is this possible?

hey guys,

thanks in advance for your input. I recently let a buddy use my old 86 bayliner with a 50hp force(which you should never do :0) when i got the boat found a large chunk missing from the power head. I took the boat into the shop after I finally found a old power head with the exact model. I was just going to replace the rear part of the crankcase and hope for the best. but i figured i was going to sell the boat so i took it in for repair. when i took it in we found that a nut came off a coil pack and that is what caused the problem.

we found that the power head i purchased had low compression, from there i was told that we couldn't just replace the rear crankcase. Is this true?? the orginal motor was just rebuilt and had about 30hrs on it but am leary to just popping on the new crankcase.

should I just try it and see?
if it was a nut that caused the problem and end caps on the rods look fine would i need to disassmble the whole motor?

any help on this would be great

thanks for reading


James

Re: is this possible?

I would not mix and match crankcase halves, I believe that they are matched at the factory. I think what you are calling the rear half is the part with the cylinders so if the new powerhead has low compression it will probably need to be bored oversize. attach some pictures if you can so I can better understand what you are asking.

Re: is this possible?

jimb is right,
the cases are "linebored" at the factory as a unit
Mixing and matching is a bad idea unless you intend to have block matched or linebored as a unit when it's together

Re: is this possible?

That engine is very similar to the old Chrysler 35, 45, 55. If that is the case AND if the nut you are talking about is the top nut holding the starter motor, then: These engines frequently break the mount which is integral with the front half of the crankcase and a large chunk usually breaks off. This is the only nut I can think of that would cause breakage of the crankcase. Side loads on the starter motor while cranking breaks the mount and the nut works loose.

If this is indeed one of the three nuts that hold on the starter motor assembly, then it is possible to fabricate a steel plate to fit and reinforce the mount without disassembling the engine. In fact, this type damage was so common that Chrysler used to offer the plate as a repair item.

If you try mix and matching front and rear crankcase halves, the two halves will not align properly and the bearings will be improperly seated. If the engine runs at all, it will self-destruct in a period of time variable with the degree of mismatch.

Re: is this possible?

thanks for the quick reply guys I am chalking this up to a loss hopefully this is covered under my boaters insurance with state farm


thanks

James

Re: is this possible?

Does your auto insurance cover your 20 year old car, if the starter fails?

Re: is this possible?

I'm sure you got a letter from your Insurance company saying thank you for sending your payment. Well that's all you are going to get. A few weeks ago one of my friends blew his motor & called his insurance co. & was told he IS NOT COVERED!! Read your policy!!!