Valve chest covers

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Valve chest covers

Post  parador on Sun 22 Oct 2017, 5:37 pm

A week ago I spent most of the day with wet and dry 400 paper making sure the valve cover seatings were flat and smooth. Today when fitting the actual HP/LP covers I noticed that the cover plates were very bowed-especially the HP cover. Used a bench belt sander with good effect to get them really flat. Very time consuming but I guess necessary to get a good steam seal. Has anyone else had this issue?

The front of the covers have quite deep machining marks and as I plan to keep these bare metal and hopefully shiny they are going to take a lot of time and effort with wet and dry paper to get them ready for plating.

Also I have read some of the earlier posts concerning issues with the regulator. I don't really understand what the problem was, whether there was a fix or whether it is still recommended to put a cut in the regulator. The build instructions are silent on this. Could someone explain whether there is still a problem with the regulator please.

Kind regards
Martin

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Re Valve chest covers

Post  Simon C on Sun 22 Oct 2017, 9:30 pm

Hi Martin
I personally I did not encounter any problem with my Valve chest covers however they were slightly bowed but this was taken up by the gaskets that I made for them, and the closeness of the studs.

LynnR has done a post on here showing the use and cutting procedure for corn flake packets others have used Clinger(a pig to remove later) I used graphite material easier to clean later as it doesnít weld itself to the joint faces.

There is a grub screw blank in the block behind the valve covers at the 6 oíclock position and on my block this leaked slightly so its probably worth removing this and putting some steam seal on it before putting the covers on, saves disassembling later.

Simon C (A full roofer)
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Re: Valve chest covers

Post  Steve Traill on Sun 22 Oct 2017, 9:42 pm

I gasket everything with something like a cornflakes packet, any reasonable cardboard is fine, I tend to stick one side with hylomar and grease the other side. Always regrease when fitting & the gasket will last for ages.
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Re: Valve chest covers

Post  parador on Sun 22 Oct 2017, 10:51 pm

Thanks Simon/Steve
Good info about the grub screw I will make sure I put some steam seal on it. I will need to start thinking about gaskets then.

Any thoughts or info regarding a regulator fix -if needed?
Just had another look in the remaining 'bag of bits' and there is a regulator Spring but the build instructions are silent about a spring or where to put it.

Regards
Martin

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regulator

Post  Simon C on Mon 23 Oct 2017, 6:56 am

Good Morning Martin

The Regulator spring goes in the bottom of the nut 41118 to put downwards pressure on the hockey puck, you will need to take care not to turn the regulator shaft after you have fitted it as it springs out of place and may need disassembling to get it back in place.
I havenít filed a groove in the valve plate 41203 as I think that once driven a feel for the regulator position will come. I did spend a lot of time lapping in the puck and plate with 400 grit as in the instructions using a glass plate, a worthwhile effort I think.
My engine ran on air with only a couple of minor leaks to contend with but the regulator was fine without any problems. It also seems to work ok on my test steam a couple of weeks ago.
The main valves need to be a loose fit on the stems, the nuts either side of them should not hold the valves from moving in and out the springs being very fine. The nuts will however need to be against the sides of the valves to provide the longitudinal actuation.
Donít get to carried away with the chest cover gaskets at this point as the covers will need to be on and off a few times for timing etc. but donít forget the need for them before running for the first time.
Simon C (full roofer)
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Re: Valve chest covers

Post  sonick45 on Mon 23 Oct 2017, 9:08 pm

I went a different route regarding gaskets and used instant high heat/pressure gasket sealant.
Its like a sticky glue that when heated and under pressure cures like a rubber seal.

Loctite due a version which is rather expensive so I tried one from Eurocarparts for under a tenner for a can that will last ages.
Its a pressurised can so it is very easy to apply a thin bead where you want it. any access peals away when cured and doesn't stain.

I have had no issues with leaks up and down from full pressure and if you need access the plates just pry off with ease. cleaning the old material off is also very easy.
I have aplied it quite thick in places and it has cured and held with no problems.

I would recommend this product to anyone who doesn't want to faf around with cutting and replacing gaskets.
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Re: Valve chest covers

Post  parador on Tue 24 Oct 2017, 12:33 am

Thanks Simon C - that is very detailed and useful information. thanks

Sonic45 - I like the sound of that gasket product. Do you have a name please? I have some Locktite 510 which may be similar and which Steve B recommended but have yet to use it. I guess with a lot of these sealing products you can't tell whether they are any good until under steam. This will be an awful long way off at my rate of progress but I am enjoying the building.

Regards
Martin

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Re: Valve chest covers

Post  sonick45 on Tue 24 Oct 2017, 10:27 am

Loctite 510 is good but is expensive and messy. I use this with no issues. Easy gasket

Check the home page first for discount codes before purchasing
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Re: Valve chest covers

Post  Capricorn1 on Tue 24 Oct 2017, 12:38 pm

I would use a "proper" gasket material, such as Beldam Pilot 34, 0.75mm thick. There is no need to use any jointing past as it is designed to be fitted dry. If you clamp the valve chest cover on over the gasket on a piece of plywood you can drill through on a reasonably fast speed and get nice clean holes. Fit the covers loosely to keep any foreign objects out of the valve chest once you've set the valves, but as the boiler barrel will expand when in steam you'll need to check the valves again to ensure you get equal opening of both steam ports.


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Re: Valve chest covers

Post  sonick45 on Tue 24 Oct 2017, 1:10 pm

I used Beldam Pilotseal before discovering liquid high heat gasket as at £55 for a small sheet i know which one I would choose.
Its all down to personal preference in the end.
Both work just as well.
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Re: Valve chest covers

Post  Capricorn1 on Tue 24 Oct 2017, 6:25 pm

It is down to personal preference, and there's nothing wrong with using liquid gasket, I'm fortunate in being able to get off cuts of gasket material. When you've worked on hydrogen gas compressors that discharge at 273bar - or just shy of 4000 psi you tend to lean towards the higher spec' solutions.

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Re: Valve chest covers

Post  sonick45 on Tue 24 Oct 2017, 6:39 pm

affraid affraid affraid affraid affraid

Yeah not sure id be using liquid gaskets at 4000 psi !!!

I wouldn't be anywhere near it..
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Re: Valve chest covers

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