Detroit Diesels in a 1983 54b Bertram

I am interested in purchasing

I am interested in purchasing a 1983 54' Bertram convertible.
The engines are Detroit Diesels 12V71TI at 800 hp. I have several questions about these engines.
1. How reliable is this model engine? Any particular problems?
2. How many gallons per hour would they burn.
3. Annual maintenance costs assuming no major repairs.
4. How many hours before they would need a rebuild?
I am trying to determine if I could afford to run this vessel without killing myself.
Thanx

"Hello Paul,
I am not qualifi

"Hello Paul,
I am not qualified to answer these questions, but will relay information that I have learned from others on this site. This is all general DD information regarding 2strokes, as I have never worked on one as large in size as yours.

1) Detroit's are known for being good running engines, but keep an eye on the seal between blower and engine block. When this begins to leak oil will be pulled from the crankcase and consumed in the cylinders. (known as a runaway, and can be hard to shutdown)
2) GPH is variable in that factors like a clean hull, weight, and proper prop size must be taken into account.
3) Maintenance would only get costly with a major repair like all Diesels. DD strongly recommends you only run a single weight oil, as I have heard multi weights can lead to a runaway.
4) When it comes down to a final rebuild, Detroit's have an advantage over say a CAT because they have removable cylinder sleeves, where CAT does not (throw away blocks)

Hopefully one of the other more experienced active members will chime in to offer their wisdom on all I have missed. Best of luck."

"Paul ... I purchased a 1984 B

"Paul ... I purchased a 1984 Bertram 54 with the 12V71TI engines in December. I did quite a bit of research on the engines and I'm comfortable that they will be fine. They seem to be good for approx 4000 hours. My starboard engine was rebuilt at 4000 hours and I just had the port engine rebuilt at 4500 hours. They are tough and known to be very reliable. With an engine survey, at purchase it was determined the port engine was ready for rebuild. One ring was broken .. the sleeves worn out ... 4500 hours since new ... and it still ran strong, which is impressive.

If you go 10 knots, (which is practically idle), it will only burn 20 gph or so. But ... cruise at 22-24 knots and it will burn 65-75 gph. That is expensive with the price of Diesel at $2.40 BUT will be VERY expensive if the price of fuel goes to $5.00.

Still ... it's a big boat and with all the money you save buying an older Bertram 54, you can spend more on fuel.

The rebuild was $45k+++ because there is always so much more you want to do and a couple things came up like bad cams and a cracked head. Then the transmission needed a rebuild due to a bad main shaft ... $10k. It's possible to do a cheapy overhaul for $25k-$30k but you will know you are cutting some corners.

As I'm sure you are experiencing, the purchase price is very compelling. It's common knowledge that if you can find a cream puff boat that somebody else restored and make your best deal, that will be cheaper than finding a fixer upper.

Mike"