Registered users don't see ads

Perkins 4-108 rear engine seal...

Discussion in 'Engines and Propulsion' started by nat55, Nov 7, 2017. Add this thread to a FAQ

  1. nat55

    nat55

    Joined Feb 11, 2017
    108 posts, 95 likes
    Gulfstar 1979 Gulfstar 37
    Un BELFAST
    So, I have removed the transmission Velvet Drive 71C replacing the fwd seal. My mechanic suggests that I replace the main rear seal on the engine as well. The quoted time for this job is 16 hrs., does 2 days seem like a reasonable time estimate. I've been loosing oil from the transmission for a bit and the attached pic shows why! The front seal is buggered.....
     

    Attached Files:



  2. Michael Davis

    Michael Davis

    Joined Jan 5, 2017
    593 posts, 247 likes
    Beneteau First 38
    Ca Lyall Harbour Saturna Island
    While it's apart that may be a good idea. Looking at the service manual for my 4-108 it doesn't look like a 16 hour job. Looks pretty easy to do yourself.
     


  3. nat55

    nat55

    Joined Feb 11, 2017
    108 posts, 95 likes
    Gulfstar 1979 Gulfstar 37
    Un BELFAST
    Thanks Michael, I have another quote for 3 hours! I would do the work but my body just doesn't bend in the right places any longer. I've spent countless hours under the cockpit doing maintenance and replacing things. The guy that is rebuilding the transmission got it off in under an hour, it took me almost 4 hours the last time I did it! Granted, I got the hard part done of supporting the engine as the rear mounts are part of the transmission and the engine needs to be supported. I've ordered the seal from Foley engine as they seem to have a better seal than the "stock" replacement. I was reluctant to use Foley as I had heard some not very good reports of their service, my experience was very different, in fact they were very helpful and quite pleasant.
     


  4. Michael Davis

    Michael Davis

    Joined Jan 5, 2017
    593 posts, 247 likes
    Beneteau First 38
    Ca Lyall Harbour Saturna Island
    That sounds more reasonable. Glad you found someone to do it. It's hell getting older and less nimble, isn't it?
     


  5. nat55

    nat55

    Joined Feb 11, 2017
    108 posts, 95 likes
    Gulfstar 1979 Gulfstar 37
    Un BELFAST
    :)
     


  6. flyfisher999

    flyfisher999

    Joined Jun 27, 2018
    1 posts, 1 likes
    NAUTOR SWAN 44
    BLACK SWAN Un PORT LUDLOW WASHINGTON
    I came across your discussion on the seal replacement for the Perkins 4108 engine. I am just in the process of completing that job. I agree with you that it is hell getting older and less nimble.

    I have a 1973 Nautor Swan 44. The engine ran fine but leaked oil. When I pulled her to do the bottom I thought I would do the seal and maybe have a lot at the Velvet Drive BW trans. I had the trans rebuilt since I was concerned about it being the weak link in the drive line. That went well. Then the issue of getting the damper plate off and replacing it. It is held on by five hex cap screws. The allen wrenches just rounded the holes so I had to resort to other means. I finally found a vice grip pliers that I could grab the head of the bolts with and turn them off. Once loose they came out easy after some soaking with PB Blaster to loosen them up. To get a better grip on the heads I ground off the three rivets holding the damping plate together. It worked like a charm on 4 of the 5 cap bolts. The 5th would not allow a grip. I broke off the plate on the damping plate but still no love. I just continued and decided to take it to a machine shop later to get it out. I loosed the 5 flywheel bolts fine and after realizing that they have a plate with keepers on two faces. The flywheel came of easy but it weighs about 50# and had me at an odd angle laying on my side. Next I had to remove the plate that holds that starter. On my engine, which was hanging on chains, I had to lower it and rest the attachment point since the heat exchanger bracket covered two of the bolts on the starter plate. After that it was a cinch to get to the seal. Now to put it all back together again. I am also adding a serpentine belt kit to replace the fan belt. Once again, a needed item for piece of mind.

    I had to pull the engine and set it in the air because the bulkhead and space did not allow me to get through the bell housing to the damper plate. No room. I jury rigged a Ibeam made of two 2x6s and a 2x4 for the middle of the "I". Since I have a blue water entry I put a 4x6 across the opening and using a trolly and chain hoist that I bought for less than $100 from Harbor Freight I unbolted the motor mounts and raiser the engine. It worked pretty slick but you have to make sure you support it safely on both ends.

    More after assembly. If you got a bid for 3 hours it is a great price but I think it will take longer though your accessibility to you engine has a lot to do with the time factors. Mine was not easily accessible so 16 hours for someone who knows what they are doing is probably a good estimate. More if you are figuring it out as you go. More if you have bolts that have not been taken out for 20 years.
     


    jssailem likes this.
  7. jssailem

    jssailem

    Joined Oct 22, 2014
    5,883 posts, 2,055 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    Great write up.
    I have the 4-107 VDrive transmission. And I have been wondering if my Damper Plate was shot. I recently changed the oil in the transmission. I now wonder if the noise I was hearing may have been associated with low transmission fluid. The last time I ran the engine the sound level was much better and the engine changed gears and idled with less noise. Perhaps we can meet in Port Ludlow and I can learn your tricks regarding the engine/transmission repairs.
     



Sail Trim Chart and Guide
When it comes to sailing, as basic as salt and pepper and just as indispensable!
Mainsail covers
Pre-patterned mainsail covers to fit your boat
20% OFF innovative boat clips!
FixClip holds laundry, tools, anything to rails and life lines even in strong winds.
Winch covers
Any brand, every size, any color!