Water Cooled Webster

[bmac2]

I was going to go with Viton rings but everyone is making cast iron so I thought I’d follow the crowd and give making cast iron rings a go. After all what else do you do with half a leftover dumbbell? Saw a tip on the internet that said to put a magnet under a paper towel helps control the mess when turning cast and gave it a try. I have one out of an old hard drive hidden under there and it didn’t catch everything but I must say it did help.

 

[bmac2]

Going with everything I’ve read on making rings for small engines, and having never tried it before, I needed 2, so I made 5.

 

[bmac2]

Piston 2.0 with its 5 little friends. I made the disk in the front with a recess the depth I need for the rings. I’ll just hot glued some sort of handle to the other side so I’ll be able to clean them up with some wet and dry.

 

[bmac2]

Hum, could be worth a try. I’ve had dumber ideas

 

[danstir]

I think you need to make the tool holder a magnet too.

 

[bmac2]

There is a proverbial ton of excellent information on this site especially with all the Nemett Lynx builds going on right now. And I’m probably going to use then but. Back in the Q&A part of this adventure in chip making “Kquiggle” out of Michigan sent me a good link with info on making piston rings.
https://sites.google.com/site/lagadoacademy/useful-links#misctools

 

[bmac2]

"Make piston rings easily" caught my eye. Though unconventional it did look a lot easier and if it doesn’t work . . . . I can just make new ones.

http://users.tpg.com.au/agnet/make%20piston%20rings.html

Please don’t shoot the messenger. I said at the start of this I was going to “try new things and push the envelope”



http://youtu.be/7oTV_0On_SU

 

[bmac2]

Well 2 are crap. Total eggs but the other 3 . . . . . don’t look bad
On the website I got this from it says to split the ring and have it hang on to a piece of metal the same thickness as the required gap. When the ring reaches the correct temperature it will just fall off and to let it cool slowly. He was making a much larger piston ring and using a much wider torch. As it shows in the vid I wasn’t getting exactly what I would call even heating and with these small rings I really don’t think they have enough thermal mass to keep them from cooling too quickly.
Hay It didn’t take long and it was sort of fun to try. Will these work? I’m not going to hold my breath. Worst case . . . spend $5.00 on another dumbbell. Or go with Viton . . . na.

 

[Mechanicboy]

Thick piston ring is not good idea.
The formula to make the pistonring:

Bore diameter / 25 = Pistonring thickness
Pistonring thickness = height of pistonring
Pistonring thickness x 4 = ring gap (mount the distance bit in the ring gap before heating up piston ring between 2 thick disk with bolt/nut to prevent distortion the ring by heat.)

It will give good compression and easy to mount on piston ring groove. Do not cut the piston ring, break off only due cast iron is fragile. Adjust ring gap with needle file to correct size due heat of expansion. In my engine ring gap is 0.02 mm when ring is mounted in the sleeve.

 

[bmac2]

Thick piston ring is not good idea.
The formula to make the pistonring:

Bore diameter / 25 = Pistonring thickness
Pistonring thickness = height of pistonring
Pistonring thickness x 4 = ring gap (mount the distance bit in the ring gap before heating up piston ring between 2 thick disk with bolt/nut to prevent distortion the ring by heat.)

It will give good compression and easy to mount on piston ring groove. Do not cut the piston ring, break off only due cast iron is fragile. Adjust ring gap with needle file to correct size due heat of expansion. In my engine ring gap is 0.02 mm when ring is mounted in the sleeve.

Hi Mechanicboy
I have no idea what I was thinking when I made those. Their too thick to even fit the piston groves. I’m not sure if it is the material I started with of the heat treating but the rings just break like grass. Thanks for checking in on me, I will be making some new rings.Thm:

 

[Brian Rupnow]

Rings should be made from grey cast iron. The method used in the second link, where the rings are wedged open with a piece of material and then heated singly until the wedge falls out is given in "The shop Wisdom of Philip Duclos." However the formula given for determining ring size is a bit complicated--you have to incorporate the thickness of the slitting saw used to slit the rings into the formula for the ring diameter. I fought quite a battle making rings over on my thread "Nemett Jaguar--Canadian Style". I lost, and had to resort to a Viton ring, but will try again. You might pick up some useful information on that thread.--Brian Rupnow.

 

[Mechanicboy]

Here is the link.. http://www.jerry-howell.com/PistonRings.html

Slitting saw is too coarse, better to break off. You can use cast iron from brake disc or old cam shaft as piston ring material.

 

[bmac2]

Rings should be made from grey cast iron. The method used in the second link, where the rings are wedged open with a piece of material and then heated singly until the wedge falls out is given in "The shop Wisdom of Philip Duclos." However the formula given for determining ring size is a bit complicated--you have to incorporate the thickness of the slitting saw used to slit the rings into the formula for the ring diameter. I fought quite a battle making rings over on my thread "Nemett Jaguar--Canadian Style". I lost, and had to resort to a Viton ring, but will try again. You might pick up some useful information on that thread.--Brian Rupnow.

Hi Brian – I’ve been following your build and I too may have to go with Viton but I’m going to go with a tried and true method this second go round. I may try to copy that carb.

 

[bmac2]

Here is the link.. http://www.jerry-howell.com/PistonRings.html

Slitting saw is too coarse, better to break off. You can use cast iron from brake disc or old cam shaft as piston ring material.

Jens – Thanks for the math and the link. I like the method Swifty used, breaking the rings on a taper. I’ve got a friend that teaches automotive at the local technical collage that owes me a favor or two. I think it’s time to give him a call.

 

[Swifty]

Bob, I feel that one great benefit of breaking the rings on a taper is that they will break at their weakest point. This could save a broken ring problem later. I realise that the cast iron should be homogenous and you should be able to break it anywhere with no weak points, but why take the risk.

Paul.

 

[Mechanicboy]

How to break off piston ring? The picture tell more than i can write.

 

[bmac2]

Damn Jens I’ve seen that before. Just can’t remember where

 

[bmac2]

Not much done today. The head is pretty straight forward and follows the original Webster plans (well, except its round) just drill, recess, and tap. I then used the head as a jig to drill through the cylinder and into the block

 

[bmac2]

Tapped the holes in the block and opened them up to clearance size in the head and cylinder and milled a flat spot for the manifold.

 

[Mechanicboy]

Damn Jens I’ve seen that before. Just can’t remember where

See after the list "Making piston rings" and find "Feeney" in this link: http://www.modelenginenews.org/techniques/index.html

With thin piston ring:

1. Less friction on cylinder wall.
2. Easy to assembly/disassembly the piston ring on the piston.