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Wondering if it makes much of a difference whether I have the mechanic adjust the valves and injectors with the boat in the water or out of the water. Only negative I can think of out of the water is that he cannot turn engines over to test. My babies smoke like Cheech and Chong when there cold – which I hear is somewhat normal for cold turbo charged Cummins 903’s, but hope proper injector adjustments may reduce it. Any feedback appreciated, thanks – Scott.
I think virtually all mechanical turbo engines smoke when cold....by cranking and holding down the stop button you crank without fuel being injected and that can reduce, but likely not eliminate, cold start smoke....It also insures you don't have water in a cylinder which would otherwise bend a pistion rod.
Setting such adjustments at the wrong temperatures is a bad idea....what's Cummins call for? Follow the Cummins spec...
Also, why strain your engines starting them cold?? put in electric block heaters and warm them instead for,say, an hour...better lubrication, better combustion, less wash down, less starter strain, less battery drain,immediate start, etc...a cheap alternative is to run an electric heater in your engine room for a day before starting...
Valve adjustments can be set cold but SHOULD be checked hot. How 'ya gonna do that with the boat on the hard?
Thanks Guys - When I say engine is 'cold' I mean she hasn't been started in past 24 hours on a 70 degree day. Previous owner really neglected her and $600/engine for valve and injector adjustment seems like money well spent. The manual says you need a special tool (Cummins part number ST-1170) which is basically a dial indicator holder that screws into head as far as I can tell. The manual also says you can use the "Torque Method" for injector adjustment, but the valve covers state you "Must use ST-1170 for Injector Adjustment". These are high performance 903's, so I'm going with sign on valve covers. Don't remember the manual making mention of checking clearances with engine hot when using dial indicator, but I will read again tonight as it would certainly dictate I have to adjust in water. Think they really smoke (it's diesel smoke) more than they should and hope injector adjustment will reduce.
So pending the manual makes no mention of checking adjustments with engine hot, do you think a mistake to have done out of water? I'm being a bit of a cheap hump - the yard I keep her in now won't charge me for bringing in my own mechanic. The yard slip is will probably add 50% to price (they did this last summer when I had new AC installed and it left a bad taste in my mouth - 20% OK, but 50%! I even found the AC vendor and scheduled him).
As a mobile marine mechanic for years if I did the adjustments on the hard and had to come back that would cost you. Always check the work while the mechanic is there.
Valve adjustments DO CHANGE hot or cold - make sure what the spec says in the book. For Detroits there is a "cold" spec but it is just to get the valves in the "safe" zone for initial starting - to get it right they have to be set hot.
YMMV with 903s - the book is right, eveyone who thinks they're smarter than the book is wrong :)
I've rebuilt cummins on Taylor forklifts. Aslways went by the book,,,,an old aviation habit,,,,,,nominal set cold,,,,,buy you got to get em hot to really set them properly. Now if it is an injector problem, not knowing how old they are,, moisture or water will cut the nozzle which can cause smoke. Only you would know the history of past water problems in fuel. If the engines are old the injectors could need rebuilding, most times at a quality diesal shop,,nothing I would want to do myself. That is a relatively simple job. Take em out let them rebuild,,,,reinstall. Timing could be a slight issue also.
Yep - got to agree. As the old saying goes if you are going to do something do it right. Think this would best be done in the water. Thanks All