fiery

My Feedback: (2)

I recently looked over and ran a NIB example of this Soviet era Russian plain bearing 1.5 c.c. (.09 c.i.) CIS sport diesel

The Good:

Nicely turned and finished black anodised alloy prop driver, venturi, back plate and steel spinner nut.

Forged and very nicely finished connecting rod.

Steel insert in top of cooling jacket for compression screw. Compression screw a nice fit in insert with no play. Bottom cut off at 15 degree angle - agricultural, but effective to resist 'wandering' when running.

Nicely machined threads for back plate and cylinder.

Nice shaft/ main bearing fit. Gudgeon pin is correct length.

Crank web has 'cut outs' for balancing and is chemically treated with a black finish to minimise chance of rust.

No swarf found in case. Case full of congealed cosmoline which was removed prior to test.

Contra piston fit is perfect. No leaks, but moves up readily when compression is reduced when hot; unlike many Russian engines where all too often they are fitted too tight, causing 'lock up' when hot.

No excess fore-aft play on shaft. Running clearance from front of case to prop driver is perfect.

Mass with needle and spinner nut is 70 grams. That's light.

Comes with a nice combi-tool and mounting bolts and washers. Detailed instructions in four languages and schematic diagram.

The Bad:

Connecting rod big end is a slightly loose fit on crank pin, but within acceptable tolerance (racers would say it 'just right').

NVA spray bar thread is fine with very small diameter jet holes. You get fine needle adjustment (good). I stripped the alloy thread on the spray bar when nipping up the too thin section spray bar fixing nut (bad). I will sort it with a thicker section nut which will have more (and still good) thread area on the spray bar to spread the tension over.

Piston fit is on the slack side of acceptable. Minimal running in needed, but fit is slack when hot.

The tommy bar is well done but uses an overly thin gauge wire. When hot it is unpleasant to adjust. I suspect it is the same as fitted to the OTM 0,8 c.c.Hummingbird (Kolibri).

Combi-tool is wrong size. Clearly for the Hummingbird!

The Ugly:

The shaft is one to two degrees off perpendicular looking down on engine due to the main bearing not being bored straight. Imagine looking down at a traditional clock face. This one is at two to twelve.

Venturi is not centred in intake, it is offset to one side slightly.

Mounting holes in lugs are left with swarf on upper surface where the drill bit has 'burst' through. Compare with the Russian MK-17, where the holes are 'finish faced' on the upper surface to clean them up. Forward holes are also too close to case bottom, and front end of lugs.

Verdict:

An older 'classic style' nice looking engine which ticks a lot of box's, including price, for use in 1.5 c.c. sport F/F and C/L. Let down by wayward machining. Fairly easy to start and handle apart from the 'skinny' tommy bar. Runs well despite issues noted above.

Not recommended for beginners unless thoroughly inspected before purchase by someone with experience.