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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: BRICKKIT on July 10, 2014, 02:12:59 AM
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Hi all,
I am new to the forum. I currently have a Vintage (Fiberfab Avenger) kit car which is vw pan based and was looking for something more exotic to install in it for an engine. Typical transplants are Mazda rotaries and Subaru boxers but a host of other car motors are possible as well as indicated by Kennedy Engineering slew of adapters. I have also seen a few motorcycle engines adapter to VW transaxles.
Most motorcycle engines have an attached gearbox not making them suitable. Others have too rough of an idle. The Brick seems ideal providing good displacement, being known for long life, having good power and having a detached gearbox. Additionally I like its sound, its a BMW and it has the potential for hopping up (as seen by www.rbracing-rsr.com (http://www.rbracing-rsr.com) options).
I have seen on the web that the Brick is used in Formula BMW racing, has been fitted to a Grinnall Scorpion III, a Fiat 126, and a Reliant Fox so there is already some history of it in other vehicles. In the Formula and Grinnall the engines are vertical and in the others they are in the standard horizontal.
Does anyone know if mounting the Brick vertically will pose any issues (oil flow, etc...)?
Does anyone know where to get a gearbox adapter for it? If not, I have engineering resources to create one.
Great forum, - Jon
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I don't know for sure but mounting the brick vertically doesn't seem to be a good idea. I would think it would need to be installed in the orientation the manufacturer designed it to be. It is indeed a robust engine and I was told once that it has a 80% service duty by a guy who was going to put one in a ultra-lite airplane.
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One could say that the engine was designed to be vertical anyway and BMW knocked it over ;)
To do a real vertical conversion would be a lot of work though, you'd have to fabricate a new sump and pickup system, probably change a couple of oilways so that it returns/drains down properly (instead of 'across') or go for dry sump (with the same return/drain issues).
The K engine flat really isn't all that wide though, and with all the weight laying down it's going to reduce your centre of gravity compared to a vertical motor
(https://mediapool.bmwgroup.com/download/edown/pressclub/public?actEvent=zoom&filename=P0009108.JPG)
Things like the FB2 use the K12 engine flat...
With the vertical ones you've seen, are they native flat K engines turned upend or are they something like the A series with a K head conversion?
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Looks like I made a mistake. Neither the Grinnall Scorpion nor the Formula BMW car use the engine vertically. Based on that I will keep it flat.
Anyone know how off balance the weight is from the crank centerline? I know the engine is light (like the VW) but I wonder how much uneven stress will be put on the transaxle mount / frame horns.
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Under stand that the clutch is not actually directly connected to the crank. It's gear driven to it. The end of the crank shaft is up and to the right of the clutch. It's fairly balance from the center of the bell housing/clutch.
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Under stand that the clutch is not actually directly connected to the crank. It's gear driven to it. The end of the crank shaft is up and to the right of the clutch. It's fairly balance from the center of the bell housing/clutch.
Yeah, it should be almost perfectly balanced. The crank is quite heavy, more so than the whole head, just from my memory while I had one of the engines torn down.
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Mystic Red: What does "it has an 80% service duty" mean?....totally lost me there cocker :dunno2:
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The engine is doing useful work 80% of its life and is in maintenance mode 20% of its life. I think this is excellent for an aeronautics application such as an ultra-light.
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Ok thanks for that...never seen this way of measuring engine life before.
Is 80% a good figure? :dunno2:
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I've never heard of service duty expressed in those terms either. Any chance of a source?
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The way it was explained to me was that if you could run an engine at full throttle 100% of the time without blowing it up it would a 100% service duty. An example would be a large diesel truck engine.
If you could run it at full throttle only 50% without damage it would have service duty of 50%. Example would be Harley D motor.
This is what that guy told me who was going to build the ultra lite plane....Google turns up nothing.
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The way it was explained to me was that if you could run an engine at full throttle 100% of the time without blowing it up it would a 100% service duty. An example would be a large diesel truck engine.
If you could run it at full throttle only 50% without damage it would have service duty of 50%. Example would be Harley D motor.
This is what that guy told me who was going to build the ultra lite plane....Google turns up nothing.
That's much more like I thought - with an electric motor with a 50% duty cycle, you have to have it idle 1 minute for every 1 minute of running (usually comes with a max time in use before idle too).
Rating an IC engine is a little different, as you state above - 80% power output is 'safe' for constant running between services.
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I'm still lost here....why can't I run a motor at 100% whilst keeping to the specified service schedule?
If an airplane said the engine is rated at ONLY 80% I wouldn't get on the shed! :mbird
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Because it's not about speed, it's about load...
With an 80% (say) duty rating you can of course run at full load, but not continuously, only for 80% of the time........
A prop aeroplane doesn't present a full load 100% of the time, except in very exceptional circumstances - once you're 'cruising' I'd be looking at maybe 60% absolute max, even at full revs.... Like in a road vehicle, you can use full throttle (hence full available power) to GET to 60mph (or whatever) but to HOLD it there you usually only feather the throttle.
EDIT....
You can also rate an engine the other way of course, so the 100% cycle is actually 60% of it's maximum capacity - hence why some engines can be run at 120% or more ;)
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A good example is seen with turbocharged engines. There, the load is really clearly visible as the manifold pressure.
Engines have a peak rated boost. For a naturally aspirated engine, you could just say the peak boost is 1 atmosphere. Some can even "overboost" for a short period. There are different things which limit an engines output. There is the peak strength of components, there are issues of detonation, there are issues of over-speed (valve float, excess wear on pistons). There are also issues of heat: components (or the whole engine) overheat, and melt/burn. Pistons, spark plugs, etc. One of the new ford ecoboost engines has a 15 second overboost built in for some cars (Focus ST). [size=78%]FORD ECOboost Overboost (https://media.ford.com/content/fordmedia/fna/us/en/news/2012/06/11/ford-focus-st-features-factory-overboost-turbo-engine.html)[/size]
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I'm still lost here....why can't I run a motor at 100% whilst keeping to the specified service schedule?
Hmmm ... we had a guy show up for a ride yesterday morning. Backroads 220 km ride not expected to go over 90 kph (~56 mph). His ride ... a 150 cc China scooter. He weighed 190 lb. :hehehe
Given the above, how long before it blows up? :nono
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Not quite the same, we used to have a Honda C90 'step-thru' thing, that was used by anyone in our circle as transport as/when needed: That thing saw some serious abuse, it just wouldn't die! :hehehe
It got some engine oil now and again, that was it...what a machine, designed to run for ever
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Well, I got my K100 engine. 1991 K100RS. Missing a few parts but ran good when removed.
I have a rotation question. The motor turns clockwise when viewed from front, right? Since there are gears in the rear of the block and the transmission is not directly inline with the crank does that mean the output is opposite the engine turning direction? Does it actually output counterclockwise when viewed from front looking to the rear?
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The engine runs anti [ counter ] clockwise viewed from the front.
It's a PITA as I am planning on fitting an Eaton Blower [ runs clockwise ] to my spare 1100 bottom end [ with 8V top end ]. That will mean using a jackshaft to reverse the drive, but on the plus side, means I have two more places to adjust the the drive ratio.
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So it's actually the opposite of what I thought?
The engine runs counter clockwise and the output to the transmission is clockwise (due to the extra gears in back)?
The engine runs anti [ counter ] clockwise viewed from the front.
It's a PITA as I am planning on fitting an Eaton Blower [ runs clockwise ] to my spare 1100 bottom end [ with 8V top end ]. That will mean using a jackshaft to reverse the drive, but on the plus side, means I have two more places to adjust the the drive ratio.
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So it's actually the opposite of what I thought?
The engine runs counter clockwise and the output to the transmission is clockwise (due to the extra gears in back)?
The engine runs anti [ counter ] clockwise viewed from the front.
It's a PITA as I am planning on fitting an Eaton Blower [ runs clockwise ] to my spare 1100 bottom end [ with 8V top end ]. That will mean using a jackshaft to reverse the drive, but on the plus side, means I have two more places to adjust the the drive ratio.
Correct - opposite to your assumption - it's actually opposite to 90%+ of ICEs out there ! There is a gear which drives from the rear end of the crank which reverses the rotation. Confused me initially, as I just presumed a clockwise rotation. That was until some 8 years ago when I realised that. I was looking at using MSD crank trigger equipment for ignition mapping.
Of course that reared it's ugly head again when I was contemplating the fitting of an Eton supercharger. The Eaton spins clockwise, so a jack shaft is required to reverse the drive - and reverse the orientation of the blower with the blower inlet towards the front of the bike.
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Of course that reared it's ugly head again when I was contemplating the fitting of an Eton supercharger. The Eaton spins clockwise, so a jack shaft is required to reverse the drive - and reverse the orientation of the blower with the blower inlet towards the front of the bike.
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Are you driving the Eaton off the front crank or the rear flywheel?
I would be interested in seeing your solution as I may have to drive the alternator (probably a larger than normal version) from other than the standard rear location.
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Of course that reared it's ugly head again when I was contemplating the fitting of an Eton supercharger. The Eaton spins clockwise, so a jack shaft is required to reverse the drive - and reverse the orientation of the blower with the blower inlet towards the front of the bike.
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Are you driving the Eaton off the front crank or the rear flywheel?
I would be interested in seeing your solution as I may have to drive the alternator (probably a larger than normal version) from other than the standard rear location.
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The Eaton will be driven from the snout of the crank - where the Hall sensor cover is. Several people have used the same location to drive a large car type alternator, but these have been sidecar applications where space / overhang hasn't been an issue.
There's no suitable drive at the rear of the engine - the crank snout is the most robust and simplst to execute.
K1100 alternator ???? More than enough output to run heated everything, radios, etc.