V8 nitro engine

[Parksy]

Gday all

First time poster and relatively new machinist(6 months maybe). I've made a couple of steam engines, first was a single cylinder double acting steam engine from plans, the second is a 4cyl double acting engine that I just made without plans, and works very well, in fact I can power it with lung power alone.

Anyway, I'm making my first IC engine and have decided with a v8 four stroke nitro engine. It's progressing well and my inspiration came from an engine made by DickinOhio. I found this a fantastic looking engine and wanted something similar.
I've just finished making piston rings and running them in on the lathe, and they sure add a lot of resistance to the engine. Is this the norm? Without the rings installed, the crank spun nice and freely, even with Pistons installed.

I'm starting to work on the heads and will be making bronze valve cages with stainless valves. What is the preferred material for the rocker arms?

Thanks all for viewing and I'm sure I'll have a lot more questions later on.

Cheers

Andy

 

[Parksy]

Having issues uploading multiple images, only allowing one per post for some reason.

 

[Parksy]

 

[gus]

Hi Parksy,

Your build is fantastic.

 

[Parksy]

Thank you Gus.

Here are some shots I took earlier in the build.









The cylinder liners I made out of steel. I was concerned with corrosion so I've electrically plated them with nickel, which is surprisingly easy to do at home with very basic ingredients.
When breaking the rings in, I was concerned that the nickel would cause issues, but it didn't and compression is excellent. If I cover the valve ports with my fingers while it's turning on the lathe, the oil inside sprays out as a fine mist. (Or sucks my fingers in, depending on the stroke).

Cheers

 

[Parksy]

Soon I intend the drill the intake and exhaust ports through the heads. I was just wondering what a suitable size hole I should make? Engine bore and stroke are 22mm.

 

[petertha]

..
I've just finished making piston rings and running them in on the lathe, and they sure add a lot of resistance to the engine. Is this the norm? Without the rings installed, the crank spun nice and freely, even with Pistons installed....What is the preferred material for the rocker arms?Andy

Very impressive build Andy. There are way smarter guys than me on the forum to chime in, but here goes with my 2 cents:

- re the piston & rings: the ringed nitro 4-stroke engines I've seen generally have piston diameter about .002" smaller than bore. So no 'resistance' from the piston only standpoint.

- re rings, a whole subject with varied views. But many successful builds have followed the Trimble method for sizing. Once you know the bore, basically the remaining ring parameters drop out of some simple formulas: ring cross section dimensions & what distance they are spread to 'heat set' & final gap (assuming cast iron as he recommends). The radial I'm building is quite close to an RC OS-56-4S & I validated the commercial ring seems very close to the Trimble parameters. Then the piston groove to accommodate the ring with appropriate clearances results from that.

- re rockers, I think the norm is to harden at least the face area that contacts valve stems if that's the configuration. Personally I'm going to try O1 tool steel. I've read others use plain steel & case harden with those powder dip products.

I'd like to learn more about your liner plating methods & materials. If you saved any pics & notes that would be awesome. Is the plan to post lap the plated surface? What sort of thickness do you figure it added?

I'm looking at your engine & wondering about cooling. What's the plan there?

 

[Parksy]

Gday Petertha and thanks for the response. With regards to cooling, the plan is to build it first and get it running, then monitor each cylinder to see what the temp wants to do. if it wants to get hot then I'll mount the heatsinks onto the rotary table and use a slitting saw to cut some cooling fins.

The nickel plating was straight forwards. Vinegar, a dc power supply and some nickel. I found the nickel the hardest part to source but found some on eBay. Put a chunk of nickel on each end of the positive and negative leads and dip it into the vinegar with power applied. Takes a few hours, but the nickel slowly dissolves into the vinegar and it turns green creating nickel acetate. Remove the nickel from the negative terminal and put your work piece onto it (after its been cleaned, free from oils etc). I left the liners in the solution for about 15mins and this produced a fairly thick layer that did create issues with reinstalling into the engine, but this was overcome with a little extra effort. I didn't measure the size before and after but it did change the size slightly. The liners were honed before plating, and i ran the rings onto the plated surface. Seemed to have worked and the plating is very durable. Mind you this is a very vague description so if you want more details I'm happy to help where possible. But at the end of the day it worked a treat and gave the me the rust protection I wanted.

 

[kadora]

Hi Parksy
I have cylinders inner dia 22mm on some of my engines and i drill
6 mm portholes.
I am surprised to read your remedy for nickel coating.
It seems to be very easy but could you tell me please ---
when i have nickel acetate solution done then work piece is
connected to the same voltage as during making acetate solution?
How high is amperage?
Here in Europe nickel plating solution is terribly expensive and your process
would dramatically decrease coating price.
Thank you a lot
Kadora

 

[Parksy]

Hi kadora

From what I've read, the recommendation is to use a couple of D sized batteries (1.5v each). I tried this and didn't have much success. That or I just needed to wait longer. I tried a 12v battery charger and this worked a treat. According to the meter, it pulled close to 4 amps and the solution did get warm. This could have been too much, but I had success with it.
With regards to making the nickel acetate, if the solution turns a nice transparent green(like green cordial) then you've got a pure nickel source. If it's cloudy or a different colour, it's mixed with other metals.

I hope this helps.

 

[kadora]

I am going to try this process right now is Sunday rainy morning here
ideal time for experiments .
I will inform you about results.

 

[Parksy]

Good luck kadora.

I've attached two photos of the same object, what I've done is very quickly machined the outside diameter to remove what ever scale/rust and what not, and have left the inside untouched. I didn't clean it either, was just a test piece. But I've nickel plated it, and because I didn't touch the inside diameter, it didn't receive any plating. Too dirty or something.
Anyway, I left it out in the rain to expose it to the elements and I'm happy with how it's performed. The outside shows no rust, and the inside, well as you can see has performed as well as it does.

 

[kadora]

Nickel coating works .
Coating is not shiny but it is much much better than painting by zinc spray or so and it is excellent rust protection.
This week i will coat my already machined parts for new V twin.
On picture is partly coated piece of brass .
Thank you Parksy for your help.
One more question.
Do you have some picture of crankshaft machining for your V8?
I would like to see your way of crankshaft machining process.
Thank you

 

[Parksy]

Glad it worked kadora. I believe the nickel can be polished to produce a shine.

Here's some more pics of the crank shaft. What I've done is machined the discs separately and fixed them to some rod which I turned down on the lathe to try and produce a straight crank. I've also mounted ball bearings for the main bearings onto the rod, and used bronze bushes as the big and small end bearings. The discs are loctited using max strength retaining compound then drilled and pinned to the shaft. Then milled the required bits off the rod to give me the final product.

 

[Cogsy]

I believe the nickel can be polished to produce a shine.

No plating really gives a natural shine unless the surface it is going on to is already shiny. If you polish the surface before you plate then you'll be able to get a nice chromed look on your parts (although nickel plating has a slightly different sheen to chrome).

 

[kadora]

Thanks Parksy
I machine crankshafts in the same way.

 

[Parksy]

Started some head work today, drilled the exhaust ports, tapped them and made some stainless tips that I've threaded and simply screw into the head.
I'm looking forwards to making the valves and cages and rockers. Should really set the engine off, I hope.

 

[Parksy]

Valve cage and valve. Cage is bronze and valve is 316 stainless. Not the nicest to machine but I've managed. Haven't had much luck sourcing 303 stainless here in oz. if anyone knows, I'm all ears!

 

[mnay]

Beautiful work. Keep us posted.

 

[Parksy]

More valve cages. Just need to clean them up and mill a hole so they can work.
Had issues with making valves today. The stainless just wanted to flex too much, even if I used a live center on the end. Was ending up with uneven thicknesses across the stem. What methods does everyone else use for making valves? And what materials? I was using 316 stainless.


With regards to valve seat angles, I set the compound slide on the lathe to 40 degrees and cut the valve seat. Would I be correct in simply setting it to 40 degrees to cut the opposite angle for the actual valve? Or will this angle be 50 degrees? I apologise for what may be a very straight forward question. Been a very hot day here in oz.

Cheers