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GM 454 Crusader engine preventive maintenance, **New Owner**

Discussion in 'Engines' started by Beauregard, Oct 13, 2014.

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  1. Beauregard

    Beauregard New Member

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    Massachusetts
    I Just bought a 1989 (37) Silverton with (2) 454 Crusader engines with only 450 hours total. This survey concluded as few "engine must do's" I need to complete in order to preserve continued service throughout the years, and Iam looking for your feedback.

    1. Survey said to remove and inspect both engine exhaust risers for possible replacement. I understand the importance of consistent replacement, but what am I looking for once I take off the risers? What is an acceptable allowance of corrosion? Previous owner stated that the risers are new.

    2. This vessel will be used in salt, however it is freshwater cooled; does raw salt water make it to the exhaust manifold (trying to see if this needs to be inspected also) past the risers? These do not look fun on my pocket to buy.

    3. During the sea trail run, the Starboard engine ran at 180 degrees and the port ran at 165. The survey deemed that the Starboard heat exchanger should be cleaned out and stated that it is a seamless process. Then hopefully the temperature should back down to match the port 165 degree levels. Would you recommend using this new product called "Sea Flush" to clean out engine heat exchangers? How have you cleaned your heat exchangers, if so, what is the best process for this?


    Please note that Iam trying to learn all I can about this machine and Iam no mechanic.. I look forward to your responses.
  2. NYCAP123

    NYCAP123 Senior Member

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    Welcome to YF Beauregard. I'll leave 1 & 2 to the mechanics here to give you better answers. What I will address is that you have scary low hours on those motors unless they're replacements. Motors don't like to sit idle. Sure that's not since major overhaul (SMOH)? The other thing is that temp. It could be something as simple as the sensor or a bad thermostat, even a clogged sea strainer or bad impeller. It's only a few degrees high (one generally runs about 5* above the other). Did the surveyor check the temperature at your motor or did he go by the helm gauges? Does it hold at that temperature? If so any problem should be small. A real saving grace is that she's a fresh water boat, although some fresh water areas have a snail problem.
  3. RT46

    RT46 Senior Member

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    I would pull and replace the risers.
    You cant tell when they are going to go from looking at the outside.

    When they do fail you suck water into the engine through the valves when you shut down, that usually means the engine is toast unless you get the water out right away and don't bend valves, push rods, or piston rods.

    I recommend boiling the risers out every two years and replacing every 4-5 years.

    the 8inch risers cost around $200 each, you need 4 of them, plus gaskets, throw in a few hose clamps and hoses if needed and you are upto $1000 DIY project every couple of years.

    The 454 is a great engine, that is simple to work on and there are still lots of parts available.

    You will be happy with 454 Crusaders.

    change the oil, keep them tuned, cool and clean and they will last a long time.


    AS far as one engine at 165 and the other at 180 that could be just about anything from a faulty gauge, to different thermostats, to a warped head;

    a few other things to consider, sometimes one engine is used to heat domestic water and that engine will usually show a cooler temp.

    were both engines operating the same wot RMPs, could be one prop is fouled.

    Other reasons why one engine could run hot and not the other, raw water pump or impeller, raw water flow, coolant, heat exchanger, also those engines have a trans and oil cooler that can catch be blocked with pieces of the impeller.
    Last edited: Oct 13, 2014
  4. Beauregard

    Beauregard New Member

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    The surveyor did check the engine with a thermal scan and compared it to the gage, and all were corresponding correctly.. 180 degrees is read true. Also, I will just clarify that this vessel was not a prior fresh water boat but antifreeze cooled. She has been operating in the ocean prior to my purchase. Thanks for the help!
  5. Beauregard

    Beauregard New Member

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    Thanks for the recommendations.. The props were checked and cleared for operation.
  6. Old Phart

    Old Phart Senior Member

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    I dunno
    Does this boat also have a bad vibration

    and an obnoxious fume detector?
  7. Beauregard

    Beauregard New Member

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    Yes, I am guessing I got hosed. On the bright side, I am learning a lot of what not to do...
  8. Capt J

    Capt J Senior Member

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    1. do you have reciepts from the prior owner with the date on when they were changed? If you're going to take them off, you inspect the water passages for corrossion, scaling and blockage. I have never had risers boiled out, nor know anyone that has that done down here. I replace the risers every 5 years, you can also hit them with a heat gun at cruise speed and measure temperatures between them all. Usually you can tell a hot one that is clogged up doing this......

    2. Crusader exhaust manifolds are fresh water cooled, so no saltwater, just the risers.

    3. Check raw water impellor first, then go for the heat exchanger if the raw water impellor looks good....They should be changed every 2 years (impellors.)
  9. dsharp

    dsharp Senior Member

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    The manifolds are cooled by antifreeze. Salt water runs through the heat exchanger then dumps out through the riser/elbow. The engine running 165 is actually on the cool side for a heat exchanger cooled motor. A little vibration at wot is nothing to get too excited about. Check the engine alignment. If it's ok have the props checked.
  10. Beauregard

    Beauregard New Member

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    Thanks CPT J!!
  11. Beauregard

    Beauregard New Member

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    Thanks dsharp!!!