455 olds to be rebuilt

Discussion in 'Powerboats' started by MF455OLDS, Jul 8, 2009.

  1. MF455OLDS
    Joined: Jul 2009
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    MF455OLDS New Member

    So hear is my situation. I have a 1972 marlin with a 455 olds, berkley jet drive, duel carbs, high rise intake, chrome headers and more. the engine block is in the shop and what i have found out about my engine is that everything in it is high performance. My total costs are going to be around 3,000 for a complete rebuild of the block with all high performance parts. I am somewhat new to the whole jet boat world and am wondering if this is a good deal or not. The boat itself has been sitting for about 5 years now and I am in the process of getting it cleaned out and ready. One problem i have noticed when i dumped the old gas out of the tank is that there was rusty water in the gas. I believe it is getting in through the top piece were two wires are running to the tank. which i think some sealant would solve that problem. Should I replace the fuel line from tank to the engine? Is there anything that I definatly need to do before reinstalling the rest of the parts on the engine block. Any help and advice is greatly apreciated.
  2. fasteddy106
    Joined: Apr 2009
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    Location: connecticut

    fasteddy106 Junior Member

    Be sure to get the parts list from the machine shop. You want the brand of the parts and all the part manufacturers part numbers. Also get him to detail each machining process that he does. For 3k it should include decking the block, resurfacing the heads, line boring the block, shot peen and balance the crank, resurface intake, hone or bore the cylinders, and a complete valve job. New parts should be, valves, rockers, pushrods, lifters, pistons,piston rings, rod bearings, main bearings, oil pump, cam shaft,new or reground crankshaft, fuel pump, & water pump, and distributor,(converted to hei). If he balks at any of your requests, pay for his time and go somewhere else. It's your ride, your rules. I deal with machine shops all the time, they tend to be uppity and cranky, but it's your money he's spending not his, you get to ask all the questions you want. Do yourself a favor and learn about what each part above does so that you will know what he is talking about.

    Here is one video to watch - follow the url to the others in the series, best of luck!!!!

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  3. Jimbo1490
    Joined: Jun 2005
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    Location: Orlando, FL

    Jimbo1490 Senior Member

    A couple of points. First be aware that the Olds engine has a known weakness in the coolant passage sealing between the heads and intake manifold. Search the threads as this has come up a couple of times. If not addressed, it can DESTROY your new engine!

    Second, the Olds engines have a non-adjustable valve train. If you get the heads and block decked as Festeddy suggests (and you should), the original pushrods will be too long to work. Your options at that point are to either get custom pushrods made from calculations (not difficult or too expensive) or buy a set of adjustable pushrods. Some people don't like the latter option because these are a little heavier. But if you don't spin the motor past 4500-5000 RPM, then it's really not going to be an issue. And you really should not be spinning a 455 faster than that anyway as it is a long-stroke torque monster. If you want a 'revvy' motor then get a Chevy 427.

  4. MF455OLDS
    Joined: Jul 2009
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    MF455OLDS New Member

    Thanks for the advice. I have wrote down all of that info and will be talking with the guy that is doing the engine. If there is anything else I will need to know please inform!
  5. mreoe4sure
    Joined: Jul 2009
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    Location: trustafarian land

    mreoe4sure who me

    Olds problems

    Having a couple of boats in the 70s with olds and jetdrives, here are some things to think about. These motors were known for eating up bearings, a couple of trips across the lake at full speed to get more beer, and you had a rod knock. The expert on these motors (they use to call Dr olds), his name was joe Mondoelo, He did have a shop last I knew in Paso Robles Ca. If he is still alive. He showed me the problems with the oiling system, He said it is a great engine( He held drag racing records for many years with this motor). He said that the olds oils too much to the upper end, and at High rpm the oil is up in the valve covers, and the pump sucks air, thus the crank runs dry for a few seconds. Do this a couple of times and you have crank problems. He manufactures restricters that go between the mains and lifter gallery, He also makes his own oil pumps, pans etc.. He also said to work in the lifter gallery and grind any slag, and open up the oil return holes. Putting a big pan, and hv pump doesn't fix the the problem but it helps. It is hard to find a good crank for these motors they are all 20 or 30 over. good luck with the rebuild.. steve

    Joined: Oct 2002
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    FAST FRED Senior Member

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