Engine Swap

[FirstTimeSeaLegs]

Greetings everyone. New to the forum as of today. I recently purchased a 1981 23' Carver Montego cabin cruiser with a 260 Mercruiser. I had a feeling the engine would need to be replaced before I bought it, and after getting the motor "un-seized" found that cylinder #4 had a nice 3" crack in it. So, I went on a search for a new engine and found a steal of a deal on a late 60's early 70's Chevy 350 block. Has new cam bearings (no cam), and also has the cross hatch in the cylinders. Anyway, I noticed that the oil dipstick is on the opposite side of the block compared to the original boat motor. I was thinking of just using the truck/car oil pan seeing how the original pan won't work due to the dipstick notch being on the wrong side. A concern I have is the baffle that is in the original pan. It is also oriented/made to accommodate the original tube from the original dipstick. Is the baffle a requirement? The 350 block I have for a replacement does NOT have 2 dipstick holes as I've read about on some blocks.

I plan on using the heads, water pump, and everything else I can from the boats original Mercruiser 260, leaving me only changing the pan (if possible), and the freeze plugs. Also if the dipstick placement is a huge issue, could I replace it with an after market mechanical Pressure gauge and also an electric oil level sensor?

Looking for any advice as I've never built a marine engine, but I've built a few pro street engines. Thank you in advance!

 

[tpenfield]

Re: Engine Swap

The crack in the existing engine is probably from freezing ???? so, you would want to check the cylinder heads and the exhaust manifolds for similar cracks.

You will want the marine core plug set as noted and a marine head gasket. Use the cam from the original engine, as an automotive cam would have too much overlap. Perhaps you can figure something out with the oil dipstick.

All the fuel, ignition and electrical stuff should come from the marine engine as that has to be fuel spill and spark protected.

Other than that, you should be fine.

 

[FirstTimeSeaLegs]

Re: Engine Swap

Thank you Tpenfield. I will be going over the exhaust manifolds as well and the pistons. In fact, I'll have the rotating assembly (Crank, Rods, Pistons) out of the old block either tonight or by the weekend.

I greatly appreciate the advice. Have a good day amigo!:watermelon:

 

[dan t.]

Re: Engine Swap

The baffle is called a windage tray, just drill it to accommodate the dipstick on the other side, use the pan and dipstick and tube that matches the block.

 

[FirstTimeSeaLegs]

Re: Engine Swap

Well, should have the engine assembled tomorrow. New bearings, new oil pump, new timing chain set, new gaskets, new rings, etc. Heads will be going on tomorrow and hopefully running the motor in the driveway by early afternoon.
Thank you all for the assistance!

 

[flipbro]

Re: Engine Swap

Ha FTSL im in the process of doing the same change over! When you get it installed could you let us no how it worked out for ya. My concern was if any of the electrical or power steering pump would be in the way of the new dip stick tube Thanks

 

[tpenfield]

Re: Engine Swap

Well, should have the engine assembled tomorrow. New bearings, new oil pump, new timing chain set, new gaskets, new rings, etc. Heads will be going on tomorrow and hopefully running the motor in the driveway by early afternoon.
Thank you all for the assistance!

Post a youtube video, if you can . . .