WT2527 15cc Glow Engine

Hi all, Merry Christmas to all. Well it's been a while as I've been working on the Spitfire which is almost finished, so I've managed to find some time to get back onto the engine. The next couple of posts give an update of the last weeks work.

Cam follower guides from Colphos made. You can see the o-rings in the photo below.

I had a go at the crankshaft (EN16T) which started out well but I ended up taking a bit too much off the diameter for the big bearing. Only a margin but enough that I can feel a bit of slop in it.

So once I get some more material I'll make another one. I'm also going to up the thread size from M6 to M8. That feels a bit better for an engine this size and will also fit the standard 8mm diameter on the props.

Edited By Craig Booth 1 on 29/12/2018 20:57:03

For the carb I am using a standard unit from an A.S.P. engine and needed to make an adaptor that will fit the head.

The end will receive an M10 thread to fit into the head inlet.

I also had a bit of a play and made an inlet trumpet.

As an aside I am also starting to organise the bits I need to do some DIY anodising. The trumpet, and rocker head cover will get a red anodising (if successful)

On the exhaust side I deviated from the 2-piece unit on the plans and bored out from a single piece, then made an end cap with integral exhaust hole which I aluminium soldered into place.

The head connection piece will also get soldered in once threaded.

Lastly, one unsuccessful attempt to make the rockers. Made from silver steel which I had to firstly machine out of 12mm round. Then made a jig to hold in place on the rotary table.

All was going well, but made a silly mistake with dimensional error when I took a radius for a diameter and cut off too much length. So will be starting those again too. At least I have the jig to use.

Couldn't resist a temporary assembly

Ploughing on and tonight I got the piston and gudgeon pin finished. Happy with the fit. Piston is 0.06mm undersize to the liner.

What I'm not sure about is how I will fit the circlip on the other end of the pin. Looks pretty tight between the faces. Maybe need to try an E-type.

no real machining progress, but have been playing with a bit of home anodiziing. Mixed results. With sulphuric acid not available to the home user due to the new laws (unless you get a license), I've gone with using Sodium Bisulphate.

This part turned out alright. Think I'll also try doing the rocker cover.

Looking great!

Thanks for sharing the updates.

Nice looking engine and good finishing.

Emgee

well, its been a while, but I've been slowly finishing things off and fixing some earlier problems.

Firstly, my beginners error on the valves. When machining I drilled a pilot hole for the live centre, not thinking that it weaken the top of the valve where the rocker makes contact. So have made new set of valves.

Second error, trying to cut teeth for the main timing gear on the rotary table on mill without a tailstock. Tailstock now bought and new timing gear made.

Third item, tried to aluminium weld the silencer pipe. Made a mess on the thin wall so have redesigned it with a threaded connection.

Final role call before assembly...

Looks lovely, Craig

MichaelG.

Looking great Craig! All present and correct I'd say.

Not long before noise and smoke I think!

thanks guys, not too much smoke hopefully

assembled her this afternoon and first wee problem. Was running it using the cordless drill and the circlip holding the valve spring slipped off. Valve slipped down into the cylinder and bent. Fortunately no other damage. Will need to make another valve and try to get a good fit on the seat again.

It's alive!!!! It works

Very very happy after the first runs today. Started super easy, idles well, and has good throttle response.

Only put 1.5 tanks through it and didn't want to pusjh it hard, so looking forward to getting it run and tuned in.

I don't have a tacho so not sure what the RPMs where but certainly souned like a good range.

Linky to videos here:

First Runs

First Runs

And heres the plane shes going in. Can't wait to get it finished now.

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I am totally amassed, this is your first project, the quality is fantastic. What will be your next one? a 9 cylinder gnome replica?

Thanks guys. Adrian, no not a 9 cylinder, I have plans afoot for the design of a 80cc V Twin 4 stroke, currently drawing it up in Autodesk Inventor.

So I put 2 tanks of fuel through the engine over the weekend and borrowed a tacho. As I said, the idle is great, down at 1500rpm and smooth, but am a bit disappointed in only revving to around 3500rpm which I thought was a bit low.

I've stripped her down to inspect everything and check for anything rubbing, wearing, or loose. Everything seems ok, but I did discover that the timing gears were one tooth out, i.e. 15 degrees retarded from where it should be. What I'm hoping is that advancing will give it more power/higher rev's but not sure. Looking forward to trying it again to see the difference.

Edited By Craig Booth 1 on 25/03/2019 21:22:02

Congratulations on the first runs.Well done Craig! Good luck on next ones after timing adjust.