610 and 620, different clutch, same engine, or... ?

[Eriks]

When looking for a clutch for a L20B i noticed that Exedy sold one for the 610 and another for the 620.

 

Exedy 06008 - for the 610 with L20B

Exedy 06004 - for the 620 with L20B

 

Now if the engine is from a 620 and I put the engine in a 610, which clutch should I buy and why?

[DanielC]

I believe the trucks had a larger diameter clutch disk.   I would buy one for the vehicle the engine came out of.  But I would not be totally surprised if the clutch disk is a different diameter.

Going to a different diameter of clutch disk, and pressure plate may also affect the height of the throwout bearing collar needed.

[datzenmike]

Cars use 200mm diameter clutch disc. Trucks L18 and L20B use 225mm. This is, of course determined by the flywheel pressure plate bolt pattern and because all 6 bolt L20B and Z series flywheels interchange it's best to measure the present disc diameter.

 

If you swapped a 620 L20B into your 610 it 'should' have a 225mm pressure plate and disc. Daniel is very correct. The release bearing holder or collar (or sometimes called a sleeve) comes in different lengths to match the varying heights of the pressure plate. This is to keep the clutch arm operating in the same position. If you get the exact same height of PP as was in the 620 you can re-use the old collar, but if different you have to get the correct one. (always replace the throw out bearing with a new one)

[Eriks]

Again thanks :)