Bob Cotsford Posted August 17, 2014 Share Posted August 17, 2014 Some time ago I received this engine in a bundle of bits that came with an ebay buy. It seems in fair condition, the bearings are smooth and it has compression. It came with a single needle carb that looks very SuperTigre with no idle mix adjustment that I can make out. I've popped in a Meteor 40 carb that I had hanging around but I haven't got round to trying it yet - I'd prefer top have an exhaust on it first Does anyone recognise it, or even better have some info on it. The only thing I remember about OPS is that they were exotic and cost a lot more than a Merco The engine: The original carb: Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 17, 2014 Share Posted August 17, 2014 Have a close look at the carb barrel. I think there may be a slit cut into the inlet side of the barrel that causes the mixture to be diluted as the throttle is closed, same way as the airbleed on single needle OS carbs except it's not adjustable. Webra did the same with some of there older engines. I once used a Webra 60 carb on a Merco 61 that had had some crash damage & it actually improved the throttle response. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 17, 2014 Author Share Posted August 17, 2014 Hi Pat, there doesn't look to be anything resembling you description, just a conical ended spraybar and a plain barrel. I'd have said it was just an engine cutout except the barrel doesn't completely close off the venturi. I've had the barrel out and it's just that - a plain brass bar with a 9mm hole cross drilled through it. The body has a plain bore with no channels cut. Quote Link to comment Share on other sites More sharing options...
cymaz Posted August 17, 2014 Share Posted August 17, 2014 Does this page help at all? Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 17, 2014 Author Share Posted August 17, 2014 not so far, I had put a plea for help on the end of that thread too. Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 17, 2014 Share Posted August 17, 2014 Bob, IIRC some OPS engines were popular for FAI pylon racing, this may have been one. The carb may have been a intended as a simple full throttle with limited low end control then cut by choking when closed for a glide landing. Quote Link to comment Share on other sites More sharing options...
Former Member Posted August 17, 2014 Share Posted August 17, 2014 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 17, 2014 Share Posted August 17, 2014 PercyV, I think the Ursus was a 60, though it may be a range name. IIRC the non pylon racer OPS engines had carbs with a sliding throttle. I do know all OPS engines were very expensive which is why I never had one. Quote Link to comment Share on other sites More sharing options...
roger graves Posted August 17, 2014 Share Posted August 17, 2014 OPS engines for pylon were RE RI not front, the intake size is to small for a pylon carb. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 17, 2014 Author Share Posted August 17, 2014 I think this one is an 'SLA' model, possibly also known as a 'Sport'. The venturi is 9mm, which is a fair size for a 40. It needs a through-bolt exhaust with 3.5mm bolts on a 30mm silencer or a strap-on, I'm thinking an Irvine Quiet silencer would be near enough,or an MVVS 40, or an OS 40/45 FSR. Quote Link to comment Share on other sites More sharing options...
Former Member Posted August 17, 2014 Share Posted August 17, 2014 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 19, 2014 Share Posted August 19, 2014 Good old engine but dated now and you will have a job getting a decent silencer with that type of fitting . Most modern engines have bolt through silencer mounts and are much more user friendly.. I still have an OPS Ursas 60 that once had a red anodised head Great powerful engine last used back in the early 90's in a scratch built Spitfire . Again difficult to find a silencer with that type of fitting and had to make one even then . Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 19, 2014 Author Share Posted August 19, 2014 MVVS still make these style of silencers, and I've sourced a 'quiet' one for a .40 which should fit - €14.90! If it will run reasonably well I'll stick it in a suitable period airframe, maybe the Bullet or KwikFly 40 clone. I guess the ultimate would be a Dirty Birdy 40 with a pipe slung underneath! Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted August 19, 2014 Share Posted August 19, 2014 If it's an OPS it is DEFINITELY worth messing with, no matter which carb it has! OPS are fabulous engines. I am not familiar with the .40 but I have had .60s and they are second to none. I have tried various carbs and ended up using the OS No.7, not because there was anything wrong with the OPS carb but mainly because I happened to have an OS carb with an inflight mixture facility....... Try your .40 with anything you have that will fit and I am sure you will be pleased with it. Yes, the silencer could be a bit of a challenge, it looks as though an Irvine silencer might fit, perhaps with the help of a needle file on the bolt holes. Otherwise perhaps you could get some kind of "strap-on" silencer like the old P&R. Keep an eye on ebay....... Quote Link to comment Share on other sites More sharing options...
ROY DAVIES 1 Posted August 19, 2014 Share Posted August 19, 2014 Looks like an on old Super Tigre wire needle valve will fit that 40. Lovely high quality build motors. I had 2 of their 4 strokes which I bought new in a closing down sale in Germany - 2 for the price of one ! Also had a 30cc 2 stroke and a 60cc twin 2 stroke. Beautiful build quality needle bearing top and bottom ends. I still have an OPS 'hot' glow plug I had it in my hands 2 days ago. I met the agent a few years ago and he said he didn't have any spares any more he claimed he'd binned them all !! because the company were hopeless with back up. OPS broke up when the two brothers went their own way. The UK agents name began with 'J' methinks and could have been in Southampton and was more a boating shop but he did OPS aero engines. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 19, 2014 Author Share Posted August 19, 2014 I thought the ST wire needle might do the job but they're also as rare as rocking horse poo and to be honest that carb is way beyond primitive, positively stone age. If the Meteor throttle doesn't work out I can always get a Just Engines 12mm aftermarket throttle, or a Perry carb. I'm confident the MVVS silencer will fit and I've got feelers out for a laser cut DirtyBirdy 40 kit. Quote Link to comment Share on other sites More sharing options...
ROY DAVIES 1 Posted August 19, 2014 Share Posted August 19, 2014 Spotted plenty of brand new OPSs for sale on a boat site Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 19, 2014 Author Share Posted August 19, 2014 I think Mantua Models stock them but they look to be very different beasts Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted August 19, 2014 Share Posted August 19, 2014 What is the distance between the bolt holes on the exhaust stack? For info the holes on my OS40 FSR silencer are 28mm between centres Also, this looks like a definite maybe...... **LINK** Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 20, 2014 Author Share Posted August 20, 2014 thanks Paul, it's 30mm between centres. The ebay one looks like the newer bolt on style rather than the pre-OS bolt-through. There are a couple of others on e-bay but the seller doesn't seem to understand the difference between mm and cc so I'm not sure what fitting they are. Anyway, the MVVS unit should be here soon and I'm pretty sure it can be adapted as it's a straight fit on an OS 40 FSR. After 50 years messing around with engines of various types the one thing I've never invested in is a test-stand. Time to remedy that. Quote Link to comment Share on other sites More sharing options...
David Davis Posted August 20, 2014 Share Posted August 20, 2014 IIRC the old Irvine silencers were 28mm between centres. Can't check as I've packed all of my engines prior to emigrating! Just Engines sell a strap-on silencer which would suit. Someone at my club has one attached to an Irvine 40. It's very effective but somewhat expensive at £32.04. It could be a worthwhile investment if you fly out of a noise sensitive site or if quiet two-strokes are your thing! Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 20, 2014 Author Share Posted August 20, 2014 this is the one I've ordered, I was looking for an Irvine Q40 quiet silencer on ebay but they only seem to come with engines attached, then I spotted the MVVS one. Edited By Bob Cotsford on 20/08/2014 10:24:34 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted August 20, 2014 Share Posted August 20, 2014 Posted by ROY DAVIES 1 on 19/08/2014 18:15:08: Looks like an on old Super Tigre wire needle valve will fit that 40. Lovely high quality build motors. Re the needle valve . I think but not sure that the Super Tiger wire type had a different thread so could be a problem. They are also now extinct, so unless its old stock somewhere then your out of luck. A replacement carb is probably the way to go . Good luck with the silencer . Edited By Engine Doctor on 20/08/2014 11:57:58 Quote Link to comment Share on other sites More sharing options...
David Davis Posted August 20, 2014 Share Posted August 20, 2014 Posted by Bob Cotsford on 20/08/2014 10:23:31: this is the one I've ordered, I was looking for an Irvine Q40 quiet silencer on ebay but they only seem to come with engines attached, then I spotted the MVVS one. Edited By Bob Cotsford on 20/08/2014 10:24:34 I had one which I fitted to an Irvine 61. It worked very well. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted August 23, 2014 Author Share Posted August 23, 2014 I ended up tapping the exhaust screw threads 3.5mm as the original 3mm threads were well worn. Now to find something to bolt it to! Quote Link to comment Share on other sites More sharing options...
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