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Wide or Narrow Cam Shaft Bearing?

1422 Views 5 Replies 3 Participants Last post by  ducks13
I am in the process of rebuilding my first Onan engine for my JD 318. While pricing parts I have found that I have the option to purchase either wide (.700") or narrow (.310" ) cam bearings. What are the reasons for the different sizes and which ones are better?

Thank you.
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Go for the wider ones, I've seen the results of the narrow bearings ending up in the oil pan. If your engine has points you need to make sure your cam bearing that goes under the points is installed correctly to allow for the points plunger
My engine does not have points so I shouldnt have any alignment problems. What about using Locktite to secure the new bearings..is this necessary...or even recommended?
I used Permatex Bearing Mount part # 20297
I am thinking of going with a narrow set from www.gphope.com. (the prices are the absolute lowest I've seen!!!) I called and spoke with the guy and he told me he has his bearings made from the same material as the ones in the diesel engines and are actually better than the wider ones.

He explained that if I used bearing locktite when installing them I should have no trouble with them moving or coming out. It makes sense to me to use the narrower bearings because they would have less surface contact with the cam shaft...therfore less friction, heat and wear. They may also allow for more contact with lubrication. Again, my main concern is that they dont come loose.

Does anyone have any input or experiences with using bearing locktite on these cam bearings?
I had the narrow bearing installed at the engine shop. About 50 hours later the front bearing spun out of the case. I had not been driven in far enough in the first place. When I went back together the second time I used red loc-tite and drove the bearing in until it was centered on the area where the old bearing rode and I haven't had any trouble since.
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