88 capri 3.0 conversion

Discussion in 'Inboards' started by deereguy, Mar 18, 2009.

  1. deereguy
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    deereguy Junior Member

    Hello all!

    am interested in converting my boat from a 3.0 4 cyl to a chevy 350. was wandering if anyone has done this or can point me in the right direction. its a 19 foot 88 bayliner capri. thank you.
     
  2. PAR
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    PAR Yacht Designer/Builder

    Are you running a OMC Cobra drive? If you toss much more HP at that drive, you'll likely spit out the gear set fairly quickly. To answer your question, yes. It's not a drop in replacement, but it can be done. Those Cobra drives ate up gear sets anyway (usually bad shift cable adjustment), so you'll probably be looking at a full up package (engine and drive).
     
  3. deereguy
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    deereguy Junior Member

    is there a combination u would recomend or possibly a company you know of that sells conversion kits. the reason for the switch is the 4 cyl is iffy an i have a 4 bolt main 350 sittin around. heck id do a 6 cyl if its easier... i jus bought boat an trailer for 400$ an would like to keep it cheep but would splurge a bit for mor power. thank you for ure suggestions an input.
     
  4. deereguy
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    deereguy Junior Member

    sorry an yes it is the cobra drive
     
  5. PAR
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    PAR Yacht Designer/Builder

    With a slightly warmed up 181 CID (what you already have), that boat will run around 50 MPH, which is very fast, considering what she is. More power will get you a slight speed increase, but you'll pay a huge fuel bill increase doing so. Basically you'll run into a wall, a point of diminishing returns, for several reasons, which aren't necessary to go into here (fairly complicated to explain).

    The 350 can be mated to the Cobra, but it'll crap the bed in short order if more then 200 HP. That particular drive had a number of issues with it, as a result was only produced a few years before being replaced with a newer unit.

    In the Seattle area there are dozens of shops that could arrange a transplant, but I think you'll find it cheaper and more reliable to just fix what you got.

    The 181 is a very reliable engine, capable of 180 HP, though a 140 to 160 are better targets for this engine, if long life is expected. Parts are cheap and readily available.

    If you change out to the 4 bolt small block, you'll need a whole lot more then just the engine. You'll have to wire it, plumb it, put manifolds on it, mate it to the drive, new mounts, etc. After all this, you'll still not go much faster and likely kill what's left of the Cobra.

    If you're familiar with these systems, you could find a used drive that has a spent 305 or 350 attached to it, for not a lot of money, which can solve a lot of issues. If you're not comfortable with outdrives and marine equipment, then a package would probably be a better choice.

    I'm a Mercruiser fan, personally, but each drive and brand have good and bad points about them. If you keep the Cobra, make sure it's got a new transom cable assembly and that it's adjusted properly. This one thing has killed a lot of Cobras over the years. It was a recalled issue, plus several "service bulletins" had been issued by OMC, attempting to fix it. The basic problem is if permitted to shift out of adjustment, it will eat it's gear set and it doesn't take long to do this. The adjustment is difficult to do correctly and to make matters worse the shift lever assembly is prone to jamming from sand and mud.

    A $400 boat usually needs pretty much everything. Check the soles (soft floors) and engine beds to make sure they're solid. If you're reasonably handy, you should be able to fix most of the problems it might have. The big question is how many issues do you want to have to address, just to have a two decade old boat. My basic point is, that model and brand were at the bottom of the ladder for quality and engineering, so the things that will need fixing may be overwhelming, especially if you're new to this sort of thing.

    For what it's worth, I redid an '89 Capri for a buddy last spring, just like yours. It needed a new sole, new electrical, the engine needed seals, gaskets, tune up parts, water pump and fuel pump, but was other wise in fairly good shape. New transom cable, new bellows, one trim cylinder, new hydraulic hoses and a prop. His was like yours and a "good deal" for little money. He spent a whole lot more then he paid for it, just to get it on the water. He did a fair portion of the work himself, but still spent a few thousand to have a reliable boat. In fact, I told him, if he wanted a boat that wouldn't let him down, then it would take 3 to 4 grand and that's what it worked out to be.

    I'm not trying to discourage you, but just let you know what you might be in for.
     
  6. deereguy
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    deereguy Junior Member

    thank you for the info will be working one the 3.0... guy said it jus needs a head gasket. as far as its shape the guy i got it from bought it from someone that had garaged it its whole life so most everthing is in wonderful shape... sept the vinal upolstery. do u know if there is a re-covering kit for these models, or even a good place to find a bimni and side windows? again thank us so much for your input.
     
  7. deereguy
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    deereguy Junior Member

    one other thing i jus thought of... i have seen people talk about this being a chevy 181... does that mean i may find parts at a auto parts store or is this a strictly marine kind of parts motor... i am well versed in auto motor building and work.. jus the boat thing throws me.... my neighbor built a motor an had to pull it back out an change the cam... somting bout a left hand turn or somting of the sort. are there that many differences in a marine to car motor ?
     
  8. PAR
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    PAR Yacht Designer/Builder

    Actually it's a GMC 181. No you can't just go out to the local auto parts store and get parts. They'll fit the motor, but they'll drive you nuts with questions you can't answer, like what year car, with or without air conditioning, etc. You see they look up parts by make, model and year.

    For example a set of points (if it has points ignition) off a 1970 Nova will work, but they'll rust in no time on your boat, because they're not marine parts.

    This is an on line store that will provide the vast majority of parts you could need. There will be many others too, so shop around.

    bpi.ebasicpower.com

    As for seat covers and the like, you're much better off doing them yourself, having the wife do them (a cool trick to make them feel "involved" and get some free labor) or have a local canvas shop do them up. It's really easy to staple new vinyl over the old seats. Take a good look at them, pull out some staples and you'll see how simply built they are. A trip to the local fabric shop (again, let them get this stuff, it's their kind of store) and you can have enough seat covering material to do the whole boat.

    Ditto the deck covering, which is carpet and a real source for rot in these puppies. If you deck isn't soft or spongy, consider removing the carpet and using textured paint. It's cheaper and will not trap moisture against the deck, rotting out the plywood under it.

    Those little 181's are very hard to kill. They probably over heated it for one reason or another and chunked a head gasket. This is a fairly common issue. Check the head for straightness, have it surfaced if it needs it. Check the manifold and riser for cracks, replace if necessary (also common on an over heated engine).

    The timing cover on these is known to leak, replace the gasket and seal. Replace the raw water impeller, regardless of what it looks like. Ditto the thermostat. This way you'll know precisely what you have and not have to wonder about it cooking you motor again.

    The first purchase you need to do is a repair manual for this boat/engine/drive combo. EBasic will have that on their site too.
     
  9. deereguy
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    deereguy Junior Member

    now when u say raw water impeller u mean the one on teh out drive corect... also would a engine water pump be another ting to replace or am i chaseing parts i dont need too... im jus asking cause the people at bpi were real sticklers about wat info they gave out... questioning every reason why i wanted to do this or that... and why im not doing this or that... not very good sales people if ya ask me lol... i was bout to spend a few hundred dollars with them an ended up not spending a thing cause of all the questions and jus go soo confused ...
    another thing ive noticed in cleaning of things is a patch on the side of the block... my neighbor told me it was good stuff an not to really worry about it... somting he called marine-tex or somting of the sort.... ill post pics if u would like prob a good idea with all the questions i am asking.... if i can figure it out i will, jus gotta wait for good weather day to uncover lol.. ty again for all ure help. an yes a manual is on order ...
     
  10. deereguy
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    deereguy Junior Member

    another thought i jus had too... sry bout all the questions an back an forth stuff... but if the block i have is now possibly a crap shoot is there another engine u could recomend... i just hate to put 2 to 5 hundered dollares out an it crap the bed fast... i have sercherd for a used one an cant really find much... is there another 4cyl chevy engine or other marine 4 cyl (merc or volvo) i can use that is compatable.. i saw a new 3.0 omc for 2000 dollars plus shipping an just cant justify putting that much into a 400 boat thats gonna get used 4 to 8 times a year... i really jus wanna go fishing in the thing lol.. not salt water either jus fresh water lake stuff it that makes a diff. ty ty again :)
     
  11. PAR
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    PAR Yacht Designer/Builder

    You have an engine that over heated and blew a head gasket. Clearly your cooling system needs to be okay to insure you don't do this again. You can save 60 bucks and skip the pump, but if you don't know why it took a dump in the first place then it could be an expensive crap shoot.

    In cases like this, it's best to either test the parts or replace them with parts you know are good. Since there's no real good way for the back yard mechanic to test the pump, you have to hope to get lucky or replace it. Okay, before some one jumps in, you can test the pump, but considering the basic nature of your questions so far, I'm guessing you wouldn't know how to do this.

    The folks at basic power are who I recommend for the reason you said you had difficulty. They don't want to sell you a part you don't need. They also like to get a feel for the persons knowledge, so they can make recommendations for other things you may have missed. These are actually boat people who have changed water pumps on 181 GMC engines and know to ask if you want a gasket with the thermostat you just ordered, when most outfits will happily sell you a thermostat without the gasket because you didn't ask. I consider this real customer service. Then again you could just order through another parts house and they'll send you whatever you want.

    It sounds like you might have some epoxy smashed into a crack or something on the side of your engine, though this is just a guess. This is something to worry about, but only if it's leaking. If not leave it alone and keep an eye on it in the future. It's probably on the lifter access covers, which can be replaced easily.

    Yes, other engines will bolt to that drive, but I don't think you understand the headaches associated with this type of change. You'll need everything, control cables, manifolds, you'll have to butcher up the wiring, plumbing, adapters, engine mounts, everything. You'll spend three times as much then fixing what you have. Even if the engine is crap, you can swap out a long block and have all the parts (now, some of them new) to make the new 181 work, just like the old one.
     
  12. deereguy
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    deereguy Junior Member

    kk an about the raw water impeller is that in the out drive or a marine term for a water pump on the engine?? also another question that came to mind about the seats an what not... the covers and foam are attached to ply wood that has been coated with paint or somting... is this waht they call gel coat or somting... i was wandering cause i need to re make a few of the wood pieces and wandered wat was best to treat them with before doing the recover... thx again
     

  13. PAR
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    PAR Yacht Designer/Builder

    The seat fabric wouldn't or shouldn't be coated with anything, it's just marine grade vinyl, which you can get at the local fabric or crafts store. If the old foam is mold or mildew filled, then use new. Drape the fabric over the seat core (plywood with foam pad), using staples (stainless or Monel) tack it to the underside of the plywood, just like before.

    The raw water pump is in the drive. On the Cobra it lives under the "L" shaped cover on the aft side of the upper gear case. Your manual will explain all of this.
     
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