Author Topic: james coombes. (Read 10870 times)

kellswaterri · « **on:** June 09, 2015, 10:53:20 PM »

Hi folks...back in the shed and finally have the Coombes finished...the little compressor unit is basically only for tyres or air beds and has not the power to turn over the engine, although it did give a few kick overs about half a rev...a few questions if I may ask...what pressure will i need to turn it fast enough ... 2nd & 3rd questions are related to the drawings...I started the build with the original first drawings...then a long break of a few years...when I got back in the shed the first drawing had faded with the sun new drawing had some valve gear linkage problems....so current situation ...not enough air pressure (run on steam)???...valve gear dimensions ...or possibly the occillator dimensions ...please can any one supply those dimensions from an engine which has been running...Cant be all that wrong if it tries to start???
all the best for now,
John...lancelot.

Jo · « **Reply #1 on:** June 10, 2015, 08:07:26 AM »

We don't accept excuses

Sorry I don't have a copy of the Coombes drawings

Jo

Ian S C · « **Reply #2 on:** June 10, 2015, 01:03:28 PM »

Sounds as though you just need a compressor with a bit more capacity, I found that the Stuart Turner S9 would just give a bit of a kick when hooked up to the 12v car tire compressor. My home made workshop comperssor had a job keeping up with the volume of air required, it only needed 10/20psi, just quite a bit of it. The James Coombs should only need about that pressure, maybe a fraction more until it frees up.
Ian S C

kellswaterri · « **Reply #3 on:** June 10, 2015, 03:21:32 PM »

Hi Jo and Ian...thank you for the speedy reply...I ran it on steam this after noon ...not a blooming twitch!!!It turns over quite freely I am beginning to believe that the throw dimension for the valve gear con rod is wrong and the steam valve is not getting enough movement in either direction...
a little bit of further work still...
John.

kellswaterri · « **Reply #4 on:** June 13, 2015, 07:14:52 PM »

hi folks...on further checking I got loan of larger compressor...made up a set of fittings for inlet.... checked for linkage looseness to valve gear applied pressure...the flywheel whipped round about just over 1/2 way...no amount of fiddle with eccentric sheave helped ...the problem I am fairly certain is the throw dimension in the new drawing I am working to supplements all previous ones including the build book ...(giving 11/64'')...THE NEW DRAWING HAS IT AT 9/64'' which is what I made the part to...I can now see that 11/64 '' is the more likely measurement so I will have to make a new one ...could anyone confirm 11/64''as the right dimension...
this would be most appreciated...
John.
Sorry Jo the photo machine is not playing fair at moment will keep trying...

smfr · « **Reply #5 on:** June 13, 2015, 09:54:04 PM »

My 1977 plans for the James Coombes show the eccentric throw as 9/64". I haven't built it yet, so I can't verify that this is correct!

But if you throw is wrong, it should just affect the valve travel. Is the valve fouling the inside of the valve chest, or is there interference on the outside? A bit of inspection while turning it over by hand should tell you why it's not running.

Simon

kellswaterri · « **Reply #6 on:** June 14, 2015, 08:33:37 PM »

Hi Simon...my drawing is 1993 issue and still gives 9/64'' as throw... the valve s are ported in the cylinder already when kit was supplied inlet valves 3/32'' with 3/8'' between top and bottom...the exhaust port is 3/16'' (careful...right on centre line of centre two stud holes for the valve chest...
LOVELY......cheers...John.

AOG · « **Reply #7 on:** June 14, 2015, 11:14:46 PM »

Quote from: kellswaterri on June 14, 2015, 08:33:37 PM

Hi Simon...my drawing is 1993 issue and still gives 9/64'' as throw... the valve s are ported in the cylinder already when kit was supplied inlet valves 3/32'' with 3/8'' between top and bottom...the exhaust port is 3/16'' (careful...right on centre line of centre two stud holes for the valve chest...
LOVELY......cheers...John.

have you checked that there is no moulding sand in the passage ways? Pull the end covers off and try to blow air into the ports and see if you can feel it come out the cylinder. If not the ports are probably blocked with sand. Get a piece of wire and clean them out.

Tony

smfr · « **Reply #8 on:** June 15, 2015, 12:27:55 AM »

Quote from: kellswaterri on June 14, 2015, 08:33:37 PM

Hi Simon...my drawing is 1993 issue and still gives 9/64'' as throw... the valves are ported in the cylinder already when kit was supplied inlet valves 3/32'' with 3/8'' between top and bottom...the exhaust port is 3/16'' (careful...right on centre line of centre two stud holes for the valve chest...

Those dimensions agrees my my plans too. Any luck?

Simon

kellswaterri · « **Reply #9 on:** June 15, 2015, 10:43:57 AM »

Hi Folks...just off the phone to Stuarts ...picking their brains ...after checking what was done and my description of how the engine reacted to pressure he said it should work just fine on 9/64''.....but he thought same as you Tony sand possibly partly ckocking the port passages.
back soon...with good news I hope...John.

Jo · « **Reply #10 on:** June 15, 2015, 10:52:52 AM »

Quote from: kellswaterri on June 15, 2015, 10:43:57 AM

back soon...with good news I hope...John.

AND PHOTOs

Jo

Stuart · « **Reply #11 on:** June 15, 2015, 12:44:20 PM »

John

If you are a win doze user ( I am not )

This site will help with the valve gear dims

First lot are DOS. But the windoze

files are lower down

They will show with reversing ,but put in the dims and see if it will work try both sets and look at the difference

Stuart

kellswaterri · « **Reply #12 on:** June 17, 2015, 12:03:12 PM »

not possibly the correct thing to do ...having some difficulty ...latest photo to go.....

C:\Users\John\New folder (2)ME ONLY\2015-05-17\Phone\DCIM\Camera\20150426_170825_2.jpg

Jo · « **Reply #13 on:** June 17, 2015, 01:05:58 PM »

John you need to insert that link into the add attachment box below the box where you type in your messages before posting. The we will be able to see the Photo

Jo

kellswaterri · « **Reply #14 on:** June 17, 2015, 02:19:27 PM »

trying this''......head sore now ...think I will go and lie down......

Jo · « **Reply #15 on:** June 17, 2015, 02:32:26 PM »

Looking all nicely engine shaped

.

Now that you have worked out how to do it

Could we have a couple of others

Jo

kellswaterri · « **Reply #16 on:** June 17, 2015, 02:52:53 PM »

Jo · « **Reply #17 on:** June 17, 2015, 04:15:10 PM »

I do that: link to the same photo twice

Do you have any.. different photos of it

Edit: that's better you can see the whole engine

Jo

kellswaterri · « **Reply #18 on:** June 17, 2015, 08:43:55 PM »

some more as i can catch them......

kellswaterri · « **Reply #19 on:** July 22, 2015, 09:40:59 PM »

Hi folks,...i have put the Coombes to bed for a while and have cleared the decks to do some work on building the corliss......milled one of the bed plates to size after marking out the points to mill to...a lot of working out the dimenions ...definetly not a stuart and turner jobby...went to one of our local Dentists and Scrounged about a dozen tiny little Tungsten ( i think ) ball ended rotary burrs ...they are perfect for spotting or starting holes in awkard positions I used the Cowells mill with a cutter normally used for cutting Carbon fibre ...like a knife through butter the set up for the slide bed will be some what tricky I think,
Cheers ,
John.

Jo · « **Reply #20 on:** July 23, 2015, 07:27:48 AM »

John are you going to start a seperate thread about your Corliss engine?

You might even convince me to get on with building my

huge one .

Jo

kellswaterri · « **Reply #21 on:** July 23, 2015, 08:57:58 AM »

I will more than likely do just that...invested in a descent calculator and a couple of (crap,o cad) Pukka pads one pocket sized...I have a brand new Bosch industrial l electronic \router, which i am going to make a rig to allow for more milling ops ...will see how that works...currentlu browsing fora build sequence ...if I can find one.

cheers,
John.

b.lindsey · « **Reply #22 on:** July 24, 2015, 12:32:47 AM »

Another Corliss....will be looking forward to that!!

Bill

kellswaterri · « **Reply #23 on:** July 25, 2015, 11:27:57 AM »

Putting the Coombes to bed for a while ......Over to the Corliss build,
Good night folks.
Kellswaterri.

kellswaterri · « **Reply #24 on:** September 15, 2015, 06:45:56 PM »

Hi folks...back in shop again..Corliss cylinder on hold while i make a parellell long grinding tool from a tapered stone !!!I am going to try grinding out the hard spot'''anaway ,
now back on the ''James Coombes''...had to make a new ocillator sheave out of bronze...and make good fit to the big end. some minor faffing about and then I gave itfull power from my new compressor...AMAZING!!!the reluctant sod actually works ...I ran it while yelling at top pitch for a photo or videoAll cloth eared ?***!!It eventually slowed down and stopped ...I found that the slotted grub screw was notholding the sheave so need to obtain someallen type grubs...
The bit that I am happiest with is that my design changes work...
All the best for now...
John.

Admiral_dk · « **Reply #25 on:** September 15, 2015, 08:20:08 PM »

Great - looking forward to the video.

kellswaterri · « **Reply #26 on:** September 16, 2015, 03:44:33 PM »

Hi folks...I have just made a video of the engine running...I hope that I can show it here...

firstly not having posted a video to a forum , how do I go about doing so
John (kellswaterri)

Jo · « **Reply #27 on:** September 16, 2015, 03:49:02 PM »

Hi John,

A runner

You need to host the video on something like Utube and then provide a link to the address (URL) in a post here if you look above the smilies there is a button which adds the characters to the address to make it work on the forum.

Jo

kellswaterri · « **Reply #28 on:** September 16, 2015, 05:26:27 PM »

[youtube1]

<a href="https://www.youtube.com/watch?v=_bvYfiyr9jc" target="_blank">http://www.youtube.com/watch?v=_bvYfiyr9jc</a>[/youtube1]

Hi folks ...as I have not tried this before ...Here's good luck...
Kellswaterri.

Jo · « **Reply #29 on:** September 16, 2015, 05:33:11 PM »

A runner

I see you find focusing the camera as challenging as I do

Is there an automatic focus setting I find using that helps no end.

Jo

Roger B · « **Reply #30 on:** September 16, 2015, 06:11:58 PM »

Well done

A runner is always good

kellswaterri · « **Reply #31 on:** September 16, 2015, 09:53:01 PM »

Yes Jo, it is both auto and manual focus ...i had it set on manual with out checking ,it was mounted on a tripod behind me and i had to use a mirror to see what was on the screen,then switched over to auto ...U tube did a pretty good job of tidying up my efforts ,...thanks U TUBE...i have just ordered some grub screws in BA sizes...and am realizing that BA material is almost a bad word to traders ...I could obtain a box of 200 easily enough 30 of them ...different story same with silver steel rod ...It is rather costly investing in new metric tooling.
cheers,
John. (Kellswaterri)

kellswaterri · « **Reply #32 on:** September 21, 2015, 03:36:54 PM »

S.O.S.####
Spent about 3 hours on the net , trying to obtain NO 5BA...grub screws steel allan key type could anyone tell me of a stockist or spare me a couple,,,the occilator sheave keeps slipping as those ruddy slotted ones are not up to holding.

all the best ,
Kellswaterri John.

Jasonb · « **Reply #33 on:** September 21, 2015, 03:43:37 PM »

http://www.ba-bolts.co.uk/grubs.html

kellswaterri · « **Reply #34 on:** September 25, 2015, 10:53:43 PM »

Hi Jasonb...just obtained some no 4 and no 5 grubs
cheers,
John.

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Author Topic: james coombes. (Read 10870 times)