Ok,so here is my first engine I'm going to "hopefully" attempt to covert. Its a 1998(I think) homelite 30cc from a weed trimmer. I know its probly not the best engine to be converting and what not,but it was dirt cheap and came with a bottle of homemade wine!!!!! I was actually looking for a smaller engine,and I really dont know what to look for too much in these engines as some of you know from reading my recent posts. This engine went from running at my buddies house to what you see in about an hour,so the pics look pretty ugly. It has a "ZAMA" carb on which I think I heard alot of bad stuff about. It ran before I ripped it down. The exhaust side of the piston looks to have some scorching marks(not sure if this is normal or not),but the cylinder from where all I can see looks perfect with not scratches that I can see,but its hard to tell without taking off the cylinder. The intake piston side look brand new. It seems to have pretty good compression too. And I dont notice any play in the bearings.

Anyway.....It looks like it should be fairly easy and should come out to be pretty light. Its gonna get EI and I plan on cutting off all the excess housing and magnito mounts. I liked the fact that it has the carb and exhaust on the sides rather then in the rear like some engines. I should be able to make a simple flat mounting plate to mount over the engines backplate. And my next door neighbor is a welder,so I'm thinking he can weld me up an aluminum exhaust. And one of our club members owns a gunsmith shop,so I'm hoping to sweet talk him into making me a prop hub on his lathe......maybe I'll share my wine with him,lol. I know I'll probably hear that I'm just wasting my time and money(and please tell me if I am),but this engine is hopefully going to be more for the practice and experience then anything I hope.

Now a couple question....

1: Are new piston/rings easy to find for these engines?
2: Should I even bother putting in new piston and rings?
3: Can I take off the cylinder to clean and inspect then put it back together without new parts,or are new
parts a must once you take off the cylinder?
4: Am I going to need a new,or better,or bigger carb?
5: Do you think the stock bearings will work?....Not sure what kind they are.
6: Please give me any other thoughts,comments,or concerns that I dont know about......




Thanks!!

This may be what you do not want to read! Go to more places and find a engine that looks like it has been treated well and has good compression. You do not want to waste time on one that has a scorded piston ect. Find one where the ignition went bad or whatever. You should be able to find several engines and use only the better ones. Maybe the one you have is ok...but the engines I found like that one was not any good, except for parts. I always take exhaust off first to see how the piston and cylinder looks. Some I junk right there. Do not urn a engine over if it seems sticky....take it apart and find out why. Maybe others can chime in and give you more hints, in the process. Best Regards, Capt,n

the homelite 30 is one of the better cheap engines, if it's just some scuffing under the exhaust port and the ring isn't scored, it could be fine.

go ahead and take it apart, the worst thing that can happen is you have to make new gaskets, just to to the auto parts store and grab a roll of gasket material, go thin... go at it with a Xacto knife and you have yourself a cheap gasket... when you take it apart, just take note where the ring gap is, and keep the orientation of the piston. when you have it apart, take some scotch brite or fine steel wool and clean up the piston. If any scoring is below the ring, and below the exhaust port, it's probably fine and runable, if you have a compression tester, check what it has, above 90psi is runable, below 90psi is questionable. if the compression is low and it doesn't really have any scoring on the cylinder, get a new ring, Frank Bowman is the man to talk to, his contact information is around, I need to make an order with him one of these days, I have a list of engines that could use a ring...

if that engine is salvagable, it's a good base, the homie 30 is very popular, out of like 5 homies, I only have 1 30, and it's slated to stay as a weedie for the time being, as it's the strongest runner I have... after I stole the Mac 32 to put in a plane...

that carb might be usable, probably undersized, but at least it has two needles. and for an even cheaper engine mount, just get a stick of 10-24 allthread and make studs to put in the backplate, use nyloc nuts on the other end inside the plane, good to go...

Ok,I just took off the cylinder(couldnt resist). Now,I've been working on 2-stroke motocross engines my whole life and was surprised to see how scratch free the cylinder and piston were,but this could just be typical on these little engines. There is no real scoring on the exhaust side of the cylinder. Like I said,the piston has some carbon scoring buildup on it,but no bad gauges or scratches....seems like mostly carbon deposit. When you rub your fingernail over it,you can feel some VERY slight roughness,but I think most of that would polish off. The rings look pretty good,but the piston ring grooves have some good carbon buildup in them and the bottom ring seemed kinda stuck in place before I wiggled it were the "blowby" carbon was on the piston. This is also where the top ring gap is. So,I'm just wondering if that ring gap didnt cause some blowby that caused the carbon buildup on that spot?

I'm honestly thinking its still in ok shape,just needs cleaned up. Normally I would not think twice about a new piston and rings,but not sure if a new piston is practical for this engine......but new rings would sure be nice regardless. And I already planned on getting some auto parts store gasket material,but the base gasket is still in great shape,so maybe I'll try to reuse it.

And while thinking of the best way to clean up everything.....I couldnt help to keep thinging of an idea my "glow" buddies use alot which is to cook thier mufflers and engines in a crock pot of anti-freeze. They say is works miracles for clean burnt muffler oil residue off. Have any of you ever tried this to clean up pistons and/or cylinders and stuff? Wonder if it would take off carbon?

If nothing else...it will be a good learning engine. If you replace piston ring....break the old one and grind it square on end to make a good ring grove cleaning tool. That gets the carbon out. Capt,n

I would clean it all up good with carb cleaner spray and some scotch brite. Break one of the rings and carefully use the broken piece to clean the ring lands in the piston. The carb spray will soften the carbon. Then lightly sand the cylinder with some 400 grit sandpaper. Clean it really good and put a new Frank Bowman ring in it. From what you describe, it should still make a good engine.

If you try the crockpot/antifreeze idea on the carbon, let me know how it works.

AV8TOR

Heres a pic of my sons 30cc homy in his 84 inch Balsa USA DVIII.11-12 lbs if i remember right.Flys it real nice,and a hair above scale.Hand starts on th 2nd-to 3rd flip even cold.Mines the short shaft version.Home made pitts muffler.I was running an 18x8 dynathrust so i know the performance of the engine could be better.I know it was about 7000 rpms though.I recieved the engine used and never changed it at all.Just converted and stuck it on there.Might need new rings,dont know.Works good enough.

Heres a pic of my sons 30cc homy in his 84 inch Balsa USA DVIII.11-12 lbs if i remember right.Flys it real nice,and a hair above scale.Hand starts on th 2nd-to 3rd flip even cold.Mines the short shaft version.Home made pitts muffler.I was running an 18x8 dynathrust so i know the performance of the engine could be better.I know it was about 7000 rpms though.I recieved the engine used and never changed it at all.Just converted and stuck it on there.Might need new rings,dont know.Works good enough.
STUPID dial up isp.Kicked me off just when i was uploading.Then when i sighned back on it uploaded twice.Anyway to delete it?.

It is a great engine-good rpm, power and easy to convert-My first conversion on a plane

I have one that I did all the hop up mods to such as porting, etc. It turns an APC 16 x 8 prop at 9400 rpms. That's some really decent power.... The boat guys regularly turn them around 10,000 rpms.

AV8TOR

Thats big power! The homie above is stock except for carb/muffler and spins an APC 17x8 at 8300. So even at stock the motor really does a nice job. Go for it, you won't be disappointed.

I've got the cylinder and piston in a full crock of anti-freeze right now! I'll let it in there overnight and see what happens. I dont think it will work like it does on oil residue,but its worth a try. I'll let you know how it turns out.