OT Starting a big Clark

David G

Well-known Member
Nice to have fellow Clark people here, they were a beast, but hard to get online.

Here is my opinion, please join in.

They were a 2 stroke that was prone to detonation due to over rich mixture if boost was not kept up. The tubochargers were massive, and required a lot of energy to spin and heat. Heat is required to make a turbo work. There was no heat during starting and the cold massive turbo would suck it all up. The ones I worked on had compressed air sprayed on the turbo to get it spinning. We had a finite supply of compressed air, so the engine must produce enough energy to take over on the turbo before the air ran out. The quickest way to do this was retard the timing, I think like 24 degrees ATDC. This produces a ton of heat in the exhaust but totally cuts the torque the engine can produce. Once the engine was online the HP would keep the turbo hot. It was a balancing act to advance the timing and load the engine at the same time so it could run on its own.

I had fun working on them, they are just brutes.

The fuel injection really increased the torque.
 
If I recall correctly, the V16's did not.

Some of the engines had none, some blowers, some turbo and some both.
 
Hello Dean,

He said the tutbos would nof kick at start up. Turbos require heat to spool up. Blowers on the other end are gear or belt driven, as you know.

However the suck up lots of H. p., But the profuce enlugh air tbat during valve overlap they hejp scavenge the unbjrned vased for a clean cgarge on tbe next cycle,

Seems strange to some that huge engines are two cycle, but tbe can be made pretty efficient,

Guido.
 
Understand that, Guido, but the blowers provide the charge/scavange air.

Detroits and EMDs will not start without blowers.

I suppose the large stationary engines can be made functional without blowers because starting is such a rare occurrence.

Dean
 
Hello Dean,

Yep!
i know you do, Turbo is free H. P. But some engines are a bear to start witb turbos like Dave said,

Guido.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top