Sunbeam S8

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bobolob
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Sunbeam S8

Post by bobolob » Mon Dec 01, 2014 2:13 pm

Hi there
I have converted my Sunbeam S8 to diesel. The engine is a VM of 500cc theoretically 10 – 12hp. The engine is rubber mounted and with an amount of modification fits the frame really well. If you were to look at it you would not know it is a diesel as there is no fan. All this is good but now the bad bit. On Saturday I decided to take it for a run down the street. There is very little vibrations but very little power. If I say a dumper truck would be faster you probably get the idea. The engine just will not rev, now the engine was used as a generator so the stops were set for that RPM. The engine has a governor on bob weights that come out as the engine RPM rises it turns the pump fuel down. The throttle loads the actuating arm controlling the engine speed. If I open the throttle effectively loading the governor nothing happens. I have cleaned the injector in petrol and then lubricated it with diesel oil. I have not checked the spray pattern. The white smokes comes out of the exhaust (which has no baffles). I would suspect the injector but is it more fundamental like the type of pump or the control method I have used.
Bob

gilburton
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Re: Sunbeam S8

Post by gilburton » Mon Dec 01, 2014 6:01 pm

Don't know about this engine but white smoke indicates unburnt fuel so could be injector or possibly low compression eg rings/piston/valves.
Take out the injector and check the spray pattern.
Stick it in a bottle for safety. I know it's not an accurate check but you'll soon know if its not right.

tonyd
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Re: Sunbeam S8

Post by tonyd » Mon Dec 01, 2014 10:38 pm

I have used Liquid Moly diesel purge. This is used instead of diesel, no dilution and it restored performance and took away an awful knock I was getting. Of course when I say performance I use the term loosely.
Tony

sbrumby
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Re: Sunbeam S8

Post by sbrumby » Mon Dec 01, 2014 10:44 pm

white smoke can also be injector timeing, just put another engine in my JCB cause mine welded itself together. I saw the engine run with cluods of white smoke, bought it anyway, altered the timing and now it runs fine with no smoke.
Sam

gilburton
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Re: Sunbeam S8

Post by gilburton » Tue Dec 02, 2014 1:41 pm

Oh and keep clear of the Sunbeam owners club :D

bobolob
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Re: Sunbeam S8

Post by bobolob » Tue Dec 02, 2014 9:57 pm

Just a quick update. Took my injector out and it squirts very nicely out of the four holes. I decided to take my pump out and suspect the problem was the fuel lever on the pump was not engaged in the throttle mechanism. Reassembled it all, primed the pump and now it makes a chirping sound which should be good. I will have to wait till Saturday to test run it as I cannot start it with the pull cord because I have removed most of the flywheel. I will get it dragged around the block and try again.
Bob

tonyd
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Re: Sunbeam S8

Post by tonyd » Tue Dec 02, 2014 10:06 pm

Was that a tongue in cheek comment about the Sunbeam Club. I had an S7 deluxe and found them lovely people and not adverse to some interesting specials. They have a brilliant old school type of Annual Rally with lots of silly fun.

gilburton
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Re: Sunbeam S8

Post by gilburton » Tue Dec 02, 2014 10:34 pm

Yes it was lol
I know in the past that there have been Beetle and 2cv engines transplanted.
Like everything else though as the years roll by they are getting rarer.

pietenpol2002
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Re: Sunbeam S8

Post by pietenpol2002 » Wed Dec 03, 2014 4:49 am

I know in the past that there have been Beetle and 2cv engines transplanted.
With this being one of my 2cv faves. If for no other reason than the hand start.

http://sakeracers.blogspot.com/2014/06/ ... wered.html

But now back to the diesel build. Which model of the VM are you using? And we desparately need some pics.
Ron
Goshen, IN USA

bobolob
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Re: Sunbeam S8

Post by bobolob » Wed Dec 03, 2014 7:21 pm

Hi again
I will post some photos of the engine installation and more details of the engine at weekend. I am thinking of putting a starter motor on the front using a sprag clutch arrangement. Has anybody done this as trial and error with ratios is a bit of a drag. Regarding the sunbeam owners club or as they call it fellowship, they actively encourage modifications and on their stand at Stafford there is always interesting modifications. If you are looking for a club that is up its own ‘---‘then it’s the velocette owner club for you. I have four Velos from cammy to Thruxton for over thirty years covering over a hundred thousand miles and I am still an outcast. I think the problem is I actually use them all year round come rain, snow or ice I am out there pounding the road.

albertaphil
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Re: Sunbeam S8

Post by albertaphil » Thu Dec 04, 2014 1:54 am

So the sunbeam with the 2cv on sakeracers...how hot sites that rear engine cylinder get; tucked in there out of the wind with no cooling fan. ..

pietenpol2002
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Re: Sunbeam S8

Post by pietenpol2002 » Thu Dec 04, 2014 3:36 am

tucked in there out of the wind with no cooling fan. ..
It might push the concept of "cooling fan" a bit, but if you look behind the grid on the end of the crank you'll see a little fan that feeds the tin in front of the rear jug. Might we consider that a "cooling fan"??? Sort of???? Click on pic to enlarge and then I'll stop for fear of highjacking this thread.
Sunbeam.jpg
Ron
Goshen, IN USA

albertaphil
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Re: Sunbeam S8

Post by albertaphil » Thu Dec 04, 2014 4:27 am

Wow. I remain skeptical but it must work well enough. I love the bike though.

bobolob
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Re: Sunbeam S8

Post by bobolob » Sun Dec 07, 2014 10:15 pm

Hi again
I am not having much luck getting my engine to rev. I now suspect the pump, I striped the thing down to see how the valve works. What I found was the plunger has a slot cut in it with a shaped slot around its body. Now when I have messed with fuel systems like the Wal-Phillips Fuel Injector which uses a snail slot that gets deeper in a symmetrical spiral. The slot in my diesel pump is in tow steps. Now is this normal or is this the plunger valve for static engines and if so where can I get the correct one.
Bob

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