Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 1438113 times)

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Offline dadsolds

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #555 on: October 03, 2011, 12:13:03 PM »
Isn't scavenging what you do when you need a part and know you have one somewhere but can't remember in which old coffee can you pitched it?
Or is it the interaction between the returning exhaust pressure waves with the incoming intake charge in the combustion chamber during the in/ex overlap period. It usually has little to do with the displacement of the cylinder but rather the design of the ex system, the shape of the comb. chamber and the design of the intake tract. What you did with the small engine to optimise the intake length, cam timing and exhaust length. All that interaction worked to maximise the scavenging effect to boost torque at a certain rpm.
Or is it when they give you a list of weird stuff and tell you to go and find it.
Brain says no, right hand says go
1979 UJM 750

Offline Koncretekid

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #556 on: October 03, 2011, 09:28:03 PM »
Bo,
Panic has a spread sheet program to determine the optimum length for your primary pipes, taking into consideration the valve timing, intake length within the head, and the RPM you want to tune for.  It seemed to work for me, and I ended up with a 22" pipe.  If your pipe is too long, the reversion wave will not arrive back at the exhaust valve at the right time, and with a race cam with lots of overlap, incoming charge can exit straight out the exhaust pipe.  Similarly, with the proper length, a negative wave can arrive just when the exhaust valve opens, which will help to "scavenge" the exhaust gases. (I'm basically just repeating what I believe is the correct analysis.)
Tom
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #557 on: October 03, 2011, 11:51:51 PM »
Lars, I am not sure about the "obey" part.  We are a typical American family.  The kids are on the bottom rung of the command chain, the husband thinks he is in charge, the wife actually is, and everyone would be better off if they listened to the cat.

This might be another type of scavenging but I am not sure.  Scavenging in this case might be the engine's ability to reach peak horsepower before it hits red line.  I have seen this in the past and the solution was to either increase compression or displacement.

There is new English magazine about racing old bikes.  See www.classicracing.com  The adverts are the most useful part for the old British bike enthusiast.  The Barnes and Noble bookstore carries it here in Oregon.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #558 on: October 04, 2011, 01:28:58 AM »
A lot of aluminum is used around here.  The 0.020 sheets for the skin are common and found in hardware stores.  No problems there.  Thicker sheet aluminum, up to 1/4 inch thick, is hard to find in small sizes.  I go to a metal fabricator and look in their supply and scrap bin.  They sell it to me by the pound.  I use enough to be on an "industrial user" account and I get a discount.  The 1/2 inch by 1/2 inch bar stock seen in the photo is not very expensive and I use a lot of it.  I buy standard 12-foot long lengths from the metal fabricator.  They are a metal supplier, too.

It is not economical to buy standard lengths of the larger aluminum bars that I used for the triple clamps, tailpiece end, and the front fairing brackets I will make next week.  I order the larger bar from Fastenal.  They sell it by the foot.  This makes much more sense than buying a full bar when I only need a small piece.

It is very important to use good metal.  Chinese metal can be of awful quality and it should be avoided.  The better suppliers stock metal from reputable sources.  I always ask to make sure.

Alloy is important, too.  The 2" by 2" aluminum bar stock I ordered today is a good example.  It is available in 2024 or 6061 alloys.  Volume 2 of the book "The Racing Motorcycle" by John Bradley has a chapter on aluminum and its alloys.  The major alloying element in the 2000 series is copper and in the 6000 series it is magnesium and silicon.  These additives give the aluminum different properties.

Bradley has a lot of information about these alloys, in summary, the 2024 is heat treatable, has high strength, poor corrosion resistance, does not anodize well, and neither TIG welding, gas welding, or brazing are recommended.   The 6061 is heat treatable, has good corrosion resistance, color anodizes well, has moderate strength, and TIG or brazing are recommended.  Gas welding is "fair."  Strength, weldability, and anodizing are not concerns in this application.  Corrosion resistance is.  These brackets might get salty and 6061 is the choice.  In fact, almost all structural aluminum on this bike is of the 6000 series.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #559 on: October 05, 2011, 12:32:17 AM »
The performance shop I work with told me the cams I have are the best ones for an 865 cc engine.  The next hotter cams will make me go slower, they say.  Several years ago I did a bunch of posts about engine math.  In those posts I did the math on a 994 cc big bore kit.  I knew this day would come.  The kit is on the www.triumphperformanceusa.com website and it is listed in the performance parts section for the Bonneville.  High compression pistons are available for this kit beyond the 11.5 ones that come standard.

Plans are to finish the front fairing this year, install a 2 tooth smaller rear sprocket, plug in a Stage 3 ignition module instead of the Stage 2 I have now, and race at BUB in 2012.  This winter I will buy the big bore kit and start collecting all of the seals, gaskets, etc. I need for a rebuild.  The winter of 2012/13 will be devoted to installing the big bore kit.  Cams, etc to match the big bore kit will be done in winter 2013/14.

This is a long time.  My racing budget is $500 a month.  I am not complaining.  How far would that money take me in NASCAR or NHRA?

Offline Unkl Ian

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #560 on: October 05, 2011, 11:53:59 PM »
  My racing budget is $500 a month.  I am not complaining. 
How far would that money take me in NASCAR or NHRA?


You could buy tickets for a couple events.
I guess the answer is "a Secret" .

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #561 on: October 06, 2011, 01:14:24 AM »
There was on the landracing.com webpage a link to Dr Mafy's aero stuff.  It had tables and lists of all sorts of drag coefficients, frontal areas, etc for different vehicles.  I could not find it this evening.  Is that info posted anywhere?

Offline Seldom Seen Slim

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #562 on: October 06, 2011, 09:46:35 AM »
Good question.  I remember that we've moved things around -- I'lldig and see where it went.  If nothing else I'll ask Mayf (who doesn't visit this site but does watch the land-speed.team.net list) where he's got it.
Jon E. Wennerberg
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 Skandia, Michigan
 (that's way up north)
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #563 on: October 07, 2011, 01:00:39 AM »
Thanks, Slim.  I am sure you are tired after the World Final fiasco.  Get some rest.  I am in no hurry.

The streamlining rules I race under say that the entire rider must be visible from the side.  This includes my hands so there is a slot in fairing side.  The slot has a round front and I need to bend some bar into the right shape.  A steel ring from an old Yahama crankcase assembling tool will give me the perfect radius.  It will be the mandrel and I will bend the bar around it.

The bar is 6061 aluminum alloy and it has been described in a recent post.  It has a T-6511 temper.  The alloy and temper are printed on the bar.  Bradley has this to say about the T-6000 series tempers.  "Very common.  Product is solution treated and artificially aged (precipitation).  Gives maximum strength but ductility is reduced.  Fatigue life may also be reduced compared to T4 condition.  Often referred to as 'fully heat treated.'"  My triple clamps were made from tempered aluminum billet like this.  I did not do anything in the fabrication process to alter their temper such as welding or heating.  This would reduce the metal's strength and strong triple clamps are best.

I need to heat these bent sections during the forming process.  The aluminum after heating and cooling will have "O" designation temper.  Bradley says about O "Very common.  Fully annealed material.  This is the softest, weakest, most formable condition for the alloy concerned."  This weaker material will not be a problem in this application.

First, I roughly shape the loop with a rebar bender.  Next, I clamp the piece in a big vise.  The chain clamp holds the mandrel against the aluminum bar and the two other bars and c-clamp keep everything in alignment.  The vise is tightened and the bar is bent into a loop.

The tempered bar would spring back quite a bit when the vise is loosened and it would not have the correct shape.  It is annealed to temper designation O with a propane torch to make it relax onto the mandrel.  The torch is moved SLOWLY over the bar on both sides at a rate of 2 to 3 millimeters per second.  I count one alligator, two alligator, etc as I move the torch 2 or 3 mm per alligator.  Finally I let the bar cool.  It expands a tiny amount when I relax the vise, but not much.  This is typical.  Job done. 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #564 on: October 13, 2011, 12:40:57 AM »
The next two posts shows "putting an engine to bed."  That is what I was taught.  I do not know if there is a proper name for this.  This is best done while the motor is warm after the last run.  I am doing most of it in the Smith's parking lot.  I forgot my top end oil and they had some spray oil in the hardware section.

First, I unscrew both spark plugs and check them for aluminum deposits.  This will tell me how busy I will be over the winter.  Next, I spray some oil down the plug holes to lube the cylinders.  They make oil for this purpose.  I use Marvel Mystery Oil.  My father used it and I need to keep the tradition.  Then, I drain the carbs.  Now, I turn the engine over with the starter and spray oil down the bellmouths.  This lubes the valves.  Last, I grease the plug threads and reinstall the plug using lubricated thread torque.  (About 2/3 to 3/4 of dry torque).

Road dust can travel up the pipes and down the bellmouths.  It sticks to the oily engine parts.  I stuff oily paper towels into the pipes.  The Triumph has air cleaners.  I would stuff the bellmouths if it did not.

Now I remove the chain and soak it in water to dissolve any salt.  Then I dry it in a sunny spot, oil it, and put it in a plastic ag for the winter.  The oil I use is FP-10 Lubricant Elite by Ventco, Inc www.shooters-choice.com  This is good stuff.  The chain looks like new and has no rust after four meets on the salt.  In all cases, it was on the bike, on the salt, for several days without lubing.

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #565 on: October 13, 2011, 12:43:12 AM »
The other 3 pix.

Offline Seldom Seen Slim

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #566 on: October 13, 2011, 09:36:44 AM »
Bo, where did you come up with your estimate of how much torque to use on the threads of a lubed spark plug?  I'd like to know if there's an official (so to speak) source of this information.  I ask 'cause when my dad sold for Premier Industrial (makers of fasteners including up to "Supertanium", supposedly at or above grade 8 nuts and bolts) that the lube reduced the needed torque to something less than 25% of what's needed for a dry threaded fastener.

25% or 65% of "normal".  Got some hard and factual information to back it up?
Jon E. Wennerberg
 a/k/a Seldom Seen Slim
 Skandia, Michigan
 (that's way up north)
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Offline Vinsky

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #567 on: October 13, 2011, 01:22:52 PM »
Champions torque specs say that after 'finger tight', which should be the same with or without lube. Then you go 3/8, 1/2, 5/8 more turn. depending
on type of seat, new or old crush washer and so on.
I'll read it again, but o don't think you would want to put a new plug in an aluminum head dry.
John

Offline Seldom Seen Slim

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #568 on: October 13, 2011, 02:56:34 PM »
Ah - they don't give a numerical torque value but rather just X turns after Y, another value without numerical definition.  I guess I'll go looking. . . :-)  Thanks anyway.  The only other method of tightening to some specific was given to me by a Chem. Eng. student when I was at Tech.  He was a backyard mechanic and offered, for when using a ratchet-type wrench, that one should do the following procedure"

(sound) widgegiggy, widgegiggy, widdgigiigggy, unh! (The "unh" being the grunt one would make when doing the final tightening stroke).
Jon E. Wennerberg
 a/k/a Seldom Seen Slim
 Skandia, Michigan
 (that's way up north)
2 Club member x2
Owner of landracing.com

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #569 on: October 14, 2011, 01:30:57 AM »
Three things happen when a bolt is tightened.  Some torque is used to overcome the friction between the bottom of the bolt head and the piece underneath.  More torque is used to overcome the friction between the male and female threads.  The remaining torque is used to stretch the bolt.  it is important to stretch the bolt enough to get the desired clamping force.  Too much stretch will deform the bolt.

Torque figures are for bolts with clean dry threads unless noted otherwise.  The listed values consider the relatively higher friction between dry parts.  Lube on the threads, and especially lube on the threads and head, reduces friction.  As a result, less torque is used to overcome the friction and more is used to stretch the bolt.  Torque figures are reduced to account for lubed threads.  See the chart.  This is where I got the percentages I posted.  I did some division using these values and arrived at the posted averages.  Note that too much tensile force on the bolt is a problem and a worse problem is too much pulling force on the soft female threads in the aluminum head.

I use a 75% reduction for lubed threads if I am too lazy to look in the chart.  It is close enough.  Nothing I work on is the space shuttle.

There are two reasons I lube the plug.  The plug is in a deep well and it collects salty water.  One year a plug was corroded into the head.  The lube prevents this.  The second reason is that plugs are screwed and unscrewed a lot in a race engine and lube reduces wear on the threads.

There is a reason I use a torque wrench.  The "count the turns" method works great instead of the torque method when a new crush washer is used.  Some of the turns are used to squash the washer and others are used to tighten the plug.  The plug is overtightened with the turns procedure if the washer is  crushed from previous use.  I am reinstalling used plugs with squashed washers in the post so I use the torque wrench.

A long post.  Now I know what a spawned out salmon feels like.  It is time for a pre-bedtime beer.