Caterpillar 3196

I m guessing The guys telling to run at 70% load are not the ones paying for the fuel... or the maintenance

What speed do you get at 50% ? As long as the boat is fully on plane, or the engines are running at operating temp, they're fine

Caterpillar recommends running them at 80% load. From what I've seen on most all CAT powered boats, the Gallons per mile from 1650 rpms up to 80% load stays virtually the same.

Maintenance intervals are given in hours or gallons burned. The more fuel you burn the more maintenance...

As to fuel burn, the faster you go, the more fuel you burn per mile. For instance we can get as low as 3.05 gallon per mile at 18.4 kts (1500 rpm, 36%) to 4.3 GPM at 23kts (1850, 56%). I didn't even write down the exact numbers at 80% but it's about 5 GPM (about 125gph for 25.5/26kts).

400 off the top is the cruise RPM. 300 of the top is the high cruise.

Watch those 3196's closely, do not be afraid to check your oils twice a year looking for sodium increase.

What temp do you run at cruise I'm about to purchase a searay 480 motor yacht with 3196's they are running at 200 at 2100 rpms diesel mechanic says they should be at 185
Thanks in advance for any input

That's where these are rumming right at 200 how long have you been running them at that temp

Recently surveyed a boat with C12's (3196's). The engine surveyor was adamant about oil samples for sodium and aftercooler maintenance for the 3196/C12 Cats. He also said they run hot... 200 plus a little.

Thanks for the help from what I've seen they run at around 200 just wanted to confirm before I bought the boat. I've heard a lot about after cooler problems aperently the boat I'm buying had them serviced last year.

If not already done, get a copy of the invoice to confirm the aftercooler service...

I just emailed the broker asking about receipts for work done.

Good, Cat recommends servicing every 13000 gal of fuel, or 1000 hrs, or 2years which ever comes first and "replacing" the aftercoolers every 6 years.

Yes, this is a fairly recent CAT mandate or recommendation, before it was just service them every 1000 hours and never a provision for replacement.

What I don't understand is back in the old DD 2 stroke days, I don't remember having any issues with aftercoolers on those engines.

Because back then nobody cared about the weight of these things...

I m about to pull 325hp 8V71Ns with Allison gear and put in 450hp cummins C series with ZF... weight difference is over 3000lbs

Yes, and probably many still think 1000hrs. regardless of calendar time. Think Cat changed last year... I as told because of warranty's. The same for 3406's, not sure about the other models. There are a lot of Cats out there that would require new aftercoolers... Owners not very happy! I was also told the 3196 aftercooler was cuprous nickel which you think would last last if serviced regularly. Speaking of old DD's... had a pair of 453n's and 671tib's... don't recall any aftercoolers.

Ralph, I thought you would know about the DD's. My understanding is intercoolers/aftercoolers do the same thing...