Milwaukee Midget

[Peter Jack]

I'm just curious and I do realize that it could cause other problems but, might it be possible to add weld to any part of the chambers to reduce the volume and maybe if you're really lucky increase efficiency? 

I realize my perspective may be distorted by what I do. 

Pete

[fordboy628]

I'm just curious and I do realize that it could cause other problems but, might it be possible to add weld to any part of the chambers to reduce the volume and maybe if you're really lucky increase efficiency? 

I realize my perspective may be distorted by what I do. 

Pete

Actually, I think your perspective is great, and normally I would contemplate going that route.    I repaired/modified dozens of Cosworth and Lotus heads by welding, BUT, this casting is so thin, I'm paranoid just looking at it.

The problems:

Have to replace the valve seats for sure and probably the valve guides too.    LM25 casting would need to be heat treated after welding since once welded, it would be dead soft . . . . .

Might warp the head, and since the cams ride in the head, now you aren't just surfacing both sides of the head, you are line boring for the cams also . . . . . .
Possible distortion of the tappet bores.   Yeah, tappets in the head, would require oversize tappets and boring or honing to fit . . . . . .
etc . . . . .

So even though it appears to be a useful choice, I'd prefer to stay away from welding unless it is the only choice.
 
Fordboy

[fordboy628]

Some photos of the cylinder head.



Compared to a more proven race design 4 valve head, say a Cosworth, the Rover chamber is deeper and more "squared off" at the ends.   This is probably due to the smaller bore diameter than the Cosworth, and it also creates a larger chamber volume, not an issue at 1600/1800 cc's or even 1400 cc's.    But for a 1000 cc engine it is a problem.

The other issue is the relatively small valve diameters for the chamber size/volume.    And the relatively wide valve centerline spacing prevents significantly larger valves from being fitted to the head.    About 1mm larger are available from REC, but that's about the maximum that can be fitted to a 75/76mm bore.

Still, a significant upgrade from the 'A' series power plant.   Once the valve area is calculated and the flow numbers are available, I think that will put things in perspective.
 
Fordboy

[Peter Jack]

And the valves are far enough from each other that crascking between the valves shouldn't be a problem. If a person looks hard enough you can always find something good! 

Pete

[fordboy628]

Some photos of the slider block construction process.    The material used is mdf and laminate.    The threads for the studs are threaded directly into the mdf and "hardened" with slow set epoxy.     I use a high helix tap to thread the mdf.    I also wax the threads of the fixing studs and install them into the fixture to prevent the epoxy from pooling in the threads.    After the studs are installed, the head is also installed and the nuts and washers are added to make sure everything sets up while aligned.











The slots to fit the Brzezinski slider fixture are not yet routed into the block, but are center-marked at the top and bottom of the block's base.   The witness lines are visible in the last photo.

Brzezinski will make custom slider plates for any engine, and stocks most V-8 applications.    But if you want to save more than a few bucks ($379/$395 each plate for standards, $695 each plate for customs to your print.) this method will work out just fine.    I just want to add that you also need the flow test stand fixture to utilize a slider plate.

Single cylinder flow test adaptors can be more easily fabricated, you just can only test one cylinder at a time and then you must reset the rig to the next cylinder.   Don't be fooled into thinking that testing only one cylinder of a head gives you representative values for the whole head.    I have lots of data that shows the differences between cylinders . . . . . . .

 
Fordboy

[fordboy628]

Some close up photos of the combustion chambers with the slider block installed.

76mm bore in the slider block Vs 75mm stock bore.







I used red Dykem machinists layout dye to show some contrast on the head face.    It looks like the 75mm bore is an exact match to the existing combustion chamber.

Narrower valve centerline spacing would lessen the valve edge shrouding that is readily visible in these photos.

Next up, the flow testing.   I'm betting a 12 pack of micro-brew I'll be happy with the numbers Vs the "tractor" . . . . . . 
 
Fordboy

[fordboy628]

midget,

Any word from Wossner on possible dome volume?

 
Fordboy

[Milwaukee Midget]

midget,

Any word from Wossner on possible dome volume?

 
Fordboy

You know, let me jump on that Tuesday.  When we spoke today, I was climbing on the roof of a church taking down a paging system and when I got back, I had to whip up cables for the New Berlin 4th of July festival.

If ya’ll haven’t already noticed, Fordboy’s woodworking skills are par excellence, and he is now the proud owner of what is likely the only MG/Rover K-series flow bench adapter in the Western Hemisphere!

Thanks, Mark.

Meanwhile, North of the Cheddar Curtain –

I am now on day 8 of a 19 day stretch where I have some sort of work commitment every day, 8 of which are double shifts.  But having my free time so limited, it has given me great focus on moving the Pom Rod toward its maiden journey to the Flats in about 37 days.
 
I now have the brake lines in, and managed to get some insulation into place to protect my tootsies from blistering on the way out, both under the hood . . .



and in the passenger compartment . . .



I also made a good start on what I hope will prove to be effective shrouding between the bonnet and the radiator.  I had some steel honeycomb speaker grills I trimmed up to fit and glassed into place between the underside of the nose and the outer edge of the radiator – and they actually stiffened up the bonnet considerably.  A bit more work here, but coming along . . .



I also opened up the grill.  I’ve got room now for 2 - 7” electric radiator fans, if necessary.  I’ll tidy it up and paint it when I get back, but this is good enough for the time being . . .

. . .

Summerfest is closed tonight, it's 10:30, and I'm going to get 8 hours of shuteye if it kills me.
 

[tauruck]

As always you guys turn a mountain into a mole hill.

If you were a soldier, The VC for you IMO.

Great going. I like the red colour!!!!.

[fordboy628]

If ya’ll haven’t already noticed, Fordboy’s woodworking skills are par excellence, and he is now the proud owner of what is likely the only MG/Rover K-series flow bench adapter in the Western Hemisphere! 

If I could have clamped this 76mm bore turd with 88mm bore spacing onto a Chevy/Ford/whatever bore adapter I would have done it.   

Oh well, had to make slider plates for MGB, Lotus, Cosworth, Ford NCF and Ford CF, big bore 'A' series, and now Subaru for Tom, so what the hell . . . . . .   

I suspect the Rover plate will get the least use though . . . . . .     but it will deliver what we need in terms of . . . . data.

 
mdfboy

[SPARKY]

 

[grumm441]

I'm liking where this is going
G

[Stainless1]

I'm liking where this is going
G

We all do Graham, its going to Bonneville     

[fordboy628]

A numbers exercise . . . . . .

midget,

As promised the valve diameter and area calculations.   And yes, I was a bit surprised.    The traditional thinking is:   "A four valve HAS to be better than a two valve!!"

Really?      Some number juggling:

BMC 'A' series:

Bore diameter: 2.815"

Intake valve diameter:      1 x 1.475"
Intake valve area:             1.7087 sq. in.
Int valve dia/bore dia:       52.4%
Int valve area/bore area:   27.46%

Exhaust valve diameter:    1 x 1.150"
Exhaust valve area:           1.0387 sq. in.
Ex valve dia/bore dia:        40.9%
Ex valve area/bore area:    16.69%


Rover 'K' series:

Bore diameter: 75.5mm (2.972")

These are the stock sizes.  REC has slightly oversize valves available.
Intake valve diameter:       2 x 1.089" (27.67mm)
Intake valve area:              1.863 sq. in.    an 8.3% increase over the BMC
Int valve dia/bore dia:        73.3%
Int valve area/bore area:    26.86%           a 2.2% decrease over the BMC

Exhaust valve diameter:     2 x 0.949" (24.10mm)
Exhaust valve area:            1.415 sq. in.    a 26.6% increase over the BMC
Ex valve dia/bore dia:         63.9%
Ex valve area/bore area:     20.40%           an 18.2% increase over the BMC

REC 21-4N Stainless Valves
REC #739
Intake valve diameter:       2 x 1.161" (29.5mm)
Intake valve area:              2.1173 sq. in.    a 19.3% increase over the BMC
Int valve dia/bore dia:        78.1%
Int valve area/bore area:    30.52%             a 10.0% increase over the BMC

REC #740
Exhaust valve diameter:     2 x 1.023" (26.0mm)
Exhaust valve area:            1.644 sq. in.    a 36.8% increase over the BMC
Ex valve dia/bore dia:         68.8%
Ex valve area/bore area:     23.70%           a 29.6% increase over the BMC

I did not use any comparison percentages for valve dia/bore dia between the two engine types.    Although the comparisons are valid two valve to two valve, and four valve to four valve, my own opinion is that it is not a valid comparison two valve to four valve.     I use valve area/bore area as a valid comparison.


REC also has 21-4N valves in the stock diameters, and the shapes are probably better for flow.

It is possible that the increase from the larger REC exhaust valve might not be necessary, but the head needs to be flowed before this can be determined.   Flow increases on the order of percentages that are seen here, would allow a "softer" exhaust cam to be run without penalty.

The best choice could be to fit the larger, aftermarket valves, even if they need to be cut down slightly on diameter to fit the existing valve seats.   The larger valves would also allow "reshaping" of the valve seats (and possibly the valve seat angle) to a "radius" style seat form.     JMO at this point, I still need to flow the head and analyze those numbers . . . . . . .

The takeaway here is that it is easy to be fooled into thinking: "Well, this just has to be better."     It's why you should always, "Run the numbers".     Increases in the number of valves might be negated by the increase in bore size.   As it turns out, limited valve size and the resultant reduced flow available is a well known problem with the 'K' series.   It probably is not going to be an issue at one liter of displacement, but is always better to find out ahead of time . . . . . .  

And yes, before somebody chimes in, the first comparison here is between a race developed head, (the BMC), and the stock Rover head, not really a "fair" comparison.    But, once again, we are trying to make a silk purse out of a sow's ear . . . . . . . . . on a budget . . . . . . . .    

The budget for refreshments needs to be increased . . . . . . . . . . . . . .    

JMO
 
Fordboy

edit:  Checked my math and I had to do some edits . . . . . .  
Rechecked my math after prying my head out of my a** and corrected a second time!!     I gotta write a spreadsheet analysis program for this.    These hand calculations and number transpositions are driving me nuts . . .   

[fordboy628]

I'm liking where this is going
G

We all do Graham, its going to Bonneville     

And perhaps other places.    Depending on the performance, uhmmm, and the brakes . . . . . 
 
Fordboy