Member postings for John Vietti

Thanks for all the input. Used the methods suggested. Turns out Westbury's weights as designed weighed 67 grams each. After balancing exercise the resultant indicated weight is 38.7 grams, big difference. I will use this weight but worried since its so different from what the designer suggested. Won't know till I try to run it. Currently working on magneto mount and drive, starter drive complete.

Will report results.

John

Thanks for all the input! Obviously I was only doing it half right. I think I’ll try 55% of the reciprocating weight plus the rotating weight. Finishing up the piston now. Will be interesting to see how close it comes to Westbury’s design.

John

I'm building the Kittiwake and made the crank and rod to the plans including the crank counterweights. It looks massively overbalanced.

What is considered the best way to balance the engine? I'm aware of the concept of adding a weighted blob on the crank, the blob equal in weight to 1/2 the weight of half the conrod measured at both ends. The counterweights are then whittled down till the assembly balances on knife edges. ' Ive used this method on hit and miss engines but they are obviously made to run much more slowly.

Is there a better way or is this good enough?

Thanks for your input, John

Malc,

I asked a similar question a while back. A variety of answers. If it were me I'd fit the piston rather tight and if it proves too tight the piston can easily skimmed.

I have a Myford S7 and the tail stock locks drops to a 6 o'clock position when not in use. It used to park at 1 or 2 o'clock. is this a simple fix? Suggestions welcomed.

One dodge I've read about to help stop chatter while using a boring bar is to wrap the bar with o rings, sometimes big ones overlapping. Seems to help a little.

John

Thanks for the heads up. Her write up is amazing.

Jason or anyone,

Read the whole construction series, very good. It ended before he got it running and I wondered how it turned out and if there are any videos? John

Well I,m ticked. The plans for the location of the tappet guide hole was off by 1/8". Thought it looked off but after checking and checking went ahead and followed plans. I think I can recover but it irks me no end esp after smelling a rat. Once the crankcases are finished the remaining parts are mostly from stock or fairly straight forward. Grrr

Jason, Thanks! Thats a wonderful help and it explains how to do many tricky tasks I have been pondering.

John

I was struck with the same thing, no mills. Im finding some tasks are much easier in the mill than the methods he described using a face plate and angle plates etc.

Considering their disadvantages compared to all the technology we have, mills, DROs, etc it makes their accomplishments all the more impressive.

30 or 40 years ago I bought the castings, plans and Westbury's building notes for the Kittiwake engine. I thought it was the most attractive of his engines. Decided I better start making the engine while still able.

Its intimidating to machine these old, irreplaceable castings.

I wonder if anyone has built this engine and has suggestions for improvements or machining ideas. Pictures would be great too.

For once I've decided to build to the plan without modifications. Well only a few, I want to make the cylinder barrel bigger and with large aluminium fins ala a Goldstar. Of course it will have a magneto too!

Comments?

John in Wyoming

Don Grimm’s article on a magneto for the Red Wing was in issues 23,24,25 of MEB.

His previous article was on high tension mags but could be useful in any magneto building venture.

Hello again John V here.
I went on sort of a crusade years ago to get more magnetos on our engines. I was upset to see virtually all the engines sitting on a largish box that had a big 12 volt battery and a motorcycle coil. I wondered then, and now, how builders can make such beautiful faithfully detailed models and then when it came time for an ignition system they happily added something more appropriate for a car. Now days of course CDI ignition is even easier and much smaller. Still twenty first century technology on a twentieth century engine.

In spite of my efforts writing a how to article and haranguing people at shows, plus showing my engines at shows, I believe very few were ever built, fewer than 5?. I’ve since mellowed and just enjoy the ride.

I think many builders are intimidated by electronics. I am too as a retired geologist, but magnetos are an amazingly simple device. I guarantee that if you can build an engine you will have no problem with making a working magneto. That said when the size gets really small the difficulty goes up. On high tension mags the coil is a challenge though commercial ones are available. Low tension mags are really easy and the coil can be wound by hand using relatively large wire.

For the Red Wing I cannot stress how great Don Grimm’s magneto is. It’s relatively easy to do and works great. Get the article, you will be glad you did! The Red Wings push rod is very well supported and makes an excellent candidate for the magneto.

Im prepared to answer questions but hard questions I will refer to Don Grimm who is an EE.

John

John,

Congrats on choosing the Red Wing. I built one after seeing many at shows here in the US. Most ran very well. If you are considering a magneto might I suggest using the low tension magneto designed for the Red Wing by Don Grimm and serialized in Model Engine Builder magazine. I sit next to him at most shows and his Red Wing runs great for the duration of the show.

i built one highly modified with increased bore and stroke and heavy brass flywheels. I like magnetos so in the interest of something different I equipped mine with a low tension, oscillating magneto modeled after the Webster magneto. It works well but the output is marginal and occasionally needs a battery to get it going. I will attempt to post a picture at some point.

John in USA

It occurs to me if anyone is interested in high tension magnetos I believe there are now better designs from what Minimag presents.  I was a good friend of Bill Linfield from Carterton who’s magnetos are shown in the brochure from Minimag.  I bought many coils from them and they are fine if a bit big.  A coil from an old Stihl chainsaw works great.  Must be a points model.  I and Don Grimm both wrote articles on magnetos in MEB magazine.  One big change was using rare earth magnets resulting in a stronger and smaller magneto.  JSV

Edited By John Vietti on 10/01/2020 01:51:39

Video test

Edited By John Vietti on 30/11/2019 21:43:21

I have added a picture of the Silver Bullet. I ran it in for a couple hours and the oiling problem is improved.

Thanks for the reply’s.

The engine runs about 170 degrees, it has a cooling system. Running no hotter than this I think I can go with a tighter piston to cylinder fit. Believe me I’ve tried about everything re. the rings. They appear to be seating ok. I have dippers on the rods. I run a low oil level and installed a windage tray. Not comfortable with such a low oil level. Others who have built the engine have had similar problems cured with low oil level.

I guess I’ll just make new pistons with only a couple of thou clearance and see what happens. I can make pistons pretty quick.

Will o rings work on a relatively high speed engine? It idles around 1,200 rpm and probably goes up to maybe 5,000 rpm.

John

i have a small, 3/4” by 3/4” two cylinder engine I’ve built. It slobbers oil from the exhaust. It actually run pretty well inspite of that.

Currently the piston clearance is .004”. It’s an aluminum piston in a cast iron liner. I wonder what is the tightest fitting piston that will work without seizing when the engine heats up? Comments please. Done all I can regarding rings with 4 rings and oil drain holes in lower ring groove. Had very high compression with domed pistons but flat topping them and lowering compression didn’t help the oiling problem and dosent idle quite as well.

The engine is Bob Shores Silver Bullet but modified to 180 crank, hemi heads with Harley knuckle head type rocker arms.

Thanks, John

I too was surprised by the inexpensive nature of those foreign rings and pistons so I bought a few. A caution regards the pistons. Because they are for two stroke engines, the ones I got were far from round or consistent diameter top to bottom. I assume this is because they are two stroke pistons and made for high rpm and heat.

i did buy a piston for a Honda four stroke about 1 3/8” bore and it is beautiful with very nice oil rings etc. consistent dia. Top to bottom. Not as cheap as the others though.