Milwaukee Midget

[Interested Observer]

Fordboy/Midget:
This last flurry of discussion about the barrels/head/gaskets etc. has me a bit confused as to what the current proposed configuration is thought to be.  Do you have a cross-section sketch that you could show of the arrangement that might be clearer in detail than the wordy description?  The words leave room for some variation in interpretation.   

And, given the thrust  of the two recently cited "technical" articles, are these mods sufficiently consistent with the basic philosophy of the engine?

[Jack Gifford]

... [SCE] made custom solid copper head gaskets for us...

Ditto. .022" thick most recently.

[Jack Gifford]

... running larger copper wire, say .06 or even .08 diameter... is also acting as a key that provides location and strength for the head/block interface...

From my experience, I don't recommend this. Due to build-up of dimensional tolerances, some cylinders would be fighting against others to do "location"; not to mention fighting against head-to-block dowels. Traditional (and proven) receiver grooves is better (receiver groove wide enough to prevent the "fight", but still create a compression seal via the copper). Drawing shows typical deminsions for .024" copper).

[Milwaukee Midget]

 
And, given the thrust  of the two recently cited "technical" articles, are these mods sufficiently consistent with the basic philosophy of the engine?

It's certainly not in keeping with the philosophy of the engine, in that it was designed to be put assembled quickly, easily and inexpensively.

Those are not adverbs we're encountering on this build.  

The way I'm looking at it is that at the end of the day, I want this engine to be absolutely bulletproof.  If that means overcompensating for fixes that have been addressed and proven by the manufacturer, and in some ways, reengineering it into a more conventional design, then so be it.

Drawings - yes, I should at least get some sketches put together, but in essence -

1 - Pressed in siamesed liners, OD oversized to be controlled laterally on the top by the bosses which the long bolts pass through.
2 - Lower step of barrel into block machined for a press fit - block machined to accept.
3 - Top of barrel to be machined for O-ring to seal combustion chamber with copper head gasket.

I'll work on clarifying that.

Rex, Jack - we're still thinking this through - I'm grateful for both of your inputs - the drawing in particular.

My concern is that by going with siamesed liners, we don't put so much steel at the core of the engine that it has a negative impact with dissimilar expansion rates.

[Rex Schimmer]

Chris and Mike,
After reading the "Racecar Engineering" article on your engine type (I actually have that issue!) I noted the discussion regarding the through bolt that hold everything together and so I review your earlier post and I think that you are planning to go with some custom studs in place of the factory bolts. The article discussed the over torquing of the bolts causing localized material yielding around the bolt head and the nuts which is a good reason not to exceed the specified torque but also you need to make sure that the shank of your studs are the same diameter as the stock bolts so that at the specified torque you have the same clamping force. Obviously you will be making the studs from a higher strength material and the specified torque should be sufficiently below the material yield strength to allow multiple use. Lubrication between the nut (or bolt head) that you are torquing is the most important thing you can do to assure proper torquing if you cannot measure the increase in length. Back in 1968 Volkswagen decided that they could save some money by making the case studs out of rod with rolled threads on each end and do away with machining/grinding the stud shanks down to the thread minimum diameter as all previous engines had been done. Well after 70-80000 miles the heads would become loose and literally lift off of the cylinders and you could not re-torque them because the threads were pulled out of the engine cases because the case studs would not stretch with the expansion of the engine when it got hot. 

Rex

[Milwaukee Midget]

Chris and Mike,
After reading the "Racecar Engineering" article on your engine type (I actually have that issue!) I noted the discussion regarding the through bolt that hold everything together and so I review your earlier post and I think that you are planning to go with some custom studs in place of the factory bolts. The article discussed the over torquing of the bolts causing localized material yielding around the bolt head and the nuts which is a good reason not to exceed the specified torque but also you need to make sure that the shank of your studs are the same diameter as the stock bolts so that at the specified torque you have the same clamping force. Obviously you will be making the studs from a higher strength material and the specified torque should be sufficiently below the material yield strength to allow multiple use. Lubrication between the nut (or bolt head) that you are torquing is the most important thing you can do to assure proper torquing if you cannot measure the increase in length. Back in 1968 Volkswagen decided that they could save some money by making the case studs out of rod with rolled threads on each end and do away with machining/grinding the stud shanks down to the thread minimum diameter as all previous engines had been done. Well after 70-80000 miles the heads would become loose and literally lift off of the cylinders and you could not re-torque them because the threads were pulled out of the engine cases because the case studs would not stretch with the expansion of the engine when it got hot. 

Rex

We're on it, Rex -

http://arp-bolts.com/kits/ARPkit-detail.php?RecordID=1226

Kit is destined to arrive Thursday.  The instructions indicate 50 ft/lbs.

I suspect that we won't see the block temperatures one sees in an air cooled Vee Dub, but checking the torque settings while we're dynoing will become part of the ritual.

But it's still a tall sandwich to hold together with cocktail skewers . . .

[Rex Schimmer]

Chris,
Quoting myself: "The article discussed the over torquing of the bolts causing localized material yielding around the bolt head and the nuts which is a good reason not to exceed the specified torque " The material they were talking about was the head and the lower end girdle. If you plan to exceed the specified torque, which I think was 34 ft-lbs, then I would trust that you are using some larger diameter and thick washer on both ends to eliminate this problem? I know that I am picking at the nits but there is no reason to go down the creek that is full of failed K series motors.

Damn fun to watch you guys go through this "reloading"!!!

Rex

[Milwaukee Midget]

Ahhh . . . RTEQ.

Let me get some photos together - I think we'll be good, but now I'm better understanding your point.

Thanks, Rex!

[Interested Observer]

Rex,
In the RE article, where he talks about the bolts causing fatigue failure of the block, it can't very well be an underhead crushing problem since the bolts don't bear on the block, only the head and ladder.  And when he talks about "bearing crush" I believe he is referring to distortion of the block/ladder due to overtorque overloading, and consequent distortion of the main bearing housings and/or alignment, not the underhead area of the bolts.

[Finallygotit]

From all of this info, it sounds like the Grenade was a cakewalk compared to what this K motor is going to be.

[Interested Observer]

MM,
Ref reply #5433, second photo:  Should the "OD" label actually be on the 3.44" dimension?

Also, what are the bore spacings?

By "siamesed" is it simply meant to have clearance flats cut at the points of close approach to the adjacent barrel?

[fordboy628]

Chris,
Quoting myself: "The article discussed the over torquing of the bolts causing localized material yielding around the bolt head and the nuts which is a good reason not to exceed the specified torque " The material they were talking about was the head and the lower end girdle. If you plan to exceed the specified torque, which I think was 34 ft-lbs, then I would trust that you are using some larger diameter and thick washer on both ends to eliminate this problem? I know that I am picking at the nits but there is no reason to go down the creek that is full of failed K series motors.

Dodge fun to watch you guys go through this "reloading"!!!

Rex

Glad you are enjoying it.   Read on.

Rex,
In the RE article, where he talks about the bolts causing fatigue failure of the block, it can't very well be an underhead crushing problem since the bolts don't bear on the block, only the head and ladder.  And when he talks about "bearing crush" I believe he is referring to distortion of the block/ladder due to overtorque overloading, and consequent distortion of the main bearing housings and/or alignment, not the underhead area of the bolts.

Some clarifications, if I may,

A)   A point raised by Rex and clarified by IO, the lower bearing area of the OEM "sandwich bolt", now with a proposed change to an ARP stud, is what the OEM refers to as an "oiling ladder".  This part serves 2 functions.   Its' oil passageways deliver the oil supply to the bottom end, and its' threaded portions secure the "sandwich fastener".   It has "plenty" of bearing area to prevent "crush", as long as the material spec itself is adequate.   This is the point of "upgrading" to the "newer" type ladder, supposedly made from stronger material.    Nothing prevents the fabrication and use of a steel ladder, should the need arise.

2)   Anytime fastener torque is "altered" from its' former specification, nearby housing bores will "most likely" be affected.   This type of "distortion" (just a clamp load change actually) is easily determined by precision measurement of the components in a "mock-up" and "torqued-up" format.    We plan to do this.    Correcting any main bearing housing bore distortion will be accomplished by "align honing" the mains, usually a "piece of cake" operation.    Because the K has an aluminum main cap "girdle", surfacing that item is more complicated than grinding individual steel/iron or aluminum main caps.   But, of course, this can be accomplished.

     A further note is that the main bearing bore needs to be established early on in the build cycle, because other dimensions such as block "deck height", con rod length, piston compression height, etc, are tied to this dimension.

d)   At the upper end of the ARP stud assembly will be a large area "bearing washer" as supplied with most ARP stud kits.    This should solve any "crush" issues with the seating area on the head.    Any cylinder head material crush issues that arise in the "mock-up" process, could be addressed with a solution heat treatment of the head.    Call me "optomisty", because I doubt that this would happen and heat treatment be required.    Even @ 50 ft/lbs, the applied clamp load is low compared to other alloy block engines, and we are increasing material spec and bearing area where we can.     And additionally, although ARP "recommends" 50 ft/lbs as the applied torque, we can choose to utilize a lesser amount, should the block itself prove to be made of "cheese".    I have it on good authority that Sargento is ready and willing to supply a firmer cheddar.  

z)   A greater concern for me was the regression of the cylinder head material at the point of the compression seal when using an MLS type gasket.    Readers of the build diary may recall that the Rover OEM fix is to install an .030"/.040" stainless steel "sandwich plate" between the head surface and the upgraded MLS gasket.    I believe that this issue is reduced, or perhaps even solved, by the decision to use a solid copper head gasket with a wire o-ring and receiver groove.   Instead of the load being applied to a 2/2.5 mm wide compression seal area, the clamp load will be spread across the full width of the cylinder barrel combined with as wide an area of the head surface as practical.   This has to be an improvement.   And additionally, we can not afford to give up ANY un-necessary amounts of compression volume, such as with thick MLS gaskets and/or sandwich plates.   That would just be stupid . . . . .  

X)   Bore center to center spacing is presumed to be 88 mm, since that is the port spacing layout.   Of course we are going to double check this critical dimension.

Y)   In this application, what I mean by siamesed is that the barrels WILL need to have a "clearance flat" machined into the water jacket/head face areas for the purpose of fitment of a larger OD barrel than the existing bore centerline spacing allows, to allow water flow between cylinders, and to allow simple single cylinder manufacture of barrels, as opposed to a "block of four".    The purpose of the larger barrel OD is to gain bearing area at the "foot" of the barrel where it bears against the cylinder block.    This is, in my opinion, a crucial weakness of this engine when modified for higher output.

And, finally, my labeling of the Simon Erland articles as "technical" was somewhat "tongue in cheek".    I'm sure Mr. Erland is a gentleman and he is obviously a fine writer.    He is also clearly enamored with the Rover K engine series, and his lack of redress to what are some, "short-comings" of the design, leads me to speculate that he may not have ever dealt with the frustration of trying to modify an engine designed for one purpose, into something else entirely.    But of course, I could be wrong about that, and if so, I apologize in advance to Mr. Erland.

HAPPY HOLIDAYS TO ALL!!!!        And ta ta, for a bit . . . . . .


Eggnogsuckingboy

[fordboy628]

... running larger copper wire, say .06 or even .08 diameter... is also acting as a key that provides location and strength for the head/block interface...

From my experience, I don't recommend this. Due to build-up of dimensional tolerances, some cylinders would be fighting against others to do "location"; not to mention fighting against head-to-block dowels. Traditional (and proven) receiver grooves is better (receiver groove wide enough to prevent the "fight", but still create a compression seal via the copper). Drawing shows typical deminsions for .024" copper).

Jack,

Thanks for the sketch.    Your sketch is pretty much what is planned, except for .031" rubber coated copper gasket material from Flatout, combined with their wire/groove machining dimensions.


F/B

[distributorguy]

I just read into this build very late, but why use copper O-rings instead of stainless???  Many applications use stainless and skip the head gasket. 

[fordboy628]

I just read into this build very late, but why use copper O-rings instead of stainless???  Many applications use stainless and skip the head gasket.

The gasket will be annealed & coated copper.   The O-rings will be either stainless steel (typically .041" ss "safety wire") or hardened steel (typically .041" piano wire).   Both have advantages and disadvantages.

I've seen copper used on some older engine styles, designed in the 1950's or so.   It seemed to work OK.   Consider for a moment that the peak and average combustion pressures seen then, were lower than what is seen now, coupled with the softness of the copper.    And you have to be VERY careful with the copper O-rings as they are easily damaged when the head is off for service.   These factors rule out copper for me at least.   I'm not saying you can't make it work, it's just in the pita (*) category as far as I am concerned.


F/B