Milwaukee Midget

[fordboy628]

And now, a "time out" to watch the Australian Gran Prix!

From Melbourne, no less . . . . .

Ah, Melbourne, ranked #1, as the "Most Livable City in the World",   not just once, seven years in a row.

I guess I know where I'm spending my year of retirement in Oz . . . . .

 
Can'twaitfor70boy

[jacksoni]

Beautiful work, Mark!

[fordboy628]

Major Engine Update:

Changing the Crankshaft Oiling System Porn, uhh . . . . . photos . . . . .     (I tried to get Stormy Daniels to hold the pointer in the photos, but, as luck would have it, she's busy . . .)

SO, I get asked:  "Why are you doing this?   You think you are smarter than the guys (sic, engineers) who made (sic, designed) the engine?"

Buzz and I only need one bullet point to answer this question . . . . . .

A/   YES.


The problem, as I see it:

A/   This engine was designed as a "grocery getter", not with high rpm "performance potential" in mind.     (More or less direct quote from the primary engine designer.)
2/   Within the "performance engines" based off this unique design and using the standard oiling system, higher than normal rod bearing wear, at high rpm, is well known, and accepted.
d/   Servicing, ie, replacing worn rod bearings, although a simple procedure on conventionally designed engines, on this unique design, results in a major disassembly of the engine.

SO, knowing this, the decision that has to be made is:
Am I willing to accept lowered performance, compromise engine longevity and possibly risk catastrophic failure to an expensive engine that can not be easily repaired or replaced?

With knowing those factors and placing the question into that context, it becomes an easy answer . . . . .

A/   NO!!

And Chris agreed, since it was his wallet that was going to take the hit.


So, what is it going to take to resolve this potential problem?   Both design-wise, AND, cost-wise . . .

A/   Well, the crank oiling passages needed to be revised.   But since it needed a special de-stroked billet crank, revising the oil drillings was not an issue.    Additional cost $0.00

2/   The main bearings on main journals #1 & #5 need to be revised to permit oil feed to their adjacent connecting rods.    This was an easy solution as the requisite bearing already existed.    The main bearings for journals #1 & #5 were originally BOTH plain, ungrooved shells, as they only oiled the main journal.   BUT, the main journal bearings for journals #2, #3 and #4, since they oiled the connecting rods normally, used the conventional bearing construction.    A plain ungrooved shell on bottom, with a grooved shell on the upper.    This represents the best compromise of load carrying and oil supply.    So additional grooved bearings were needed to be added to the #1 and #5 positions.    Fortunately, Mahle Motorsports produces a competition quality main bearing set in Vandervell VP2 material.   (Produced in the original Vandervell factory, as I understand it.)   But, they are supplied for the standard oil system of 3 grooved shells and 7 plain.    So the additional cost is the price of a second set of competition grade main bearings approximately $125.00     And this allows us to "steal" 2 more grooved bearings for the re-designed system.

d/   Since the different bearings have different tangs, (so they can't be mistakenly switched), the block would need some fairly trick machine work to revise the bearing tang notches.  Additional cost  ? ? ? ? ? ?

So that's how we got to here, and the photos are below.    But first this:

We are publishing this for a variety of reasons:

A/   Chris has always intended this "Build Diary" to be a complete compendium of his journey.   Warts and all.    Flatlanders included.    And I agree with all.   Except the cats . . . . . . .
2/   It is an example of how engineering experience can avoid potential problems using good judgment.    Readers should apply this judgment and logic to their own builds.
d/   This post is intended to provide a "blueprint" for a way forward, to those racing these K series engines, and experiencing this problem.


And now, the porn . . . .  uhhh . . photos . . .

So here is the problem . . . . .   #1 journal



Same problem, #5 journal . . . . .



The setup for the "correction" on #1 journal . . . . .



And, of course, the block faces are not "flat" . . . . .






And the finish . . . . .



Grooved bearing fitted . . . . .



Repeat for the #5 journal . . . . . .












And before anyone asks, YES, the bearings were slightly shifted longitudinally.    This was done to retain as much material as possible between the original bearing tang notches and the new notches.    I wanted to avoid welding up the old notches and "creating" more machine work.    This "shift" needs to be done carefully, so the bearing chamfer doesn't interfere with the crankshaft journal radius.

I'll post the results of this operation later in the day.

For now, I'm asking for feedback from any reader who is racing a K type engine and having bearing problems.    I know you are out there lurking, sign up and post a comment.

 
Machinistboy

[jacksoni]

Mark- again nice work. I have read somewhere that locating tangs may be superfluous other than for the initial placement of the bearing and that they really don't hold the bearing but that bore crush does. Making the complicated operation you have gone through unnecessary. You could just grind off the offending tang. Thoughts? Obviously you felt the above likely untrue as you have gone to considerable work to make the bearings fit as mfg'd. Just askin'.
Clueless Jack

[fordboy628]

Beautiful work, Mark!

Thanks Jack.   I try to get a passable result.    But on this site, there are many fine machinists and fabricators documenting their work.    I don't consider myself to be at their level.

But I have an ulterior motive.    My participation in this "Build Diary" is now intended to provide some instructions and guidelines for those who choose to follow in my footsteps.    Early on in my career I came to the conclusion that I simply could not "pay back" those who had helped me, pointed me in the right direction and corrected my path.    A sage adviser suggested that the best way to "pay off my debt" was to "pay it forward".   And since none of my children will follow me into this line of work, that is what I am trying to accomplish in various ways.

Thank you to all who have helped and guided me.    I've learned something from all of you.

 
Teacherfornowboy

[fordboy628]

Mark- again nice work. I have read somewhere that locating tangs may be superfluous other than for the initial placement of the bearing and that they really don't hold the bearing but that bore crush does. Making the complicated operation you have gone through unnecessary. You could just grind off the offending tang. Thoughts? Obviously you felt the above likely untrue as you have gone to considerable work to make the bearings fit as mfg'd. Just askin'.
Clueless Jack

I agree about the tang being the initial locator only, and crush (pre-load) retaining it in place.    Because of the larger radii on the billet crank, I wanted precise placement of the bearing inserts.    And moving the tang notches was the best solution in my opinion.    With the girdle/ladder assembly on this design, getting and keeping everything lined up during assembly was the main consideration.     I'd worry without tangs to positively locate the main bearings.    And there is enough to worry about.

I am aware that others have used the method you suggested with success.    In spite of some of my radical ideas, I'm really quite conservative, at least engineering wise . . . . . .

 
F/b

[wobblywalrus]

The Triumph has an aluminum crankcase and the oil feed goes up to a grooved main bearings before it flows into an oil passage that goes in the crank to the rod big end.  There are fatigue issues with the rod big end shells on one side.  Custom rods are used with the bolts facing the direction that allows relatively painless renewal without tearing the motor completely apart.  This big end shell problem is a known and anticipated issue.

The main and rod clearances were always calculated using the standard procedure described by Mahle.  The rod big end clearances continue to use that method.  They are steel rods.  A link to info from King bearings was posted in my build diary by Woody.  One of those discusses how bearing clearance increases with temperature and crush decreases in an aluminum block engine when it heats up.  The crank journal clearances set to Mahle's recommendations are too loose when the block heats and expands and oil pressure to the big ends is lost is my best guess.  This year the crank journal clearances are set at the minimum recommended by Triumph for a street engine.  The clearances will increase to Mahles recommended when the aluminum block expands due to combustion heat.  This will give proper oil pressure at the rod big end.  The downside of this is the engine needs to be warm before the fling down the salt.  Otherwise, the crank main journals will be too tight.

This is all calculations and hope at this stage.  I will not know if it works until that first run down the salt.

[fordboy628]

Daddy, what kind of porcupine is that?



That's not a porcupine!    That's Mr. Wilson!

[Milwaukee Midget]

I will not know if it works until that first run down the salt.

Testing, calculating, doing you're "gozinta's" - at the end of the day, getting it down the salt is what matters.

ARP - 9mm "Long Bolts" for the K.

That's a really long quill to draw up, and it was frightening watching Mark with the torque wrench CONTINUE TO TURN THE DAMNED THING until it came up to spec.

One of the other aspects of the crank is that we had the throws turned to the 1275 MG spec (1.625"), rather than the standard K series dimension (43 mm, 1.693").  This gave us a good selection of readily available competition grade rod bearings, and a tad more leeway to go with 3/8" con rod bolts, rather than 5/16".  Mark was rather insistent on that spec, and to be honest, we've got too much time, sweat, cash and energy tied up in this block to start inadvertently installing windows.

By the way - after the crank was installed and brought up to spec, it was a two-finger turn - smooth as a baby's butt.  Considering the work Steve Demirjian did, boring the block and pressing in the Darton sleeves, I was mightily impressed.  I expected warpage to the point that it wouldn't turn at all.  It still needs to be properly checked, but we MIGHT be able to slide on an align hone ( ).

[fordboy628]

More photos of the "trial fitting"






More photo "porn" later this coming week.     Chris can add descriptions for these if he wishes.

As for me, TTFN.

 
Needsomesleepboy

[wobblywalrus]

There are a few things I forgot to say in the recent post.  The rod bearing fatigue issue has been a big problem for years.  Changes made were to ceramic coat the piston tops to reduce the heat going down the rods to the big ends and this keeps the oil cooler and more viscous.  Also, polymer coatings on the big end shells and switching to a 15W - 50 oil that is specifically recommended for aluminum block engines.  All of this helped to reduce the big end shell fatigue.

The shop was about 55 to 60 degrees warm when I set the main bearing clearances so I used Triumph's minimum.  Had the shop been at 68 degrees I woulda used Triumph's mid range clearance for a street engine which is a bit tighter than Mahles recommended race clearance.    

[WhizzbangK.C.]

Minor update:

Coolant outlet Porn!! . . . . . er, photos . . . . . .

So you end up spending time on some things that are just typically taken for granted . . . . . . .


With the new exhaust flange installed on the head, an alternate provision for coolant outflow is required.



This beaded water pipe connector is from CSR Products.








Since I wanted the outlet neck centered over the cast passage in the head, I made a template of the space available:




And the fitted plate.   Fabricated from 1/2" thick 6061T6.




Yeah, I know it's overkill, but the material was leftovers from one of the midget's previous dyno adaptors.    Poetic, isn't it?
And I'm a charter member of the "clean plate club".




The tapped plate.     3/4" NPT








The finished product.







Another "small job" that "consumed a morning".     One more detail out of a thousand . . . . .


And that, boys and girls, is why racers are hopeless optimists . . . . . . . .  and why EVERYTHING takes longer than you think it will.

 
I'mafflictedtooboy

P.S.   Hopefully, I'll soon be obsessing over the details of the flies I'm tying.    I'll be the same Mark, just a different blog on a different board . . . . . . .

I love this thread and read every post, even though I have absolutely zero interest in the specific engine type. I find it very informative on the general tech level and have applied many things I've learned here to the the way I approach problems with my own work. Thank you for going into the detail that you do, and please keep doing it. 

Not trying to find fault or be critical here, but personally, I would not trust that outlet adapter. I have had to repair far too many failures on things just like that. The cut threads create a stress riser in the tube, and the long stand off with the weight of hose, clamp, and coolant bearing on it along with vibration from the engine running is just begging for the adapter to snap off at the worst possible time. I would redesign that detail, or at very least make sure that the pipe was firmly supported and not allowed to flex at all.

[Milwaukee Midget]

I would redesign that detail, or at very least make sure that the pipe was firmly supported and not allowed to flex at all.

Thanks for that. 

The direction of the plumbing is still to be determined - I need to allow for the header, EFI and an Accusump, along with fire suppression, so there's a 50/50 chance I might be changing this out to an AN fitting.

I bought a LOT of aluminum tubing, so any flexible runs are going to be fairly short, and we're going to use solid motor mounts to minimize movement.  Yeah, vibration always remains an issue.

Stay tuned.

[manta22]

Chris;

What size AN fitting might work in your adapter? I have a few very large AN fittings in aluminum and stainless that I'd be happy to donate to The Cause.

Regards, Neil  Tucson, AZ

[fordboy628]

Not trying to find fault or be critical here, but personally, I would not trust that outlet adapter. I have had to repair far too many failures on things just like that. The cut threads create a stress riser in the tube, and the long stand off with the weight of hose, clamp, and coolant bearing on it along with vibration from the engine running is just begging for the adapter to snap off at the worst possible time. I would redesign that detail, or at very least make sure that the pipe was firmly supported and not allowed to flex at all.

K.C.

Thanks for the observation.    Every thought and observation is welcome on this thread.     It is "difficult" to make an "informed" choice, if you ignore the experience and advice of others who have gone before you . . . .

The very same thought has occurred to me.   The folks who make these items are V8-centric, and those engines just do not have the torsional vibrations that Inline 4 cylinder engines do.    We are leaning toward everything being "well supported" and vibration isolated, whatever the hell that means.

The possibility does exist that the line might become an AN -20 or AN -16, as I have some bits that could be used.    But I still like the idea of beaded 1-1/4" diameter aluminum tubes with silicone hoses for the bends.    Lighter, simpler to fabricate.    And I continue to make no secret of the fact that I am basically lazy, and smart enough to carry spares.     I could also turn a outlet spigot with a 1" NPT thread Vs the 3/4" NPT shown.   There just might be enough room to "squeeze" it in.    I just might do that if the "nightmares" start . . . . . . .  but after I get more of the "special" bits fabricated.

I suspect the final decision will be made late one night in Beerhaven, after we import Dr. Goggles and Grummy to assist with the last minute installation details.     We are laying in a supply of yellow paint in preparation . . . . . .

Wish I had access to a CNC lathe . . . . . .

 
Overworkedboy