Milwaukee Midget

[Milwaukee Midget]

Of course, this method won't work for us - we have no way of installing the head without the oil rail in place . . . 

Can we use the torque plate? 

[Milwaukee Midget]

OR . . .

Cut up the old oil rail? 

[hoffman900]

I've used bondo. Had zero issues.

[Milwaukee Midget]

I've used bondo. Had zero issues.

Did you pour through the block?  I suspect they're looking for a dimetrical reference as well. 

Thanks for the photos.  What kind of head is that?

[hoffman900]

I've used bondo. Had zero issues.

Did you pour through the block?  I suspect they're looking for a dimetrical reference as well. 

Thanks for the photos.  What kind of head is that?

It’s a single cylinder, so I bolted the jug to the head, wiped all surfaces with a a rag with light oil, poured the bonds and let set. Before pulling I referenced it to the crank centerline and scored a line across the back.

Other information I gave was the ring set that Total Seal picked out for me, valve angles, valve drop, and target valve lift. I also had a Wiseco that came with the bike and sent out to Racetec.

Basically the instructions were make me a better piston and move the top ring up as high as safely reasonable to reduce crevice volume. I’m really happy with how it came out.

The engine is a Yamaha SR/TT/XT 500. I’m about 4 years into a motor build on it (life tends to be pretty disruptive as you get a foothold on a career out of school). Nick Smithberg did the head. Fordboy has two cams of mine and I’m sending him two more to have profiled. I use them for simulation work and to evaluate what the aftermarket companies are doing. With a OHC rocker set up the geometry requires a specific lobe shape due to the varying rocker ratio. As you profile, you sometimes find out that the lobe was taken from another application and while close, it may have weird dynamics. One aftermarket cam I measured had a large spike in positive acceleration at valve closing. Not good.

[Milwaukee Midget]

Fordboy has two cams of mine and I’m sending him two more to have profiled. I use them for simulation work and to evaluate what the aftermarket companies are doing. With a OHC rocker set up the geometry requires a specific lobe shape due to the varying rocker ratio. As you profile, you sometimes find out that the lobe was taken from another application and while close, it may have weird dynamics. One aftermarket cam I measured had a large spike in positive acceleration at valve closing. Not good.

A smart move - for that very reason.

You really, really want to believe the cam manufacturers are doing it right, but having now seen dozens of cam profiles and comparisons, it's way too often a crapshoot.

And as with any part, the manufacturer will seldom stand behind it after it's been installed.

As to the engineering, it seems they all steal from each other.

But if you take it out of the box, run a profile, and call them on the issues, the reputable grinders will either fix it or get you a refund.

I'm reasonably certain most of the engineers at the cam companies hate it when their work is checked, and non-conforming cam profile files fill their e-mail in-boxes.  And in 9 out of 10 applications, their grinds probably work just fine.

But given the small displacement of what you, me and Mark are doing, and the slim margins for error, an incorrect cam, or an improperly ground lobe can mean the difference between success and shrapnel.

Mark checked the Piper Cams when they came in last summer.  They were spot on, which is great.  The idea of sending cams back and forth between the US and Great Britain is not my idea of a fun time. 

[Dynoroom]

The way the piston people find the "center" of the chamber mold is before you pour the bondo place a head gasket on it's dowel locators, pour the bondo, then remove it when hard. They will draw a cross front to read & side to side to find the center & measure from there.

[fordboy628]

Mark -

Did anybody at Diamond tell us that they actually make a kit to do this?

I don't think they did . . .

http://www.diamondracing.net/about/how-to-videos.php#howtopour

midget,

Well, no, it was not discussed.    When they were informed I had a "plug" of the chamber, "Great." was all they said.   No material spec was discussed.


Since I did not get any further response on whether they can design the piston from the "marked-up" print via email, I will call them first thing Monday morning to determine an action plan to go forward.    That will probably mean casting a new plug from their material to scan, or, sending the second head for them to scan.     I can order their material kit Monday if need be.

This is all becoming a real "pita".    But I am sure of only 2 things at this point:

A/    The original choice does not offer viable manufacture and delivery,
2/    Other options for manufacture and delivery may be similar.

You can check with other potential suppliers if you like, just let me know what you are going to decide.

Of course, this method won't work for us - we have no way of installing the head without the oil rail in place . . . 

Can we use the torque plate? 

OR . . .

Cut up the old oil rail? 

I have a plan for casting a chamber plug and marking a reference line for their use that does not require the use of either component.    I'd prefer to NOT use the torque plate.     I don't want the hassle of centering the torque plate precisely on the head to match the block alignment.    And there is no need to cut up the old oil rail.    I'll just go "wood shop" on you and use some bar clamps to fit it all up.


There will be "block leveling photos" . . . . . . .   


Sure, go ahead, race an orphan . . . . . . . .       How much extra work could it be anyway? ? ? ? ? 


    
Tiredboy

[fordboy628]

midget,

And just a reminder:

Still going to need that dimension from the top of the pin to the top of the rod.


And as you have probably guessed by now, making a new chamber "plug" is going to add a week to the process.


    
Justtired

[Milwaukee Midget]

Of course - and NEVER think for a minute your herculean efforts are unappreciated.

In additional news, I've made good progress on changing out the brake/master cylinder.

I've replaced the original dual master cylinder with a combination master cylinder out of a '59 Bugeye.  It has a common resevoir for both the clutch and the brakes.

As we're only running rear brakes, it will be more than sufficient.

The pedal box is cut away into the footwell, a proper blanking plate is ready to go, it all lines up really nice, and I've got the new slave cylinder for the clutch - appropriately sized, of course.

I need to come up with a cover for the actuator end of the pedals - probably make it out of steel plate with a fabbed-up rubber gasket.

Dash is out, and I picked up a -3 bulkhead fitting to rework the oil pressure line.

I want to eventually be able to pull the entire dash out with 3 bolts, a multi-pin connector and a fitting.

Need to get the garage warm enough to paint the footwell - probably fire up the heater this afternoon and work on it this evening, seeing as there's NOTHING ON TV TONIGHT WORTH MY TIME TO WATCH . . .


I'll view the commercials tomorrow on line . . .

[fordboy628]

And just for the "Permanent Record"

Connecting rod design dimensions:

143.75 mm          Center to center length   +.000"   -.002"
  18.0  mm           Pin diameter
  16.0  mm           Pin end width
   ? ?                    Pin bushing dimensions       Needs to be a thin wall high strength bronze material without a steel backing
                           Pin end to be centered over Big end

                           Big end sizing and bearing tang notches to suit nominal 1-5/8" Spridget bearing  King part #CR 417 CP    OR can substitute Mahle Motorsport bearing.
1.7705"/1.7710"   Big end housing bore diameter      Big end bearing length of .879" maximum
1.063" +/- .001"   Big end width     Results in .008"/.010" big end side clearance.
3/8" diameter       ARP Big end bolts     Big end MUST fit through a 75 mm bore diameter.


Big end MUST fit through a 75 mm bore diameter.

This is easily achieved.   3/8ths diameter ARP through bolts are used on BMC race engines with bores of only 2.820" and as small as 2.780"    Non-through bolts require extra material at the big end parting line, but since the bore being used is 2.973", there is PLENTY of room.

And before anybody mentions it, I am aware that a superior grade bolt in a 5/16ths diameter would do the job and be lighter.     I am specifying the bigger bolt because I want my rod bolts to be reliable, to the point of boredom.   And I want them to be "re-usable".     Big buck 5/16ths bolts that need to be "float tested" and replaced at every rebuild are no "bargain".

Oh and one other "intangible" is that 5' 17" sized feet, somehow tend to "get caught up in the pedals", resulting in serious engine rpm overspeeds.          And since this is going to be a higher rpm engine than the "Grenade" anyway, a set of 3/8 ARP rod bolts will let me sleep better at night . . . . . . .

    
Thinkyboy

[fordboy628]

Need to get the garage warm enough to paint the footwell - probably fire up the heater this afternoon and work on it this evening, seeing as there's NOTHING ON TV TONIGHT WORTH MY TIME TO WATCH . . .


I'll view the commercials tomorrow on line . . .

WHAT? ?   NO SCONNIE NATION MEATPACKERS AT THE SUPERBOWL? ?

Well, I guess they will have to buy their seats, just like the other "fans" . . . . . . . .


Hhhmmmm, if it would happen . . . . .  Brady Vs Rodgers? ? . . . . . . 

No brainer, gotta go with the best of all time . . . .  Brady


Sorry buddy!    Can't go with your choice of PBR either.     But you already knew that.

 
Darkandmaltyboy

[Stainless1]

 NOTHING ON TV TONIGHT WORTH MY TIME TO WATCH . . .

Got to agree to that.... no "take a knee during the National Anthem" watching has occurred here since the first round.  I don't need to watch millionaires protest against the symbols of the country or our military.... Have not watched anything with Hanoi Jane in it since 1973 either...

can't see the difference between them  

OK, back to your regularly scheduled "beat your heads against the wall it will make you feel better" racing story  

[fordboy628]

Adventures along the Milwaukee Shore, Season 4, continues with Episode 6748 . . . . .

Connecting Rod photo Porn! ! ! !

OK, here are some photos of the difference between the Rover con rod and the BMC con rod, both shown in a 75 mm cylinder bore . . . . .


Top: Rover rod      bottom: BMC rod



Rover rod, 8mm bolt.     Note clearance.


BMC rod,  3/8ths bolt.     Also note clearance.



Comparison of the stock bolts.   Note that the Rover, while an 8mm thread size, has a 7mm "stretch" section.



Rover rod, ~ 2-13/16" width



BMC rod, ~ 2-3/4" width



Sooo, no excuses on the 3/8ths big end bolt thing . . . . .

No further commentary necessary.

 

[fordboy628]

Adventures along the Milwaukee Shore, Season 4, continues with Episode 6749 . . . . .

Rod und Cranken mating PORN! ! ! ! !

For all you perverts out there . . . . . . .










SEE, intermingling of the species is possible! !  With clearance even . . . . . .


Even without Star Trek and Star Wars . . . .