Poly Flex helped James Hamilton, the owner of MV Dirona, to overcome issues with height restrictions and the inability to lift the engine to replace his engine mounts. Poly Flex developed and manufactured custom engine mounts for his vessel.
MV Dirona is a Nordhavn 52 powered by a 6.8L John Deere Marine Propulsion Engine producing 266 Hp. This is an ocean-capable recreational vessel with a range of 4,000 nautical miles. MV Dirona has crossed the Pacific and Indian Ocean, plus the Atlantic Ocean three times.
While in Newfoundland, James noticed his engine mounts started deteriorating after 8,000 working hours. One morning after picking up vibration in the drive line he measured the rear mounts and noticed a 0.025” drop.
James knew the engine mounts would need replacing fairly urgently and the drive line would need to be realigned. He did a temporary adjustment and raised the mounts by the 0.025” and continued onto Bras d’Or Lake.
James contacted Poly Flex and spoke to the General Manger, Jason. He had worries about the height restriction and not being able to lift the engine up far enough to remove the old rear mounts. After the conversation, a proposed solution to use custom engine mounts was agreed upon.
To get the engine low enough for alignment our P#8.4CTF and P##8.4CTF mounts were modified to suit a low-profile core, this would drop the minimum adjustment height lower allowing James to align the engine properly.
James’ biggest challenge was the engine wouldn’t lift high enough without disconnecting the prop shaft and exhaust. Jason said, “no problem” and suggested cutting the old studs and replacing them with hardware that included removable centre studs.
Once the custom engine mount replacements, James got underway with changing the engine mounts. The front mounts came off quickly using a hydraulic jack. He lifted each corner of the engine, removed the old mounts, disassembled them, swapped out the mount inserts, and reinstalled the custom engine mounts in under thirty minutes total.
The rear mounts were more challenging; however, the solution was surprisingly simple. Rather than lifting the engine, they left the engine in place and lowered the adjustment nut enough to allow the mount to no longer bear any weight. The engine was still supported by the other three engine mounts. This worked well for James and allowed the mount to be changed in seconds. Because we sent James new hardware with a removable centre stud, he was able to use a cut-off saw and cut the old stud to allow for an easier change. James stated, “with the new removable-stud mount hardware, the mount inserts can now be changed in minutes rather than hours”.
After spending some time pulling the old mounts apart with a impact wrench James was able to reassemble the mounts and reinstall them. With the new configuration James will be able to change isolation cores in under an hour. However, they don’t expect to have to replace these for another 8,000 working hours.
With the new custom engine mounts installed and a fresh alignment, James is happier than ever stating, “Dirona now is running as smoothly as we can ever remember, possibly better than since new”. James believes the Poly Flex mounts are a very well made mount and is happy with the longevity as well. He is confident the new custom engine mounts will last considerably longer than the seven years and 8,000 hours due to design changes with the thrust washer and improvements with the advanced polymer isolation core.
For more information regarding Poly Flex Mounting Systems click here, including our Core Replacement and Engine Mount Assembly Procedure. For enquires regarding replacement engine mounts or custom engine mounts, contact us today.