Author Topic: Webster I/C Engine - Mike's 5th Engine  (Read 922 times)

Offline mikehinz

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Webster I/C Engine - Mike's 5th Engine
« on: January 21, 2019, 01:16:06 AM »
This is probably a bit of insanity on my part but I decided to build 2 engines sort of / kind of at the same time.  I decided that my 5th engine was going to be an I/C engine and the common wisdom on the internet said that the Webster was the best 1st I/C engine to start with.  I considered several, including one of the Upshur engines, a Kerzel, or maybe the Howell Powerhouse.  But based on the volume of builds that I found and a careful examination of the various plans, lead me to decide on the Webster.  I have most of the raw stock needed but I'll have to order ignition parts (most probably the S/S CDI system) and a carburetor.  I'll also go for a Viton o'ring vs CI rings. 

Since I tend to model everything I build, I also figured that process would give me something to do if I wasn't working on the PMR #1 engine.  I'd just had a substantial bit cut off my back and raising my left arm is difficult at the moment so I figured the CAD work and drawing preparation would be a good fill-in.  My plan didn't exactly go to schedule as I guess I'm getting better at Fusion 360 modeling.  I substantially finished the CAD model yesterday and today and got it pretty well animated in order to check for any interference.  And here it is!  I made the cylinder semi-transparent just to show the movement a bit more clearly. 


I've started on the 2D drawings but they'll take me a bit to complete.  I also order the gears, ignition bits and carb this coming week. 

Also, I will need to ask a few question on this engine as there were some places that things weren't completely clear to me on the original drawings and during the modeling process I didn't fully resolve the issues.  So maybe tomorrow I'll post to this thread with my initial set of questions.

All for today!

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline b.lindsey

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #1 on: January 21, 2019, 01:39:57 AM »
Good choice Mike. Will be looking forward to the build.

Bill

Offline mikehinz

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #2 on: February 13, 2019, 04:10:15 PM »
Well, I've not been on the forum for  a bit of time due to various personal issues going on but I did managed to make a bit of progress on this engine build and so I thought I'd do a quick update!

I had the 4J chuck installed doing some other work so I decided to start on the Webster flywheel.  My brother had given me a few old cast iron weights for raw material, so I decided if I could use one of those for the flywheel. 

I didn't take a pix of the flywheel before I started but here the first pix after i got a start on the first side.  I chucked it up in the 4J gripping a little less than 1/2 the width and turned the OD down to 3.85" (just a bit larger than the print calls for) and turned the very rough thru-hole to just under 1.5".  My theory is that I'll turn a plug to the required dimension(s) and press it into place.  My brother has a large hydraulic press and I think using that plus some Loctite I can get the plug to be secure within the body of the flywheel. 


After i finished the first side, I turned the casting around in the 4J and indicated the center to run true using a DTI plus I spaced out the raw piece using a thick feeling gage. 


A 2nd pix of the process I used.


Lastly the part laid on the print.  The ID is about 1.47" and I've ordered some 1.5" stock to use to make the plug.  I'll show that operation as soon as the material arrives.


All for now.  I do have a few questions on this engine but I'll ask those in a separate reply so as to avoid confusion.

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #3 on: February 13, 2019, 04:43:41 PM »
All, I've come up with a few questions on the Webster that I thought I'd ask the group about.  Here goes:

On the valve guides, the original print calls for 'bronze/brass' which I take to mean either is acceptable.  I have on hand 3 materials, 360 brass, SAE660 bearing bronze, and C954 AL bronze.   These progress from quite soft to quite hard.  Which material would be preferred? 

On the valves, I have 2 questions.  First the valve stem diameter is spec'd as 3/32"  That's quite small!  I was thinking about going to 1/8" but that makes the valve guide get quite thin in places.  What's the wisdom?  Keep the stem diameter at 3/32"

On the valve construction.  I've read a lot of posts on this and Mr. Brian Rupnow certainly advocates for turning the valves out of a single piece of materials.  But others call for 2 pieces silver soldered together.  I'm sort of leaning toward the silver solder process but wanted to ask everyone's opinion on the best method at these very small sizes.

Carburetor.  I don't want to attempt to build one on my first IC engine.  Model engine carbs seem popular and are reported to work well.  Several carbs are mentioned:  the Traxxas 4033 (6mm bore), Joe Webster recommends a '4 or 5mm bore' carb, and S/S Machine sells both 3mm and 5mm bore carbs.  Various posts talk about smaller bore carbs being better.  So, what's the best?

Finally, on ignition systems, I'm heavily leaning to the go with the S/S Machine CDI setup as it's very compact and seemingly reliable.  Any opinions on this vs standard points based ignitions or other electronic ignitions? 

Thanks in advance for any and all help and feedback!

Mike
MIke
Wichita, KS, USA

Offline b.lindsey

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #4 on: February 13, 2019, 05:28:32 PM »
Hi Mike, here's my 2cents worth. On the guides I would use the bearing bronze, keeping the valve stems at 3/32" and made in one piece. Can't comment on the carbs as I haven't used purchased ones yet. As for the ignition system, I am a big advocate of the S/S system, simple, neat, and reliable, with the usual disclaimer.

Bill

Offline Brian Rupnow

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #5 on: February 13, 2019, 08:22:49 PM »
I make my valve cages from cheap, run of the mill brass. I turn my one piece valves from cold rolled steel. There is a good reason for this. Even the best lapped valves will leak "some". BUT--Once the engine fires up the first time, the force of the rapidly expanding gasses in the cylinder will drive the steel valve into the seat so hard that the brass will deform a little bit to perfectly match the steel valve, and the seal between the valve and the cylinder will become a perfect air tight seal. Stick with the 3/32" diameter valve stems. The Traxxas carb you mentioned works well on the Webster. As far as the ignition system goes, I prefer t use an old fashioned points and condenser from an early 1970's Dodge or Plymouth. The trouble with CDI systems is that they are very easily damaged by any unintentional grounding, and this damage is not visible. This is guaranteed to make you absolutely crazy when your engine won't start and you can't figure out why. The use of ignition points may be somewhat outdated, but they are almost indestructible and easy to tell if they are working or not.---Brian Rupnow

Offline Ye-Ole Steam Dude

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #6 on: February 13, 2019, 08:24:30 PM »
Hello Mike,

I am following your build and hope you get lots of replies on your questions and their reasoning on each issue.

Have a great day,
Thomas

Offline mikehinz

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #7 on: February 13, 2019, 08:32:42 PM »
Bill, Brian, thanks very much for your replies and information.  It's very helpful! 

Using the 360 brass for the valve seats makes sense from the 'i want it deform just a bit' standpoint.   I think I'll start with that and if necessary, I think i could change the seats out with a bit of luck. 

I understand both views regarding the ignition.  I may end up trying out both approaches as I think my brother has enough parts laying around from various autos and motorcycles he's had over the years to come up with a standard points based system plus the S/S CDi ignition is fairly reasonably priced, so I might try both if I can manage to get the valves done! 

As a bonus question, it seems like the main issue is getting sufficient compression, almost always due to valve related issues.  I was thinking about making some adapters and plates to be able to check compression during the build.  Is that a worthwhile thing to do?  And if so, is it better to check via compression or via vacuum?

Again, thanks so much for your input!

Mike
MIke
Wichita, KS, USA

Offline Brian Rupnow

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Re: Webster I/C Engine - Mike's 5th Engine
« Reply #8 on: February 13, 2019, 11:41:10 PM »
Mike--Special fittings etcetera sorta, kinda work. Best bet is to make a fitting with the same thread as your sparkplug. Turn the crank so that both valves are closed with piston at top dead center and put about 20 psi of air on the fitting. If air is leaking past a valve you can tell if it's from exhaust valve or from intake valve. Just be careful--if the engine rocks off top dead center, the crank will take off like a bobcat for bottom dead center, taking your finger with it.