Here's some background on this project, and I have a few technical questions, and I'm sure more will pop up down the road. This boat was a 19ft. 84 Chapparal that was left to me in an estate. It looks like it was repowered with a 72 Merc 888. This thing was junk, and I planned on parting it out, using it to help finish the boat I want to keep, which is sitting right next to this one and will probably end up in anther thread. Anywho, I pulled the motor and drive, which were in decent shape. Motor was stuck, badly, but the drive and transom assembly are in good shape. I did a little research and found that the whole running rebuilt engine is worth a lot more than the sum of its parts, so I decided to rebuild it. I'm wondering if I should have just parted it out. Anyway, here's where I am:
I bought a rebuild kit for a regular 302 motor (rod bearings, main bearings, rings, oil pump, gaskets, timing set, cam bearings, , figuring that the base of the motor would be a regular 302 with the peripherals designed for marine use. I think I'm finding out that the differences go deeper than I thought.) I put the main bearings and the crank in without much issue. So far so good. Put the new oversize pistons on the connecting rods, rings and install. Still going good. I put the rod bearings on and bolted them onto the crank. (The Seloc manual calls for the bolts to be tightened past the failure point of the rod bolts, so I had to replace the bolts after they all stretched and a few snapped.) I tightened the bolts to spec, and after tightening only 2 caps, the engine won't turn. At. All. There's no way this is right. With all 8 tight, this thing should turn over with minimal effort. I took it out, one of the caps is cracked, and none of the rods go back together without a fight. I'm thinking the 302 bearings may have stretched or distorted the rods, and that the Merc bearings are not the same as the 302 bearings.
This creates 2 questions:
First, Are the Merc bearings the same as the regular 302 bearings?
Second, I obviously have to replace at least some of the connecting rods, which are no longer made by Merc. There are a handful of used ones available, but they are incredibly expensive and will most likely require work if I get them. Can I get a set of racing-quality connecting rods and replace the set? A set of 8 aftermarket racing rods is still about half the cost of Merc rods, and I think they might be stronger than heavy-duty cast of yore. My head says that as long as the dimensions are the same, it should work fine. Since no one lists a replacement rod, I might have no choice. If I do that, I would assume that the regular 302 bearings will fit better, too.
Lastly, moving forward, is there anything else I need to look out for using 302 replacement parts? I think I need to get a Merc head and intake gasket, but the rest should be fine.
- I gutted the motor, block tested good, I rebored and sleeved a few cylinders. Cleaned out the rust in the cooling jacket. This thing had never been touched. All the rod bearings, etc, had the original ford date stamps from 1972 on them, so everything was original inside the block, and in relatively good condition, aside from the 2 rusty cylinders.
- New pistons on the old connecting rods, new rings, etc.
- cleaning and powder coating the old pulleys, oil pan, etc. (that's been fun, and looks GREAT!)
I bought a rebuild kit for a regular 302 motor (rod bearings, main bearings, rings, oil pump, gaskets, timing set, cam bearings, , figuring that the base of the motor would be a regular 302 with the peripherals designed for marine use. I think I'm finding out that the differences go deeper than I thought.) I put the main bearings and the crank in without much issue. So far so good. Put the new oversize pistons on the connecting rods, rings and install. Still going good. I put the rod bearings on and bolted them onto the crank. (The Seloc manual calls for the bolts to be tightened past the failure point of the rod bolts, so I had to replace the bolts after they all stretched and a few snapped.) I tightened the bolts to spec, and after tightening only 2 caps, the engine won't turn. At. All. There's no way this is right. With all 8 tight, this thing should turn over with minimal effort. I took it out, one of the caps is cracked, and none of the rods go back together without a fight. I'm thinking the 302 bearings may have stretched or distorted the rods, and that the Merc bearings are not the same as the 302 bearings.
This creates 2 questions:
First, Are the Merc bearings the same as the regular 302 bearings?
Second, I obviously have to replace at least some of the connecting rods, which are no longer made by Merc. There are a handful of used ones available, but they are incredibly expensive and will most likely require work if I get them. Can I get a set of racing-quality connecting rods and replace the set? A set of 8 aftermarket racing rods is still about half the cost of Merc rods, and I think they might be stronger than heavy-duty cast of yore. My head says that as long as the dimensions are the same, it should work fine. Since no one lists a replacement rod, I might have no choice. If I do that, I would assume that the regular 302 bearings will fit better, too.
Lastly, moving forward, is there anything else I need to look out for using 302 replacement parts? I think I need to get a Merc head and intake gasket, but the rest should be fine.
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