rangerfredbob

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ok, I figured I'd start a new thread at this point, since I might have a few questions or make it easier for someone else that decides to convert one of these in the future...

first off it's a Pioneer Holiday II 970 model from '71ish

I got this engine for about $25 shipped from ebay, I looked it up on acresinternet.com and they said it was a 51.4cc with ball bearaings on the crank, and it seemed fairly light at 9ish pounds for the whole powerhead. so I started tearing into it and found left hand threads on both ends of the crankshaft, so I'm either going to go with Aviator's solution to that or rethread it on the lathe (it's 3/8" threrads so there's some room to go to 5/16"). acresinternet said it was reed induction and it's piston ported so I questioned the displacement and bearings, so I confirmed both tonight, definetely ball bearings and bore is 1.615" with a 1.5" stroke which comes out to just over 50cc, add in the combustion chamber and chance of error and it's close enough...

does anyone have any experience with Pioneer brand carbuerators? the one that came on this engine is kinda funky looking, but is very light compared to the Tillotson's I have sitting around from chainsaws... the background for this question lies on my ignition choices, currently it's a point style ignition, but a homoelite style coil might fit (will try soon), and if that doesn't pan out I'll most likely go with gas/glow, but don't know if any of the carbs I have will survive the fuel, I have 4 or 5 spare Tillotsons waiting to be put in something, if they handle the gas/glow then that's fine, the bolt pattern of the Pioneer carb is the same as the Tillotson's...

I attached the pic from the ebay auction, since that's kinda how it looks at the moment, I'm going to pull the jug soon and hack the tanks off (they're cracked anyway), I'll try to get some pics after that and of the prop adapter I end up with

the plan is to start with a 22-10 prop, all I could find was a Zinger pro, only other option was a 22-8 carbon fiber unit, which was almost twice the price... and when you start at $30 for a prop... I should have looked for 10-10 glow fuel while I was there...

Thanks,
Scott

Ralphbf

My Feedback: (27)

They make a points replacement modual.
You simply disconnect the points install this $25.00 modual and your in business.

Personaly I would go with Gas-Glow.
Pioneer makes great saws, You will probaly not need to make any other mods to the engine.
But you should replace the rings.
Frank Bowman makes the best rings, and they are cheap.
I don't have his email address any more, but some one will give you that information.

10/10 glow fuel should be just right for this engine. Chainsaws are strong engines and 3% nitro will be plenty.

I don't know anything about Tilson carbs, but flushing them out after running them should help.

Good luck and keep us posted.

rangerfredbob

My Feedback: (13)

the transfers on this thing are HUGE compared to the weedie's I'm used to looking at, and the cylinder walls look nice and thin and light, after I get rid of the tanks I'll weigh the thing...

yeah, I was figuring on going gas/glow, but wanted some type of baseline, I might just make the prop hub extra long and shorten it when I get to the final phase...

w8ye

My Feedback: (16)

Frank C Bowman
1211 N Allen Ave
Farmington, NM 87401-3568
505-327-0696
[email protected]

rangerfredbob

My Feedback: (13)

ok, chopped the heck out of the engine, now my arms are sore... it looks a lot more like what I need now than when I started, I'll just have the fun of making new gaskets, I'll try to go for a thinner gasket between the crankcase halves since there was some endplay in the crankshaft.

need to do a bunch of cleaning since there was some sawdust in the crankcase... now there's some magnesium shavings... it looks well built and as I said before and would like to reiterate, the transfers are HUGE, I'll try ot get some pics in the next couple days...

anyone have any experiences with Tillotson carbs and gas/glow? the ones I have are bigger ones from saws not the small weedie sizes, I'll get some numbers soon to see if anyone recommends one over another.

Thanks

Flypaper 2

Scott:
This motor is the basis for the Quadra 52. At that time Pioneer was owned by OMC, makers of evinrude and Johnson outboards. The flat carb you have is OMCs own carb and didn't wotk very well. Later they used the Walbro carb. The few I have use WA 144 Walbros. You can get the module to go to electronic ign at the local saw shop. Turn the fins off on a lathe. Standard prop for the 52 is 20-10. Should turn in the mid 7000 range. Hope this helps. Quadra 52 was a little on the heavy side but as reliable as you could get. Should be able to get a muffler and other parts from B &B Specialties as they still sell them.

Gord.

rangerfredbob

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sweet, I made a good choice then, thanks for the info. I'll try to remember to grab the tillotsons out of the garage when I get home and give you guys some numbers, and look at what else I have. any idea on throat size I should be looking for in a carb? I'm pretty sure I don't have any big enough in a Walbro, but should in a Tillotson as I have at least 5 of those and all look like they came off of decent size saws (got a lot of carbs off of ebay for cheap)

rangerfredbob

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ok, forgot to grab the carbs, long day, will try to remember thursday...

acresinternet.com mentioned these all coming with that OMC carb but had a conversion to some tillotson carb, didn't say anything about Walbro... but they also said it was reed induction...

I know someone with a Q52 and it hauls up the 28# "Big Stick" with no problem, and it's used to tow up gliders also, and has a storage area to drop candy and stuff... if this thing has that much power it should power my 15lb Extra 330 without a problem...

looking at the B&B website I noticed the Q52 was a single ring configuration while mine is dual ring.

anyone thought about adapting a spring starter onto a conversion engine? I'll check all up weight first and see if it wouldn't hurt to add an extra pound, but it wouldn't be too hard to turn the back of the crank down to 3/8" or whatever ends up working out best... I noticed B&B had them for around $35 which doesn't sound too bad for easier starting...

Flypaper 2

They may be talking about the holiday 1100 series, which are reed valve engines. 52 would have no problem pulling a 15 lb. plane. I'm presently flying my 18 lb. Ground Pounder with a Quadra 42 and fully aerobatic. Rewind spring is a good idea. Mine consistently starts on the second flip. Makes for much safer starting too. I'll measure the carb throat size later today. Have fun.

Gord.

rangerfredbob

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ok, still didn't look at the carbs... but got the engine cleaned up and all in one place, with just the block, crankshaft, crankcase, piston and jug without muffler or carb or prop or prop adapter it's 3 pounds, I'm assuming it's mostly the 3" of shaft out the back and the second counter weight making it heavy, I'm not going to chop the rear shaft until I decide if I want to go with a spring starter or not, and if I go with one I'm most likely going to shorten it as much as I can and hollow it out as far as I can as big as I can...

I think I'm just going to go aviator's route on dealing with left hand threads, it seems the simplest, and at the all up weight I have so far, I'll probably just go gas/glow, by the time I'm done it'll probably weigh at or below the weight of the Mac 32cc I'm replacing it with... I'm not going to worry about trimming off the magnesium to drop weight, I know it doesn't add up very fast, I will do some trimming though.

rangerfredbob

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so I'm slow...

I have 4 choices in carbs that are any where near the size of the stock carb which has a .435" or 11mm venturi

Walbro HDC 39 with a .6" or 15.2mm venturi
Zama s4b oxa with a .6" or 15.2mm venturi
Tillotson HS45C with a .575" or 14.6mm venturi
Walbro WS17A with a .6" or 15.2mm venturi (this one has a worn out choke shaft, so it's the least likely candiate)

the pulse hole doesn't match up on any of the carbs, but the HDC doesn't have a port on the gasket surface, it has a barb for it on the side instead (I'm assuming the barb on the valve cover is the fuel supply, I could have it backwards)

the next size carb I have are all near .75" venturi size and the next smallest size carbs are the stock from a MacCulloch 32 trimmer... or the 13mm one I have on the mac at the moment...

the zama is the lightest and most compact out of the 4 options, the HDC is my next choice, so, anyone have any suggestions? keep in mind I'm expecting to go after gas/glow so that sounds like it kicks the zama out of the game...

oh, I decided to go with Aviator's solution on the crank threads, and decided to go with a 3/8" coarse stud since we have 2.5" long 3/8" set screws at work which should work perfect for this purpose, and be handy with the hex drive in one end...

Flypaper 2

Fraid I'm a little slow too. Stock Q52 carb is WA 144 Walbro at .500 size throat size.

rangerfredbob

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everything but prop hub, glow plug adapter and plug, prop, prop bolt and prop washer comes to 4 lb 7/8oz, I haven't modified the muffler yet either, but that won't add too much weight...

the mac 32cc I was running on the plane I plan to put this engine on weighs 4 lb 4 oz with everything but muffler, prop, prop bolt, and prop washer

rangerfredbob

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ok, I'm done with everything but modifying the muffler (will do that at work sometime this week, I have the tubes cut out and ready to be fitted), including prop and everything but ignition it's up to 4 pounds 8 oz, so it's right at the weight of the 32cc I'm replacing it with. it's over a pound heavier than a DA 50, but I'm blaming that on the rear end of the crankshaft (it's a beefy piece). I do still have some things that can be trimmed from the block to loose weight, but time is limited sometimes and just wanted to get it mounted up. I haven't gotten to the spring starter yet, I'll worry about that later.

if I can track down a camera I'll get a pic of this thing, it almost looks like a airplane engine now...

rangerfredbob

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ok, I got a camera for X mas, and I know the pics are huge (sorry people on slow connections), I'll try to shrink them in the future...

that's the engine in all it's glory, I need to finish the split ring I'm using for the magnet, and mount the sensor and it's done. I know the welds on the muffler are bad, but it's sealed and attached . and as far as weight, 4 pounds 10oz with everything minus ignition battery, I might just make a glow adapter...

Ralphbf

My Feedback: (27)

Remember weight only matters if you need to add it as a counter balance.

An aluminum muffler would probaly give you the greatest weight reduction.

I'm getting ready to build 2 for my twin.

dogshome

I like the muffler Tucked round the back is good.

One thing I spotted:- Will the carb rotate 180 degrees? It might make the throttle linkage easier.

rangerfredbob

My Feedback: (13)

the muffler is mostly aluminum, it's what came stock on it, the only thing that's steel is the cover plate and the tubes, which are fairly thin wall, as shown the muffler weighs 7oz. I like the way it looks too, I don't exactly need the room on the side since it's going in an extra that has a fairly large cowl, but it just looked cool

the carb could be flipped 180, but I'd have to rework the pulse hole on my adapter, and I think it'll work out the way it is, I was going to make a new throttle arm anyway

rangerfredbob

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ok, I'm tired of screwing around with the ignition, I'm 3/4 through making a glow plug adapter, now I just need to find a 1/4-32 tap...

anyone know which batatery would be better for EI, a 1500mA/hr nikd or a 2500mA/hr nimh (both AA cells), I don't know how many amps the nimh will handle, just for curiositys sake for when I put the ignition on something else.

KI8FR

If you can not get a tap. you can make one. Find a long glow plug. Cut a grove in the side of the threads. You can make 1,2 or 3 cut. It does not mater that much. Heat it up with a torch until it gets red hot. Drop it in to kerosene. Or just some old used oil will work. Have the Kerosene or oil in a coffee can. (not a plastic can) Do that 2 or 3 time. That will make it very hard.

If not, you can get the tap from tower. I know they have them. That is a special tap. I have not see one any were but a place like towers.

I made mine about 3 years ago and am still using it.

Try it. It works.

Paul

rangerfredbob

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I took a somewhat more sophisiticated route, I chopped the threads off of a long 1/4" bolt and threaded part of the remainder on the lathe... first time I'd cut threads on a lathe in about 4 years, and first time cutting threads on this lathe, it's not fancy, but it worked... I then took the dremel and made a cut lengthwise down the bolt with the sharpest edge being on the RH turn like a tap would have, it isn't elegent, prety or the best way of doing the job, but it worked

rangerfredbob

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all set up and installed on the plane with gas/glow in mind, bought a gallon of premium on my way to lunch, will test fire it tonight hopefully, tune it in at lunch tomorrow at work (more room, less worried about noise and neighbors)

now I'm all excited... hope it runs as good as I think it will.

Ralphbf

My Feedback: (27)

It should run just fine.

Remember a little rich on the idle to make it run good and smooth.

My friend Gary, a small engine mechanic said several times,

I can't believe how well it runs.

That was on my first conversion, a Mac 32.

Good luck

rangerfredbob

My Feedback: (13)

slight setback, I apparently got little happy with the lathe on my first glow plug adapter to make room for the glow warmer and there wasn't any material at the taper left to hold it together... needless to say there was a compression leak, so I made another adapter tonight, I'll go from there I guess that's what you get with one off quickie parts, but at least I'm using stuff up, I got the donor spark plugs free, and the aluminum I'm pressing into the middle was leftover from when I shortened the standoff's for this engine, and I made the tap, my lathe is making it's moneys worth...

rangerfredbob

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ran for a couple brief seconds, but my arm is now dead...

if the weather is decent tomorrow I'll drag it to work at lunch and get it going, with more than just me to hold the plane, turn it over and control the throttle... gets a bit awkward