.......oh crap! Help please????

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.......oh crap! Help please????

Post  TheFodenBrothers on Sat 07 Mar 2015, 10:33 am

Hi all,

Me and a friend are currently building the 4.5" foden c type and are in the later group up to kit 22.

Last night we went to run the engine on air but immediately hit a problem. When we try to pressurise the boiler (we're doing it via one of the holes in the top cylinder block cover) all of the air immediately comes straight out of the exhaust (that vents to the chimney).

I am now seriously doubting myself that I have missed something! I am missing the instructions from kit 12, was that the cylinder block?

Are there any plugs/grub screws that have to be put into the cylinder block before fitting to the boiler that I may have missed? What could be causing this issue?

Any help from anyone is greatly appreciated.

Andy

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Re: .......oh crap! Help please????

Post  mikero on Sat 07 Mar 2015, 1:52 pm

Does the sound of the hissing change if you turn the flywheel Andy, that would tell you if it was coming via the cylinders and valves? I can't remember any blank off apart from the plug on the opposite side to the exhaust port.

Mike

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Re: .......oh crap! Help please????

Post  TheFodenBrothers on Sat 07 Mar 2015, 3:28 pm

Absolutely no change if we turn over the engine. The strange thing is that if we inject air straight down the boiler holes it comes out of the exhaust like it is open to boiler pressure? Which makes me think that we have missed some cylinder plugs? We have also tried sealing the regulator valve with paste.

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Foden Cylinder

Post  atomenter on Sat 07 Mar 2015, 11:45 pm

Hi Guys
There are 2 x 1/4" BSP plugs to be fitted to the underside of the cylinder between it and the saddle as well as a 3/8" BSP plug on the side of the block.
There are also 2 M4 grub screws in the top of the cylinder.  Hope this helps!!
Regards
Tom

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Re: .......oh crap! Help please????

Post  TheFodenBrothers on Sun 08 Mar 2015, 12:25 am

Hi Tom,

Thanks for your message, that would be it! We have some how missed those Sad.

This is going to be a huge job!

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Re: .......oh crap! Help please????

Post  Sick of brasso on Mon 06 Apr 2015, 7:06 am

Also check you havent nipped the slide valve on the spindle with the locking nuts. It should be able to float very slightly so the pressure can push the valve onto the face.

jamie

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Re: .......oh crap! Help please????

Post  TheFodenBrothers on Mon 06 Apr 2015, 7:23 am

Hey guys, thanks for all your help and replies. This has now been resolved. After a short phone call to STW it was definitely the two grub screws we missed out on the underside of the cylinder block. Everything from crank, motion gear, pistons etc all had to come off the boiler to fit and then reassemble.

Although sounding like a complete nightmare it was actually all done in about 4hours.

The engine is now running bbeautifully on compressed air and will tick over on as little as 10psi

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Re: .......oh crap! Help please????

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