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Repower or rebuild

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trebot
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Repower or rebuild

Post by trebot » Sun Sep 09, 2018 7:48 pm

Have a '56 Continenal 18'. Cracked block #4 cyl. Is repower to CC 283 realistic or should I pay ridiculous price for a rebuilt KL?

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Bilge Rat
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Re: Repower or rebuild

Post by Bilge Rat » Mon Sep 10, 2018 7:52 am

Just my humble opinions based on previous rebuilds of old power... Depending how #4 cylinder is cracked it could be sleeved but a crack in an internal combustion engine will always be a weak spot and prone to more cracking. It is a great thing to maintain the old original power, I have done this 2 times on 2 different boats and I am happy with the machinist's results. There is however the tipping point of pouring dollars into a problematic rebuild versus the same or less into more modern power.

Parts are of course another issue. Most engine internals are still available but some are increasingly hard and expensive to source. Exhaust manifolds are also pricey if they need replacing. I am having an MCL rebuilt now which was mostly complete minus the valves. The usual over-boring of the cylinders, new pistons, crank grind, bearings and hardened valve seats along with all the bolt on stuff rebuilt. It will not be cheap but for the boat this will be installed in, it will return it to a more period correct engine with a few more horses. The nice thing about this installation is the engine box does not have to be enlarged for a V8. I can retain all the cockpit space the boat was designed with.

A 283 V8 is a wonderful power plant for our boats and as it is a very common Chevy engine, internal parts are readily available. Some of the marinized parts are more limited to Chris Craft part sellers, but it is an improvement in reliability over the old Hercules 6 cylinder design. Options to upgrade the block to a 350 cubic inch are also available. As noted, you will probably have to design and build a new engine box as the V8 is wider than the 6 cylinder. You will also need to replace the prop to match the new horsepower.
1966 Lyman Cruisette 25 foot "Serenity Now!"
1953 Chris Craft Sportsman 22 foot "Summerwind"

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drrot
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Re: Repower or rebuild

Post by drrot » Mon Sep 10, 2018 8:08 am

Bilge Rat hit most of the important points. One more. Does your boat have an original bottom? I wouldn't add V-8 power without a new bottom.
Jim Staib
www.finewoodboats.com

1931 Chris-Craft 26' #898 "Ashes"
1929 Chris-Craft 28' #3107 http://www.finewoodboats.com/1929%20Chris28.htm
1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

davidvn
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Re: Repower or rebuild

Post by davidvn » Tue Sep 11, 2018 12:15 am

It’s not uncommon for a K block to have a crack. I would say 50% of the blocks we work on have a crack someplace. The most common crack is from the valve seat running over to a cylinder and maybe down the cylinder. Normally you would pin the block replace the valve seat and install a sleeve. If done correctly this is a permanent repair and shouldn’t be considered just a patch. Sleeving a cylinder usually costs about $100 plus the cost of the sleeve which is about $30 and pinning could take an hour to do. So to take care of one cylinder should only add about $300 to the total job. Again if done correctly it’s not A patch put a permanent repair. Hope this helps a little bit

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Captain Nemo
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Re: Repower or rebuild

Post by Captain Nemo » Tue Sep 11, 2018 4:02 pm

All very good advice. I have always been a bit of a purist, feel a bit disappointed when I see modern power in a boat that wouldn't have come with such a mill.
David is right, when done correctly a repair is permanent. My opinion is that these old flatheads are pretty tough and reliable power when maintained well.
Boats are to be made of wood, otherwise, God would have grown fiberglass trees.

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Matt Smith
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Re: Repower or rebuild

Post by Matt Smith » Wed Sep 12, 2018 5:20 am

This is one of those questions that like a loop. There is no right answer for all. Just for you. I assume the real question is MORE POWER. A K is a very reliable engine. Also, the paragon transmission is really the hero. Makes driving a pleasure and docking. You will miss that big time. But the extra power can be a blast. We have boats with new power and old power and I will say the newer engines are nice. No worries. But does drain the soul of the boat. We live in brackish water and use all the boats all the time. I will add, that it can be a bit of a pain to keep hunting parts, HEAD GASKETS.. etc. But with folks like V
anNess it helps dramatically.
1948 25' Chris Craft Sportsman
1958 Chris-Craft 17' Cavalier
1937 16' Special Racer
1968 40' Rice Trawler
1968 11' Crab Skiff
2018 Hole in my head

http://www.WoodyBoater.com

trebot
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Re: Repower or rebuild

Post by trebot » Fri Sep 14, 2018 7:32 pm

Thanks for the input.
Decided to stay with original motor. Stripping her down and sending to engine/machine shop and hope for the best. I talked to a very knowledgable boat guy in Algonac, Brian Cuthbertson, and the discussion showed the many possible gliches with a repower in a relatively small, 18', boat.

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Matt Smith
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Re: Repower or rebuild

Post by Matt Smith » Sat Sep 15, 2018 6:17 am

Brian is a great guy and you are doing the right thing. Although I understand the debate for sure
1948 25' Chris Craft Sportsman
1958 Chris-Craft 17' Cavalier
1937 16' Special Racer
1968 40' Rice Trawler
1968 11' Crab Skiff
2018 Hole in my head

http://www.WoodyBoater.com

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Bilge Rat
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Re: Repower or rebuild

Post by Bilge Rat » Mon Sep 17, 2018 7:34 am

Let us know what your new engine guy has to say about the rebuild.
1966 Lyman Cruisette 25 foot "Serenity Now!"
1953 Chris Craft Sportsman 22 foot "Summerwind"

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