Stuart No 10 cylinder ports

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I'm making R R Raymans high speed marine engine from bar stock,the drawing calls for a Stuart No 10 cylinder. The drawing has no measurements for the port central distances from exhaust to the ports. Any idea please for this as knowing me I would work it out but bound to be incorrect.

Thanks Bob

[BOB BLACKSHAW 1Participant @bobblackshaw1]

[JasonBModerator @jasonb]

[John RuddParticipant @johnrudd16576]

My turn to help….

 

From my Stuart 10V drawings, assuming the ports are centrally displaced;

the outer edges of the ports are 7/16" apart, the inner port edges are 9/32" apart. The central port is 1/8" wide centrally displaced. I make the outer port width to be 5/64".

all ports 9/32" high

 

HTH..

ah. Jason beat me…my maths is a bit too slow…😂

 

Edited By John Rudd on 14/10/2020 14:24:53

Edited By John Rudd on 14/10/2020 14:26:17

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks that's brilliant, Jason, John,

Bob

[BOB BLACKSHAW 1Participant @bobblackshaw1]

I've started to assemble the engine but have come up with a problem, the slide valve looks on the big size. as when the cam rotates no gap in the valve chest for air intake. On my drawing the slide valve is 5/8ths long is this correct for the Stuart No 10 cylinder. The valve chest on my drawing is 7/8ths so something must be wrong as that leaves 1/8 either side.

Or I've done something drastically wrong. Bob.

[JasonBModerator @jasonb]

My drawing has the valve as 1/2" x 13/32" and the chest cavity as 3/4"x 9/16"

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks Jason, is the internal gap on the valve slide 3/8ths as it is on my drawing, also the throw on eccentric on mine is 1/8th. This looks like a remake of valve chest and valve as I've made the cylinder to measurements given on the previous post.

Bob

[JasonBModerator @jasonb]

Cavity is shown as 3/8" across the rod and 9/32" along the length of the rod, Eccentric 3/32" offset giving 3/16" total movement.

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks, all the measurements don't work out here, it's a Stuart 10 cylinder measurements but incorrect on other parts on the A A Raymans drawing. I shall bung it in a bag and start on something else .

Bob

[Old SchoolParticipant @oldschool]

I have built the high speed marine steam engine, it’s a while ago but I don’t remember any problems with the build. It’s now in a boat with flash boiler it gets up and planes no problem at all.

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks Old School, I cant work this out. The A A Rayman drawing calls for the Stuart cylinder which in the past post the measurements are given for this so if the casting was used these ports are cast in the casting. I have made the cylinder from bar stock to the measurements required from the post from Jason so the same as the Stuart cylinder. The drawing from A A Rayman calls for a 1/8 th eccentric, so a 1/4 inch total, but if its the same cylinder then it should be 3/32 and not 1/8th, so if the 1/8th was used how can it work? the total length on A A Raymans drawing for the valve is 5/8 th.

Any help please, Bob    Nice pictures of your cars old School .

Edited By BOB BLACKSHAW on 31/10/2020 15:57:06

[JasonBModerator @jasonb]

You may have less lap on your alternative design of valve making it shorter and that would not require a smuch valve movement. Can you scan or post a photo of the valve on AAR's drawing.

[BOB BLACKSHAW 1Participant @bobblackshaw1]

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks Jason, if not I will scan it.

Bob

[Old SchoolParticipant @oldschool]

Bob

I have MAP Specialist Booklet No 9 High Speed Marine Steam Engine by AA Rahman, I can if you wish scan the relevant pages on the engine build if you pm me your email address.

Oliver

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks Oliver, I've got the the same book.

Bob

[JasonBModerator @jasonb]

Bob any chance of a close up of the port and valve sizes, they are a bit fuzzy when blown up then I'll draw it out in CAD

[alan-lloydParticipant @alan-lloyd]

I'm sure back in the 70s when I made a 10v the ports were not cast in the cylinder as they are nowadays

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Sorry for the delay Jason, My drawing shows that its the same as the Stuart cylinder drawing that you sent me the other day. My drawing is blurred but its 5/64 ths from edge of ports. Why a 1/8th eccentric on the drawing when it should be 3/32. Book states that the ports are cast in the cylinder.

Thanks Bob

[BOB BLACKSHAW 1Participant @bobblackshaw1]

[JasonBModerator @jasonb]

These sketched show the Rayman valve at the top and the Stuart at the bottom.

Firstly at full eccentric throw of 1/8" for the Rayman and 3/32" for the Stuart, Valve does come close to the cavity ends on the Rayman no wonder it says 7/8" FULL, actual port uncovered is very similar.

This shows the valve in the mid position, a lot less lap on the Stuart, quite a lot of exhaust clearance on the Rayman.

Edited By JasonB on 01/11/2020 17:33:18

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Thanks every so much for the cad drawings Jason. I am a bit lost by the port not fully uncovering when on the full stroke and bottom stroke,obviously if this is the case then this is what I am seeking on the valve set up now.

My past engines work great on a nebuliser but as they where assembled I could not see the valve movement with the ports.

Thanks Bob

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