M42 crankshaft gear doesn't fit snug?

[autox320]

Hey guys. Building a new M42 from scratch. The crankshaft has been sitting in my possession during the block and head being worked at the machine shop. Everything is back and I have all new parts. Just a quick check I took the new BMW crankshaft gear and went to test fit on the nose of the crank. It slid on pretty easy and I can rock it about a thousandth on the woodruff key. This can't be right. Has anybody encountered this?

I checked with the old crankshaft gear and yup it fits exactly the same way. I never did have to use a puller to get it off. The original motor had about 400,000 miles on it. Most motors I have to put the crankshaft gear in the oven to 400 degrees and slip it on. When cooled you can't move it and requires a torch and puller to remove.

Seems bad to ride the timing components and cams on just the woodruff key, but obviously the motor was before teardown. Is there a shim or something? ETK online has nothing in the exploded diagram.

Help

[autox320]

A few google searches come up with some interesting results.

-Have a custom gear machined (umm what lol)
- install using loctite 660 (liquid metal; aka expensive JB weld) It may never come off again
- Weld it on; may not come off again but least if the nose is welded I could grind it enough to get back off.


Not sure what to do at this point. Still weighing options and any input is appreciated. Never encountered this before.

[autox320]

I'm told the assembly of the dampner pulley spacer and pulley torqued to spec clamps the gear tight in place. If the front pulley bolt every came loose it would cause issues with the gear like the suzuki and miata cars. They have keyway problems when the front pulley bolt starts getting loose. The M42 one is torqued pretty high and a little loctite won't hurt.


From a gent working a Merc engine who replied to me about it also.
"Once you have the front nut /bolt tightened it will lock everything into place and the key wont take any of the load. I am currently working on a Mercedes M102 Cosworth engine and they only use a 3 mm pin to locate the front sprocket, and the load is taken by friction once the front bolt is tightened."