OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines TROJAN MAJOR - Motor Fitted To Ogden Rotamatic

I need some help, I have a Trojan Major engine fitted with a Wipac Series 90 Magneto. Pic below is of the electrics



Now IanOZ has helped me out via messages but what I need is a pic of the electrics from the Trojan Major engine as it has the magneto mounted on the inlet port side giving it a clockwise direction. Maybe any rotary mower that has the Trojan mounted Flywheel up will be the same.

What I am suspecting is that my coil should not be at the bottom as I have spark but not at TDC. The plate mounting only has two holes so it will only fit one way or the other but I am not sure so would like to compare electrics with a working one. A big ask but I am grateful for any help.

Hello Paul

All I have is an illustration of a Major.
It shows the coil at the 2 O'clock position.

Sorry I can't be of more assistance.
---------------------------------------
Jack.

Thanks Jack, I have the same pic in one of my mower digests. With my coil at two my points will be at four which is not consistent with the picture. Makes me feel that my set up is perhaps not original a photo would be conclusive as to what should be where.

Thanks for helping

Paul, I thought that the coil, itself, was fitted to the wrong stator core.

See:-

http://www.brightsparkmagnetos.com/easycap/universal/wico-pacy_series_90.htm

http://www.tanygraig.force9.co.uk/John/wipac1.htm

You just might be right there Jack, shifting the coil would also bring the coil lead into line with the exit holes in the back plate. Good to have another set of eyes look at a problem, I will give it a go tomorrow. Thanks

Yes

the exit holes for the HT lead was one thing I noticed.
I love the lighting coil for automotive applications.

I wasn't aware you had an Ogden Rotamatic. A very rare machine!

All very interesting.
-----------------------------
JACK

I have the engine, cowl and fuel tank. If a base ever turns up I am ready for it :-). I will post a pic of the engine unit when I get it running. Hmmmm optimist I am !

Hello Paul

I see. These are such a handsome and interesting machine.
I hope one turns up.

Looks more like a moon buggy than a mower, very space age.

Nearly going, broken ring so I fitted another good piston and bore off my junk motor then found a cracked rear seal so I swapped that as well. Once I get it running I will fit new rings and seals, bearings etc.

It wants to go and nearly does but just won't, pulled carby down again and checked timing but to no avail.

G,day Paul,

I was giving your magneto thing some thought. Did you end up swapping the coil position?

Reason I ask is that you say you had spark but not at TDC. If you had spark then the magnet neutral to points timing must have been at least fairly right - and changing the coil position would have thrown that out the window?

Just curious.

Cheers,

Cheers.

Hi prd,

Thanks for your help, I had spark but it seemed to be at BDC. I changed the coil and now have a very good spark and the motor is timed correctly. Points just start opening a few degrees before TDC and fully open at TDC.

Still not convinced it's getting a proper dose of fuel, a lot of cranking and the plug is not wet ?

OK, that is interesting. Not what I was expecting but your new coil position agrees with the photo in the motorbike link.

Gotta confess that I would have blasted in and flipped the whole thing on the 2-screw mounting if I'd been faced with that.

Sounds like your annoyingly close to a goer. Hate it when that happens.

I did flip it but it was a no go, I am still not sure if its position is right. A photo would be conclusive. It wants to go with the drill spinning it over but won't carry itself. I have pulled the cylinder off again and tipped it up and a lot of crap ran out. I am going to split the cases and replace the bearings, seals and gaskets, clean it all out. There could be that much carbon and rubbish down there that's it's destroying the fuel mix.

Bearings are no problem, they are the same as Victa and I have loads of spares. I will try the bearing place for seals and make my own gaskets. Rings not to sure about. Once The engine unit is sorted it one thing off the check list.

Hello Paul and prd,

I'm pretty happy that the coil is now on the correct stator plate core.
The second link also showed that as well. I just wish the design was more
'service friendly', making it impossible to fit the ignition coil or
lighting coil (if applic.) in the wrong place.

Here is a reconditioned one from Villiers Spares UK:-


[Source: http://www.villiersparts.co.uk/wip.html ]

p.s. Paul, I have added this page to the Master Record:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=60982

Yes Jack I would say the electrics are sorted. Mind you after draining the crankcase out I bet it would go. With all that was in the crankcase compression of the air fuel mix would be difficult.

Hi Paul

What amazes me is that I have no record of anyone owning a Rotamatic.
We're talking about a very big company - Ogden Industries - that sold these
machines for a couple of seasons: yet where are they?

For the record, may I ask how you know your Trojan is off a Rotamatic?
I certainly believe it is; because of the fan above the flywheel.
I suspect Ogden made the fan, and cast the unique alloy cowl.

The Rotamatic, in its Olympic colours, would have looked outright stunning.
A green and gold moon buggy, I guess

All very collectable.
-------------------------------
JACK

Hi Jack, I have the cast cowl which has the fuel tank strap on top and the Ogden logo on the front. Colour looks to be a mustard, may have been gold. I will post up a pic.




Spacers are still present on the mounting bolts to lift the motor up clear of the deck, photos are of as found. You can't see the large scrawled Ogden logo in the pic and it is only barely visible anyway.

Hi Paul

I was wr ... wro... wron... close.
I meant that it was painted with a gloss green enamel base,
with yellow cowl (not gold) and yellow wheels.

Thanks for the photos - first non-factory ones I've seen.
----------------------------------------------------------
JACK

It's a bit cleaner now :-) pity the fuel tank wasn't kept on it.

Just curious on looker...Have you checked the compression? I know borderline minimum compression can give me fits sometimes on 2 cycles here.

Hi AVB,

Found a broken ring and cracked rear seal. Giving it an overhaul now and will see how it goes from a fresh.

Secured the crankshaft seals today, looking for piston rings now. 46 mm bore, 2mm ring. Anyone bought rings for a Trojan/Tor before, mine is 75cc engine with Std piston ?

Ive Not seen New parts for Trojan Paul, I think you'll need to find a collector or club who may have old stock, if no one here has a set.

Ive had success with JP before for impossible pistons and rings, if all else fails check em out. Pretty sure they do A fair bit of Villiers as well....like the 7F.

Send them a sample ring and they may be able to match them.

http://www.jp.com.au/JPPistons.html

Thanks Mal,

On to them and sent a few emails back to the Mother country. 46mm rings are a common size and even the gap profile can be found but 2mm thickness is what I need. Still trimmers use 46mm and there's loads of them, just a bit more digging required.

Lucky the gaskets are only paper type, wonder how thick though ? Corn Flake or Weet Bix type :-)

Rings are sorted, coming from JP Pistons, odd thing with the crankshaft bearings. I have another motor for spares which I stripped down, found that the two cranks use different bearing sizes.

One crank has a 20mm I.D. Bearing either end but the one used on the Ogden mower has a 17mm on the blade end and a 20 mm on the magneto end. Wonder why they went to using a different size bearing on the stressed up end of things. Perhaps this is the reason for the fancy clutch ? Above the blade plate as the crank is thinner down there.

Well done Paul on the Rings Paul, they've helped me a few times.

Not sure on the bearings?

Gasket size Im unsure of. Basic rule for crankcase to barrel is, fit the barrel and measure the distance between barrel end surface and piston to find your thickness,and use the appropriate material allowing a few thou for crush. Crankcase halves are usually dry,sealant or of the thinnest material...eg paper thickness.

As for the head, see if there is any salvageable material to measure,or just run std Victa 125 thickness?

Anyways glad you got your rings, cant wait to see it running:)

Thanks Mal, Bearings are all sorted, crankcase and base gasket are just paper and sealant. The crankcase has an inner lip to seal the halves, very clever. I can salvage the head gasket but I may make a new one. I will put up some pics soon.

A few pics of the progress

First for Jack some better pics of the Ogden cast alloy cowl
Gallery images include:-

Remnants of Ogden logo
Carb side
Underneath
Engine progress
Sealing lip on one side of crankcase
Engine number
Piston
Look what I found
I am hoping it will clean up for a good spare :-)

Hello Paul and ODK Members & Guests

First, thanks to HT6 for recommending JP Pistons.
They appear to be the premier company for sourcing pistons, rings and etc.

Paul, thanks again.
These are invaluable photos in recording this Ogden version of the Trojan 75cc.
The yellow (not gold) cowling would have looked absolutely stunning on this
moon-buggy mower.

This mower was painted in green and yellow for a single purpose: the Melbourne
Olympic Games, in the year this rare mower was introduced. I hope this motor
will mate with a chassis ... some day.

p.s. I love the lipped seal on the crankcase. It was kismet!

All very significant.
---------------------------------
JACK

I have to Agree with Jack...I'm really hoping you can complete this little gem with the aquisition of a base and parts.

Thankyou also for breaking down the engine, as engine building/restoring is one of my main passions,and this is one I've never had the chance to build. I really like the fact the casings still retain alot of their original casting lustre after so many years.

Im quite excited about the restoration,as this is one very elusive mower id really love to see complete.



Please keep your progress info coming.

Spent most of the day cleaning parts, the spare magneto cleaned up nicely. It has no condenser, I am wondering if anyone knows what one will do the job, I have plenty of spare Victa ones. Would one of the Victa ones do the job ?

Victa condenser should be fine...I occasionally use the later Special conds on the Rotomo wipacs,when I run out. Never had a problem.

Do you have an image of the original condenser on your good engine? Should be the brass one with screw on connection.

Thanks Mal, no original condenser to view. My other magneto already has another in its place, I think they were a long thin one with a nut on the end from memory. I will put a Victa one on for now.

New rings arrived today and there spot on, tried them in the bore and they are perfect. Made some gaskets while my son looked on, he was very interested as to why there needed to be a gasket and so the lesson began. I have all the bearings and seals so on Saturday I will take my time and enjoy putting it back together

:-)

Hi Paul and ODK Members

Thanks for this exciting update. This posting has attracted a lot of interest.

For one thing, It has been most helpful in Mal's recommendation of JP Pistons.
Clearly, for rare piston or ring needs, JP is probably the first point of call in OZ.
For another thing, the larger Trojan was rarely used on AUS lawnmowers.

I digress now, because I am compelled to say something about photographs.

I know that most images that appear on these forums here are illustrative.
But - some images - do a little bit more - they tell a more rewarding & complex story.

This narrative tells the 'ring story' and the 'son story' in such a nice way; and this is
reflected in the composition of your excellent photograph.

It is an exploration in geometry - circles and squares - but with a twist. Note:
- the rings on their package, but the package is on the diagonal.
- the circles and half circle (almost) of the c/case, cylinder, rings and can.
- the contrast of light table to dark background.
- the gasket that appears on the cylinder base.
- the hammer, with circular head, has more complex connotations.

This photo reminds me of the importance of images as part of the words in
telling the story of members' machinery. For example:-

https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=59799#Post59799

Sorry for the indulgence here.
My message: photographs form part of the provenance of members' restorations.
They can clearly add value to machines down the track - but also act as an historical record!

All very interesting.
------------------------------------
JACK

Hi Jack, your comments are always interesting and much appreciated. So many circles in one picture, the crankcase has 11 alone ! I had a look at the post in your link and have added it to my watched topics to enjoy later, I also realise that I haven't posted a pic of the crankshaft. I took one but didn't post it as it is blurry, it's a very interesting build so I will take another one.

Tapped the crankshaft seals in this afternoon, just a note on the back seal. It goes in the reverse way, why I am not to sure but that's how the original seal was fitted on both of my motors. It does have an alloy cover that keeps the rubbish out though

Hi Paul

That's an interesting observation on the seals.
Crankcase seals are, I guess, unusual; in that they have to work
both ways: the upstroke creating vacuum, and down-stroke creating
positive pressure. I wish I knew more in this area but I don't.
Can these seals be driven in from either side?

All very interesting.
--------------------------
Jack

I drove them in from the inside but I guess you could fit them from either side.

Was there any wear on the shaft surface?

Ive seen seals in further and upside down so the positioning changes and the sealing lip runs on a good section of the shaft.

It shouldnt matter unless the sealing lip is tapered on a directional 45�, as you would lose a large section of sealing surface area.

Here is the crankshaft, very solid
Big end roller bearing, conrod is quite slim
And one for Jack :-)

Ive seen seals in further and upside down so the positioning changes and the sealing lip runs on a good section of the shaft.

It shouldn't matter unless the sealing lip is tapered on a directional 45�, as you would lose a large section of sealing surface area.

No obvious wear, that's the way the seal is facing in the parts diagram as well

Cool....I assumed you didnt have a manual, Since you said you weren't sure why it was upside down....:)

There does appear to be some wear on both ends? Minimal groove or are they just scuff marks?

Hi HT6,
Surfaces are fine just cleaned them up, I don't have a manual it's all guess work. I found the exploded parts view here

http://www.users.globalnet.co.uk/~pattle/nacc/arc0119.htm

It's pretty much all the info there is on these engines, I was sure which way the seal went just not why ?

Ahhhh....Cool:)

Well at least you found this engine diagram, as it confirms your seals positioning.

All back together fired up, ran and then stopped, sheared the flywheel key ! At least it runs, now I have to find a key.

Muffler and exhaust is off the spare motor as the correct one was still soaking in the cleaner.

Found replacement keys here, in Australia. After an afternoon of computer cross referencing and a lot of searching. Found it by the American reference number 203

http://australianmetalworkinghobbyist.com/store/index.php?route=product/product&product_id=386

Ordered a few spare

Hello Paul

Thanks for the updates.
That mag came up real pretty - and still with the oiled felt
cam wiper. They are a handsome engine.

The story of the key is real detective work.
p.s. Did the key fail because there was no flywheel (bladeholder)?

The Trojan war is almost won.
----------------------------------
JACK

Hi Jack,

I think the flywheel wasn't pulled down all the way on the taper, I replaced the spring under the cam with another one that was a bit cleaner. But it was also a fraction longer which when compressed under the cam held everything up just that bit more. Blade holder shouldn't make a difference on this one as they can run a pulley or a roller or a mower blade. Pretty versatile little engine.

Hi Paul,

Yes, of course. Thank you.
How do you plan to present the cowl? Will it be painted?

Here's a great ad (detail) I recently found.
A couple of OZ manufacturers took the awkward route of protecting
the engine from shock via a spring clutch. They did this because the
blades were rigidly mounted. The clutches were prone to wearing out
(in doing their job) and in the field repairers would remove the clutch,
giving the engine no protection from shock loads.

Cheers
------------------
JACK

Interesting, in the advert it states that there are 3 bearings supporting the crankshaft. I think Victa also stated this in their advertising which of course is correct. A bit misleading to the purchasing public as the Trojan motor has only 2 bearings supporting its crankshaft, I suspect that if there is a third bearing/bush perhaps it is in the clutch assembly. Unless the shaft with the 3 bearings is not the crank but the shaft travelling from the clutch to the blades ?

The crankshaft would only accomodate the clutch assembly, there must be another shaft supporting the spring and blade holder, doomed ! Probably why there are none around now, small fuel tank as well. Just not up to the job, I wonder what other mower you could buy for the same money ?

I was looking at the cowl this morning and there is not enough of the decal and the paint is rubbish so it will get a fresh coat of yellow paint. I will make up a new bracket to take a Victa fuel tank.

Hi Paul

Yes, the 'outrigger bearing' may be above the clutch assembly, but external
to the lower crankcase. I never noticed that before ...

I will link an OGDEN booklet to the record tomorrow. Here is an extract:-



Here is the link to the full booklet HERE.

Cheers
----------------------
JACK

Postie came today, raced out to the mailbox ....... bloody junk mail !! maybe tomorrow :-(

Picture or Video is worth a thousand words

[video][/video]

Awesome Paul!

And a true 1.6 h.p. I bet...
Thanks for the video.
-----------------------------
JACK

Where's the link?

Video above but here is a link
Hope this works for you

sounds nice , lot of links didnt work last week or so too .
thanks Jack
hope he didnt kill it dead though !!!

Still alive !

Awesome work in getting the old girl up and running paul_c!, Thanks for sharing the journey ...

I gave the cowl a test fit today, also wanted to see how it effected the cooling as I wanted to give the engine a long run
I gave it a good run with the shroud on with no problems but the fan doesn't give much of an airflow over the cooling fins.

Hi Paul,

It's starting to look like a Rotamatic engine.
The fuel tank is probably the same as that on the Motamatic(?)

Thanks for the update.
------------------------------
JACK

Cleaned up the cowl this afternoon

It's in undercoat at the moment and it will get a coat of yellow tomorrow.

Nice weather today so gave the cowl a few coats of paint

I wish I had the fuel tank but in its absence a Victa 18 tank will do the job, more painting ! I like the painting but the prep can be painful.

All fitted up

Yes, all fitted up and no place to go ... at the moment.
It is unfortunate that this engine was separated from its chassis long ago.

All I can say is that we are lucky one of these Ogden Tor Majors survives.
I just hope, one day, one of the bases will turn up.

Paul, I'm glad you saw the historical significance of this little moter
in the context of AUS vintage mower history.

This has been a great post and story. One for the record.

p.s. I love the old lanyard handle.
----------------------------------------
JACK

Thanks Jack,
I have asked Grant aka Silensmessor to work on a decal for me, hopefully will have it soon along with a few others. Once it's all finished I will take a final photo and video for the record.

Won a fuel tank off EBay that looks and measures the right size




Hopefully the tank will be with me soon and the decal is being worked on :-)

The postie came through with the goods,

I will repaint it very soon :-)

An update on this one, I have been unable to find a mower base to put this engine on but have been successful in purchasing a complete mower

Hopefully after some work I will have it running again :-)

Thats awesome too see Paul!

I was going to have a crack at this one but you beat me too it.
If I had just gotten that base at the swap meet you could have had 2!

G'day Paul & Kye

Congratulations Paul.
I feel these are one of the top 'desirables' of the 1950s era.
They would have looked stunning in their green and yellow livery.

I note this one has no branding cast in the base or wheels.
Paul has told me it still has two original design fixed blades, and
has retained its spring shock clutch! They have never been recorded.

I note that my brochure shows a similar machine:

I did some work on the mower yesterday, required a set of rings and a carby clean. Wanted to remove the engine but ran into some problems with the blade plate. Mine doesn't have a hex nut like the model shown in the brochure but a bolt that has two flats, this would not budge.

Clutch is still there with the spring above it.
I am sure I have seen a photo of another blade plate that has the clutch on the other side, leading me to think that there is another model of this mower out there ?

Found it.

I can only say this is new territory, and put in my two cents' worth...

The photo you show is an amalgam of an ad and a separate maintenance
manual. The brochure suggests an above-holder spring clutch. The
maintenance manual photo suggests a below-holder clutch. A non-hex nut
is new to me. Is that a brass nut?

It may be that Ogden did change the blade holder design, taking into
account another source: the Ogden Story book (that you also have).
All sources suggest to me a conventional RH hex bolt.

In any case, the issue is, I guess, left or right hand threads?
My understanding of the clutch design is that this bolt does not,
and could not, connect directly to the crankshaft. The bolt screws
into the female-side of the clutch. The male side of the clutch is
secured by another bolt (or boss) to the crankshaft. The maintenance manual
does not hint at a LH thread.

Did other makers use this clutch system?
The answer is 'yes' - but with a twist (pardon pun).
I know that both Whirlwind (Sabre) and Pye-Tecnico (Automotion)
used a similar arrangement, but with a rigid bar blade, rather
than your rigid blade-on-disc system. Here is the Tecnico system,
with the spring clutch below the blade:-



I guess this doesn't really help, Paul.
I have written before about the lack of documentation of these safety clutches.
I believe they were replaced - in service - with a simpler and more elegant
solution - the swing-back blade. After all, these clutches suffered constant wear.

But this conversation is part of the record of this most fascinating and
important Australian lawnmower - the Ogden Rotamatic.

--------------------
Jack

Hi Jack,

Yes I agree, looking at the picture I would say the blade plates are different with the clutch remaining in the same position. Either way I will have to remove it to paint the base, it does look brass in the photo. I will have to have a closer look :-)

Sorted out a few carby issues and I am now happy with how the mower starts and runs, I am not a big fan of these Dellorto carbs with variable mixture.

[video][/video]

That runs awesome Paul! Great to see you do your magic on another one. Just wish I got that base at Gympie for you, you could have had 2!
Oh well, next time.

Cheers Paul!

Hi Paul & Kye,

I guess that's the first video of an Ogden Rotamatic!
Just a couple of years ago, no one had heard of these mowers.
Now we have a complete running one. The mower seems to attract
women in beach attire ...

Paul, can you explain this to me ...
its the 'baffled ejector opening'.
Is it 'impossible' to injure your foot?

Sorry for the late reply Jack, a child probably could wedge their foot into the chute opening

Here is a pic of the full under-body.
Nice and clean under there, I don't think this machine did much work.

Hi Paul

It's in amazing condition!.
I now understand.
There is a stopper there not shown in the brochure.

There are a few differences in the base casting also, the ribs on the front don't continue through. I wonder if this is a prototype base in the brochure, perhaps the only one to have had the Rotamatic lettering cast onto it ? A few other minor cast points removed as well.

I guess so, Paul.
I do note that the chute post is not shown in this parts list though.
This could well accord with your suggestion - that the brochure (and the
sample parts list from an Ogden booklet) were both made prior to, or early
in production of this great lawnmower.

And I guess you are the owner of the best example!

Cheers
------------------
Jack



A NOTE ON SAFETY
p.s. Paul, it may be that that seemingly insignificant chute post or bollard
is a great, early example of the emerging issue of the safety of rotary lawnmowers.
I note that the Ogden has, in essence, a rear safety skirt.

It is true that electric rotaries received some bad press because of
a few fatal injuries - electrocution. But evidence strongly suggests
that it was the petrol rotaries (the 'toe-cutters') that produced the
vast majority of non-fatal injuries in the 1950s.

The Rotamatic - not being a toe-cutter - and having a chassis base
with a rear safety skirt and chute post, would have been as safe a
machine as the safest produced in the 1950s.

Hello ODK Members,

Just posting this great advert for Ogden mowers with an Olympic tie in, Jack can it be added to the history record?

G'day Paul
That's a great find!

I would like to say why this ad is an important find.
I had always argued the Rotamatic colour scheme was related to the Olympics.

But here is proof that the Bronze medals awarded Ogden were
not metaphorical - they were real medallions awarded at the
Industrial Design Exhibition with official connection to the Olympics.

I will certainly add it to the record.

Many thanks
---------------------------------
Jack

I'm a little bit late to this party!
Here is a picture of my magneto.( I hope it loads!)

Runs clockwise looking at the mag. My coil is in the correct position and is producing a nice spark.

I built a mini-bike in 1967 using one of these motors, so I have a nostalgic soft spot for them.
I recently acquired one and am in the process of getting it running.

I need a Carby and the bits that attach to the magneto to wind the rope on to pull start it.

Where did you get the seals? They appear to a wacky size! 0.875 x 1.560
I'm in Melbourne