2wd 1/8 nitro desert buggy - 4 stroke adventure

[LongRat]

Hi there,
not really posted much on this site before. My name is Dave, I would describe myself as a committed RC hobbyist in all senses of the word :D. My area of interest is in full custom scratch built vehicles, control systems, electronics and engineering. I built this buggy a few years back as a test bed for new interesting ideas, like tension wire steering, home made engines, suspension control ideas etc. The completed car is the same size as a 1/8 buggy but is rear-engined, 2WD and a little more realistic in appearance than a normal buggy. A full build thread is on RC Kingdom, although that site doesn't have a large membership interested in 'true' custom work as I would put it.

Also, my personal site with details of the project is here:
http://www.fulloption.co.uk/ProjectVehicles.html

So here are some pics of the car as it was finished off, running a Collari .32 2-stroke.

http://pic100.picturetrail.com/VOL660/2777486/17301719/334645089.jpg

http://pic100.picturetrail.com/VOL660/2777486/17301719/330118567.jpg

Engine mounting arrangement
http://pic100.picturetrail.com/VOL660/2777486/17301719/325323280.jpg

Layshaft mounted metal-ceramic disc brake system
http://pic100.picturetrail.com/VOL660/2777486/17301719/316365010.jpg

Tension wire steering
http://pic100.picturetrail.com/VOL660/2777486/17301719/307385728.jpg

So the point of this is that I am going to build my own DOHC 4-stroke engine for the buggy. This is a big project so before I dive right in, I am going to run the car with a commercial 4-stroke engine. I need some 4-stroke experience first. I have an ASP 52 4-stroke in there (roughly). I've read everything I can find on the web about 4-stroke nitro engines in cars - there isn't much. I'm here to listen to any advice anyone has that may be useful. I know that I am going to be running the biggest gearing I can, and that cooling will be critical. The 52 runs WAY hotter than the 32 2-stroke. The good thing is, because this is a completely custom car, I can do pretty much anything needed. Liquid cooling, any gearing needed, etc is all do-able.

[LongRat]

Here's my current set-up with the ASP 52 engine. Weighs a similar amount to the old engine and is a tiny bit smaller. I'm under no illusion that it will be as powerful, but frankly the 32 was way too powerful for this 2wd car anyway.

http://pic100.picturetrail.com/VOL660/2777486/17301719/398436845.jpg

The hex-ended steel secondary flywheel on the end of the engine allows the car to be directly stared with a power drill running in reverse. I made a dedicated socket for the drill incorporating a 1-way bearing. This means the 1-way comes off with the starter and the engine isn't running the bearing all the time, but I still don't need a starter box. You couldn't use any starter box on this configuration anyway. Or on this engine - way too hard to turn over.

[bert digler]

Here's my current set-up with the ASP 52 engine. Weighs a similar amount to the old engine and is a tiny bit smaller. I'm under no illusion that it will be as powerful, but frankly the 32 was way too powerful for this 2wd car anyway.

http://pic100.picturetrail.com/VOL660/2777486/17301719/398436845.jpg

The hex-ended steel secondary flywheel on the end of the engine allows the car to be directly stared with a power drill running in reverse. I made a dedicated socket for the drill incorporating a 1-way bearing. This means the 1-way comes off with the starter and the engine isn't running the bearing all the time, but I still don't need a starter box. You couldn't use any starter box on this configuration anyway. Or on this engine - way too hard to turn over.
that is the finest work ive ever seen on here machine work is bang on:thumbsup:others take note and learn;)

[mrspeedy]

That's also the nicest buggy I have ever seen :wub

and the man is from Bristol !! what a guy :woot:

If you ever want to sell it, I'll have first dibs ....

[Jedi Master]

Awesome work. Love the design and look of the buggy!!!

[adam lancia]

Great looking stuff!!!

[teamorsum96]

Hi there,
not really posted much on this site before. My name is Dave, I would describe myself as a committed RC hobbyist in all senses of the word :D. My area of interest is in full custom scratch built vehicles, control systems, electronics and engineering. I built this buggy a few years back as a test bed for new interesting ideas, like tension wire steering, home made engines, suspension control ideas etc. The completed car is the same size as a 1/8 buggy but is rear-engined, 2WD and a little more realistic in appearance than a normal buggy. A full build thread is on RC Kingdom, although that site doesn't have a large membership interested in 'true' custom work as I would put it.

Also, my personal site with details of the project is here:
http://www.fulloption.co.uk/ProjectVehicles.html

So here are some pics of the car as it was finished off, running a Collari .32 2-stroke.

http://pic100.picturetrail.com/VOL660/2777486/17301719/334645089.jpg

http://pic100.picturetrail.com/VOL660/2777486/17301719/330118567.jpg

Engine mounting arrangement
http://pic100.picturetrail.com/VOL660/2777486/17301719/325323280.jpg

Layshaft mounted metal-ceramic disc brake system
http://pic100.picturetrail.com/VOL660/2777486/17301719/316365010.jpg

Tension wire steering
http://pic100.picturetrail.com/VOL660/2777486/17301719/307385728.jpg

So the point of this is that I am going to build my own DOHC 4-stroke engine for the buggy. This is a big project so before I dive right in, I am going to run the car with a commercial 4-stroke engine. I need some 4-stroke experience first. I have an ASP 52 4-stroke in there (roughly). I've read everything I can find on the web about 4-stroke nitro engines in cars - there isn't much. I'm here to listen to any advice anyone has that may be useful. I know that I am going to be running the biggest gearing I can, and that cooling will be critical. The 52 runs WAY hotter than the 32 2-stroke. The good thing is, because this is a completely custom car, I can do pretty much anything needed. Liquid cooling, any gearing needed, etc is all do-able.
now all you need to make some down tubes and autograss special
http://i111.photobucket.com/albums/n147/retardedcamel/13006687small.jpg

[LongRat]

Thanks for the positive comments guys.
While I am striving for good performance, I place an equal emphasis on fun new technology experiments and good looks.
I just finished machining the rear wing mount which is mainly to give more engine protection. There will be a rear skid plate and carbon tubular bumper to come to help with this. I need to work out how to duct some more cooling air back there, at the very least.

http://pic100.picturetrail.com/VOL660/2777486/17301719/398450555.jpg

[teamorsum96]

you could do what we used to do in the old days of grass tracking, and get some of whatever you have used for the panels, and just bring it up the back tubes but slighty high up over the roof line. if that makes sence?

[Matisse]

Gurt Lush!!:thumbsup:

[LongRat]

I'll consider that, I think it will need a fan somewhere too though. The body panels are made of sheet lexan.
Oh and I might add, even though I live near Bristol I don't actually come fromt he area so I don't say things in such a traditional Bristolian way ;)
Actually, I'm an Essex boy.

[teamorsum96]

u could use double fan under the tuned pipe mounted on the rear shock towers. i do like it alot tho fella :drool::thumbsup:

[Rebelrc]

Lovely car. Great skills!:thumbsup:

[LongRat]

Rebel, thanks.
Orsum, that's a definite possibility. I am trying to bias a little more weight forward, but the fans shouldn't weigh much. I already have the auxiliary shocks to assist the rear springing - the piggyback units actually contain a couple of springs per side which adds up to the right stiffness to support the heavy back end. By the way this engine is running a simple muffler only and no large tuned pipe, unlike the 2-stroke which is a big plus as that was difficult to package in.
I guess I will run it without fans first and just monitor the temps. Need to machine up a throttle linkage first as currently there's no simple way to connect to the rotary carb. I can't have any servos anywhere near the engine. The vibration is way too much. If this drives as well as it idles it will be a wild ride, the idle is violent. Hard to believe it is a 90 quid engine, it is a real beast and the machining in it is unbelievable value for money.