Ron’s Jowitt Popett Valve Engine

[JasonBModerator @jasonb]

You should not be able to feel any compression or air trying to push the piston until you are over TDC

Inlet valve should open just after TDC and close say 20 degrees before BDC.

Exhaust wants to open at or just after the inlet closes so open at 20deg before BDC and should remain open until the piston is back up at TDC

[Ron LadenParticipant @ronladen17547]

Jason, I reset the eccentrics and I have the engine running but I only have one speed (slowish) but at least I have it running and have had it running for half an hour now.

I know the crank, big and small end are all good so I am guessing the O ring is holding back the speed, do they take much running in. I am hoping that once it gets easier I will be able to fine tune it and get variable speed.

[Former MemberParticipant @formermember19781]

[This posting has been removed]

[JasonBModerator @jasonb]

You could try it without the O ring.

If your springs are a bit strong that won't help either as they will be taking engergy to compress, the inlet can be lighter than the exhaust.

[Ron LadenParticipant @ronladen17547]

I did try it without the O ring but couldnt get it to run, I,ve checked the springs and think they are ok.

A bit of handheld video below of what I have at the moment, it is certainly a bit better for some running. Going to give it some longer runs and see if it beds in some more. Despite the teething problems I am quite happy with it and hopefully can get them sorted.

p.s. apologise for the sound of the compressor, I need a longer airline to get it off the bench.

Edited By Ron Laden on 02/04/2020 16:06:45

[Clive Brown 1Participant @clivebrown1]

How big is your compressor Ron, could that be the limiting factor?

Looks a very nice engine.

[JasonBModerator @jasonb]

Looks to be running smoothly enough so I would also say you may be at the limit of what your compressor can deliver, the volume is about 50% more than the oscillator that you did so will be a bit hungrier.

[Ron LadenParticipant @ronladen17547]

Thanks Clive/Jason, I think you are right it did cross my mind but thought it was the engine being tight and not set up correctly. The engine is now set correctly and spinning it over it feels really good, smooth and free so I,m sure it is now ok.

My compressor is an on demand type it doesnt have a tank, it is rated as 40psi and 0.8 cu ft per min. Using it to run the little oscillator it switched on and off but with Jowett it is running full time so I guess thats a sign that it is at its limit.

Anyway, now I know the engine runs ok I will sort a new compressor it will be good for shop use as well.

I dont want a largish type with a large tank, I dont have the room so would have to bring it into the shop when needed and then store it somewhere else.

I have found a bench type compressor with a 6 litre tank, 8 bar and 6.3 cfm I,m guessing that should be fine..?

[JasonBModerator @jasonb]

That should be a lot better

[Ron LadenParticipant @ronladen17547]

Thanks Jason, thinking of getting one of these, should do the job and quite compact can live under a bench.

Edited By Ron Laden on 03/04/2020 08:33:56

[Ron LadenParticipant @ronladen17547]

Made some further adjustments and I am really pleased with it, yes its a bit starved of air hence the need for a higher output compressor. It starts first time every time so the settings must be pretty close a bit more video below.

[Ron LadenParticipant @ronladen17547]

The Muncaster wheels arrived, amazed at how clean the castings are..excellent.

[JasonBModerator @jasonb]

Is that hole open?

Also make sure the brass fittings don't have too long a thread which could be blocking the hole from cylinder to valve chambers.

Edited By JasonB on 03/04/2020 16:20:16

[Ron LadenParticipant @ronladen17547]

No Jason it has a M4 grub screw locked in there and I will fill over the top on finishing. Also the fitting threads are short of the cylinder hole.

Edited By Ron Laden on 03/04/2020 16:42:58

[JasonBModerator @jasonb]

[Former MemberParticipant @formermember19781]

[This posting has been removed]

[Ron LadenParticipant @ronladen17547]

A bit of video of the Jowitt running on the new compressor, no sound I,m afraid as the compressor is so noisy it drowns the engine sound. I need to get an airline extension to get the compressor outside the workshop. I had another problem in that the in line regulator developed a leak so had to remove it from the line which left me trying to control the engine on the compressor regulator. Also had to hold down the engine to stop it walking across the bench, it hasnt got its base fitted yet. Anyway enough of my excuses at least the video does show the engine has a good turn of speed with the better delivery of air.

[Jim NicParticipant @jimnic]

Well done Ron. Coat of paint and a base and it's on to the next one.

I'm surprised we dont see more of these Jowitts, as you found they're a little bit out of the ordinary run of steam engine and with care produce a good looking result.

Jim

[JasonBModerator @jasonb]

Would be better with a Chuff, Chuff, Chuff.

What you can do is set the compressor reg to about 5psi and fill the tank then switch off, depending on size of engine and speed you run at you can get a quiet run that's what all my videos are done like. That Muncaster No1 I did recently goes for 38mins off my 20lts tank.

[Ron LadenParticipant @ronladen17547]

Thanks Jim, I am on to the next one actually, I,m half way through Jasons Entablature and thats a nice build also.

Ron

[Ron LadenParticipant @ronladen17547]

Good idea Jason I will give that a try.

I didnt make too good a job of the flywheels did I, they are annoying me. I should have set them up to the inside of the rim or as close as you can before machining the outside but I didnt. The outside of the rims run true enough but its amazing how the out of true inner grabs your eye.

Oh well you live and learn, at least the entablature wheel wont have that problem.

Edited By Ron Laden on 13/05/2020 17:19:40

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