1948 PAYA 2.00 c.c. Model Diesel Engine (2)
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- Опубликовано: 11 сен 2024
- This is the second run of my 1948 RAI PAYA engine no. 583 following disassembly, inspection and minor modification. Changes made are as follows:
1. Lap the contra piston external wall to relieve fit and ease movement within the bore. Deburr top of contra-piston to avoid possibility of scratches to the cylinder liner. Clean threads of the compression adjustment lever base (which screws into the top of the cylinder jacket) and grease with automotive lithium grease to reduce friction when adjusting compression.
2. File a groove leading on the main thrust bearing face to the main bearing journal to improve oil feed. Main bearing play is as supplied is minimal, and the initial run revealed bearing tightness leading to overheating due to insufficient lubrication.
3. Remove factory applied rubberised mastic sealing compound for the:
a. cylinder flange to case joint, and
b. crankshaft extension housing to block joint;
and replace with pattern laser cut 0,4 m.m. automotive gasket paper seals.
The engine now runs very well. It is shown running slightly under compressed. It will empty its generously sized square shaped tank despite the variation in fuel head from full to empty.
Fuel Composition:
Equal parts Kerosene, Diethyl ether and Castor Oil, plus 1.5% B.V. 2 Ethyl-Hexyl Nitrate (AMSOIL Diesel Cetane Boost).
Propeller
Zingali composite black grp 10 x 4
Sputtering for break in? Lovely condition relic. Thanks, Thailand Paul
you've just taken me down memory lane. I remember testing fuels from cracking crude oil in something very similar to this back at our school science club in 1979. one of my mates brought it in. my father used to fly control-line model aircraft in the 70s so I was familiar with glow-plug methanol 2-strokes. the model diesel engine is interesting because it uses a type of carburettor (unlike most other diesels) and you can tune the compression as well as the fuel mixture.
Memories ❤️
Nice Running Engine 👍
Presumably that lever on the top is for compression adjustment?
It noticeably had an increase in revs as it warmed up.
Correct Jeremy. As the adjusting lever is cast alloy, I am very careful when moving it and treat the engine as a fixed compression diesel for all intents when running it.
How are you getting enough compression? Also, does it have a glow plug?
Thank you for your enquiry, Fred. This is a homologous carburetted compression ignition engine. There is no external ignition source. Compression is variable. Anywhere between 16:1 and 20:1 typical. The compression adjustment lever is on the top. It operates a contra-piston installed in the top of the cylinder sleeve.