Landracing Forum
Bonneville Salt Flats Discussion => Build Diaries => Topic started by: ProjectROTM on December 30, 2018, 07:03:24 AM
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Hi everyone,
I have been hugely inspired by the usual things (Worlds fastest Indian etc.) and loved a series that was on a few years ago in the UK documenting a number of British bike builders and their journey to Bonneville. I know a few of them are on this site as that was how I first came across landracing.com
While I will likely only be running my bike in UK land speed events I thought this would be a good place to start my build thread as there is a colossal amount of experience and knowledge here that I would be stupid not to try and tap into.
I am going to document the project in video, the first of which can be seen below.
https://youtu.be/YF-VxQccAak
ProjectROTM
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Sadly, most of the UK speed trials events are run by a guy I'd rather not talk to or talk about :dhorse: : O ( ...
Still, if I had an English bike, it would have to be a Velocette... So much like Harley-Davidson on numerous points of views... Family set up, weird engineering of German descent, slow changes and a race history equal to none despite their small size. Friend of mine in France had a Mk VII KTT in the 70s, it had collected a silver replica at the 1938 TT riden by Roger Loyer, what a bike and noise!!!
(https://lh6.googleusercontent.com/-tgIcdUB2CM8/TYvMILo6RCI/AAAAAAAAAaw/AYKS_VZN4NE/s320/velo+KTT+R+side.jpg)
So, good luck on your project and tell us more on your bike, the MAC had a long life and the name covers a lot of variations...
Patrick
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Thanks Patrick. That Velocette looks beautiful!
I am very new to this so haven’t had chance to make any friends or enemies yet :-D but I won’t ask about the organiser.
Would your bike be a supercharged flat head Harley that I remember seeing at the VMCC festival of 1000 bikes at Mallory a few years ago?
ProjectROTM
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Yep, that's the one and only, but now retired...
(https://i.imgur.com/FrP2V0q.jpg)
The KTT MkVII picture above is just generic, I don't know where my friend's one is these days, he sold it along time ago...
Patrick
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Yes, that's the one. I remember thinking it looked awesome.
If i have managed to do it correctly here are a couple of shots of the bike in its current form.
(http://<a data-flickr-embed="true" href="https://www.flickr.com/photos/167233183@N04/45860242634/in/dateposted-public/" title="Seating position"><img src="https://farm8.staticflickr.com/7907/45860242634_7cb4f53971.jpg" width="500" height="282" alt="Seating position"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>)
(http://<a data-flickr-embed="true" href="https://www.flickr.com/photos/167233183@N04/31643717707/in/dateposted-public/" title="black and white"><img src="https://farm8.staticflickr.com/7894/31643717707_034a28cb29.jpg" width="500" height="393" alt="black and white"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>)
(http://<a data-flickr-embed="true" href="https://www.flickr.com/photos/167233183@N04/32710722178/in/dateposted-public/" title="black and white2"><img src="https://farm8.staticflickr.com/7927/32710722178_59687b27ca.jpg" width="500" height="375" alt="black and white2"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>)
Regards,
Project ROTM
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Good luck with the build on that Velo, they are certainly decent bikes to start with.
I look forward to seeing how you develop it and wish you success with the build. It should be fun ( most of the time ;) )
John
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Burt Munro raced a Velocette.
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Stuart Hooper in Australia can tell you all you want to know about the World's Fastest Velocette.
http://www.worldsfastestvelocette.com/
Tom
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Thank you all for your input.
It seems my IT skills aren't quite up to scratch. I will try one more time with the photos.
(https://i.imgur.com/wiAul9W.jpg)
(https://i.imgur.com/AjTCEvM.jpg)
Regards,
Project ROTM
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I have now uploaded the first video on the bike.
I would welcome any expertise or suggestions on the exhaust routing and trying to reduce the frontal area. I think this is going to be very important as the bike is only 350cc.
https://youtu.be/A0ZRUQXUtqM (https://youtu.be/A0ZRUQXUtqM)
Project ROTM
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That looks like a fun project. Thanks for posting the video.
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Hi, ROTM,
I would fit the seat further back, its end right in the rear axle vertical and lift your rear set to make room for the standard exhaust pipe. As high as you can where you can still shift/brake. This will allow your knees to be at quite an angle for a touch of ""allowed"" streamlining.
For a 350cc, you can look up at exhaust length pipe calcs on the web, but part of the calcs is dependent on your cam timing, the exhaust opening phase angle before BDC. Contrary to general belief, the higher the better, nearly all 4 stroke race bikes have more than 90 degrees there and some more than 110 degrees.
Then your max revs obviously.
As a rule of thumb, for a 350/400cc, 1"1/2 ID pipe, about 36" long from valve head to end of pipe.
30 to 45 degrees slash cut at the end of the straight pipe will act as very small megaphone, make a nicer noise and slightly improve your torque curve. Since you're probably like me with minimum funds, gear box new set is out of the question, so, yes, power at top is important, but good torque will help you be able to gear the bike higher via rear sprockets.
I don't know if the inner dimms are that common between MAC and Viper/Venom/Thruxton, but if yes, a look at their camshafts/followers will be an eye opener!!!
Patrick
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Thanks Wobblywalrus, I have been following your Go Dog, Go thread for a long time. It is full of really useful info.
Thefrenchowl, I really appreciate your advice. I am a novice at this.
I have an M17-8 cam (used in the Venom & Viper) which I will compare to the standard one. I think I will have to walk a fine line with CR, timing and valve to valve and valve to piston clearance.
36" seems very short for the exhaust, it is about 38" in its current form. Once I have looked into the cam specs further I will carry out the calculations to define the theoretical best length. The MAC engine is a long stroke engine so RPM will be quite modest so I would expect to need a slightly longer exhaust (compared to a 350 Manx etc.)
Regards,
Project ROTM
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Earlier exhaust opening effects:
reduces the duty cycle
exhaust is louder
strengthens the pulse returning to the chamber
If you have a choice of internal box ratios, consider the closest 3-4 shift (smallest RPM drop) as a priority
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Thank you all for your input so far. This is exactly why I joined this forum, to try and borrow some experience (which I am definitely lacking).
I have done some calculations this morning and the exhaust length is coming our in the region of 34" based on the anticipated cam timing. This is shorter than my gut feeling, but shows thefrenchowl knows his stuff.
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At least being shorter than you gut feeling you could have trimmed the pipe to suit. Better that way than trying to nail 2" back on again. :-D
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It's only a theoretical calc for exhaust length...
As a rule of thumb, one can also add:
Shorter = less torque/more power,
Longer = more torque/less power,
And bigger diameter = NO NO :-D
Most bikes I have seen in me time are always over-carbed and over-exhausted...
Sweetest Harley Sportster I ever had was a bored/stroked (from 900 to 1200) 1959 Iron head CH with std 36mm Linkert DC carburetor, 1"1/2 high level pipes, OEM std 57/58 small valve heads and 45 deg fixed advance magneto...
See ya,
Patrick
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At this stage it might be a good idea to have digital profiles made of your cams, flow test results from the cylinder head, a measured compression ratio, and rubber castings of the intake and exhaust ports. Then, a virtual model can be made of the engine in an analysis program to figure out the answers. The big benefits are getting the model, but more important, the things you learn about engines from reading the program user's manual and working with the example data sets that are included with the program. This is a lot of "up front" work that saves time, money, and frustration in the long term.
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Wobblywalrus - That is the plan and thank you for the link you sent.
I have just finished the 2nd part of my project video where I try to start the bike for the first time.
:eek
https://www.youtube.com/watch?v=OmkGMLe9l8M
Let me know what you think.
Cheers,
Christian
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:-D
Tip to find the real TDC rather than a + or - 5 degree approximation with piston and plunger:
Fit sommat on top of bore to limit the piston travel on its upstroke, like a bar fixed across the top of the cylinder with a bolted screw sticking down in its middle. Or use a fixed version of your plunger.
Fit degree wheel and pointer in any position, then turn crank CW until the piston touches the bolt, way before TDC.
Measure the angle on the degree wheel.
Now turn the crank CWW until the piston touches again the bolt.
Measure the angle again.
Genuine TDC is right in the middle of the 2 measurements.
Move pointer and/or degree wheel so you read 0 degree at that spot.
Continue the good work...
Patrick
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Thank you Patrick.
All advice and experience is welcomed.
Christian
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That's a good tip from Patrick. I have used a dial gauge in the past as well as it is more accurate than the depth gauge method.
Christian another option for your steel requirements is an online company called Metals4U. I have used them a couple of times ( no ties or relationship with this supplier) and you will find them cheaper usually than B&Q. They have a lot more choice too.
Nice job on the engine stand that came out well.
cheers
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Christian, this is what heats my shed. This is an oil radiator heater. There are no open flames or glowing exposed electrical coils. It works great and is a lot safer than many other methods. It is the Italian brand De Longhi.
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I am getting to the stage where I am starting to think about port flow and porting, so I dug this out from under my desk for inspiration.
If I ever make it over to Bonneville I will buy a cold beer for the first person to guess what engine the port is from. It has a ~300cc cylinder capacity.
(https://imgur.com/a/w4d6dum)
Christian
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It often helps to get flow data for the ports you have and to enter it into the computer model along with the cam profile data. The cam lifts, port flows, and engine demands need to be compatible with each other.
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Thanks Wobbly, I am going to see if I can get the head flowed so that I can baseline any porting work.
I thought I should get some practice starting the bike. Oil flow to the tank seems good. Here's a short clip for everyone that wanted to see more running. P.S. if you haven't already subscribed to my channel, please do.
https://www.youtube.com/watch?v=929tKg-4UYs (https://www.youtube.com/watch?v=929tKg-4UYs)
Christian
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A problem with old bikes is that we do not know what we are working with unless measurements are taken and we look at them analytically. Years ago I owned a BSA Spitfire. The bike had bigger intake valves installed and the ports were flowed in the factory. Of course, I enlarged them and the bike ran worse. Same with a Matchless G80CSR scrambler. Someone, maybe Jerry Branch, ported the head. I "improved" the port size without knowing they were plenty big to start with. The bike ran terrible except at very high rpm after I did this.
Typical flow data is for the valve lift at .025 inch increments with just the head. Then, with the head and manifold and carb. Then with the head, manifold, carb, and filter. Usually flows are measured at increments up to .5 inch valve lift. Usual results are three flow vs lift curves for the inlet and one for the exhaust. The fellow that flow tests my exhaust port puts a short stub pipe on the head to simulate the exhaust system.
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No body guessed what the port was from, but i will show you anyway :-D
It is the intake port from this, a development flow log for a V8 F1 engine. Small cylinder capacity, but big bore.
(https://i.ibb.co/FmqPxTG/Port-2.jpg)
Also, I have finally worked out how to post pictures onto the forum!!!!!!
Cheers,
Christian
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I do love the sound of an old single. You cant beat it.
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The development flow log is from this engine...
https://youtu.be/X3mFKjKosbI (https://youtu.be/X3mFKjKosbI)
https://www.youtube.com/watch?v=X3mFKjKosbI&t=28s (https://www.youtube.com/watch?v=X3mFKjKosbI&t=28s)
I promise the next post will be fully back on topic!!!
Cheers,
Christian
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Hi all,
I promised the next post would be back on topic. Here is the latest instalment of my project video. Don't forget to subscribe.
https://www.youtube.com/watch?v=YL3RNZe9xVA (https://www.youtube.com/watch?v=YL3RNZe9xVA)
Cheers,
Christian
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https://youtu.be/IRQJUJ_dKyk (https://youtu.be/IRQJUJ_dKyk)
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It has been a while since my last update.
Here is instalment 4 of my project. In it I take a brief look at the Cosworth SCA engine for inspiration.
https://youtu.be/X-2_ETvpubY (https://youtu.be/X-2_ETvpubY)
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https://www.youtube.com/watch?v=lbkccBdeCug&t=285s (https://www.youtube.com/watch?v=lbkccBdeCug&t=285s)
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Very slow progress recently on the build, mainly due to moving house.
The garage currently looks like this...
(https://i.ibb.co/4T0Mt6J/IMG-2732.jpg) (https://ibb.co/MVJpSY9)
...so turning it into a usable workshop is going to be a project in itself.
I did manage to take the bike out to a local Vintage Motorcycle Club day at a nearby stately home earlier in the summer though.
(https://i.ibb.co/HLc8Nyf/IMG-2586.jpg) (https://ibb.co/wZnmJqF)
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I have finally got round to making some progress. I have managed to sort the garage out and turn it into a usable workshop.
https://youtu.be/UoHDH_AdmgA (https://youtu.be/UoHDH_AdmgA)
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Another update on the workshop project. I have always wanted a lathe and this is the first time I have had enough space to squeeze one in!
https://youtu.be/mzxFlAzp2Ns (https://youtu.be/mzxFlAzp2Ns)
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A lathe is so useful I don't know how I would do without one. Your Velo is looking great.
Tom
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That lathe is great. It is nice to see you back on the forum.
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Thanks Koncretekid and wobblywalrus.
I seem to be short on space, time and money. But I am expecting the lathe to be worth its weight in gold when it comes to usefulness. Up until now I have had to try and rush small jobs on a lathe at work in my lunch break, so any job longer than 30 minutes wasn't possible.
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I hope everybody is keeping well during these very strange times.
Being on lockdown has allowed me to start thinking about the engine in my MAC.
https://youtu.be/5JMXbxOpjLY (https://youtu.be/5JMXbxOpjLY)
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Cheap flow bench: https://www.musclecardiy.com/cylinder-heads/build-flow-bench-port-flow-testing-cylinder-heads-part-3/
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Hi ROTM,
I'm on furlow as well, paid by the GB Gov... Getting back some of the monies I gave in taxes over 35 years...
Good luck with the Myford, it is a good tool, I used to have one... However I found over the years it's very hard to do anything other than real small MC jobs on it due to size.
Went one day to a friend to buy some wood working tools and as soon as I enter the workshop, this lathe shouts at me BUY ME... T'was a Raglan Little John from 1947, say 1.5 bigger than the Myford... Got it for ?200 and sold the next day the Myford for twice as much, so a good day all round!!!
Keep on the good work...
Patrick
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Hi Monsieur Owl, that Myford is doing me proud so far.
I have spent a bit of time doing some cylinder head work trying to match the port to the carb.
https://youtu.be/JSfuLCM65Zc (https://youtu.be/JSfuLCM65Zc)
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The late great Roland Pike knew a thing or two about single cylinder OHV bike heads. Amongst other things he was responsible for much of the development of the BSA Gold Star in the 1950's. Here is an interesting snippet from his memoirs regarding inlet port work that you may find interesting. i have been following your progress having once owned a very fast MOV that had been used for sand racing. Just toadd, I miss my regular dose of French Fowl Longhi exploits :-D.
ttp://www.beezanet.com/beezagent/rolandpike/roland%20pike%20memoirs.pdf
Excerpt from page 18
One of the strangest occurrances to do with carburettors was when one day Reg Wilkes sent an apprentice from the test shop into our,
main shop for a 1 3/32 GP carburettor and he misread the size and gave Reg: a 1 3/16th carburettor and they immediately got quite a
jump in power. They reported this to me and I went to the shop and the test was repeated and there was no doubt it was quite a gain in
power. I suggested to Reg to open the port to match, immediately we lost what we had gained plus a bit more, so we made a thin
sleeve and pressed it in and the power was back. We repeated this on other engines always with the same results. A number of private
owners of DBD Gold Star noticed the carb being bigger than the port and opened up the port thinking to gain power, but not having a
dyno were not aware of the results. Later on we fitted a venturi behind the carb and picked up even more power. The smallest diameter
of the venturi could be 80% of area of the carburettor. We tested this on several engines and it always worked and seemed to improve
carburation.
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Hahaha!!!
I gave the Jonghi a well deserved retirement from Bonneville... I just about finished reconstructing it after the salt did attack absolutely everything on it... 2019 was the worst salt I've seen in my few visits there...
Anyway, back to the ports. Since a flow bench is not sommat everyone can have in his garage (and it will only give you basic static figures... not real life engine breathing), yes, it's worth looking at what's been done on similar engines as the ones we try to tune.
As far as OHV and OHC engines go, they always seem way over-carbed (and over-valved, but that's another topic!!!) from the word go at any factory... Donno why, buyers seem to think bigger is always better... While peak power will usually be synonymous with biggest carb available, that leaves the torque curve way too high in the rpm range... And you'll need low down torque as well as high up power with only std street 4 speeds to play with.
In all the iron head Sportsters I've had, quite a few, the best ones were always the earliest ones fitted with the oh so simple Linkert DC carb, 34mm venturi, so none of this S&S 1" 7/8 (47mm for you metric boys) nonsense here...
As far as the port goes, a small decreasing taper (ie getting smaller) towards the valve speeds up the mixture and help it getting and staying laminar. Last "venturi" about 2" from the valve, just before the bend and then it gets bigger to join the valve OD.
Once you get the basic engine going, look at the air trumpet to see how much mixture gets back out due to inadequate inlet track length (could be either too long or too short). Factories did use telescopic inlet tracks to tune the length at the revs of the peak torque, that's easy enough to do on a loaded engine... Look at the Thruxton inlet track compared to a std MSS/Venom one... They had to lower the oil tank to clear the GP carb!!!
Bye for now,
Patrick
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I apologise for one too many "F"'s Mr Frenchowl :-D
P.S. Those were my last words to my ex-wife too :-D
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What is the engine displacement and the rpm that you expect peak power to occur at after full development of the engine?
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A big problem with engine building is figuring the valve and carb size, as mentioned in earlier posts. Here is the method I use. First, using the actual rather than nominal displacement, and the realistic peak power rpm limit my wallet can afford, this is entered into the equation on Page 83 of Harold Bette's "Engine Airflow" book ISBN 978-1-55788-537-1. Let's assume 21.1 cubic inches (346cc) displacement, 7,000 rpm at peak power, and the rpm coefficient from the table in the book is 1196 for 28 inches water.
peak power cfm = (rpm at peak power x displacement per cylinder) / coefficient at peak power = (7,000 x 21.1) / 1196 = 123 cfm air flow at peak power.
Now, using this airflow and the horsepower equation on the same page and the horsepower coefficient for 28 inches of water from Page 82, which is extrapolated to be 0.26 for a one cylinder engine:
peak power hp = coefficient at peak power x displacement per cylinder = 0.26 x 123 = 32.0 hp at peak power
These are what I always called the Dynojet equations and they are based on measured wheel chassis power and measured intake air flow for the full system including manifold and carb. This is based on my foggy, aged and pickled memory and there is a chance that I am wrong.
Crank dyno power is used in most automotive based analysis programs and equations. Assuming a primitive style chain driven primary like on Harleys and old BSAs and Triumphs, crank dyno power = wheel dyno power / .90 = 32 / .90 = 35.5 crank hp. Assuming a more efficient drive system like a geared primary, crank dyno power = chassis dyno power / .92 = 32 / .92 = 34.8 crank hp.
These power estimates, based on my experience, are pretty good high estimates of what to expect. The PipeMax program is easy to use and it gives port and valve flow recommendations. It relies heavily on an accurate volumetric efficiency estimate. What I do is to use the crank horsepower calculated by the preceding estimate with an engine in good condition to get the expected VE. Then, I use the Pipemax program and others like Dynomation combined with advice from experinced tuners to get an idea of the best valve and port size. The smallest intake port and valve size with adequate sonics is what I use.
This is what works for me and I am an average redneck backyard tuner. Do not consider it to be gospel.
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Hi all,
The all conquering Guzzis 350cc won 5 consecutives World Championships between 1953 and 1957, a period in keeping with the MAC design and lifetime...
Giulio Carcano, their designer/enginer/race head honcho, said that, most of the time, they had way less than 33 HP to compete with the others guys, HP obtained at great cost with a SOHC design of impeccable racing heritage, having started in 1926 as a 250 cc with an horizontal cylinder .
The period 350cc DOHC single Norton Manx claimed more than 35 HP, but, too high and too heavy, being a reduced size 500 ie wrong approach, never got near the Guzzis.
I would think to extract anything near 30 HP from a MAC with street gasoline would be a miracle unless umpteen hundreds of hard earned cash are spent on this project.
The Velocette flagship, the 500cc Venom Thruxton, highly tuned with special head, valves and carburettor was rated at 42 HP @ 6200rpm by the factory and capable in Veeline version of 115mph on a good day... Lets not quibble and agree they found a few more, say 45 HP on their winning Production TT racer, hit 120mph, that's it...
To get speed out of his MAC, I would suggest the HP approach will not be a success and ROTM will have to explore other avenues to get the speed he wants...
ROTM should look at Carcano's work to get speed w/o HP, ie lightness, friction reducing measures, fairings and low frontal set up, small section tyres, efficiency, weight distribution etc...
All things that don't need that many dollars to implement, but mostly brain power.
Patrick
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The Bonneville cylinder displacement is 30.3 cubic inches with a 236 cfm intake airflow at 28 inches. This is flow for the complete system with carb and filter. Peak power rpm based on the Dynojet equation is (1196 x 236) / 30.3 = 9,300 rpm. Peak power is 0.26 x 236 = 61.3 hp per cylinder. The cylinder volume is 498cc.
The engine makes between 51 and 53 hp at 9,000 rpm, per cylinder, depending on the dyno. The goal is to get 55 hp per cyl this year. There has been over a decade of work on this motor with hundreds of dyno pulls. Patrick is right, the Dynojet equationa are a bit high, and especially for a vintage engine. They might result in oversizing if you use them.
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Sadly for sale now, another project bites the dust...
https://www.ebay.co.uk/itm/266070194171?hash=item3df304f7fb:g:47IAAOSwiv1jtYR3&amdata=enc%3AAQAHAAAAkAOsfFhBLzlcjNZSuIr40rwTeQFNGpWgsir1OsWO%2FvXQ%2FKhczLLp8w%2FuTLOf2Q79XYQDjVi1iO12xr2OevAZpo20MBV5y1hdghjW0IiXU%2BOMoowgDzxHhvLr5ODmroD8Swh%2B6d%2B%2BBK8uTDx5RY1sjAuvFT1tPb1u2%2F72M7Om9uxKeDwBU9mx2qidywf6LD2mQw%3D%3D%7Ctkp%3ABk9SR4jO2t2zYQ
Patrick