Cummins 480CE Props with New Heads?

[Ray Isaac]

Good morning everyone,

 

Good morning everyone,

 

I have a 2005 Sea Ray 420 Sundancer with the Cummins 480CE engines. Before last season I had the heads replaced, after cooler cores replaced,  new injectors, new water pumps installed, and new turbos being installed this spring. I’ve done all this as a “1000 Hour Service” process as well as to eliminate the “dropped valve” issue. While running on my existing props the fuel burn was below the curve and numbers suggested by Tony, and the boat easily hit the rev limiter. The existing props were 22×25 (one was de-tuned from 27) and I believe I was running at about 2 – 3 mph where I should be at cruise. In September I ordered new Veem Conquest 22×25 props with a slight cup, hoping I could sea trial those before the end of the season. They did not arrive in time to do that (I just received them this week) and after discussions with the prop shop I decided to go with a 22×26 without any cup. We agreed on this since they advised me that the cup was equal to 1” of pitch anyways. I plan to install these this spring and sea trial to get GPH, RPM, and MPH figures. My question is since I now have the new style factory heads is the fuel burn and EGT still as big an issue for longevity? I’m cautious of doing any damage to the motors but also would like a little better performance, which I’m sure the new prop design, let alone the slight pitch increase, will provide. Additionally, is there anything else I should be looking for at sea trial or any other things I should be observant of?

Thanks in advance for the help. This forum and  have been extremely helpful. 

Topic

[Steve Lewis]

It’s in the SBMAR Online Store…….

SMX Marine Pyro EGT Gauge Kit

 

I bought 2 single engine kits and long wire.  See the gauges on my upper dash on the outsides.  I have the 460 so my dash layout is different but you get the idea.

We run 23×25’s.  Boat came with 23×27.  We reduced pitch 1 inch at a time over 2 seasons.  Last season we were able to run with the reduced props and the EGT gauges so we have our base line of temps AND we have the GPH on smartcrap.  We finally got our new heads installed this winter layup. We are still a little over the curve fully loaded but I am going to live with that.  We are looking forward to our big trip this summer up and around to Traverse City, MI.  We will be putting everything through its paces on that trip.

[William Walter]

New heads

Ray The heads were done on my boat before my purchase on my 480 ce..Both engines dropped a valve in the 300 hr to 500 hr range.I have about 1300 hrs now.I have not had any issues but would still be interested if anyone has heard of any issues after head replacement as well.

[Ray Isaac]

Thanks for the quick reply Tony! I believe I read in previous posts that I should be looking for a 13.1 GPH at 2,200 RPM’s? Is that correct?

Additionally, I currently do not have a way to measure EGT. Do you sell the sensors and wiring do that?

1 user thanked author for this post.

Mike Veal

[Tony Athens]

Tough to answer other than let’s hope you do not loose that 450 fuel burn curve. VEEM props very good but are not easy to easy to plan accurately from my limited past experience with them. Your  prop guy could easily be better that mine..   You are certainly doing all you can..

In the end, the idea to not to squeeze all that 480 Metric  HP from them–new head or not.  IMO, you still have a  430C @ 2600 RPM vs. a 465C @2600 RPM

[Author]

Replies