Engine Rebuild?

Discussion in 'Mechanic and Repair' started by Gator610, Dec 11, 2006.

  1. Gator610

    Gator610 LawnSite Member
    Posts: 13

    My question is, can a Kawasaki, model FD671D 23hp water cooled engine be rebuilt? Bored out, new oversize piston and rings, rod bearings, valve guides, seal, the stuff needed for a complete engine rebuild. I have found a new factory engine however it’s nearly $2000.00 including shipping. I have not found much in the way of new parts for this engine via the Internet. Looking for some good advice.
    Thanks.
     
  2. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Posts: 1,164

    First how old is the engine you have, how many hours? Yes it can be rebuilt but are you doing the work? Parts and labor at a shop may be more then you think.
     
  3. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    A quick look at parts tells me you will have close to $600 in parts for crank, rods, oversize rings and pistons. I don't have an idea what a machine shop might charge for a rebore job, but my guess is you'll have close to half the cost of a new engine even if you do the wrench turning yourself. This doesn't take into consideration any work on heads/valves. If the valve guides are worn, you're looking at the cost of new heads as well. At least with a new engine you will have a warranty period. As MM77 indicates much depends on the hours on the engine but I don't believe a shop rebuild will be cost effective. IMHO, the decision is a no-brainer, but you're the one who has to pull the trigger.

    Dutch
     
  4. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    have you pulled the heads? why do you think it need rebored? why not a set of rings and major valve job? have you done a leakdown test? what is the compression? is it running bad? how many hours on it? tear it down and see just what you really need before you go out and spend 2 grand. you'll only be out some time.
     
  5. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    Good call, khouse. I was assuming(to readily possibly) that the decision had already been made to either rebuild or buy new.

    Dutch
     
  6. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    Dutch, Like you said $600 bucks isn't too bad if he can do the work. Being water cooled I'll bet the cylinder or crank isn't worn at all.
     
  7. Gator610

    Gator610 LawnSite Member
    Posts: 13

    Thanks for your reply's
    My engine has over 1300 hr on it. When I starts it, it blows blue smoke and when I put it under a load it also smokes and consumes oil, otherwise it runs well. I understand there are tests to do (leak down etc.) but the question was “could” a person rebuild this type of engines and availability of replacement parts. I have been a motorcycle mechanic for many years and have access to a boring bar that we use to bore out bike cylinders and feel like I could do the overhaul. I was interested in other peoples experience with this type of engine has been.
    I’m also have concerned about getting the the correct parts.
    The business I purchased the mower from has sense gone out of business, and the shop I use now, do not support this engine type. I would need to find a source for replacement parts.

    Gator
     
  8. John Gamba

    John Gamba LawnSite Fanatic
    from ct
    Posts: 10,812


    In the long run in this type situation i have found it better to buy new. When you rebuild you still have the old carb,Old electronics and so on. You should also get a new engine guarantee with the new motor.

    John
     
  9. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    Not every engine need to be rebored. You'll never know until you tear it down. That's not many hours for a water cooled engine. Buy your parts from a parts house - not your dealer. You say a new engine is 2k$ If you could rebuild it for 400$ then take the 1600 and self insure yourself. Why not pull the heads - it might just be loose valve guides not the rings.
     
  10. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    Gator and Khouse

    Let me share my experience with 22HP WC Kaw. Three years ago a neighbor brought me a JD 445 which he indicated was using coolant the year before, saying that he had finished the season adding water rather than antifreeze. Neither cylinder had compression and upon removing heads found both head gaskets blown with water sitting on the pistons. I replaced the head gaskets, inspected valves and guides, lapped the valves and reinstalled. Compression then came up to within 5 psi of factory specs. Since I was aware that the freezing situation, I pulled the water pump and found fins broken of the impeller as well as the thermostat locked shut. I replaced the water pump and thermostat and buttoned her up. Unit ran well for the next season with the only problem of having to add oil occasionally. The next season oil consumption increased and plugs fouled every three weeks or thereabouts. My next thought was that the engine had a damaged reed valve so I pulled the flywheel to remove the air breather cover and replace the reed valve. No change. As the unit had 1400 hrs on it the owner decided to not spend any more $ on it. Perplexed as I was, I called Kaw techs and they said that they couldn't give me any help since they sold the rights on the engine to JD. In calling JD, I was referred to local dealers and they didn't have any answers. Finally got a tech at a Kaw warehouse to talk to me. He told me to reduce the oil level to midway between the high and low level as well as to replace the BMR4A plugs with the hotter BMR2A's. This helped the oil consumption and plug fouling didn't occur quite so often. Strangely enough, the plug that was fouling was on the water pump side of the engine. I suspect, that even though the compression remained high, the rings were worn enough(particularly the oil rings) that it was causing excessive crankcase pressure. Before I reduced the oil level in the crankcase, with the air cleaner off and the engine warm, it would drip an average of one drop of oil every 2 seconds from the breather tube into the carb.

    As the customer intends to trade the unit in next season I will probably not get the opportunity for a complete teardown to determine the problem. Sure would have liked to determine the problem. Age and cost limitations prevented me determining this from the beginning.
     

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