Larry:

It goes in front of the chain sproket. Usually stuck tight enough you think it is part of the crank unless you take the sproket off and the spacer falls off.

It was missing on the short block my brother bought, so he didn't put a new one in. The Haynes 123 series manual doesn't show it (it does show a Chevy piston, though!). Chilton shows it in the exploded diagrams, but doesn't label it (and has pictures of a Chevy 350 head!)

Believe me, if you left yours out, you will know -- the seal will just touch the end of the crank where the spacer fits -- you will lose about a quart per hundred miles and there will be oil EVERYWHERE. If the seal is actually sitting on something, the spacer is in there. The pulleys will be about a quarter inch off, too.

If not, I'd get one and put it in -- I hate oil leaks....!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!