Magnum 18 Locked up
 

After rebuilding my Magnum 18 (for badly pitted cylinders) after about 30 minutes of runtime, I locked up the #1 rod on the crank.
I'm 100% certain I had the main bearing oriented the correct, I'm also certain I reinstalled the little check ball and spring for the oil pump correctly. Also, the machine shop said the rod and crank tolerances were good. And yes, I torqued the caps correctly and they were oriented correctly.
Has anyone had this problem before? I want to make sure it doesn't happen again.
So far the only theory I have is that perhaps some silicon from sealing the case may have blocked the oil feed passage to the #1 rod.

Do I understand this correctly, that your #1 cylinder has a seized rod to crank journal situation ?? And after only 30 minutes of run time ?

:bigthink:

Just wondering, was your “oil sentry” hooked up and operable? If so it certainly should have been getting oil to where it needed it. Another thing to check are the hoses to the remote filter if you have one. I’ve seen them swell completely shut not allowing either any or enough oil through.

That's affirmative. I had never run this engine before in actual working situation. It'd been sitting for about 6 years.

The oil sentry wasn't hooked up yet, I was adjusting the carb, just got it set, and almost ready to work on wiring when it locked up. Yeah, stupid, I know. Probably should have done it the other way around.

If one used more liberal "RTV" type sealer than necessary, it can cause a lack of flow, or stop the lubrication oil.
I don't know your experience or abilities so I won't try to guess.
Review the lubrication diagram if you haven't, and that will help you determine
where the problem occurred in the system.
Also if it has a divorced oil filter, make sure the oil lines are routed so as the flow into the filter is directed to the outside of the filter, and comes out of the center of the filter to lubricate the engine,
AND that it is the proper filter. (I use the larger FL400 Ford filter) it has a large flow, a good filter and is inexpensive compared to Kohler.
If the filter had a drain back check and it is hooked up backwards, bad things happen.
The fact that it ran 30 minutes makes me think that the flow was restricted by sealant or other debris
Do post back with your findings so we can help.
Those are my favorite engines and I have built a few.:beerchug:

if the oil lines to the filter are reversed you won't have oil pressure .btdt