While the fit piston to sleeve might be very small , production tolerances are not this tight, for the sake of keeping cost in line. The designer chooses a suitable tolerance on both parts and when you have a loose sleeve, you pick a piston on the high tolerance to mate.

My OTM 0.8 is not in good shape either. It has a tremendous amount of sub piston induction, especially at the rear of the piston where it's trimmed to clear the backplate? The centering of the machined features in the casting looks good. However. There is a crack in the bottom rear of the crankcase from an impact that is no visible in the screwed in backplate. It appears to have happened after machining. I can see light under the front of the cylinder where it should be sitting on the crankcase! The backplate itself looks like it is of much better quality in finish. Honestly, it looks like it was produced on a CNC, it looks like it might be from a Norvel. I just checked and it is. Looks like I was had on this buy. I'm sure it came from Ebay and I usually keep a record, but I'm sure I didn't pay much for it. I didn't inspect it like I usually do when I get an engine. Oh well. Maybe one day I'll see if it runs.

Greg

I've been waiting 2 years for the Mk V, finally got it. The Mk IV, I got in the 1970's (?).
This Mk V diesel feels just as smooth as the older one.
See above recent post, #4182, for link to Tom.

It looks great John...congrats...!...
Personally I like that, although doubtless beeing a "modern" diesel, the stylish tradition of a "real" T-bar comp.lever is retained..., contrary to many of the newer ones entering the market....

(...am I a conservative old f**t...?)

After my recent "engine-cleaning-mania" (which was a healthy thing to do), several engines still live in plastic bags, unassembled, as some odd gaskets are missing here and there..
Particularily older diesels, with screw-on backplates and cylinders, use various circular gaskets and fibre washers....none of them beeing standard dimension...

Pushed by the obvious need, I rigged this device, based on an old bench grinder with a chuck fitted, that I already had. (this machine has been very handy for various purposes.)
As shown on the pics, the "add-on" is a primitive gizmo, and it was easy to make.
It works great..!

Thanks Al, for the "spray-mount-glue" hint...!...making this concept work excellent....

I have used a bench drill in a similar way except the cutter and a centre point are mounted on the bedplate and I use sliding adjustment between the blade and the centre point adjusted with vernier,the centre point has a impression in the cork backing that's glued to the wooden mandrel that's chuck mounted, I made it origonally for making instrument glasses from clear ABS. If I still had it I would have included a pix but it was one of the things I let go.

Let's see who can guess what this is.

Originally Posted by fiery

Let's see who can guess what this is.

Webra

Not sure if this was OS or Saito made ? Dates from the 80'ies. Any help isappeciated

I've used O rings from the local hardware store on screw in backplates. Seems to work fine.

Originally Posted by fiery

Let's see who can guess what this is.

No, not Webra....too rough...

Lots of paint + a Taplin-Twin-like comp.lever....er....Indian....?

"You are bidding on a nice little repro of the very,very rare Healy 0.99 c.c. vintage model aircraft diesel engine. This engine is in excellent condition. It has very good compression and very smooth bearings. The mounting lugs are in excellent shape with no washer marks. It is clearly based on an original Amco 87 crankcase, but the rest has been expertly created by a skilled engineer whose identity is not known to me. The original Healy was of course developed into the lovely little Amco 0.87 (See Clanfords book). The engine carries the serial number 2307. It started easily and ran very well when tested."

http://www.ebay.co.uk/itm/Healy-0-99...item3f1dffb5b7

Those prop nuts are like the ones I made for my mate ... but mine are nicer, 'cos I polished them to a mirror finish and drilled a hole for a tommy-bar.


Not braggin' ...

Presenting the "Teapot" Taifun Hobby II.......

Originally Posted by Twin-Stack

"You are bidding on a nice little repro of the very,very rare Healy 0.99 c.c. vintage model aircraft diesel engine.

Shame the engine doesn't look much like a Healey, especially with the Amco case and the Mills propnut, but I wouldn't mind betting it's a super runner. Be great to fly.

Originally Posted by fiery

Let's see who can guess what this is.

Looks like a Russian replica Taipan. Gordon can't have made one that rough...