Okay I'll be the first to use this forum. Great Idea!!!.

How does that white nylon as found in cutting boards hold up as a carb spacer?. The engine I'll be putting it on is a Stihl around 50cc. It has a round carb intake. I was going to make a split ring type spacer and use a single small bolt and nut to tighten the split onto the intake, then bolt the carb to it. I was concerned in a year or two that the spacer would become hard and brittle.

I have also noticed (now this will get controversial ) that both my conversion absolutely do not like Zinger props. Same size props were used for comparisons and both the thrust and the rpms. were down when using Zingers ( down an average of 700rpms).
Is this because weedies and chainsaw engines need that flywheel weight, hence a heavier prop?.

Thanks again guy's. Peter

your comment on the weedeater needing flywheel weight to pull a prop seems to make for a good question,i have seen on here that with the fly wheel left on, a smother runing engine at idle is noticed. i would not say the same for a zdz or others as these motors are made for rc. weedeater,chain saw and other conversion engines are not built for rc but we are trying to make them work as per a cost saving factor and also so of us just like to tinker and make things work. maby if the flywheel is left on and still use the ch or whut ever conversion it would run very well,i think its worth a try,and yes the engine may spool up a little slower but whut ever,arnie...

I don't like Zingers and this is an opinion made recently. Over half of the large Zingers I've puchased were not true. The blades were not in the same plane. I went to my LHS and found the same thing in their inventory. Just place it flat on the counter and measure the distance the prop tips are from the counter. About half were different. This caused a vibration and reduced RPM on my engines. Sad thing is, all of my local shops only carry Zingers in wood props.

Don't know for sure, but I think that the plastic should be good for a year. The heat and UV would be your problems
Delron or fiberglass g-10 would be better.

Zinger square tips are hard turning props they exhist cause no body makes cheap big props. The Zinger Pro is a much better prop and is actually prefered by some folks instead of the high $ European ones.

I just purchased a ch conversion and the spacer is made out of some kinda machined Black plastic. It has the look of Delrin. Could be UHMW and Black usually means it is UV stabilised.
You could have a look at US Plastics on the web re compatability.

Arniebarn;

I am still using the flywheel on the conversions, albeit they were lathed down. 700 rpms and 4 - 12 pounds thrust DROP when using Zinger vs APC or MA.. Just can't figure. Maybe lower in compression and they benefit with added weight and centrifical motion on the shaft. I was just curious if anyone else found this to be true or had the answer. Could be just one of those things..... some engines prefer some props.

Thanks Andyt;

I was trying to find something I could get locally. I thought of my machine shop making a aluminum one but it would transfer the heat way too much.

i've used a 10mm thick phenolic (bakelite?) material thats used for industrial electrical applications, it's cheap too, an electrician friend saves scraps for me. it machines and threads nicely but it's best to leave a little extra material around drilled holes. hope this helps.

dave

I'm with Zagnut, made mine from 3/8" phenolic. The stuff is super hard and tough to shape but should last. On my Poulan 46, instead of screwing into the side of the intake stub, I drilled straight into the flange under the stub and tapped it. Then countersunk the hole in the phenolic for the screw.

How deep did you drill it?
I looked at that and didnt think there was enough "meat" there.
Have you been running it like that and hows it holding??

Well, haven't run it yet. Still collecting "gas" support eqiupment. But, the fit was so tight I needed to pry the manifold off when I test fit it and the screw is just insuance. It can't back out because the adaptor plate fits over the screw head. And, it's just as much meat as the side of the stub.

Just a pic of my conversion.

Another, Hope my braze holds.

Looks good.
I think the support at the ends of the pipe is going to be the most crucial

Thanks Guy's I'll go see an electrical contractor I know.