Author Topic: Webster IC Engine build log.  (Read 178871 times)

Offline sbwhart

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Re: Webster IC Engine build log.
« Reply #25 on: January 25, 2011, 01:44:07 AM »
Well done that man  :thumbup:  :clap:

Looks like all your preparation work paid off, thats the way to go :headbang: now you've got another technique in your armory.

Stew
A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline NickG

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Re: Webster IC Engine build log.
« Reply #26 on: January 25, 2011, 03:25:28 AM »
Yeah nice work chris, that's all worked out spot on and sure you'll use the bits many times again - look up on those as workshop tooling not part of the engine project.

Nick :thumbup:
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Offline Stilldrillin

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Re: Webster IC Engine build log.
« Reply #27 on: January 25, 2011, 03:34:58 AM »
 :clap: :clap: VERY nicely thought through, and put into practice Chris!  :clap: :clap:

Blummin well done!  :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline raynerd

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Re: Webster IC Engine build log.
« Reply #28 on: January 25, 2011, 10:00:11 AM »
Thanks for the comments guys.

Have any of you any advice when it comes down to piston rings. I have lapped the bore and in an earlier post I mode, I was kindly well informed that I should hone the bore if using cast piston rings and lap the bore if I was intending to use an o-rings. I intend to use vitron o-rings because I believe they will be a little more forgiving and easier to purchase - that said I`m not exactly sure where to buy one from!

I am also a little confused when it comes to dimensions...my bore is 7/8" = 0.875"

Brian Rupnow has posted some interesting info in his build log in which he explains he went for a 1/16" cross section (Which is apparently actually 0.070") and then posted these details followed by the image at the link below: The groove depth should be .055" to .057" and the groove width should be 0.095". 

http://i307.photobucket.com/albums/nn294/BrianRupnow/o-ring001.jpg


I`m not clear at all about how is based his decision on which ring to purchase... could anyone help me out here either with reference to understanding the dimensions or finding a reliable supplier?

Regards
Chris

Offline NickG

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Re: Webster IC Engine build log.
« Reply #29 on: January 25, 2011, 11:48:22 AM »
Chris, there is a lot of debate over this subject! I think there might be some info in the tiny i.c threads too. I'd be tempted to go for a lapped bore and cast iron piston with not much clearnace. I know Jan Ridders does that on his engines.

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Offline shoey51

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Re: Webster IC Engine build log.
« Reply #30 on: January 25, 2011, 02:55:38 PM »
a lovely solution to the problem there Chris  :thumbup: :clap:

cheers Graham

Offline Bogstandard

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Re: Webster IC Engine build log.
« Reply #31 on: January 25, 2011, 04:21:39 PM »
I would suggest you stick to the plans, and you will find that the the figures are almost the same as that person is showing.

Blackgates stock Viton o-rings, but I don't know if they do imperial. You will require, for a 7/8" (0.875" bore), a 3/4" (0.750") bore o-ring with a 1/16" (0.0625") cross section. The depth of the grooves in the piston give the correct wall pressure, so stick to what is shown on the plans, and if too much friction, you can always skim another couple of thou out.


Bogs
« Last Edit: March 06, 2011, 06:04:08 PM by bogstandard »
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Offline raynerd

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Re: Webster IC Engine build log.
« Reply #32 on: January 25, 2011, 04:50:32 PM »
John

Thanks for the advice. Just curious, what is your opinion on going with a CI piston, close fitting with no rings as Nick suggested. I did consider this but guessed there must be something wrong with the idea but looking at Jan Ridders plans for his simple IC engine, like Nick said, he uses this method. Or do you think O-rings best option?

Chris

Offline crankshafter

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Re: Webster IC Engine build log.
« Reply #33 on: January 25, 2011, 05:08:38 PM »
Chris.
Do it the way Bogs say. Alu. piston and viton O-ring. Regarding the piston. stick to the plans and you will be rewarded :head I used the Alu/O-ring on my Webster and it have been running for X numbers of hours and still  have the same good compresson.
Keep up the good work :beer:

Best Regards
CS

Offline raynerd

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Re: Webster IC Engine build log.
« Reply #34 on: January 25, 2011, 05:14:52 PM »
OK - thanks for that confirmation crankshafter. I will certainly go down that route. Thanks for the reply, always good to hear from people who have made the engine!!

Chris

Offline Bogstandard

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Re: Webster IC Engine build log.
« Reply #35 on: January 25, 2011, 10:43:39 PM »
As I have said many times before in different places, if it is a proven design, stick with it, do cosmetic changes if you want to, but leave the basic figures as they are.

Cast iron rings can be an art unto themselves, and to start learning new ideas and techniques half way thru a build is not something that you should be doing. Leave it to the end when you can concentrate on it a little more.

Once you have it running, THEN you can play around with a new piston and rings etc. Knowing that you can easily swap back if things don't work out.


John




If you don't try it, you will never know if you can do it.

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Offline NickG

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Re: Webster IC Engine build log.
« Reply #36 on: January 26, 2011, 06:34:36 AM »
True, many websters have been built and run. The guy mentioned has just finished another build log which I found quite infuriating - he didn't seem to listen to advice, even from people with vast experience of this, then he'd stumble across a solution in a later post and claim he'd solved the problem himself, whereas if he'd listened, he wouldn't have got into the predicament in the first place - anyway, rant over!

Out of interest though, how much clearance does it allow for an aluminium piston in cast iron cylinder? It must be right or they wouldn't run properly. When I tried that in my flame gulper it locked solid after a couple of mins - that is why you need rings with that method and presumably a hefty clearance built in. With iron and iron the expansion rate is the same, so you can go with a minimal clerance - that will also reduce friction compared to something with rings - more useful in hit & miss type applications where you want it to coast freely, shouldn't be a problem with yours.

Nick
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Offline raynerd

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Re: Webster IC Engine build log.
« Reply #37 on: January 31, 2011, 05:32:52 PM »
I have managed to get a little more done on the frames / supports for the Webster Engine. The first one to attempt was the cylinder support. I bored the blind 1" cylinder neck support in the 4 jaw on the lathe. I`m becoming increasingly fond of m  4-jaw, it use to scare me but now it is becoming a good friend! Sadly the material I was hoping to use for the cylinder support was not wide enough and the only thing I had wide enough was not long enough. As I didn`t want to purchase more materials, I have used what I have and added a brass rising block to increase the length.


Then for the long support whittled from this piece of ally:


All the parts resting on each other with a little block under the cylinder to stop everything falling over!




Parts so far:



I just need to decide on the base material now so I can start to bolt things down but I`m not 100% happy it is thick enough. I might just have to bite the bullet and and purchase something a little thicker - but that is going to cost :(







Offline DeereGuy

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Re: Webster IC Engine build log.
« Reply #38 on: January 31, 2011, 06:19:31 PM »
Chris,
Looking like you have a good start!  Mine is still sitting in a box with lots of parts....one day I may get my focus back on it and actually finish it.

Offline raynerd

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Re: Webster IC Engine build log.
« Reply #39 on: January 31, 2011, 06:44:30 PM »
Hi Bob, I was hoping this may inspire you to continue! I read all your build log posts before beginning mine and they helped a lot!

Chris

Offline DeereGuy

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Re: Webster IC Engine build log.
« Reply #40 on: January 31, 2011, 07:09:10 PM »
Chris,
Sitting here with a smile knowing those posts helped someone.  Thank you!

Offline NickG

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Re: Webster IC Engine build log.
« Reply #41 on: February 01, 2011, 04:51:05 AM »
Good work Chris, I reckon your base will be thick enough but even if not, a chunk of alloy won't be too much - don't think it was much for my flame licker.

Nick
Location: County Durham (North East England)

Offline raynerd

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Re: Webster IC Engine build log.
« Reply #42 on: February 01, 2011, 01:43:28 PM »
I`m looking for more help with sourcing an vitron o-ring if possible.

John has kindly informed me of the dimensions needed, being 3/4" (0.75") bore o-ring with a 1/16" cross section. I contacted Reeves as suggested however they informed me today via email that the o rings they supply would not be suitable for pistons and are used for waterpumps etc I would need a vitron o-ring!

Any more suggestions of suppliers of an imperial vitrol o-ring?

Offline NickG

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Offline raynerd

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Re: Webster IC Engine build log.
« Reply #44 on: February 02, 2011, 03:43:09 AM »
Cheers Nick, I`ve emailed them so hopefully I`ll get sorted.

Offline raynerd

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Re: Webster IC Engine build log.
« Reply #45 on: February 02, 2011, 04:07:48 AM »
OK, well this is from the pollymodel website:



Would any of these be any good, I get the option of the ID/bore being 3/4 but with either a 1" or 15/16 OD and also the cross section changes as well.

I don`t understand that, how can you have a 3/4" ID yet a 1" OD, does that mean the piston ring is 1/4" thick?? In which case neither of these 3/4" o-rings will fit my 7/8" bore  :scratch: :scratch:


Chris


 
« Last Edit: February 02, 2011, 04:10:40 AM by craynerd »

Offline NickG

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Re: Webster IC Engine build log.
« Reply #46 on: February 02, 2011, 04:18:17 AM »
Nice 1. I'd still be tempted to make the piston from cast iron with no rings. Infact for my first i.c. I'm definitely going to try a graphite piston before anything else. It seems to cope well with the heat on the flame gulper, the only question is whether it will cope with the extra force on it by the internal combustion. Over on HMEM a guy has used it in a 7/8" bore i.c though so pretty confident. The advantages would be great - low friction, good seal, no lubricant, no rings, easy to machine, light weight, no need to lap!

http://www.homemodelenginemachinist.com/index.php?topic=12591.0

Nick

ps no, it'd be 1/8" or 3/32" cross - section Chris!!  :poke:

You need the 11/16" x 7/8" and make the groove deeper / wider.
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Offline raynerd

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Re: Webster IC Engine build log.
« Reply #47 on: February 02, 2011, 04:28:27 AM »
 :palm: Nick, I still don`t get it! How can the inside diameter be 3/4" and the outside be 1" - that leaves a 1/4" which is the thickness of the ring or is cross section not the ring diameter!?!

Offline raynerd

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Re: Webster IC Engine build log.
« Reply #48 on: February 02, 2011, 04:33:16 AM »
Blackgates have just replied - but it looks like the same range:

www.raynerd.co.uk/wp-content/upLoads/orings-blackgates.xls

I`m totally confused  :coffee: :scratch: :coffee: :scratch:

Offline Bogstandard

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Re: Webster IC Engine build log.
« Reply #49 on: February 02, 2011, 04:40:15 AM »
A 3/4" ID ring having a 1/8" cross section.

So double the cross section (one on either side of the ID bore as it sits in it's groove), and that will give you 1" OD.

See C-o-C

I hope this explains things OK

Bogs

BTW, I told you what you need here

http://madmodder.net/index.php?topic=4232.msg46696#msg46696
« Last Edit: February 02, 2011, 04:45:34 AM by bogstandard »
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