My 4.3L GM/Chevy Automotive to Marine Conversion (Hi-Res Pictures)

[darrinwlowe]

I'll start off with a little back story on why I am doing this conversion. I bought my 1997 Chaparral 180 LE off of a co-worker a couple weeks ago, being told I needed to replace the fuel pump and filter. No big deal there, just a simple swap. I did that, along with rebuild the carb, just to freshen it up a little bit, as the boat had sat for two season prior. Got everything up and running, only to get the famous milkshake coming out from under the valve covers and up through the breather tubes. Got on here to confirm, I had a cracked block on my hands. Well after getting some of my money back (thankfully), my best friend and I started rebuilding a 4.3L out of a 1997 Chevy Blazer 4x4. We tore everything down, and got it off to the machine shop. There I had the block hot tanked, honed, cam bearings installed, balance shaft bearings installed, and brass freeze plugs installed. I also took the heads in and had them hot tanked and gave them a valve job. I got everything back, and started the rebuild. I used the pistons out of the automotive engine, as there wasn't enough taken off in the honing to need larger pistons. I put new rings on the pistons, rod bearings, main bearings, and put new valve seals in the heads. To this point, it is a straight forward automotive rebuild. After I got the assembly of the heads done, I started in on the block assembly. This was like any other automotive rebuild I have done. I did put a new timing chain on just for my piece of mind. Reinstalled the balance shaft, cam, and crank. All the pitons dropped in fine, but I did have a little trouble in finding the proper rings. For what it is worth, it had 1.5mm top and second rings, and a 3.0mm oil ring. First set of rings I ordered were incorrect. Everything went back together fine, and then the block and heads were ready to be mated. I installed the marine head gaskets and bolted them down to the block. Please make sure you read the torque specs in the service manual, otherwise you can snap off bolts and ruin gaskets (too many previous experiences on my end). Got the heads on, pushrods installed, and that's the point I am at now. I am in the process of removing the old motor as well, as I want to be able to remove a part, and place it on the block before putting it in. I have attached a couple of pictures to show my current progress. If anyone has any tips or questions, I get an email every time there is a response to this thread. Thanks.