compression ratio

[Dumpduece]

what is the compression ratio of the LDT 465-1C multi fuel engine?

 

[Crackerjax]

22.1

 

[Dumpduece]

thanks. someone told me it was 10 to one so you could use gas. just didn't make since.

 

[Crackerjax]

just cant use high octane gas and mix it with oil 1 qt of clean oil to every 5 gal of gas...but I would stick with diesel or a mix of diesel and clean UMO

 

[Keith_J]

thanks. someone told me it was 10 to one so you could use gas. just didn't make since.

That someone didn't understand how Otto and Diesel cycles function. Diesel fuel is rated on its cetane index, this is completely opposite of the octane or anti-knock index of gasoline.

Octane index is resistance to auto-ignition. Cetane index is the propensity for auto-ignition. The reason for the rather high (for direct injection) 22:1 compression ratio is to assure ignition of gasoline. And most aviation gasoline has much higher octane index, hence it is NOT an approved fuel as it might have unreliable ignition characteristics. And the addition of oil to gasoline reduces the octane index, making it auto-ignite easier.

The other adaption of the multifuel engines is lubrication of the injection pump internals with motor oil, most other distributor injection pumps are lubricated with the diesel fuel.

If you could find the injection nozzles with a star pattern, you could decrease the compression ratio of these multifuels by machining the domes in the piston and probably get a reliable 300 Hp. But they would be diesel only and I would not recommend increasing the governed engine speed.

 

[Keith_J]

just cant use high octane gas and mix it with oil 1 qt of clean oil to every 5 gal of gas...but I would stick with diesel or a mix of diesel and clean UMO

Most motor oils have appreciable ash content ans will eventually foul the combustion chambers. But the combustion chamber deposits are NOTHING compared to vegetable oils.

 

[Crackerjax]

sea foam....i have been running alot of umo sometimes up to 80% no problems yet...thank od iron gods