on pipe

Bought an OPS overhead cam four stroke from a guy here in town. Did a search here but could only find info on their two stroke boat engines. He didn't know what size it is, thought maybe a .120 or a .150. Does anyone know about these? What size they make, what props to use. Is there anywhere to find the toothed belt that drives the cam? I know they aren't common, but any info would be much appreciated. Ross

jaka

Hi!
It's a 20cc engine. Use 16x6 prop and 5-15% nitro!

donkey doctor

Hello; I recall that they were offered in two valve and four valve versions, with the four valve ones being the rarer. The only one AI've seen is the two valve.

gkamysz

My Feedback: (19)

I thought the OPS used the rotary valve like the Webra 4T.

fiery

My Feedback: (2)

I have a card of OPS 4-stroke plugs the suit the OPS 4-stroke engines.

They are by far the hottest 4-stroke plugs I have ever handled.

Similar in style to the Fox Miracle or O.S. " F ". Other makes of 4 stroke detonate at high RPM's using them, and as such they are totally unsuited to other 4-strokes.

I will send them (I think I have 4 of them) to anyone who has an OPS 4-Stroke engine for the cost of postage. Even if the engine is a collector peice, it would be nice to some of the factory specified plugs to go with it.

fiery

SON OF PALEFACE

My Feedback: (1)

Ross , is the belt broken , and do you want to sell it ??

on pipe

SON OF PALEFACE, I found a source for belts at www.sdp-si.com. The belt was ok on the engine when I got it. I simply wanted a new one before trying to start it. I also installed all new bearings while it was apart. and found that it is a "non-interference" engine, i.e., the valves won't contact the piston if it jumps time. This is good because I've been told they strip the belt teeth on a prop strike. Of course, like any poppet valve four stroke, I'm sure it will bend valves if over-revved to where the valves "float". They are beautiful engines. Needle bearings support the cam and lower sprocket shaft. The lower rod-end has needles also. I don't really want to sell this one, but will keep an eye out for you. It seems like when I buy something like this, I end up seeing more (usually cheaper!) [>:]after the deal is done. Ross

dennis

My Feedback: (90)

I ran one a lot when it became available in the 80's. It was comparable to the OS and Enya 60's of the day. It looks massive but isn't and is relatively light. It's a 120 obviously. Had mine converted to CHS ignition and ran 16/7 or 8 props on it on a Roadrunner. Was a great combination and the motor was usually a one or 2 flip hand starter. I never suffered a prop strike and when I got rid of the plane and motor a few years ago the motor was still in excellent condition. I have a NIB but probably will just keep it in the collection.
dennis

SON OF PALEFACE

My Feedback: (1)

Ok Thanks Ross and Dennis , if you see one give me a yell
[email protected]

Hobbsy

My Feedback: (102)

Here is one in the flesh, this is the last one Tower had, I also got one of the last OPS Maxis and .60s, missed out on a .40.

SON OF PALEFACE

My Feedback: (1)

I'll swap you a .40 for it ???
~{:-)

gkamysz

My Feedback: (19)

Dave, now that is a cool engine. That's a nice arrangement.

blw

My Feedback: (3)

Nice pics of the top end!

TEOSAH2

HEY GUYS
I JUST GET AN ALMOST NEW OPS 120 FOUR STROKE,BYT IDONT KNOW FROM WHERE I'LL FOUND ,GLOW PLUGS.

IF SOMEONE KNOWS, PLEASE INFORM ME.

WE ARE PERSONS OF THE SAME FAMILY{AIRMODELLERS}.

TEO THE GREEK

Hobbsy

My Feedback: (102)

TEO, that engine is not particular about what glow plugs you run in it, you cna probably get and OS-f for it, I'm sure.

Cyberwolf

My Feedback: (4)

Hobbsy That is a impressive engine , I really have my doubts about early valve float due to the fact theres no push rods or lifters to deal with. Be about the same as a modern day 4 bangers in the cars we drive, minus the injection of course*L* The only thing I can see that could make it better would be a gear set up instead of the belt.

Do you know what sort of a tensioner it has to keep the belt tight?

jeffie8696

With that light weight valvetrain I bet it can turn some great rpms. And it is a hemi no doubt.

strtnlevel

My Feedback: (84)

Just came upon this post. I have an OPS 120 in excellent condition. What are they worth? How do they compare, power wise, to a Saito or OS 120?

jaka

Hi!
Less power than both OS and Saito!
That's why they disapeared so soon.

strtnlevel

My Feedback: (84)

Thanks for your input. That would have been my guess, so I'm not surprised. I'll put it back on the shelf. It still looks good just sitting there.
Vince

RC Specialties

Can anyone tell me the exhaust thread size on the OPS 20-4 OHC engine.