Milwaukee Midget

[Milwaukee Midget]

Thanks, Mark.

55.5 seems to be the sweet spot.

That gives us the most latitude.  If we resleeve, we're still at 981, if we punch out, even to 76, we're still class compliant at 1007 on a 1015 maximum.  75.5 bore puts us at 994.

Locking in at 55.5 won't ever hurt us - 56 would limit an option.

Can I grab the block and head this week and run it over to Mel to check alignment?

Chris

[fordboy628]

Thanks, Mark.

55.5 seems to be the sweet spot.

That gives us the most latitude.  If we resleeve, we're still at 981, if we punch out, even to 76, we're still class compliant at 1007 on a 1015 maximum.  75.5 bore puts us at 994.

Locking in at 55.5 won't ever hurt us - 56 would limit an option.

Can I grab the block and head this week and run it over to Mel to check alignment?


Chris

OK, 55.5mm it is then.      THAT, changes the rod/piston length/height dimension to 173.75mm total.

If you are going to come down, bring the rest of the head bolts and the "ladder" bolts and we can it check for size at least.    Can you get a head gasket?   And yes, everything can go to Mel's any time you want.
 
Fordboy

[Rex Schimmer]

Chris,
Sorry for the late reply but yes go with the T6 heat treat, if you buy plate it will probably be T651 which means it has been stretched, which is good, also almost all 6061 alum plate comes in the T651 condition. Not only stronger threads but easier to machine.
Rex

[fordboy628]

Why the Rover 'K' is the perfect powerplant for a racer based in Wisconsin.

OK, I'm gonna let Chris tell the whole story, but . . . . . . .

During a foray beneath the "cheddar curtain" yesterday evening to the Dymaxion Design & Engineering basement laboratory and skunkworks, some basic dimensional checking & trial assembly was initiated on "Rover".    The block, main girdle, bolt ladder and cylinder head were assembled to check the main bearing housing bore sizes.  We used the original "long assembly" bolts as a "fit up".    The torque and assembly procedure for the stock bolts/parts was followed.

A few "observations":

A)  The stock fasteners could only achieve 32/33 ft/lbs of torque total, very low in my opinion.
2)  Torque could not be increased with further rotation, only further "stretching".    Those bolts are at, or are in, "yield condition".   (Probably made of "cheese" . . . .)  
d)  Block dimensional changes, vary wildly with applied load, even more so than expected.
z)  In spite of service bulletins to the contrary, torque to yield fasteners should not be reused.

According to Rover Service literature, there is a "later" upgrade to better bolts, a stronger ladder and an "improved" head gasket.   It is impossible to intelligently comment about the later spec parts without any experience with them.   Let's just say that the "original spec" parts appear to be a bit "on the limp side" for the stock application, let alone "enthusiastic driving" in a "hot-rodded" Caterham Seven.

I think an ARP stud, washer and nut kit will be on the way shortly . . . . . . .  
 
Fordboy

[Milwaukee Midget]

Mark, let me correct you.

We are no longer referring to the used block assembly fasteners as "bolts".

At best, we may be able to repurpose them as tent stakes, barbecue skewers, paint stir sticks or gutter nails.

I think we started off at 15 ft/lb (20 n/m) and followed the instructions - 180 degrees around the pattern, and again, 180 around the pattern.

It was like putting a torque wrench on a pencil eraser.

[WOODY@DDLLC]

I thought I told you all fasteners are just glorified springs!  Be sure to go to a reputable screen door manufacturer for all your springs. At least the one for the door to the drinking deck! 

[Milwaukee Midget]

I thought I told you all fasteners are just glorified springs!  Be sure to go to a reputable screen door manufacturer for all your springs. At least the one for the door to the drinking deck! 

That particular door gets a lot of use.  I'm thinking of moving the fridge out there.

I think back at all of the "innovations" that have come down the pike that have fallen into disrepute due to people not following the instructions.

The Buick aluminum V8 developed a bad rap because mechanics didn't use a torque wrench or oil the threads.
The early Corvair handled fine, if they read the manual and followed the tire pressure setting provided by GM. Early 'vette grounding issues, the Olds diesel, the front suspension on the Aspen/Volare.

K.I.S.S. is a good idea, but sometimes, keeping it simple is simply a matter of reading the instructions.

These bolts were stretched at some point, likely by somebody who thought he could reuse them, or thought a touch more would be better.

That's my belief.   

All decent ideas, all poorly understood by those charged to work on them.

[Interested Observer]

Further to the previous bolt calculations--
Assuming a (reasonable) friction coefficient of 0.08 and 33 lb-ft of torque, the stress in the reduced shank of the through-bolt would be 106 ksi, which compares well with the prescribed material yield strength of 104.4 ksi. 
It doesn’t much matter what someone may have done with the bolts earlier, that much torque is going to continue to stretch them.  Which is probably why Rover specified the 180 degree turns limitation rather than a torque.  They were assured of getting into the yield-controlled load range they were looking for, but prevented someone from just cranking away on them trying to get to some torque number using who-knows-what kind of “calibrated” torqueing device.

I suspect that Rover was undone by the thermal cycling issue.  The yield-controlled preload would have been somewhat relieved by this yielding when at temperature as well as any subsequent crushing of the gasket, resulting in reduced gasket loading.  The improved material strength of the revised bolt and presumably stiffer gasket would result in less preload loss.  Nonetheless, retorquing the ARP studs after a few thermal cycles would probably be wise.  The studs won’t be yielding, but the gasket is likely to have crushed some.

An interesting exercise --  Put one of the bolts back in and see how many turns you can get out of it and how the torque behaves.  Probably considerably more turns than you would expect.  Just because the material has yielded doesn’t mean it has given up the ghost.

[Milwaukee Midget]

An interesting exercise --  Put one of the bolts back in and see how many turns you can get out of it and how the torque behaves.  Probably considerably more turns than you would expect.  Just because the material has yielded doesn’t mean it has given up the ghost.

It's likely I'd run out of threads first!

But seriously, the whole experience was just spooky and spongy.

I could easily see somebody ignoring the directions and trying to get something that felt like bite out of them.

Yes, I suspect a retorque with the ARPs would be prudent. 

[fordboy628]

Yes, I suspect a retorque with the ARPs would be prudent. 

A cold retorque after some lightly loaded thermal cycling is what is in order here.

A basic requirement to getting this thing to live when you punch it into warp drive . . . . . . . .   
 
Fordboy

[fordboy628]

Some Progress . . . . . .

midget,

We now have probably the only set of comprehensive flow bench adaptors for the K series, in the new world . . . . .













Exhaust stubs are 1.50" OD, the ID roughly matches the opening on the manifold face.    I used my router to exactly match the port shape to the PVC flange, and overbored that to match the PVC stubs.    The intake radius plate was also matched to the existing port shape at the manifold flange.    I'm thinking that the ports will not need to be enlarged for a 1 liter race engine making peak bhp @ 8500 rpm.     Will need to run some numbers though to confirm this idea.

I've already made a blank for the slider plate.    Should be able to finish it off in the next day or so.    Will be able to start flow testing sometime next week.  

Just for yuks, once I have the data, I'll overlay the 'K' flow on top of the 'A' series flow.    Promise not to wet yourself.

I might want to grab the rest of the valves and bits to make it easy to flow all 4 cylinders.

 
Roverboy

[fordboy628]

Be sure to go to a reputable screen door manufacturer for all your springs. At least the one for the door to the drinking deck! 

In the interest of simplicity and safety, there is no door to the drinking deck at the Dymaxion Design and Engineering basement laboratory and skunkworks.

There are stairs though, couldn't eliminate them from the architect's design . . . . . . . .     Can be a bit treacherous if your judgment is impaired . . . . . . . .
 
Doppelbockboy

[Stainless1]

Hey Plumberboy... nice re-purposing
You do a great job of staying out of the box 

[Ron Gibson]

Stainless
I don't think Plumerboy even knows what a box is and doesn't worry about it.

Ron

[Peter Jack]

I sure looks to me like that flow bench is heading for a new 1000cc record! 

Pete