Overhaul Therapy

[Jim Roe]

I have a 79, 43' DC with twin DD671T's. They have 2400 hours on them and the valve covers have never been off. The engines are finally at a point where they are somewhat hard to start and I get a lot of blue smoke that lasts for several minutes after starting. For the most part the smoke goes away after the engines get warmed up but it takes a long time to do so.
I had a DD mechanic look at them and he suggests I have my injectors replaced.
My question is: Since I will have a mechanic working on the engines replacing the injectors, would I be smart to have a basic overhaul done at the same time? I understand a basic consists of new cylender kits, gasket kit, cam bearing shell set, new cylinder head bolts, thermostats, oil pressure regulator and relief valve and lower end beraring kit. I do not want to through money away if I do not need to but, if something more major is likely to happen in a year or two because of age and hours I would rather spend the money now (getting ready to retire) than when my cash flow will be greatly reduced.
I would really appreciate any feedback anyone could give me.

Jim

 

[Boatsb]

Do the injectors need replacing? Does anything else need repair soon? I go by the saying if it aint broke don't fix it.
You need to have a trust in your mechanic that he will do the maintenace properly and not do unnecessary work. My guess is that the engines if under 450 HP should do 5k hours easily.

 

[Genesis]

Pull the airbox covers and have a look. Get a boroscope and see what's in there.

If the smoke is BLUE, its lube oil. But - it may be coming from the blower seals, which is easily fixed, or the turbo seals (also easily fixed).

Don't condemn the engine without evidence. Its entirely possible that the injectors need to be replaced, but before you start tearing things apart I would give those motors a good inspection. You may find that the cylinders are suspect and opt to perform a compression test, which will be dispositive as to ring and cylinder condition, but that's expensive too (about $100/hole) and again, not worth it if there's no indication that it needs to be done.

 

[Pascal]

blue is oil, i'd be wondering why the mechanic wants to replace injectors because of blue smoke and worry about him doing any work on these engines.

replacing injectors and tuning the engines is routine maintenance... unlike pulling blower, head, dropping the pant and putting in new kits...