I didn't check it again.    But I checked it now, @ 1:30 am, so as far as I am concerned, you are getting an immediate response.   

The information you seek is somewhere previously in the build diary.    I'll also dig out my K engine notebook.   Check with me later, via phone, if you need immediate gratification.

 
Wearyboy

[SPARKY]

SSS  I am surprised  that you are struggling to recall    such a classic quote!

[Seldom Seen Slim]

Sparky, if you knew well how I spent way too much of the late 60s and 70s -- you'd understand that not only don't I recognise that quote -- I probably couldn't find my behind with both hands unless you gave me a one-hand head start or something.

"Yeah, Man, I see it too. . ."

[SPARKY]

LOL 

SSS  I posted it and I have no idea how or why my demented mind came up with it!   

[fordboy628]

midget,

What is the status/delivery esitimate @ Rodi Machine?   Does Greg need more information to finish?

Also important:  Rod journal diameter needs to be the BMC small journal sizing (nom. 1.625") to be able to use 3/8" diameter rod bolts in a 75mm bore diameter with some margin for conn-rod big end diameter.   There are some thoughts/specs previously in the diary.

 
Fordboy