Muriel 42LRC322
Veteran Member
- Joined
- Mar 9, 2021
- Messages
- 55
Thank you for this…. Clear… but I can t exchange the propellers as I thought…. Opposite side will go reverse…. ?
................. This boat is going to be my last boat and I am willing to re do and re check everything and cruise in serenity. ....................
I though these engines were simple and easy to rebuild?
DDs are easy! I learned 55 years ago with a book and a guy I could call on a radio. No idea how many since.
The liners are easy to pull. Get a tool like the one shown. Put the piston at BDC, remove the rod cap, place tool on piston and adjust to span. Tool goes into 2 opposite ports. Rotate the crank - liner, piston, and rod are out. You can pull all liners in 10 minutes.
Pulling the head is the hard part.
Tool is on ebay. Search for "Detroit Diesel liner tool" about $125
Pulling the head is the hard part.
Thank you for your recommendation. I say "overhaul" as the translation of a French word actually. I just wanted to do a check to present the engines at her best....but I understand your point.
Thank you for the gear box recommendation also...
I repowered with the 4045TFM75. It's a great engine. Very smooth and very clean.
The problems and extra expenses I ran into during the swap were mainly caused by John Deere's strict requirements to get the extended warranty. In particular exhaust back pressure and reaching 2600 RPM with 100% load at WOT. This was 10 years ago, so I don't know if they still have the same program.
The exhaust back pressure requirement was not initially met so the boat had to be pulled again and a entirely new larger diameter exhaust system fabricated and installed including new muffler and custom built elbow.
Based on "the curves" my existing prop and Velvet drive transmission ratio were not a good match, so I had to buy a new prop. The transmission was exchanged for a rebuilt from a local company that specializes in these transmissions.
The existing raw water cooling system was too small, so I had to install all new thru hulls and strainers. The fuel system ended up being mostly replaced as well.
I also had to replace the prop shaft, mainly due to the old one having a bit of wear, so this was the time to do that job as well.
After another failed sea trial I had to pull and repitch the prop to meet the WOT requirement.
The end result has been great, and I don't regret the decision, but it cost more than I expected.
I repowered with the 4045TFM75. It's a great engine. Very smooth and very clean.
The problems and extra expenses I ran into during the swap were mainly caused by John Deere's strict requirements to get the extended warranty. In particular exhaust back pressure and reaching 2600 RPM with 100% load at WOT. This was 10 years ago, so I don't know if they still have the same program.
The exhaust back pressure requirement was not initially met so the boat had to be pulled again and a entirely new larger diameter exhaust system fabricated and installed including new muffler and custom built elbow.
Based on "the curves" my existing prop and Velvet drive transmission ratio were not a good match, so I had to buy a new prop. The transmission was exchanged for a rebuilt from a local company that specializes in these transmissions.
The existing raw water cooling system was too small, so I had to install all new thru hulls and strainers. The fuel system ended up being mostly replaced as well.
I also had to replace the prop shaft, mainly due to the old one having a bit of wear, so this was the time to do that job as well.
After another failed sea trial I had to pull and repitch the prop to meet the WOT requirement.
The end result has been great, and I don't regret the decision, but it cost more than I expected.
I repowered with the 4045TFM75. It's a great engine. Very smooth and very clean.
The problems and extra expenses I ran into during the swap were mainly caused by John Deere's strict requirements to get the extended warranty. In particular exhaust back pressure and reaching 2600 RPM with 100% load at WOT. This was 10 years ago, so I don't know if they still have the same program.
The exhaust back pressure requirement was not initially met so the boat had to be pulled again and a entirely new larger diameter exhaust system fabricated and installed including new muffler and custom built elbow.
Based on "the curves" my existing prop and Velvet drive transmission ratio were not a good match, so I had to buy a new prop. The transmission was exchanged for a rebuilt from a local company that specializes in these transmissions.
The existing raw water cooling system was too small, so I had to install all new thru hulls and strainers. The fuel system ended up being mostly replaced as well.
I also had to replace the prop shaft, mainly due to the old one having a bit of wear, so this was the time to do that job as well.
After another failed sea trial I had to pull and repitch the prop to meet the WOT requirement.
The end result has been great, and I don't regret the decision, but it cost more than I expected.
Great input and information Bob. This is where to wrench meets the pocketbook and beyond relevant. Can I ask you about the back pressure demands for that engine. When you enlarged the exhaust run what diameter met the requirement ?
Rick
Thanks, Rick. We made it work by going from 4 to 4.5". A 5" muffler had too big of a footprint. The 4.5" muffler is rated for 170HP for diesel engines. A 4" muffler of the same design is only rated for 125HP.