StoneandSteel Posted 4 hours ago Share Posted 4 hours ago On my ai400 the valve bridge on cylinder #1 and #6 keeps jumping off even after doing a full valve adjustment. It will run for a few days but eventually I notice a decrease in power and a lot of white smoke which tells me the bridge came off again. I don’t see any noticeable damage to the valve springs or rocker arms. Any idea why this is happening? Quote Link to comment https://www.bigmacktrucks.com/topic/75278-%E2%80%9807-mack-ai400/ Share on other sites More sharing options...
fjh Posted 4 hours ago Share Posted 4 hours ago So is it possible you have a sticky valve on one cylinder ? one slow returning valve could cause what your seeing! I have only seen it happen once and never resolved the issue! Note be sure to replace the rocker bolts these have had breaking issues in the past! Have you checked the push rods for straightness! Quote Link to comment https://www.bigmacktrucks.com/topic/75278-%E2%80%9807-mack-ai400/#findComment-571252 Share on other sites More sharing options...
Joey Mack Posted 3 hours ago Share Posted 3 hours ago Did you run the valves by the book, or the same way as Caterpillar or John deer 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75278-%E2%80%9807-mack-ai400/#findComment-571254 Share on other sites More sharing options...
Joey Mack Posted 3 hours ago Share Posted 3 hours ago Have you looked up at the cam lobes recently? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75278-%E2%80%9807-mack-ai400/#findComment-571255 Share on other sites More sharing options...
StoneandSteel Posted 2 hours ago Author Share Posted 2 hours ago I followed the valve adjustment procedure per the manual and a video off of YouTube on an ai400 with a Mack mechanic. I did pull the push rods and roll them across a flat surface. They seemed fine. I’m going back into the engine today to start all over from the beginning and try it again. I’ll check all the suggestions so far. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/75278-%E2%80%9807-mack-ai400/#findComment-571262 Share on other sites More sharing options...
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