What happened with the old engine? 99% of the time you’re better off buying a new cooler if the engine grenaded as that crud goes into the cooler and blocks the flow.

Was this block previously used with remote filter/ cooler? If not , it could have incorrect oil bypass spring.

ive seen motors do this with the remote oil filter lines reversed

I’m not sure what happened to the previous engine- I bought the boat with no power. The cooler I had on the shelf.

The remote filter base is a Merc. I used the threaded block mount with bypass, and the conical style cap. I tosses the OE hoses and made the -10 AN hoses to the remote filters.

I’d feel like a complete ass if I plumbed the hoses backwards, but it’s worth taking a look.

Where did the block come from? Automotive blocks have a 10lb bypass valve in the filter pad that reroutes the oil straight back to the pan without going through the filter. When you add a remote filter pad it creates to much resistance and activates the valve. There’s a 30lb valve used for remote filter heads. Most of us just remove the valve altogether and plug the hole.

Baja Rooster, it was definitely originally an automotive engine. Some kid had it built for a 1970 C-10, got the girlfriend knocked and had to free up some cash. I spoke with the builder and that’s where I decided to change the cam. Wouldn’t the oil bypass just bypass the filters if I removed it?

Edit: found some pretty good threads here on OSO and I think the smart money is to go to a 30# bypass valve, remove the plug in the center of the block adapter, put on my Wix racing no-bypass filters, and get a bigger cooler coming from CP/Hardin.

You’ve quite likely found at least one of your problems (all boats have more than one problem:)

Fwiw, I was able to replace mine in the boat. Using a mirror and 3/8” bolt i was able to grab it and wiggle it out. Putting in the new one was easy. Getting enough torque on the adaptor bolt was a mother though.

Oversizing the cooler and going with an oil thermostat has proven the way to go. Also read up on the oil line threads here. They’re pretty enlightening.

Is this a MK4 block or a gen 5/6 block? Makes a big difference.

if the lines were reversed at the filter head your lifters would be singing you a song

Its a gen IV block. I read up on the 5/6 mods but not applicable here.