Results 1 to 5 of 5
  1. #1

    Default Cummins V-504 reliability compared to today standards?

    Maybe this sounds like a bit stupid question, but I will explain why I ask this. I am "rebuilding" a 9meter (30feet) fiberglass boat, but due to life circumstances, project was stopped for more than twenty years. Inside is a really new (never used) V-504 rated at 195hp/3000RPM (marine version, even with stainless steel exhausts made originally by Cummins). Since I am not in a position to re-power for some brand new engine (lighter, better fuel consumption,...) I will use this one. There is not much information on the internet I could find about it (since it is vintage engine), but what I found is promising. I also talked to some mechanics who worked on them. It seems to me that V-504s were the most reliable engines from those V series (V504, V555, V903) at that time. Another plus to keep it is because I have almost every possible part as spare(even camshaft, crankshaft, injectors,...). Downsides are big weight and fuel consumption compared to modern engines. Mechanics told me that the weakest spot of those engines was/is poor lubrication of camshaft which led to camshaft failure, but that it can be easy prevented by following some easy procedure at start-up (whole idea of procedure is to increase the oil pressure before reaching higher RPMs and while the engine is not at the operating temperature).
    Considering all this, can someone experienced tell me what to expect compared to today standards. The engine will be used as light duty (recreational boat with some longer trips), and will be driving the Borg Warner clutch and Sternpowr outdrive (all vintage I know, but all new and never used). Although engine is big, it is easily accessible from both sides in engine compartment, so maintanance inside the boat will not be the problem, I guess.
    I would really like to here your opinions, thank you.


  2. #2
    Join Date
    Sep 2008
    Maryland - USA

    Default Re: Cummins V-504 reliability compared to today standards?

    I'd expect that you will be quite happy when you are done...

    The "newer" engines run with much more stress and don't last as long as the "older stuff". A 30 ft fiberglass hull should be a breeze for that engine as long as the gear ratio and prop are selected correctly...Just keep up on the maintenance and you should be fine.

  3. #3

    Default Re: Cummins V-504 reliability compared to today standards?

    Thank you for your answer. Sorry for my late response.

  4. #4

    Default Re: Cummins V-504 reliability compared to today standards?

    It will live longer if you run at 2800 RPM rather than 3000 on a regular basis.

  5. #5

    Default Re: Cummins V-504 reliability compared to today standards?

    Just to update since I am on the water since March of this year.

    I have put 130 hours on the engine. Very reliable package and I am very satisfied. A boat is not typical (if any is) so it is not exactly a breeze, but the engine is not overloaded. It is a semi-displacement boat and its weight is around 4000kg when fully loaded (all tanks filled and 5 persons aboard). My cruising RPMs are mostly between 1400RPM and 2000RPM, but most of time it is 1400-1600RPM and the engine temperature is constant at correct range. At 1400RPM, boat speed is 6.2 knots/h in displacement and the fuel consumption is about 6.2 liters/h which gives 1 liter per 1 knot. I am very satisfied with that consumption. No smoke at any RPM. Unfortunately, I can't achieve planing, although that would not even be my preferred way of driving due to consumption. Boat is stern heavy because of engine weight. Even flaps do not help. It would be nice to try propeller with greater pitch, but that is expensive sport to experiment. Then again, it is better to be underloaded than overloaded. I have a feeling that it could have greater pitch since the engine achieves full RPM really easy and fast and stops at exactly 3000RPM, but maybe it would be more RPM if there was not the governor limit (no smoke at all). Anyway, I am enjoying the displacement ride and have made quite a few beautiful trips.

    The gearbox ratio is 1:1, and the reduction ratio in outdrive is 1:1.6 (slower on the propeller side) and propeller is 19''x17'' (Diameter x Pitch) 65% BAR, three blades Equipoise type.

    The boat was originally with two gasoline engines 150hp each, lighter and achieving 27 knots top speed. And on the net, I have found video of same boat planing (no speed shown), with 270HP VW diesel engine (newest generation), which is 400-500kg lighter than V-504-M. So I presume that with planning everything is connected to weight in my case and maybe a propeller choice.

    As for the engine, it is not too loud as I have read somewhere, of course not compared to new engines, but it is pleasant and some of my guests have no problem sleeping during the ride. It is loud if I open the hatches, but when closed, noise is as expected. Nobody complained, actually I even like that sound now. Maybe two really big waterlocks contribute to that, but that is only for the noise from exhausts. It is really steady, no unpleasant vibrations. I have never had problem starting it and there are no any prestarting heaters on the engine, but we shall see about that in the winter (until now checked with ambient temperatures from 10C to 37C). First oil changed at 50 hours, second at 100 hours and each following will be at 100 hours intervals (all filters and procedures included). As I have read one case somewhere on the net about V-555 engine, I have exact same case - engine does not like oil added to HIGH mark on the dip stick, it spends oil somehow or burn it, so I have let it to do so to see when will it stop, and it stopped exactly at the middle between HIGH and LOW mark. And it stays there forever, so now I always pour the oil to that level instead to HIGH mark. Maybe it has something to do with engine angle on the boat, although that angle is rather small. While speaking of the oil, pressure is at is high value (80PSI-85PSI) as long as the normal operating temperature is achieved and after that follows the engine load (40PSI at idle, 70-85PSI at normal load). Oil used is 15W40 mineral oil. Not sure exactly should I trust mechanical or electrical instrument about maximum oil pressure since both are really old type (have the time and climate affected the mechanical instrument precision!?), they agree on lower values, but on maximum values electrical StewartWarner shows 65-70PSI, while mechanical shows 70-85PSI.

    Only thing I will probably change is to add some newer type of belt tensioner for alternator and internal fresh water pump, so the process can be done more comfortably and more precisely, I do not like using some type of tool as a lever to adjust the tension. For the raw water pump, I have already done that and it is so easy process now, although it is a bit harder to access. Anyway, access is really not a problem for anything, since there is only one engine and wide space from both sides. I think, after doing many things myself during restoration/renovation process in engine room and using it afterwards, I will never want a twin engine boat, except maybe in some really big boats (size is relative, of course). Even with one engine, working space is at premium, and that made easy to fix some bugs while on the trip at minimum time and effort (one of oil hoses was badly crimped and it burst at the connection, so had to change it).

    Well, this post has gone too long now, the conclusion is that after the first season and 130 hours of operation I find it very reliable and hope that it will stay that way in following years. I will run it (as much as possible hopefully) and we shall see.

Similar Threads

  1. 1992 Magnum III Block compared to 2001 Mercury XR6
    By jonkell in forum Mercury Mariner Outboard Forum
    Replies: 6
    Last Post: 03-29-2012, 07:43 PM
  2. 430b engine oil change, what spec of oil by today standards?????
    By mcw in forum Volvo Penta Gas Engine Forum
    Replies: 10
    Last Post: 02-21-2012, 05:02 PM
  3. HorsePower, Old Rating Method Compared to New
    By tboltmike in forum Johnson Evinrude Outboard Forum
    Replies: 5
    Last Post: 10-13-2010, 01:59 PM
  4. shaft length compared to other side, motor mounts adj
    By bobct in forum Crusader Marine Engine Forum
    Replies: 9
    Last Post: 07-15-2010, 09:29 AM
  5. Cummins 6CTA 450hp reliability problems
    By Alistair Jack in forum Other Diesels Mfgs and General Diesel Questions
    Replies: 1
    Last Post: 05-17-2001, 08:10 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts