Stuart Turner P55MR

[AusAnzani]

Following lots of research and some much appreciated advice from TOMM forum members and friends, I've just added a Stuart P55MR, twin cylinder 8hp marine engine to my collection.

All appears to be in original/untouched condition, and although it was used in salt water there is very little rust or corrosion. It turns over very smoothly, has heaps of compression and makes no odd noises and shifts in and out of gear fairly easily. Last night I was able to crack all head, exhaust manifold and expansion chamber bolts without any difficulty ie all were tight but not seized! Here are a few pics.







Matching Serial Numbers on the engine and gearbox. Am searching Google now to see if I can use the serial number to determine year of manufacture.





Lots of bronze hardware and components painted over at the factory. These will be polished during the resto, adding some much deserved bling to this old dear.











As this is my very first inboard, I am looking forward to the new experiences it will bring. Only problem so far is its weight and lack of a trolley. Will get that sorted soon.

In the meantime any information or advice would be much appreciated. I'd really like to know more about what I'm getting myself in to here, so that I am well prepared.

Thanks & Regards,
Spiro

[Mr Craig]

Great motor Spiro, will you end up putting it in a boat ?

[cobbadog]

What a little beauty Spiro.
I have seen an inboard set up with a short shaft back to a bronze prop with a cage built around it for safety. this can all sit on a solid timber frame on castors to move it about. Look forward to seeing you wave your magic wand over this one. Does it have spark?

[AusAnzani]

Spent a bit of time playing with the Stuart over the weekend and am pleased to say all is looking good so far.

Pulled the plugs which allowed me to crank a little faster and check for spark. All good there and I’m sure with a bit more love, an even stronger spark can and will be achieved.

With the plugs out, it was also possible to do a slow rotation to check for odd noises etc. to which there were no problems noted. Removed the head and barrel anyway to check rings, decarbonise the head, pitons and expansion chamber etc and to check the con-rods for any slack in the big and little ends.   

Whilst that all looks good so far, there is a removable plate on each side of the crank case that provides access to the crank and big ends ie for assembly purposes. I'll remove these to allow closer inspection and cleaning (or replacement) of all bottom end parts.   

There is a heap more bronze on this than I originally thought and whilst that means lots more work, it will add significantly to the overall look of the restored engine.

On to a few photos. The first just shows some of the bronze components fixed to the upper section.





Had a little trouble removing the head and expansion chamber cover, otherwise she’s coming apart fairly easily. There’s still a little ways to go before she’s stripped right down.







Water pump and carburetor prior to removal and after paint stripper. Yet to be fully stripped and polished before final assembly.





Copy of the manual and lots of other useful  information has been provided by a member of the Old Marine Engines forum.

From the serial number, we’ve been able to narrow down the year of manufacture to a 3 year window between 1946 to 1949.



Not sure if I mentioned earlier on but this P55 was pulled from a rescue boat 50 or so years ago, sat in a garage under a timber cover, and started infrequently by it's previous owner ie whenever the grandkids were around still young enough to enjoy.

More soon.

Regards,

[cobbadog]

What a brilliant bit of History that should stay with the engine. They look to be very well engineered too but that is Stuart all the way. Why is the water chamber have that cup shape inside I wonder? Is there a thermostat?

[AusAnzani]

Yes Cobba, I am told and can see that the engineering is above and beyond that of many marine engines of the same era. The gearbox in particular is said to be a work of art!

Re the cup shape inside the water chamber, I've been advised that the early P55's were without thermostat and the later models with. That said I am yet to remove the full faced gasket from the expansion chamber (broke my last blade/knife) and want that off in one piece to use as a template if possible.

When I have that off, I'll let you know if there's a thermostat within. In the meantime however, the central hole located at the very top of the inner dome had a bronze hex plug in it. I'm not sure exactly what that means just yet, but I'm sure I will work it all out.

[cobbadog]

A mystery?
some of the ideas from way back were quite well thought through and I sometimes wonder why it was phased out and or discontinued. We have a 1 1/2 hp hit n miss engine that will run all day on way less than 1/2 gallon of fuel. Try and get a new engine to do the same.
I was listening to a mate talking about a tractor engine being rebuilt and how he intends to leave out the thermostat. I don't like that idea. If you have problems with over heating it is not because of the thermostat, you have a water pump or radiator problem.
For me I always run one so that the engine gets to operating temps quicker which in turn lessens wear and tear.

[AusAnzani]

Agreed.

Showed I was learning about this engine on the fly with one of my above posts. I suspect that whole exhaust/water chamber comes away from the expansion chamber, and if that's the case it should slide up and off those three studs when the gasket/seal is broken.

A few more photos by others or on the net would be nice. That would gives some clues as to how to proceed and what to look out for.

Flying blind adds to the fun I guess.

Regards,

[winchester]

That's right Spiro ,it just slides up off the studs ............you may find it badly corroded , they usually are .

[winchester]

Spiro when you get to the crankshaft you will find a center  bearing . It is not really a bearing but it is a bronze  sleeve valve that separates the two crankcases for induction purposes . From memory if there is more than 8 thou clearance then a replacement is needed . However you can avoid this by wiping some white metal over the bearing surface . This will get it back to a tolerable fit . Of course if you can get a replacement so much the better. Another suggestion ,replace the standard crankshaft oil seals ,they are a bronze type .you will able to get synthetic seals from you local bearing supplier

[AusAnzani]

Great information, thank you.

[AusAnzani]

A few more pics and that'll be it a while I think.

Paint removed from all parts and it's looking pretty good.

As I don't have a sand blaster or an electrolysis tank, I'm doing things the old fashioned way. Paint stripper followed by wire wheel.













Above pics were taken with much of the original/base hardware (all the rusted and frozen stuff) still in place. I plan to replace all of that with new, albeit that BSF hardware has proven difficult to find in Melbourne.

Unfortunately I have been unable to remove flywheel (and in fact have been advised against even trying) which inturn means I cannot tear down the crankcase. So I'm at a bit of a cross roads now, not sure whether to persist with flywheel removal etc or progress with a semi/cosmetic restoration instead of a full one. It's unlikely it'll ever be run for extended periods or see another boat, so maybe a semi resto is the go. I really don't know 

That said, I'd like to hear what you guys think as that will assist me to decide which way to proceed. If you could your with me what methods and tools you use to remove frozen flywheel nuts and frozen flywheels that would be a great help.

In the meantime, I've also been searching the net and have managed to find lots of great information via the Old marine engines forums and some of the missing/replacement parts in the UK. Hope to order those shortly if I can work a suitable postage deal with the vendor.

Regards,
Spiro

[winchester]

Spiro ...It's not hard to remove the flywheel ...........loosen the flywheel nut and tap the back of the flywheel . There is a collet  and key .

[AusAnzani]

Thanks Peter, I will give it a try.

I need to find a 3/4 Whit socket first. Largest I have is 11/16.

Thanks & Regards
Spiro

[AusAnzani]

Thanks for the link B, I will certainly consider using them in future.

Although I feel I'm not doing this in the right order (some not so good advice and the lack of a 3/4 W socket has prevented me from removing flywheel and prop shaft coupling first) a little more progress was made over the weekend. All rusted/frozen bolts have now been removed allowing me to separate the gearbox from the engine. In doing that, I could see why the unit would remain in gear after shifting back to neutral. Lack of oil, water ingress (possibly condensate) and internal surface rust inhibiting proper movement of the clutch assembly.

As you will see from the pic below, all barrel/head studs have been removed, just making the whole thing easier to work on.



A little bit of good fortune too, in that I was put on to a collector of marine engines not too far from me who has several Stuarts as well as some parts I needed. The copper drip tray (underside shown in the pic) was a mangled mess but I managed to straighten that out without too much difficulty.



All that's missing now is the bronze dome nut that's used secure the water outlet fitting, the copper head gasket which I'll likely replace with a high temp fibre unit anyway, and a bronze ahead/astern lever in good condition. I anticipated that these levers would be hard to find, but have rejected 3 so far in ordinary condition, 1 in the UK and 2 in Australia! I'm sure a good one will turn up somewhere soon.

Will have to start priming some of the removed parts soon.

Regards,
Spiro