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Wreck Samba Member
Joined: July 19, 2014 Posts: 1218 Location: Brisbane
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Mon Apr 19, 2021 1:04 pm Post subject: Re: Type4 Camshafts for low RPM |
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Just curious:
whar RPM?
what fuel?
what altitude?
boost?
adjustable fuel-air ratio?
cooling setup (cowlings?)?
carb or injection?
what temps?
twin spark?
service intervals?
oiling and fueling?
RPM cruise 2700-3000
fuel 92-95
up to 4000ft MSL
boost?-???
adjustable fuel-air ratio?-NO
cooling setup-formed intake.
carb or injection?-carb
https://aliexpress.ru/item/4000930517052.html?spm=...1273559380
what temps? -below engine limitations
twin spark?-NO
service intervals?-every 50hr oil change
oiling and fueling?-oil radiator,ctock oil pump,oil separator,electrical fuel pump,stock spark (trambler )
Last edited by Anatolviper on Mon Apr 19, 2021 1:30 pm; edited 1 time in total |
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Mon Apr 19, 2021 1:25 pm Post subject: Re: Type4 Camshafts for low RPM |
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I understand that it is necessary to lower the valve timing to reduce the RPM, I just don’t know which camshaft to choose, I don’t know much about it |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Tue Apr 20, 2021 12:07 am Post subject: Re: Type4 Camshafts for low RPM |
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WOW! Nope, no way I'm leaving the ground with a 30$ chinese carburettor. Uh-uh, no way, no how.
I don't feel I should be giving you advice, too much at risk. What are others doing with their type 4's?
I will say this, because it's important, and I don't see how I could screw up by telling you this: well-performing carb intake and manifold heating are absolutely essential!!! Carb icng is a BIG issue on airplanes.
I would want redundant sparks, and fuel pumps, etc.. not much extra weight, but a lot of extra safety.
As a starting piont, just for discussion's sake, I see the 1.7 is putting out maximum torque (also close to best mileage, then) at 2700rpm, your chosen cruise rpm. what is take-off rpm? from what oprn says, iirc, 3100 should be close to maximum limit. So no way of climbing to 4900...so now to get 85 hp at 3000 rpm is the challenge.
So you want an engine which develops max hp at 3000rpm, if i understand correctly? |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Tue Apr 20, 2021 12:24 am Post subject: Re: Type4 Camshafts for low RPM |
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Cruising the net, I found this:
"some AC cam specs
Post by Waterthunder » Tue Nov 02, 2010 2:55 pm
We are working on some EFI cam's for some aircraft pillion racers and will be dyno testing some A/C engines with various cams soon. So we just put our first A/C Lycoming cam on the cam doctor and here are the specs. This was suppose to be the HOT Lycoming cam. I will post some stock Angle valve and Cont cam's soon too.
dur @ .050 INT 220 EXH 227
Lobe lift INT .348 EXH .356
LSA 112
THE PROOF IS IN THE PROP!
"If you copy someone you will only achieve what has already been done *."
http://waterthunder.com/
321-508-5316"
So that's a "hot" cam, you want something "tamer", I imagine.
Keep us posted, I find this fascinating! Thanks for taking the time to answer. By "boost" , I meant some sort of supercharging, like a turbo.
* this might not be such a bad thing when it comes to flying. Copy something that WORKS
Now you know enough to be REALLY dangerous.
Seriously: be safe and apply KISS. |
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Tue Apr 20, 2021 12:30 am Post subject: Re: Type4 Camshafts for low RPM |
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Yes, the heating of the carburetor will be done by the pressure of hot air from the exhaust manifold area.
Yes, I need a maximum torque at RPM lower than the stock 4100 and slightly raise the power at least to 80-85 h |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Tue Apr 20, 2021 1:46 am Post subject: Re: Type4 Camshafts for low RPM |
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Vanapplebomb wrote: |
Anatolviper wrote: |
ok, please advise what do I need to replace in a standard type 4 engine to get such characteristics? (High torque at low RPM) |
1.7:
-80hp @ 4900 RPM
-98 FtLbs @ 2700 RPM |
that's what I was looking at. But still no clue how to get max hp at just 300 rpm higher. |
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Tue Apr 20, 2021 1:54 am Post subject: Re: Type4 Camshafts for low RPM |
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Ok, but my engine is 2.0 litre is was stock from bus |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Tue Apr 20, 2021 2:19 am Post subject: Re: Type4 Camshafts for low RPM |
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Anatolviper wrote: |
Ok, but my engine is 2.0 litre is was stock from bus |
But the difference in 1700 and 2000 cams is the direction you want to go, the way i see it. For instance, a 2000 with a 1700 cam (I think they're different) would come closer to what you are looking for, with the right heads.
Again: what are the others working on this sort of project using? |
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Tue Apr 20, 2021 2:32 am Post subject: Re: Type4 Camshafts for low RPM |
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Ok. Where i can order the 1.7 Cam? |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7219 Location: Videbaek Denmark
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Posted: Tue Apr 20, 2021 2:46 am Post subject: Re: Type4 Camshafts for low RPM |
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Some years ago I did a couple of aviation engines for light plane racing, but they were type 1 sgl port engines which per design revs slower and has much smaller intake ports. I was able to increase power at 3000 with 12% I only did those two because the mods were banned later. The engines had to stay "stock" Limbach. The 12% extra power along with a propeller with a more agressive pitch gave them approx 7 kmh higher cruise speed at 2,5% lower consumption.
With the 2 liter type 4. I´m thinking about reducing the intake port volume in order to increase port velocity so the engine will produce more torque in the desired rpm range. With the right cam and carbs that could work well. But I will need much more information to determine if that is even an option.
The other way around was, as Anatoly was touching initially, to increase displacement until the port velocity shows max torque and hp in the 3000-3300 rpm range. But I really don´t like big bore type 4´s unless the cylinders get heavily modified. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Tue Apr 20, 2021 3:04 am Post subject: Re: Type4 Camshafts for low RPM |
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Anatolviper wrote: |
Ok. Where i can order the 1.7 Cam? |
No, no, no, this is just a thought experiment! You're going to have to talk to Web-Cam, if you want something real. And consult the state-of-the-art. Don't do anything on the basis of what some old fool says on the web. I wouldn't consult a performance Beetle site for info on building a plane, or take any of my advice on the matter.
Be safe. |
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Tue Apr 20, 2021 3:09 am Post subject: Re: Type4 Camshafts for low RPM |
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If I understand correctly, I can reduce the intake channel by changing (lowering) the intake phases.? I also want to buy 96m flat top pistons and bore stock cylinders to 96mm.
What can I expect from the motor , what will be the power? |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7219 Location: Videbaek Denmark
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Posted: Tue Apr 20, 2021 3:26 am Post subject: Re: Type4 Camshafts for low RPM |
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That depends on everything else. Like what will you be using for fuel supply?
Will you be using pump gasoline or aviation fuel?
1 or 2 spark plugs per cylinder?
Which again relates to how much CR you can, and will be running. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12743 Location: Western Canada
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Posted: Tue Apr 20, 2021 3:41 am Post subject: Re: Type4 Camshafts for low RPM |
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Many many automotive engines were put into experimental category aircraft with single plug, single ignition systems. To change to dual plug dual ignition on a VW you need not only to machine plugs into the heads from below but you need a second distributor and something to drive it. A magneto is the first choice of most in place of the stock distributor as it is self contained and does not require the weight of a battery and complication of an electrical system. A crank trigger system would be the easiest route to go to fire a second set of plugs and would only require a motorcycle style battery. But then... you need a generator... more weight! Aircraft are highly allergic to weight!
As far as a camshaft goes I don't know if anyone makes a specific one for aircraft use. I think it would be very hard to improve on the stock cam and if you could the gains would be small. Some guys feel that the 1700 914 and 411 heads with the smaller valves have superior low end power. Those combined with the 96mm flat top pistons will get you into some serious compression quickly.
Again, follow up Ray's links and see what the aircraft guys are doing. Us car guys know next to nothing about what works in aircraft. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)
Last edited by oprn on Tue Apr 20, 2021 3:43 am; edited 1 time in total |
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Vanapplebomb Samba Member
Joined: November 03, 2010 Posts: 5417 Location: Holland, MI
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Posted: Tue Apr 20, 2021 3:41 am Post subject: Re: Type4 Camshafts for low RPM |
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FreeBug wrote: |
Anatolviper wrote: |
Ok, but my engine is 2.0 litre is was stock from bus |
But the difference in 1700 and 2000 cams is the direction you want to go, the way i see it. For instance, a 2000 with a 1700 cam (I think they're different) would come closer to what you are looking for, with the right heads.
Again: what are the others working on this sort of project using? |
In the US, all FI cams were the same. 1700, 1800, and 2.0. I can’t speak for outside the US though. I suspect the 2.0 914 and the dual carb AN 1800 may have been slightly different, but not enough to write home about. Ray Greenwood would know better than me on stock camshafts. You can have the stock Cam/Lifters reground (not many do this any more), or buy a stock replacement. The Web 142 is pretty close to stock. The web 73 is slightly hotter, which is not what you want if you want to keep peek torque at 2700. Basically you are stuck with a stock cam, or a custom grind with less duration or lift for your intended power band. As far as I know, there is no off the shelf option for something more mild than stock. _________________ 1800 Type 4 Berrien 295
http://www.thesamba.com/vw/forum/viewtopic.php?t=487021 |
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Anatolviper Samba Member
Joined: April 18, 2021 Posts: 19 Location: Rus
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Posted: Tue Apr 20, 2021 3:54 am Post subject: Re: Type4 Camshafts for low RPM |
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Alstrup wrote: |
That depends on everything else. Like what will you be using for fuel supply?
Will you be using pump gasoline or aviation fuel?
1 or 2 spark plugs per cylinder?
Which again relates to how much CR you can, and will be running. |
Only 1 spark plug,
Carb 36mm from sport bike, regular fuel 92-95 octane, electr. fuel pump.
Also, a have a 2 stock type 1 engine (CT), but it was only 1.6 liter and 50hp. |
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H2OSB Samba Member
Joined: April 14, 2013 Posts: 1294 Location: Modesto, CA
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Posted: Tue Apr 20, 2021 5:56 am Post subject: Re: Type4 Camshafts for low RPM |
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This is a bit out of my league, but 2.0L bus heads have the smallest valves, so you're on the right track there, IMO. Coupled with 96mm pistons, you probably had the most torque possible without going to a larger crank.
The stock 1.7 replacement cam from Web (142 I think) is what I'd look at, but most likely you'll need a custom grind. Perhaps cam specs from an industrial engine meant to run at a steady pace all day long.
This is a fun exercise, but I'm not certain I'm brave enough to go up in any plane powered by a AC VW engine (though I think the T4 IS the wiser choice)
H2OSB _________________ (o\_i_/o) I'm not a vegetarian because I love animals, I'm a vegetarian because I hate plants. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12743 Location: Western Canada
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Posted: Tue Apr 20, 2021 7:03 am Post subject: Re: Type4 Camshafts for low RPM |
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Air cooled VW engines have an excellent track record in homebuilt aircraft. From all reports that I have read they experiance NONE of the problems they do in cars. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7219 Location: Videbaek Denmark
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Posted: Tue Apr 20, 2021 7:08 am Post subject: Re: Type4 Camshafts for low RPM |
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oprn wrote: |
Air cooled VW engines have an excellent track record in homebuilt aircraft. From all reports that I have read they experiance NONE of the problems they do in cars. |
That is partly because of significantly stricter maintenance requirements. If car engines were built and serviced the same way there would be much fewer failiures.
WRT the type 4. I am actually thinking Web #73 ground on 104 LC since we are not looking for mid - upper rpm power, but solely below 3300 rpm. I will try and do the math when I get a moment. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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