Blown V Drives

Rseneschal

New Member
Feb 6, 2016
2
Tampa FL
Boat Info
1991 420 DA
Engines
Twin Cat 3208 435 HP
Hello CSR first post here but not my first Sea Ray. Little back story. Boat is a 1991 420 DA. I purchased this one about 3 years ago got it for a pretty good price knowing that I would need to do some work to it. Purchased it in Pensacola and brought it across the gulf to the Tampa area. Boat had 375 HP Cat 3208 Motors ZF trans and MPM ZF 160 V drives. Motors had seen better days and the decision was made that we needed to rebuild them. During breakdown it was discovered that previous owners did very little in the way of maintenance and the cost to rebuild was going to be upwards of 80k. I decided for that amount of money i would just go ahead and replace them with upgraded rebuilt 435 HP 3208's. The boat came out of the factory weighing 20,000 lbs after 33 years and the addition of a Marlin tower the boat now tops 30,000 lbs. So hence the decision to move up in HP. So now on with the story. The mechanic was paid to remove the old motors, prep the new ones and get them installed. All was good until the first run of the boat. 15 minutes out of the marina after being on plane for about 10 minutes i felt the starboard motor start to feel like it was struggling to keep up, speed dropping off and it was coming off plane. I pulled the throttles back to idle and the starboard motor immediately stalled out. Both motors put into neutral, restart starboard put into gear and again immediately shut down. Of course decision was made to limp back to marina on port motor. Got about half way back and port motor did the same thing. Dropped anchor called sea tow called the mechanic and then cracked a beer. Not much else to do at that point. Got towed back in, mechanic came out to the boat, said the v drives needed a fluid change and bearing greased. Paid to have that done. Did sea trial with mechanic boat ran there was some noise from the v drives but it seemed to quiet down. Mechanic suggested to run the boat for a few hours not pushing it hard. We did that with the family seemed to go ok. Noise was still there. Went out a second time and started to get the same feeling in the starboard motor. Said F it limped back to the marina and pulled the port V drive out. Was not easy by myself. Why you might ask did i pull the port and not the starboard. Well i will tell you. The 435 hp Cat 3208 was the largest motor that was put into this boat and the clearance on the aftercooler is less than 1/2 inch. So to get the V drive out i would of had to remove the intake to be able to lift the back of the motor up high enough to remove the bolts holding the V drive to its mount. So V drive out on port side, called mechanic and told him i was bringing it to his shop so that we could break it down with me standing there. At this point i just assumed that the bearings were fubar so i had gone ahead and ordered new ones. In case you are wondering all 8 of them cost right around 740.00. i have the numbers if anybody needs them. Moving along. Upon breakdown it was discovered that the bearing were fine but the gears not so much. Inside the case it was discovered there was rubbing where one of the gears was what i can only assume was rubbing on the housing. This indicated to me that motors were not lined up correct. Also of note and did intentionally leave this to the end was that i discovered while pulling the V Drive out that none of the motor mounts on the outbound side of motor were tightened down. All 3 motor mounts, not the studs that actually connect to the motor but the bolts that attach the motor mount to the stringers. So i can only assume that the with them being loose and the big ol motor moving around that it threw the shaft even further out of alignment and it just chewed those gears up. The mechanic is coming out on Thursday to pull the intake on the starboard motor and the V drive, i expect that we will find that one in much worse shape. I have already checked and that motor is in the same position of not having the outbound motor mounts tightened down. Now comes the big question. These gears are not available anywhere that i can find. There is one set available on ebay the guy wants 3500 per gear. A new ZF 286 IV costs about 5900 and includes a warranty. The drive shaft would have to be shortened and the back of the motor would need to go up just a bit as it only comes in 14 degree down. Has anybody made this swap or something similar. I would prefer to not have my boat on the hard for the rest of the year.
 

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Sorry to hear. Not a lot of good options. For a $5K differential between old/unknown ebay gears and new with warranty, I'd spend it up front on new w/warranty. I'd at least expect to have to rebuild the Ebay versions before install anyway and if anything else goes wrong, 5k will be a rounding error.

However, there are a couple of big issues, the down angle being one (cant just drop a different angle gear in, nothing in the drive line will be aligned). The second is making sure the new gear is sized right. The 286 IV is about maxed out for that engine and depending on the ratio might exceed the specs.

Since the boat is much heavier and nothing is mating up, might be a good time to involve a repower shop and get it done right. I love CAT's and getting those 3208's set up right would be a nice upgrade.
 

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