Hi all I'm seeking some knowledge to help with some repower issues. I have a 2001 25 Carolina Classic that originally came with a VP 8.1Gi A. 4 months ago it let go on me 40 miles offshore. After wrestling with how to rebuild for almost a month I decided on a Raylar 540 short block that was pitched to be a direct replacement using all my VP parts.

Let me make it very clear, I'm not a engine guy. I can do regular maintenance and change external parts no problem. Never had any internal engine experience prior to this. I found most of the bottom end internal fasteners didn't cross over and I had to purchase 454 not 496 fasteners. Then the VP timing set was a double set had to be changed out due to clearance issues with a truck single set. After that things started to go together. I built the engine using a Indmar Marine 8.1 manual I found online.

So the engine was assembled finally using the stock VP heads, cam, and intake, with Raylar short block and roller rockers. Prior to start up I did have the ECM tuned by Crockett Marine to account for the larger displacement and increase the power from 375 to 425.

So start up went fine, oil pressure came up to 45ish pounds at 800 idle and was 55ish around 3200. Melling 10778 pump, with remote oil filter and cooler all in line. Ran the motor for almost three hour before I changed the oil, which is 20 50 Castrol. Week later I take the boat out for a cruise along the beach plus about 1.5 hours of king trolling. All these times I'm varing rpms every few minutes and not exceeding 3500 rpm. Coming in I had a 20 min run plus a 10 min no wake zone. When I got back to the dock the oil pressure dropped to **** when I came to idle at the ramp. Turned it off, checked the bilge then restarted and oil pressure was back to 40. Didn't think much of it and put the boat on the trailer. On the hose for flushing, same 40 at idle.

This past weekend I take the boat on it first "near" shore trip. 23 mile run out the inlet for bottom fishing. Boat started fine with good pressure and ran fine out to the spot. Ran around 32-3400 rpm for about 45 min, again varing every couple mins. Ran great, got to the spot, came down to idle and my oil pressure fell to almost nothing then actually nothing. Shut down, checked bilge, no external leaks and good oil level on the stick so restarted. Still less than 5 psi. Rev to 1000 to 1100 and it went to 20. First thought was bad sending unit. Fish a few hours with engine revved to show pressure then ran back in. Running again, 45-50psi. Idle at the dock, again basically nothing.

Since then, I've run it in the yard, cold idle 20psi, hot 0-5. Added a qt, no change, replaced delco filter with Wix premium, no change. Got in touch with Raylar and they suggested 40w Rotella. No change. 20 50 that came out with about 6 hours on it was already very dark and had a slight grey tint to it. Not dirty like high hour oil.

So this is where I'm at currently, waiting to here back from Larry at Raylar and planning to pull the engine next weekend.

Any thoughts on what's happened, why it happened and how do I fix this. I'm broke at the point and this is all DIY plus machine shop support if needed. Thanks for reading.

What did you find?