View single post by Mark Rosenbaum
 Posted: 03-16-2006 01:58 am
PM Quote Reply Full Topic
Mark Rosenbaum



Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
Status: 
Offline
 Re the rotor end clearance, or end float: I will emphasize that one should not rely on an eyeball estimate, as a significant failure in either direction wll have dire results.  To determine this clearance, there are two practical methods:

1.  You can reassemble the pump with a length of Plastigauge in place, then disassemble and check the Plastigauge.  This is difficult to do unless the aux. housing has been unbolted from the engine, and does require a minimal expenditure.

2.  You can measure the protrusion of the rotors above the oil pump casting using a feeler gauge in conjunction with a straight edge placed atop the rotors, and compare this to the thickness of the oil pump casting to aux. housing casting gasket.  The difference between the two is the clearance.  This method is much quicker and non-costly, but in theory is marginally less accurate.

In either case, clearance is adjusted by either (a) installing a gasket of a suitable thickness, (Lotus used to provide gaskets in a variety of thicknesses but apparently no longer does so), or (b) removing material from the oil pump casting.

Only the proper Lotus gasket should be used as it is made of a special plastic with very good dimensional stability.  It is normally sealed with Loctite 515 or 518 (which is also an excellent adhesive and may glue the rotors to the castings if too much is used).  This means that one rebuilds the pump with minimum end play, and relies upon the thickness of the Loctite to increase the clearance by half a mil or so.

Attachment: Rotor end float.jpg (Downloaded 257 times)