Detroit 8V92 DDEC 720HP

[happyours]

Can anyone comment on the Detroit Diesel 8V92 DDEC 720 HP 1996 vintage pro or con?

 

[Captain Ralph]

If your shopping for a boat, you really need some history and survey well.
I can find no exact model of a 720HP tune. That may not mean anything, Covington, SS, JT and others did some tune changes that did make some different tune ratings from factory.
Some good, Some ??//
I don't think any of these shops could change the DDEC computers for different HP ratings. I'm probably wrong on this. Roger Pensky did not share much when he took over DDC. Double check that HP number.

The last non DDEC 8V92 that fairly ran well turned for 735 flywheel HP. It's life was fair pending on the throttle setting. 1800 rpm, on plane it seemd to last a while. 2100+ rpm, life started coming down quickly.
8V92 DDEC went to 760 flywheel HP. The DDEC kept it economical a bit, but that is still (IMO) to much junk flying in those sloppy lungs to live long.
Some did live an amazing long life. I figure the owner practiced to keep his foot off the throttle.

As my opening line, you really need some history and survey well.

If your not a hands on guy with a cash reserve after you purchase a boat with un-known quality engines, ,,, Keep walking.

 

[happyours]

Thanks for your detailed response. I'm thinking about a 52 Hatteras Cockpit MY. It is interesting to look back over the ones presently listed on Yachtworld. Actually I think there are only 2 that specifically include the DDEC spec. A 1997 and HP is listed as 730 and a 1998 listed as 800 HP. Those without the DDEC designation a 1997 735 HP; 1997, 1996, 1995 1994 all at 720 HP. The Power Boat Guide lists the standard engine as 8V92 735 HP and a review in 1990 lists the standard power as DDC 720 HP and optional DDC 535 HP. So there are a lot of numbers to choose from and who knows where any given broker gets the information.

However the boat we are most interested is a 1996 and the listing shows 8V92 720 HP and has no DDEC designation. However we now know that they are DDEC engines.

 

[jim rosenthal]

In this case you would REALLY need a serious engine survey by an experienced Detroit guy. If the previous owner(s) stayed out of the pins and treated the engines well, you might luck out. Otherwise, not. 700+ hp is a LOT of juice to pull out of those engines.