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Old 03-10-16, 09:46 AM   #1
mervyn cloake
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Default !2 Hp Blackstone

Over the years I have had to solve problems and get hot bulb Blackstones' running for their owners and I have often had to do fine tune others at rallies.

This engine was well known to me as some years ago I had to solve a small issue with it. three weeks ago it was delivered to my workshop by a very frustrated owner who had become very frustrated with hard starting and erratic running. it would not run without the lamp going all the time.

In my experience a Blackstone when set up correctly will start very easily and will never miss a beat running. In cold windy conditions running without a load they will get cold and will require some extra heat now and again.

The first thing to do is to check all the fundamentals, I always start with the valve timing. This being an early one S/n 42360 it had the Air valve on the opposite side to the side shaft so the push rod ran underneath the cylinder.
What we found was there was when it was restored by the first owner a new push rod had been made we determined that it was too long so the result was the air inlet timing was incorrect It was opening early and closing too late there was no means to adjust it so it was shortened by about 4mm.

the next move was to inspect the hot bulb. Although only one coil is required it did have two but the one in the ignition chamber was welded to a bolt that went through to hold the heat shield on. Not normal! so the bolt was taken out.
Shining a torch through into the cylinder I believed I could see issues with the Timing valve, but we decided to try to give it a run. The timing valve was sticking so we disconnected it in the open position.
It fired up on the first compression and ran but soon became apparent that all was not well as there was no forgiveness when the timing valve moved manually.
I checked with the owner to see if the timing valve was original as I was suspecting it was a replacement and not correctly made. He confirmed I was right. When removed it was found that it not enough had been machined out of it with consequence that the opening through into the cylinder was restricted and very little movement closed it right off.

This was rectified and some time was spent to get it to rotate freely then the next attempt to start it again was successful. This time there was a healthy bark coming from the stack and it ran for two hours without additional heat firing on every fifth or sixth cycle.

This engine should have never run the way it was set up. The original owner made a beautiful job of the restoration but fell short on a few details.

Merv.

Here is a video and a photo

https://youtu.be/8lU0LDgJ6NQ

[IMG][/IMG]
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Old 03-10-16, 11:10 AM   #2
Paul_Sterling
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brilliant work Merv, impressive investigation skills.

Paul.
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Old 13-05-17, 12:40 PM   #3
blackstoneman
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Default Blackstone timing

Hi Mervyn
do you know if the valve timing stated in one of the later instruction booklets for engine with inlet valve on top of the cylinder is the same on the earlier engines with the horizontal inlet valve close to the sideshaft.On my 2hp 1905 engine,if the exhaust valve is set to open at 45 degrees before out dead centres per my book and with my later 1911 3 hp engine ,the inlet valve timing is wrong, so is the valve overlap. I have slid the crank skew gear along the shaft to slightly vary the timing and it runs ok but is not as per later instructions,any ideas?
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Old 14-05-17, 11:54 AM   #4
mervyn cloake
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It is not easy to sort an engine out from the other side of the world.
In my experience many Blackstone owners do not fully understand how their engines work.
First off, the so called timing valve's purpose is to prevent pre ignition when the engine is hot and under load under a load. it has no effect on the engine timing and it can be disconnected in the open position with no adverse effect.

Secondly the valve timing is fixed so long as the marks on the side shaft, crank shaft and the main journal opposite the side shaft, all line up. Minor valve adjustments can be made with the valve clearance. The governor must be fixed in the correct position with the grub or set screw seating on the flat on the side shaft.

The opening position of the timing valve is not critical, it only needs to open somewhere about where the book says and I would think both engines would be the same as the principal is the same on all the engines. there is a lot of room for adjustment. Some of the later Blackstone's from about 1913 onward don't have that valve but use a water drip to control pre ignition.

The starting point for me, with what you have described would be to check the timing marks and the valve clearance. You shouldn't have to shift the skew gear.

As an aside the fuel mixture can be altered to suit the fuel being used by adjusting the fuel valve and the air valve clearance.

I hope this will help so let me know how you get on.

Merv.
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Old 18-05-17, 08:42 PM   #5
blackstoneman
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Default Blackstone timing N McB

Hi ,thanks for the reply, My question was really not how to run a Blackstone,but why is the 2 hp engines timing wrong to the instructions,i have owned and run a 1906 4 hp,a late type 21/2 hp and still have the 1911 3 hp,all of them ran very well and the timing on all three was as per instructions, the only differences with the 2 hp is that it is an earlier engine,with the air inlet valve operated by a small bronze rocker casting,the air inlet valve being mounted on the side of the engine, All of the timing marks,a stamped O are in their correct positions .There is no sign of anyone altering the positions of the cams on the camshaft in the past,I just wondered if the early 2 hp engines were timed differently to later engines.There is a possibility of course that the engine erectors got the cam position wrong during its assembly when new,Blackstone were not perfect in the early days,I have found some iffy examples of engineering,e.g. tapped holes not square ,and two examples of connecting rods having a set put in to get the rod in the centre of the piston. The engine ran ok last year but did not start easily, despite a rebore and new piston,which was at the time disappointing,with my slightly revised timing the engine has started first time at two shows recently and ran very smoothly,cold weather and rain not affecting the hot bulb,
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