Tiny Inline 4 Cylinder IC

[agmachado]

Hi Kel,

Very cool your job... congratulations!!!

What do you still will to do in this project ?

Cheers,

Alexandre

 

[ironman]

Thm: Kel, I watched and listened to that video 3 times and all I can say is WOW, you got some sweet sounding engine there. Are you going to make a hotter cam for it and experiment or let it ride as a job well done? What's next? What carb design did you go with?
Enough questions. Great engine.

ironman (Ray)

 

[kcmillin]

Alexandre, I plan, no need, to build a water pump and radiator. Also a nice stand would be cool. I still have some work on the carb, some tweaks are in order.

I spent some time today running the engine, It is getting smoother and smoother, I just had a scary moment though, as I was running the engine it all the sudden really wanted to rev high, so I grabbed my trusty mechanical tach and proceeded to take measurments, as I was testing full throttle rpm the engine took on a life of its own (almost like when a diesel runs away) the tach was pegging at 9,500 RPM!!!!!!! Holy Crap, I shut her down with a HUGE smile on my face. I am not sure why it decide to rev so high, on my previous runs I was maxing at 6,000 RPM, but I am not complaining.

I was under the impression that the CDI I purchased from S&S had a max of 12,000 sparks per minute, but at the reading I got (and I am sure of this) it was running 19,000 sparks per minute. I have not yet tried to duplicate my results, but an update will come soon.

I decided to re-post this video, it got buried on the last page.
(This is NOT the 9,000 rpm run)

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Kel


Ray, Thanks, You should have heard it today, I thought it was going to explode! :big:

I would like to experiment with a hotter cam, I am currently running 220 degree duration, I seen that Steve is going with 280 degree, so I might try a 240-250, well see. A choppy Idle would be pretty cool though.

I went with a scaled down version of what George posted, I am using a .082" venturi, and the jet hole is .016". It seems about right, but some experimenting is in order.

Kel

 

[doc1955]

Boy she is sounding good!
This has been a nice build! :bow:

 

[T70MkIII]

Superb, Kel!

 

[kustomkb]

Nice work Kel.

Sounds like she really screams!!

 

[coopertje]

Wow, its really running well Kel and the sound is great. Much more agressive then expected for such a small engine, really love it!

Regards Jeroen

 

[kcmillin]

Thanks the compliments guys, it really means a lot.

I made a proper flywheel for the engine today. It is 2" round steel, .650" wide. I used a split collared bushing design from Chuck Fellows. The flywheel weighs about 8oz. There are no spokes, it is mostly just a chunk of steel. I am just copying what I see, so I am not sure why most multi-cylinder engines use such heavy yet small flywheels. It does run a lot smoother now than it did with the spoked flywheel from my Poppin Flame Eater, but than again it is balanced a lot better too.

Kel

 

[hobby]

Bravo, th_wav

Beautiful job on your engine, and the real cool thing about it is, you can watch the video, and then go back into the build thread and be mesmerized seeing how the parts were individually being made, and to see all those parts come together to form a excellent running machine.

That's just so neat, it really gives inspiration, to want to learn how to design and build internal combustion models too, as well as air compressed models.

 

[Marius]

Fantastic sound
Bravo

 

[NickG]

Kel, It's a mini beast!!! :bow: Just love it so much you must be very proud!

 

[kcmillin]

It has been a while since my last post on this project, been pretty busy with work, but I have managed to get some little parts done. I have made the base, nothing fancy just a black acetal (I think) 1" thick, with brass feet. I have also checked the radiator, water pump, fan, and bracket off the list. I also made a new header, I never was quite satisfied with the original, plus it was interfering with the water pump feed tube. I hope to get time to put up some pictures up in the next few days.

During my experimental trial runs I am experiencing difficulty with the shaft on the water pump leaking. I am using unhardenend drill rod 3/32" for the shaft, and a brass bearing/water pump cap. If I were to switch to a bronze bushing this would help with wear, but I am thinking that it would still leak.

Any suggestions on getting the water pump drive shaft to seal? Water is so thin it loves to leak.

Kel

 

[cfellows]

Very nice engine, Kel. Runs great and looks great too. Now I need to go back and look at the thread to see what the parts look like!

Chuck

 

[steamer]

Jerry Howell sells a magnetic drive water pump kit...now, I won't pretend it will fit on that engine Kel...far too big , but It might give you some ideas.....

Great looking engine Kel!

Dave

 

[gbritnell]

Once again Kel, great job. I know you follow other peoples postings and read about their trials and tribulations with getting engines to run. The satisfaction of overcoming those problems and getting yours to run so well I'm sure has you overjoyed.
I don't know what you have your ignition timing set at but here's something odd that I have found. When I first got my 4 cylinder engine running I was using the original point ignition with a 12 volt battery, 12 volt automotive ignition coil and some ballast resistors. Being as my distributor is tied to my carburetor linkage and advances when I open the throttle I had set the low speed advance to about 15 degrees BTDC and the wide open throttle advance to about 30 degrees. It always seemed to run well enough so I was happy.
When I went to the electronic ignitions (Jerry Howell and S&S) I set my timing about the same as when I used the conventional ignition. It seemed to run and rev pretty well. I noticed when I built the Hall distributor for the 302 that I had to keep bumping the timing up to make the engine run better and better. The timing is fixed but is in the neighborhood of 42 degrees BTDC.
Before I go any farther here is how I set my timing. I have timing reference marks on the flywheel of the 4 cylinder engine and on the damper pulley of the 302. I hook everything up with a plug sitting on the bench. I turn then engine over until I get a spark at the plug. I do this several times just to be sure. Now I adjust my timing to where I think it should be. Seems to work fine. The only thing is when the engine is running the engine seems a little lazy, not bad but like I said I had to keep bumping the timing up on the 302 to the point where it seemed almost to far advanced, by automotive standards.
Now back to the 4 cylinder engine. I had taken the engine to the NAMES show and it was starting and running fine when all of a sudden it quit. Being that I had 3 other engines on the table I just let it go and figured I would look at it when I got home.
Upon testing at home I found that the Hall sensor was bad so I replaced it. I then reset my timing to what I had stated previously. The engine started and ran ok.
I got to thinking about the timing on the 302 and how far advanced it was so I thought about playing with the 4 cylinder to see what would happen. I reset the low speed advance to almost double of what it was, 15-25 degrees and therefore the the full advance went up around 45 degrees. WOW! I'm here to tell you that this thing runs like it has never done in it's life. It's almost to the point that I'm afraid to rev it up because I don't want pieces all over my bench.
The point I'm trying to make is that it seems with the electronic ignitions there is a minute amount of delay in the spark from when the static timing is set to when the engine is actually running.
If you should want to experiment a little, advance your timing in small increments and see what happens.
George

 

[kcmillin]

Thanks for sharing your timing method George, I agree, these do seem to love the advance. I know what you mean about shedding parts, this little guy revs pretty high sometimes, I have held it at 8500rpm for at least 10 seconds, just to see if anything would give way, gotta get the weak links out somehow :big:

What I have been doing is setting the distributer while the engine is running, I leave the screw just a little loose so it will hold, but I can still turn it. There is a very wide range where it will run, but only a few Sweet Spots where she really hums.

I am still open for Ideas on the water pump shaft seal. Dave, I have been thinking about that, but as you said it is much to large, and to fit that in such a small space would be difficult, but it may be the only option for a good seal.

I am going to try to make a new shaft bushing out of bronze, I might even try some tiny rubber sealed ball bearings.

Kel

 

[mu38&Bg#]

Have you tried an o-ring seal? I've not looked for normal shaft seals in that size so I'm not sure if they are available. Sealed bearings may work, IF, they are a full contact variety. Most do not use contact seals and would leak anyway. Check bearing manufacturer literature for details of seals offered.

 

[Admiral_dk]

This is the smallest size oil seal I could find :

http://simplybearings.co.uk/shop/index.php?cPath=19_4463

Smaller than that will have to be O-rings as previously suggested.

 

[steamer]

For small sealed ball bearings, you might try the R/C car parts stores....you would be amazed

Dave

 

[Lakc]

I am still open for Ideas on the water pump shaft seal. Dave, I have been thinking about that, but as you said it is much to large, and to fit that in such a small space would be difficult, but it may be the only option for a good seal.

3/32 is a bit tough. Mcmaster has some spring loaded lip seals for shafts in 1/8.