Archive for The Unofficial Mamod and Other Steam Forum The Original Unofficial Toy Steam Forum
Established 2006
The biggest, most popular steam forum around! Accept NO imitations!
We have a growing community of regular posting members who chat about all aspects of toy and model steam.
 


       The Unofficial Mamod and Other Steam Forum Forum Index -> Technical tips, Details, Home Builds and Help Me!!
tmuir

Se3 fine tuning

I should finish my Se3 tonight and I remember a discussion a while back about the best set up for an SE3. You would think it would be with the power stroke of each piston being 180 degrees off from the other one but I remember some discussion about it.
Was this ever settled?
What is the best position for the cranks on an Se3?
Wallace

If you are talking 180degs being directly opposite (one top dead centre, one at the bottom) then no, don't set it at that.

I was originally told to set it just off 180degs, and I did, and it ran well.

Then when removing a drive band I accidentally set it at 180degs exact, and it didn't run at all.

I asked here, and MTA told me some kind of full size engines were at 90. I set it at that, and it flew.

So I set it at 90, but the best thing is experimenting.

I did recently read somewhere someone said 180degs, but mine didn't work at that
Steve_S

For single acting cylinders I would think 180 degrees is best as you say. That's what I've done on my M140 and it runs well. 90 degrees would be right for double acting cylinders. Wallace, it's interesting what you say about an engine not working at exactly 180 dgrees... I wonder why not?
Wallace

Steve_S wrote:
For single acting cylinders I would think 180 degrees is best as you say. That's what I've done on my M140 and it runs well. 90 degrees would be right for double acting cylinders. Wallace, it's interesting what you say about an engine not working at exactly 180 dgrees... I wonder why not?


I have no idea mate.
As I mentioned, when I first got it, like Tony, I asked here and was told JUST off 180degs which I did.

Then I ran it plenty of times, fitted a driveband (undoing crank) then set it at 180. It just wouldn't run, and I moved crank a bit, and away it went.

After your tip, I'm going to try experimenting
Steve_S

Wallace wrote:
I'm going to try experimenting


Yes, so will I!
yosa

Steve_S wrote:
For single acting cylinders I would think 180 degrees is best as you say. That's what I've done on my M140 and it runs well. 90 degrees would be right for double acting cylinders. Wallace, it's interesting what you say about an engine not working at exactly 180 dgrees... I wonder why not?


As I understand it, if you set up at exactly 180deg, the pistons cancel each other out and lock.

The other guys know more than me though, and can probably explain it better.
tmuir

One more question.
On all my other Mamods there is a washer between the crank and the engine frame but not on My SE3. Is there meant to be washers here and mine are just missing?
Or don't Se3s have washers between crank and engine frame?

Ok thats two questions but about the same thing.
Steely

I have my cranks just set off 180 degrees on my se3 and it runs fine. I think the mamod locos pistons are set at 90 degrees.
yosa

All of my mobiles have a washer between crank and engine frame, but none of my stationaries do.

Never gave it much thought 'til now.
tmuir

I've finished the Se3 now but I can feel a bit of friction when I spin the wheel. Not sure where from yet.......
Mamodman123

tmuir wrote:
I've finished the Se3 now but I can feel a bit of friction when I spin the wheel. Not sure where from yet.......


Is the regulator closed?


I set my SE3 cranks at around 180 degrees, not exactly....
tmuir

No with regulator open.
I think it is just a bit of roughness in the cylinders I need to run off from them all being seized up for a number of years.
I just ran it and it works fine.
My soldering all held up and my paint on the firebox lasts about aswell as original Mamod firebox black.
Flame was coming out from top of firebox for about 5 minutes and has caused slight discolouration and very minor crazying to the paint just on the very lip of the firebox.

I think it held out pretty well considering it is only rated to 180 degrees C.

Will upload the vid in a few minutes.
Thats another project finished.
Mamodman123

tmuir wrote:
No with regulator open.
I think it is just a bit of roughness in the cylinders I need to run off from them all being seized up for a number of years.
I just ran it and it works fine.
My soldering all held up and my paint on the firebox lasts about aswell as original Mamod firebox black.
Flame was coming out from top of firebox for about 5 minutes and has caused slight discolouration and very minor crazying to the paint just on the very lip of the firebox.

I think it held out pretty well considering it is only rated to 180 degrees C.

Will upload the vid in a few minutes.
Thats another project finished.


You'll get that with an SE3 burner.

That roughness will go after a few runs Tony! they are wonderful machines. As long as nothing leaks they go like rockets!
SPOKESMAN

With the reg closed there should be some compression, a few good runs should sort it Tony, you can play around with the 'timing' of the pistos! I remeber some time ago having my SP% with both piston driving together - difficult to get going but when it did it sounded different - bit like the piston set up on an old British vertical twin motocycle.
Mamodman123

Make sure the flywheel isn't catching on the base or the pully getting caught on the engine frame!
tmuir

Mamodman123 wrote:
Make sure the flywheel isn't catching on the base or the pully getting caught on the engine frame!


That caught me out when I was first test spinning it by hand.
Took me a whole minute to figure out where it was rubbing.

With the pistons disconnected the flywheel is free running.
I can feel the stiffness coming from the cylinders.
I just think they are a little rough for when it seized up still.
A few more runs and it will be good.
Mamodman123

tmuir wrote:
Mamodman123 wrote:
Make sure the flywheel isn't catching on the base or the pully getting caught on the engine frame!


That caught me out when I was first test spinning it by hand.
Took me a whole minute to figure out where it was rubbing.

With the pistons disconnected the flywheel is free running.
I can feel the stiffness coming from the cylinders.
I just think they are a little rough for when it seized up still.
A few more runs and it will be good.


Yes keep running it tony and it will get better! They really are great engines!
       The Unofficial Mamod and Other Steam Forum Forum Index -> Technical tips, Details, Home Builds and Help Me!!
Page 1 of 1