My very first Webster Petrol IC Engine

[Brian Rupnow]

80 Grit is WAY TO COARSE!!! Best results I have had is to use a cheap spring loaded expanding brake cylinder hone to do initial cleanup, then lap with a 400 grit lapping compound. Make the lap from a solid round bar of aluminum, about .001" smaller in diameter than the cylinder. The lap should be 2 or 3" longer than the cylinder. Coat the lap with compound and work it thru the cylinder by hand with a twisting motion. Once it frees up a bit, chuck one end of lap in the 3 jaw chuck on its lowest speed, hold onto the cylinder by hand, turn on lathe and work the cylinder back and forth on the lap for a couple of minutes. Be VERY carefull to not get wound up in the spinning cylinder.---Brian

 

[gus]

80 Grit is WAY TO COARSE!!! Best results I have had is to use a cheap spring loaded expanding brake cylinder hone to do initial cleanup, then lap with a 400 grit lapping compound. Make the lap from a solid round bar of aluminum, about .001" smaller in diameter than the cylinder. The lap should be 2 or 3" longer than the cylinder. Coat the lap with compound and work it thru the cylinder by hand with a twisting motion. Once it frees up a bit, chuck one end of lap in the 3 jaw chuck on its lowest speed, hold onto the cylinder by hand, turn on lathe and work the cylinder back and forth on the lap for a couple of minutes. Be VERY carefull to not get wound up in the spinning cylinder.---Brian

Hi Brian,

Thanks for the tips. OK will look for a brake cylinder hone. Bought some mini honing stones while shopping for hardware in Hongkong. Will cook up one if I cannot locate a spring loaded hone.Meanwhile I have some tough jobs to do.
Cutting the time gears would be one of them. The valve and carb next.

Regards,

Gus Teng.



Hi Brian,

Just ordered a small cylinder hone from UK. Hopefully will arrive in a week or so. Now to look for 400 grit lapping compound.

 

[Brian Rupnow]

Gus--this is the brake cylinder hone I am talking about. The shank fits in your electric drill. The 3 stones are set at 120 degrees apart and an adjustable knurled collar determines how much force the stones have applied to them. This device only costs about $18 Canadian. It should be used with lots of light oil, and medium drill speeds, not high. It is worked back and forth in the bore of the cylinder, with special care being taken that it doesn't come out of either end of the cylinder while still spinning. In fact the ends should only extend no more than 1/8" past either end of the cylinder while it is being used. It doesn't take much--about 30 to 40 seconds with this hone should be sufficient.---Brian

 

[gus]

Gus--this is the brake cylinder hone I am talking about. The shank fits in your electric drill. The 3 stones are set at 120 degrees apart and an adjustable knurled collar determines how much force the stones have applied to them. This device only costs about $18 Canadian. It should be used with lots of light oil, and medium drill speeds, not high. It is worked back and forth in the bore of the cylinder, with special care being taken that it doesn't come out of either end of the cylinder while still spinning. In fact the ends should only extend no more than 1/8" past either end of the cylinder while it is being used. It doesn't take much--about 30 to 40 seconds with this hone should be sufficient.---Brian

Hi Brian,

Ordered same from UK. Hard to locate here in Singapore.

Lapping compound. Was given a small can of "Chemico" Valve Grinding Compound with Coarse and Fine grit but no. indication.Will the fine grit do?

 

[Brian Rupnow]

Gus, I have no way of telling how "fine" your "fine" valve grinding compound is. I know the valve grinding paste I bought at the local car dealership was far to coarse, you could actually feel the individual bits of grit in it with your fingers. At a best guess, take a small pinch of the fine grit between your thumb and finger and rub your thumb and finger together. You shouldn't be able to feel individual granules of grit.

 

[ShedBoy]

I use this stuff
http://www.ctctools.biz/servlet/Categories

This company have great products and send anywhere quick.
Engine is looking great Gus keep it coming.

Brock

 

[metalmad]

H Gus
Going great Guns Mate
The Webster was my first Engine as well.
Pete

 

[gus]

Gus, I have no way of telling how "fine" your "fine" valve grinding compound is. I know the valve grinding paste I bought at the local car dealership was far to coarse, you could actually feel the individual bits of grit in it with your fingers. At a best guess, take a small pinch of the fine grit between your thumb and finger and rub your thumb and finger together. You shouldn't be able to feel individual granules of grit.

Hi Brian,

Bought 400# from the net. Will make the aluminium honing bat too,to do a good lapping job after the honing. I messed up the last aeromodel engine with wrong # lapping paste.

One of my senior/old air compressor repair man believes in having/using the right tool for a repair job. He was our best with return jobs.

Meanwhile ,will move on to machine other parts for the next two weeks.
The valve assembly and carb worries me.Too fine a job.

Come Monday will start machining the outer head.


Regards,

Gus Teng.

 

[Brian Rupnow]

Gus--Do you plan on using cast iron rings, or a Viton o-ring. I personally haven't had a lot of luck with cast iron rings, but have four different i.c. engines running successfully with a single Viton o-ring. The reason I ask is--If you are going to use cast iron rings, then you could quite possibly get by without lapping the cylinder. A good honing and then a relatively long (1 to 2 hours) running in time powered by an electric drill or belt from the lathe while everything is well coated with a light oil to "seat" the rings may be all you need. Its imperative to lap the cylinder if you are going to use a Viton o-ring, because any roughness in the cylinder will quickly tear up the o-ring. Conversely, if you use cast iron rings, you don't want the cylinder bore to be too smooth or the rings may never seat properly. The cross hatch pattern left on the inside of the bore by a hone will hold sufficient oil for lubrication, but still be "rough" (for lack of a better word) enough to "seat" the cast iron rings for a good compression seal.----Brian

 

[gus]

Gus--Do you plan on using cast iron rings, or a Viton o-ring. I personally haven't had a lot of luck with cast iron rings, but have four different i.c. engines running successfully with a single Viton o-ring. The reason I ask is--If you are going to use cast iron rings, then you could quite possibly get by without lapping the cylinder. A good honing and then a relatively long (1 to 2 hours) running in time powered by an electric drill or belt from the lathe while everything is well coated with a light oil to "seat" the rings may be all you need. Its imperative to lap the cylinder if you are going to use a Viton o-ring, because any roughness in the cylinder will quickly tear up the o-ring. Conversely, if you use cast iron rings, you don't want the cylinder bore to be too smooth or the rings may never seat properly. The cross hatch pattern left on the inside of the bore by a hone will hold sufficient oil for lubrication, but still be "rough" (for lack of a better word) enough to "seat" the cast iron rings for a good compression seal.----Brian

Hi Brian,

After many years in the small air compressor line and small petrol engines,I
am tempted to adopt Ingersoll-Rand practice to hone to cross hatch and run in to seat the rings. Piston rings came in from "Otto Gas" USA. With professinally made rings,i would have one less hassle.Keeping my fingers crossed. Been a good day's fishing with cool weather after a morning shower.Landed to goos size snappers for dinner at the marina. Life been good to "70" young man.
Today,will machine the outer head cum bracket support. Promised myself to do a good job.

 

[gus]

Cutting O/head blank was a breeze with a Bandsaw. Milled blank as per print.
Clamping on blank to a four jaw chuck will be a hassle to centre marked circle dead on. Came up with a spigot mounted on to spark plug hole.Clamping spigot on to chuck jaws at least gave me some assurance of running true.
Boring the blind hole to depth was another hassle w/o DRO. Came up using the slide end to indicate hole depth reached with dial set to zero. Did depth spot on but 5 thou deeper does no harm.The Warner Boring Bar performed well and blind hole was well finished with no chatter marks. I.D. was spot on with slide fit.
Having a set of Transfer punch sure help drill matching holes on O/head and cylinder.

Cylinder mounted on to engine base. Sos far so good. No reworks or throwaways.
Come tomorrow will go for less tedious but easy jobs like turning the Cylinder Lubricator and crankpin grease cup.
Will finish up the piston and con-rod. Both require some attention.Still trying hard not to rush.

 

[crankshafter]

Hi Gus.
Nice progress on the Webster.
Regarding honing/polishing the cyl. I made a expanding hone and medium then fine valvegrinding paste and then(don't laugh) thooth paste for the final high gloss surface. Remember cleaning the hone in betwin.

Ps..
This is of corse only needed if you are using Viton o-ring.
CS.

 

[gus]

Hi Crankshafter,
Thanks for the tips. I am using pistons from "Otto Gas" USA. The brake drum hone and #400 grit honing paste
coming in next week. Today,will cut piston. Now preparing Work Instructions(WI) to rout machine processing.

Promise will take more tea/pee breaks to rest in between.
To avoid last cut disaster will jot each diameter reduction. Doing this mentally was usually disastrous.

 

[Lawijt]

Nice work Gus.

 

[gus]

Took more half a day just to complete the piston and ring groove fitting.
Cross slide and sub-main slide with their dials zeroed in are very good options v/s the DROs.
Cut cylinder blank,cut ring grooves and underside void of piston,drill/ream piston hole for gudgeon pin etc.
With hand me down outside mike was able to cut piston O.D. spot on 0.873 "
The piston had too many details to be done . Any goof with one them would be disastrous

Will move over to mill con-rod. Jigs and fixtures required. W/o which con-rod will be hard to machine as per print.
Con rod will take at least three days to complete.

 

[Lawijt]

Put 1 drop of gasoline , put the piston to the sparkplug & fire this one time.......Yeah , you shoot the piston away.....And than it is time to catch a big blue Marlin.
What do you think about that Gus.
But you did again a really nice work.

 

[gus]

Recalled a young repairman using a piece of rag soaked up with petrol against the intake filter port to help start
a diesel engine. It won't start. He was about to put in a few drops of petrol into same intake port when I stopped
him. Took him to the staff canteen to hear him out.Then step by step analysed why same engine ran yesterday and today it just won't. Within an hour he came back and reported fuel line had airlocked due to aged fuel hose which had cracks.Engine got going.
Have heard of nasty accidents.Also heard of diesel engine fuel tank wrongly topped up with petrol. Engine blew
up.Marina was sued for damaged boat and injury.

Just some story from my working life.

 

[gus]

Con-rod looks very deceivingly simple to do but ended up doing it for two days. Took the whole of today
to complete. Fixtures was required to get a good job done. The big end and small end would difficult to get a good profile finish w/o fixture and Rotary Table which I DIY last year.See con-rod foto.
At 3 pm ,I got tired and housekeeping went overboard .When you have to turn over everything to find the 6 inch steel rule or centre punch,it is time to take a housekeeping break.
At 5pm after a good R&R got started with peace of mind to machine the crankpin grease cup.Typical of Gussy,he came up with his own UK type grease up.
Con-rod,piston and grease cup fitted on. Quite a long way to completion which be a month or two from now. Have to cut the pinion spur gear for the timing gear train.Gear cutters just came in. I have no gear cutting experience other than the spur gear cut in trade school 52 years ago.

 

[crankshafter]

Nice one Gus, keep up the good work.;D
CS

 

[Lawijt]

Great work done.