1990Onan520-H 15 #1 Posted May 11, 2019 Just curious what you guys use. I've got a 91 244-H and an 88 520-H. I've been worrying more and more about zink content in off the shelf oils these days being used in older flat tappet engines. Been running 10w30 sn plus I think it's called now, but just been wondering if im doing damage. Thoughts on running newer oils in these old Onans? 1 Share this post Link to post Share on other sites
JAinVA 4,637 #2 Posted May 11, 2019 (edited) I don't think that oil issues are something to be concerned about in the Onans.Puking intake valve seats seem to be more of an issue.I hate to say this but I honestly feel that we all get to concerned with non issues.Good oil changed regularaly is what matters.JMHO Edited May 11, 2019 by JAinVA 1 Share this post Link to post Share on other sites
1990Onan520-H 15 #3 Posted May 11, 2019 45 minutes ago, JAinVA said: I don't think that oil issues are something to be concerned about in the Onans.Puking intake valve seats seem to be more of an issue.I hate to say this but I honestly feel that we all get to concerned with non issues.Good oil changed regularaly is what matters.JMHO Zddp content is no joke on an engine that needs it. I've seen engines wipe cam shafts within a few thousand miles with the wrong oil in them. Granted these are automotive engines and probably have higher lift cams with higher pressures on the valve trains but I still worry. Share this post Link to post Share on other sites
JAinVA 4,637 #4 Posted May 11, 2019 (edited) Again your talking about engines operating in totally different regimes.Automotive engines are water cooled and operate in a totally different environment than a garden tractor engine.If this was a problem then you can bet that the guys here would be screaming about the issue.You asked and I gave you an opinion.Take it how you want but I am in no way concerned about my Onans and my oil choice.These engines were designed at a time before computers were common place.To them in my opinion ,oil was oil. Edited May 11, 2019 by JAinVA Share this post Link to post Share on other sites
lynnmor 7,824 #5 Posted May 11, 2019 My automobile engines run at about 1/2 the RPM's of my Onans under normal operating conditions. I think that the OP has a legitimate concern about anti-wear additives no longer being used in the SN oil. I just bought a zero turn mower with a Kohler engine and decided to buy some Kohler oil because it does not have the SN designation. I hope to find the actual zinc content of that oil, and if it is high I will use it in my Onans as well. 1 Share this post Link to post Share on other sites
1990Onan520-H 15 #6 Posted May 11, 2019 5 hours ago, lynnmor said: My automobile engines run at about 1/2 the RPM's of my Onans under normal operating conditions. I think that the OP has a legitimate concern about anti-wear additives no longer being used in the SN oil. I just bought a zero turn mower with a Kohler engine and decided to buy some Kohler oil because it does not have the SN designation. I hope to find the actual zinc content of that oil, and if it is high I will use it in my Onans as well. Not to mention they're water cooled and don't run as hot as air cooled engines. Check out Amsoil zrod. I use it in my classic cars with flat tappet cams. The engines were almost instantly quieter once I started running it. Its just pricy so I was hoping to avoid it in the mowers. Share this post Link to post Share on other sites
ET160 30 #7 Posted May 11, 2019 I just changed the oil on my '75 B80. I had 20W-50 on hand and put that in. Share this post Link to post Share on other sites
