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Member postings for Craig Booth 1

Here is a list of all the postings Craig Booth 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: WT2527 15cc Glow Engine
29/03/2019 13:34:51
Posted by Barrie Lever on 29/03/2019 13:22:49:


I was very impressed with the tick over, shame you have lost some of that for top end performance.

What prop size are you running?



Hopefully when it runs in properly I might be able to get the bottom end tuned in again.

Currently using a 14x8, but plan to try a 13x6 and 13x8 this weekend.

Will keep you posted.


29/03/2019 12:39:33

Hi all,

Small update. Ran the engine again with the timing gears in correct location. Definitely an improvement at the top end rpm, up to around 5500rpm.

Interestingly the bottom end is now not so smooth as it was before, but not too bad.

My next plan to improve the rpm is to try making another set of valve springs that are a bit stiffer as I suspect the bounce back on the valves could be limiting.



25/03/2019 21:21:17

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

23/03/2019 20:31:11

It's alive!!!! It works smiley

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. smiley


16/03/2019 20:29:47

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.




16/03/2019 11:33:19

Final role call before assembly...


15/03/2019 20:38:37

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.


13/01/2019 20:19:44

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.



Thread: Completed Twin Inline IC Engine
03/01/2019 12:26:48

John, not wanting to hijack Steves thread, but what compression ratio do you think would be required to convert to spark ignition?


Thread: Aluminium Polishing
03/01/2019 07:27:05

Hi guys,

There are some amazing polished aluminium finishes on some of the projects posted here. What do you use to get such a finish? What materials, equipment, and techniques?

At the moment I have been using either 400, 600, then 1200 wet and dry paper, or 400,600,then 1200 carborundum powder mixed with oil using a soft felt pad on a dremel drill. Then finishing with a mop on a 3" bench grider.

Comes up ok, but no where near some of the examples I have seen.

Thanks in advance.


Thread: Completed Twin Inline IC Engine
02/01/2019 21:15:55

That's beautiful Steve, lovely work.

I have the plans for both that one and the 4 cylinder boxer which is next on my list.

Is yours going in a plane?

Would love to know more about it if you don't mind?

Did you stick to the materials, specifically the piston liner and ring combo? I was planning on changing to steel liner and CI ring.

What do you think the issue with the glow is? I was also thinking of changing it to petrol, but was nervous about losing power. Mines destined for a plane if successful.



Thread: WT2527 15cc Glow Engine
02/01/2019 20:57:24

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.




30/12/2018 20:57:37

Couldn't resist a temporary assembly





29/12/2018 21:08:19

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.





29/12/2018 20:56:10

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.



29/12/2018 20:53:01

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)


29/12/2018 20:49:13

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

29/12/2018 20:43:56

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.


12/09/2018 21:38:49

Hi all, thanks for all the comments, much appreciated.

Over the past couple of days I've been working on the exhaust valve (SS316) and valve liner (Colphos).

The plans call for an OD on the valve liner of 13.5mm, and therefore obviously the same size hole to fit in the head. I looked at a 13.5mm end mill but to be honest was scared away by the cost for something I will probably never use again, so have reduced the OD to 13mm. Hopefully it does not make too much difference to the performance. If my maths is correct it is a 7% reduction in area. Might be able to make up for it a bit by some port and polishing.

The valve liner will be an interference fit in the head.

My other cheat was the valve shaft hole in the liner at 3.5mm. Again I do not have a 3.5mm reamer and looked at prices and decided just to drill. Although the valve feels smooth in the liner, I'm just not sure. Any slop here and the exhaust gases will pass. Of course I did not think of a hand reamer which are much cheaper. So I think this set I've made will be put down as learning curve and practice and I'll re-do it properly once I get a reamer.




Edited By Craig Booth 1 on 12/09/2018 21:55:46

09/09/2018 20:43:58

and today milled the cylinder head slots for the rockers.


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