5 CC CI engine (and a bit of a Grump)

Great delight was taken to ensure drawings were duly stamped 'when required' and though he gave the impression he was taking it in good fun it obviously irritated. We all thought it hilarious of course but it was rather short lived as despite his ferret like but unsuccessful searching for it for several days he suddenly came upon it by chance when one of us in a lax moment let our guard down. His triumph had to be seen to be appreciated and it quickly deflated our little game. 'Well bless our souls, we said, that splendid chap Richard has just found our stamp' or was it something rather similar

Edited By Ramon Wilson on 06/10/2011 23:44:23

Edited By Bill Pudney on 07/10/2011 04:03:51

I am not going to throw teddy out of the pram but I have a touch of the ‘Grump’ again. The machining of the crankshaft is described but NO finished dimensions given (yet). I have to order a 7mm reamer from a local supplier. What else do I need?

Raymond In view of the scuffing you found and the fact that you are trying to reproduce an engine from the late 1940s early 50s I understand your design. I do not want to re create anything I am going to build a 5CC diesel based on your design.

My first change will be to use an oil seal (SOG 102711 8 22 7 2) outboard (on the propeller side) of the main 7mm race to maintain crankcase compression.

My second change will be to use a ring of holes (of a suitable size) as transfer ports.

Raymond would you (and anyone else) care to comment.

Bill - Thank you for your kind words of reassurance. I do realise that despite trying my damndest mistakes will happen - it's just not nice when you realise others are relying on you not to make any

Finally Dick could I just say that my name - Ramon - was not of my choosing, that was defintely beyond my control, but it is my name and that's the way it's spelt. I have had several nicknames over my years the ubiquitous 'Tug' being the usual but I don't refer to it on here. That said however I'm definitely not a 'Raymond' either.

Edited By Ramon Wilson on 07/10/2011 12:12:09

I now have about enough information from your postings to refigure the transfer ports. Your suggestion of drilling them at an upward angle seems good but I will only do so in those regions of the cylinder which do not face an exhaust port. Those holes will be at Right Angles to the bore. This will direct the fresh gasses into the centre where of the cylinder the ‘pent headed’ piston directs gasses upward. The idea is to avoid losing too much of the fresh charge and getting rid of the spent gasses.

When I have lapped in the piston I want to hear a descent ‘pop’ when the transfer ports open. This means minimising the dead space in the crank case.

Here's a nice big endmill making a little three-gang cutter (to an ETW design).

And proof it works:

 

Edited By Stub Mandrel on 25/10/2011 21:07:39

Please - absolutely no need to apologise and absolutely no offence taken I assure you - really. Indeed I couldn't believe what I'd written once you'd pointed it out.

That was exactly my point - It really does surprise me as to just how much slips me by these days - I had a true Classic with 'Wheeltappers' Nemmet 15 - Better have a good laugh I'm sure others will be.

Steve - don't let anything put you off - nobody's beating my door down and despite what you might think it has been well worth it. I know just how I'm going to feel if just one engine gets built and whoever makes it gets as big a thrill as I did when it runs

Edited By Ramon Wilson on 26/10/2011 22:29:59