Author Topic: Milwaukee Midget  (Read 3255228 times)

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Offline Interested Observer

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Re: Milwaukee Midget
« Reply #6555 on: January 02, 2018, 12:30:15 PM »
Something that might be considered -- trim down the impeller diameter.

Pump Affinity Laws for a Specific Centrifugal Pump

Volume Capacity
The volume capacity of a centrifugal pump can be expressed like

    q1 / q2 = (n1 / n2) (d1 / d2)                                 (1)

    where

    q = volume flow capacity (m3/s, gpm, cfm, ..)

    n = wheel velocity - revolution per minute - (rpm)

    d = wheel diameter (m, ft)

Head or Pressure
The head or pressure of a centrifugal pump can be expressed like

    dp1 / dp2 = (n1 / n2)^2 (d1 / d2)^2                         (2)

    where

    dp = head or pressure  (m, ft, Pa, psi, ..)

Power
The power consumption of a centrifugal pump can be expressed as

    P1 / P2 = (n1 / n2)^3 (d1 / d2)^3                           (3)

    where

    P = power (W, bhp, ..)

____________________

Assuming the desire for slowing the pump rotation rate is to minimize power loss into the pump, the impeller diameter could be reduced to the point of requiring the same power input as standard but at the increased rpm.
For instance, using the above relations, and the assumptions of n1= 5000, n2 = 8000, d1 = 2.5, d2 = ?, we find that d2 = 1.56 would demand the same power at 8000, and produce the same flow rate and pressure. 
If this impeller is then run at 5000, the power would be .24 of that at 8000, with flow rate fraction of .63 and pressure of .39.

This modification does not, however, treat any tendency the pump may have to cavitate at the higher speed.

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #6556 on: January 02, 2018, 12:42:50 PM »

This modification does not, however, treat any tendency the pump may have to cavitate at the higher speed.


THAT is the concern.  These things are notorious for uneven cooling across the top of the cylinder case and the head.  We're looking to obtain even, constant flow across the liners and through the head, and maintain a safe coolant level at all times.
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline jacksoni

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Re: Milwaukee Midget
« Reply #6557 on: January 02, 2018, 08:48:37 PM »
Couple of questions Mark and Chris- who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design? I have been using Gates carbonGT 8mm belts- limited lengths available- but super strong and "they don't stretch"... :roll:

Are there any spots on head and or block for drilling some ports for additional cooling in and out that might help even things out?

Jack
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
 G/GMS-182.144 2019

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #6558 on: January 02, 2018, 10:50:38 PM »
Couple of questions Mark and Chris- who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design? I have been using Gates carbonGT 8mm belts- limited lengths available- but super strong and "they don't stretch"... :roll:

Are there any spots on head and or block for drilling some ports for additional cooling in and out that might help even things out?

Jack


That's been in discussion since the day the block arrived.

The belt, I can get a HP piece out of Britain - hopefully better matched to the application than the exhaust flange . . . :|
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline Jack Gifford

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Re: Milwaukee Midget
« Reply #6559 on: January 03, 2018, 01:40:08 AM »
... who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design?...
Let's see if these old eyes can redeem themselves... Appears to be 25:50 teeth. But any 1:2 ratio is OK- if you go with custom sprockets.
The pitch appears to be 8mm, and tooth profile looks to be at least darn close to "modern" round tooth profile.
Hey- custom sprockets offer another water pump speed reduction, via a smaller crank sprocket. You'd need to consult belt manufacturer's specs for minimum sprocket size- I'm sure that a Gates GT-2 or GT-3 8mm belt can run reliably on as small as a 22 tooth sprocket.

Oops... I neglected the fact that you already invested in those nice vernier-adjustable sprockets. :oops:
« Last Edit: January 03, 2018, 01:50:59 AM by Jack Gifford »
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Offline Interested Observer

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Re: Milwaukee Midget
« Reply #6560 on: January 03, 2018, 08:20:58 AM »
Quote
These things are notorious for uneven cooling

Yes, but why uneven or inadequate cooling?
Do we know that this is due to cavitation?  On what basis?

I have a dim recollection of previously discussed concerns about overheat and head gasket troubles, which may be a chicken/egg issue of its own and apart from possible cavitation or other maladies.

All of which is to wonder if we know what the root of the problem is.

What do the UK racers with large displacement and/or turbos do about it?  (As if they would let-on.)

Offline jacksoni

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Re: Milwaukee Midget
« Reply #6561 on: January 03, 2018, 08:39:55 AM »
Couple of questions Mark and Chris- who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design? I have been using Gates carbonGT 8mm belts- limited lengths available- but super strong and "they don't stretch"... :roll:

Are there any spots on head and or block for drilling some ports for additional cooling in and out that might help even things out?

Jack

Sorry, I missed that info. Thought was a quick and easy.

That's been in discussion since the day the block arrived.

The belt, I can get a HP piece out of Britain - hopefully better matched to the application than the exhaust flange . . . :|
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
 G/GMS-182.144 2019

Offline jacksoni

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Re: Milwaukee Midget
« Reply #6562 on: January 03, 2018, 07:02:04 PM »
... who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design?...
Let's see if these old eyes can redeem themselves... Appears to be 25:50 teeth. But any 1:2 ratio is OK- if you go with custom sprockets.
The pitch appears to be 8mm, and tooth profile looks to be at least darn close to "modern" round tooth profile.
Hey- custom sprockets offer another water pump speed reduction, via a smaller crank sprocket. You'd need to consult belt manufacturer's specs for minimum sprocket size- I'm sure that a Gates GT-2 or GT-3 8mm belt can run reliably on as small as a 22 tooth sprocket.

Oops... I neglected the fact that you already invested in those nice vernier-adjustable sprockets. :oops:

Ok.  Counting I get 48. A 48 tooth sprocket is 4.758" in diameter in 8mm belt, larger than the ruler held across one a page or two back shows. So I was just wondering.
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
 G/GMS-182.144 2019

Offline fordboy628

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Re: Milwaukee Midget
« Reply #6563 on: January 03, 2018, 10:02:04 PM »
... who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design?...
Let's see if these old eyes can redeem themselves... Appears to be 25:50 teeth. But any 1:2 ratio is OK- if you go with custom sprockets.
The pitch appears to be 8mm, and tooth profile looks to be at least darn close to "modern" round tooth profile.
Hey- custom sprockets offer another water pump speed reduction, via a smaller crank sprocket. You'd need to consult belt manufacturer's specs for minimum sprocket size- I'm sure that a Gates GT-2 or GT-3 8mm belt can run reliably on as small as a 22 tooth sprocket.

Oops... I neglected the fact that you already invested in those nice vernier-adjustable sprockets. :oops:

... who many teeth on the crank and cam pulleys?. What is the pitch of the belt and tooth design?...
Let's see if these old eyes can redeem themselves... Appears to be 25:50 teeth. But any 1:2 ratio is OK- if you go with custom sprockets.
The pitch appears to be 8mm, and tooth profile looks to be at least darn close to "modern" round tooth profile.
Hey- custom sprockets offer another water pump speed reduction, via a smaller crank sprocket. You'd need to consult belt manufacturer's specs for minimum sprocket size- I'm sure that a Gates GT-2 or GT-3 8mm belt can run reliably on as small as a 22 tooth sprocket.

Oops... I neglected the fact that you already invested in those nice vernier-adjustable sprockets. :oops:

Ok.  Counting I get 48. A 48 tooth sprocket is 4.758" in diameter in 8mm belt, larger than the ruler held across one a page or two back shows. So I was just wondering.

OK guys, did some tooth counts in between other chores today.

Verified tooth count for the drive belt is:

Crank gear:            24T
Water pump gear:   24T
Cam drive gears:    48T

So, as I suspected, the water pump runs at crank speed.    OK if the crank average speed is 3500 rpm.     Probably a bit high @ 7500 rpm.    Unfortunately, the impeller is a stamped steel p.o.s. that does not lend itself well to being cut down.    There is room on the water pump for a larger drive cog, so Chris will be checking with "Briddish" suppliers, to see if anything is available from Titan or another mfg.

And, yes, the belts are HTD, metric, 8mm pitch.   I think the H/D belts are Kevlar reinforced, rather than fiberglass.   Given the "trauma" of losing a belt, Kevlar it is . . . . .

Chris made another trip "below the curtain" today, and a lot was accomplished.   I'll let him fill you in on some of the issues.

 :cheers:  :dhorse:  :cheers:
Grindyboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

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Offline Old Scrambler

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Re: Milwaukee Midget
« Reply #6564 on: January 03, 2018, 10:06:34 PM »
Try this for the photo-bucket fix.......was just posted yesterday..........

https://chrome.google.com/webstore/detail/photobucket-hotlink-fix/kegnjbncdcliihbemealioapbifiaedg/related?hl=en

This fix should be good to view pics ALREADY POSTED...........
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline fordboy628

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Re: Milwaukee Midget
« Reply #6565 on: January 03, 2018, 10:28:56 PM »
Quote
These things are notorious for uneven cooling

Yes, but why uneven or inadequate cooling?
Do we know that this is due to cavitation?  On what basis?

I have a dim recollection of previously discussed concerns about overheat and head gasket troubles, which may be a chicken/egg issue of its own and apart from possible cavitation or other maladies.

All of which is to wonder if we know what the root of the problem is.

What do the UK racers with large displacement and/or turbos do about it?  (As if they would let-on.)


I am not aware of any "uneven" cooling issue with the K engine.

The issue, as I understand it, is overheating, due to loss of coolant.   There are 2 or 3 common causes of this malady:

A/   Poor head gasket performance.  Variety of reasons.
2/   Loss of head gasket clamp load.   Reuse of torque to yield fasteners is the main culprit, but there are others.
d/   Malfunctions of the thermostat and the coolant recovery system.    Also, a complicated coolant "bleed" procedure, which could have been prevented by a "pressure bleed" system coupled with an adequately sized coolant surge tank.

I'm not going to "presume" uneven cooling.    But the other issues have been, are being, or will be addressed, prior to the next appearance at Bonneville.

I'm not going to "presume" cavitation either.     I just don't think it's good idea to spin water pumps at crank speed on high rpm engines, just from a hp standpoint.    I want to check what the Brit builders are doing on this issue.    For expediency, we might just have to spin the pump at crank speed, and raise the cooling system pressure to retard any cavitation issues that might exist.

 :cheers:
Fordboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline jacksoni

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Re: Milwaukee Midget
« Reply #6566 on: January 03, 2018, 10:37:42 PM »
I am using the Gates Poly Chain Gt Carbon  belt which seems to be their best and toughest. It has survived my own design and construction to 10250rpms multiple times so far without a whimper.  They use the modified curvilinear tooth which is a modified HDT type. Here is a listing of the lengths for the 21mm wide belt: http://www.gatespowerpro.com/Comergent/en/US/adirect/gates?cmd=catNavigateFrame

Gates has software called Gates Design IQ3 which will allow total design of the belt system with pulleys, idlers, tensioners etc and then tell you how big the belt needs to be (if you can guestimate torque loads) and more importantly if you are changing from the standard tension for which you may have specs, what the tension should be if you are using their (non stock to Rover etc) belts. If you change the water pump pulley you can use this to tell how long the belt needs to be and compare to what's available, particularly if also you are going to a non stock idler/tensioner (manual vs spring). It also tells you what deflection corresponds, with a tension gauge, to the proper load and on which stretch of belt you are measuring,. It is available for download.
« Last Edit: January 03, 2018, 10:40:14 PM by jacksoni »
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
 G/GMS-182.144 2019

Offline fordboy628

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Re: Milwaukee Midget
« Reply #6567 on: January 03, 2018, 10:46:23 PM »
Today's work list:

I'll let Chris do the flowery prose.    Just the list from me.   We are chipping away at it . . . . .

1/  Ground the block for starter clearance, 3 places;
2/  Did the offer up on the starter, looks good.
3/  Modified the starter for alternate B+ post location.  Completed, and tested.    The coppersmith was in . . . . . .
4/  Marked out the Lexan plate for revised starter location, fits, JFB, but now fits after the mods.
5/  Cut and fitted exhaust flange studs/ washers/nuts.
6/  Cut and ground clearance for water outlet into the RH side of the SS exhaust flange.
7/  Did a bit of fitting on the belt drive.
8/  Added the new oil pump to resolve belt fitment issues.
9/  Added the new water pump for belt drive fitment issues.

and I'm sure there were other things . . .

And we sent positive thoughts and a prayer for Freud.

You get the rest from Chris . . . .

 :cheers: :cheers: :cheers:
Tiredboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein

Offline Milwaukee Midget

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Re: Milwaukee Midget
« Reply #6568 on: January 03, 2018, 10:54:57 PM »

I am not aware of any "uneven" cooling issue with the K engine.


I'll clarify from my understanding.  See "d" above - #6565.

The external thermostat would open late in the engine heating cycle - or stick - or be of an inappropriate temperature - and douse the sleeves with coolant.  Maybe I guild the lily by referring to it as "uneven cooling" - I think "thermal shock" is the term used in the posts and articles, some of which pointed to this anomaly as a contributing factor in head gasket failure.

At the end of the day - we want to avoid any shock.

Nevertheless - wow - productive day, indeed.

Everything is starting to fit - more or less.  Relocated the starter terminal, Mark took a die grinder to the block, and it's determined that we actually may be able to utilize the starter to do something as crazy as STARTING THE CAR!

I've got a pdf in my e-mail inbox of the original blueprint of the adapter plate, I purchased some plate, Mark's sussing out the idler, I grabbed the intake stubs to work on intake design, we ate $1.00 tacos at a German pizza restaurant.

Yeah - good day.

If you pray, please pray for Freud.  We've been worried about him all day.
« Last Edit: January 03, 2018, 10:57:31 PM by Milwaukee Midget »
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline fordboy628

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Re: Milwaukee Midget
« Reply #6569 on: January 03, 2018, 10:57:08 PM »
I am using the Gates Poly Chain Gt Carbon  belt which seems to be their best and toughest. It has survived my own design and construction to 10250rpms multiple times so far without a whimper.  They use the modified curvilinear tooth which is a modified HDT type. Here is a listing of the lengths for the 21mm wide belt: http://www.gatespowerpro.com/Comergent/en/US/adirect/gates?cmd=catNavigateFrame

Gates has software called Gates Design IQ3 which will allow total design of the belt system with pulleys, idlers, tensioners etc and then tell you how big the belt needs to be (if you can guestimate torque loads) and more importantly if you are changing from the standard tension for which you may have specs, what the tension should be if you are using their (non stock to Rover etc) belts. If you change the water pump pulley you can use this to tell how long the belt needs to be and compare to what's available, particularly if also you are going to a non stock idler/tensioner (manual vs spring). It also tells you what deflection corresponds, with a tension gauge, to the proper load and on which stretch of belt you are measuring,. It is available for download.

Thanks Jack.

Needless to say, the vernier cam cogs are staying.

Belt width will remain the same as stock.

Might change the belt length, and the water pump cog might get bigger.

The spring loaded idler is GONE.    Replaced with a manual, Cosworth style.

I still have my Burroughs gage from my Cosworth BD days, so I'll use that to set whatever tension Gates recommends.   And a heavy duty belt from some source will be used.

 :cheers: :cheers: :cheers:
Fordboy
Science, NOT Magic . . . .

I used to be a people person.  But people changed that relationship.

"There is nothing permanent except change."    Heraclitus

"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."     Albert Einstein