How low do you go??

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How low do you go??

Post  highpressure on Sat 15 Oct 2011, 6:25 am

Been on the slide bars again today having recieved and replaced the stripped thread with my helicoil kit. What a marvelous piece of kit this is and took no more than 5 minutes. Very Happy cheers

Just wondered how far those who have done so are going with shimming the slides. I have got to a point where there is almost no movement up or down and further 0.1mm shims cause lock up and have used a couple of baking foil shims as they can go from 0.01 up depending on how many times they sre folded but I still cant get quite all the slack out . Do we think that expansion when hot will loose this or even require shim removal?? In which case I will stop here until its runs on air to see how well it performs or if it needs more or less.

Also got all the cleading back from the powder coaters this week as well as the bowser but need to get some lining on before I post anything. Does look very good now though. Smile Smile

Cheers Kev.

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Re: How low do you go??

Post  lynnr on Sat 15 Oct 2011, 7:37 am

Hi

You will need some gap for slight heat expansion. I have been asking father on this. He was a chief engineer in the merchant navy. He also commented on the need for a gap to allow oil slip. Otherwise the crosshead will scrape the oil off the guides.

I have left a guiness tin gap in my shimms.



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Re: How low do you go??

Post  highpressure on Sat 15 Oct 2011, 8:21 am

Thanks Lynn, does that mean if you grab hold of the crosshead at the pin and pull up and down it give slightly and makes a tap sound? If so thats more than I have but I could make it less.

Cheers Kev.

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Re: How low do you go??

Post  lynnr on Sat 15 Oct 2011, 11:45 pm

Hi

Thats how mine is. When all dry you get a little tap tap when you force it up and down. When the oil is in place no sound as it effectivly hydralics to the guides.

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Re: How low do you go??

Post  FosterGP6NHP on Sun 16 Oct 2011, 2:29 am

.001" per 1" is a normal running clearance.

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Re: How low do you go??

Post  lynnr on Wed 19 Oct 2011, 3:31 am

Not how low this time but how loose on the crank. Mine is stiff but fairly smooth. You need 2 hands on the counter weights to move it round. Should this be looser?

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Re: How low do you go??

Post  highpressure on Wed 19 Oct 2011, 10:05 am

Mine turns fairly easily with two hands on either end, I have been working on making sure its at loose as I feel I should go as the heat expansion may play a factor. Plus I intend to run it on air to try and bed it in further.

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Bedding in

Post  Steve Traill on Wed 19 Oct 2011, 2:07 pm

I wouldn't have anything too tight to start with as heat could build up in the bearings & cause all sorts of problems. I tend to have it a little loose with shims but not enough to make it knock. Running in on air is not really practical, it is good to check the motion work & timing but that's about it. Most DIY compressors will run out of puff pretty quickly when connected to an engine this size. When steaming for the first few times don't expect to jump on it & run down the pub! I would run it in for 15 - 20 hours minimum with 60 - 80 lbs on the clock and let everything bed in nicely with the engine just ticking over. After each steaming one can tighten up any looseness by removing the shims and also attend to any minor steam leaks.

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Re: How low do you go??

Post  Alex-Jan on Wed 19 Oct 2011, 3:26 pm

I fully agree with Steve. Some years ago I was driving a full size steamroller witch was just restored. She was just a little bit stiff to handle. Later on, the same day I drove another roller, with has been parked after her last working day in a museum. She was rattling and puffing al over, but run as the best. So I donít panic if there is some little loose in a model as long there is no knock.

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Re: How low do you go??

Post  Tim Watson on Wed 19 Oct 2011, 3:40 pm

highpressure wrote:Mine turns fairly easily with two hands on either end, I have been working on making sure its at loose as I feel I should go as the heat expansion may play a factor. Plus I intend to run it on air to try and bed it in further.

Not a good idea to run for too long on compressed air, because the oil does not carry over effectively from the lubricator into the cylinder.

Tim

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