Hello group! Been a while since I posted anything regarding my 454 blower project. Happy to say that I got everything up and running in the boat, and that she's running pretty well. I need to handle a couple of issues, but for the most part everything has been good. This thing is making good power. I haven't put the coals to her since the dyno, but I was able to cruise at close to 50 on GPS turning a little over 3K rpm.

My question:

When I first put the engine together, I primed it with my drill and could only get about 45-50 PSI out of her. This was with the entire Mercruiser oil cooling and filtration set-up installed. I kept right on priming her, turning the rotating assembly about 90 degrees every few minutes to make sure I oiled all the lifters and subsequent valvetrain parts. It took quite a while to get oil to the rockers, and even then it just kind of dribbled. Oil is Rotella 15W40. Would guestimate that the garage temp was about 90-95 degrees, Anyway, left it at that, pulled the oil cooler and remote filter off... sent to the dyno.

On the dyno we used an Oberg filtration system in place of the Mercruiser parts, and made some pulls. The oil pressure on the dyno, and throughout all testing was stable at 79 PSI. Installed in the boat with all the Mercruiser stuff, I get about 45-50 PSI. I noticed too that the valvetrain takes a bit of time to start flowing (and doesn't start to spray oil until 2K RPM or so.... was adjusting the valves). Why is this?

I have everything routed correctly, and my cooler is clean as a whistle. I'm thinking that maybe the AC Delco PF454 filter that I used initially may be causing the lower pressure. I have since installed a K&N 3002 in place of the Delco, but I haven't been able to run the engine since. Have any of you seen issues like this? I'm tempted to scrap the entire Mercruiser set-up to go with something better (and probably will), but I am a bit concerned. I've got about three hours of runtime on the engine (dyno time plus testing in the boat with a 30 minute cruise). I don't want to hurt anything and I do not think that I am, but want to be safe.

**Edit** Let me add that the engine prior to rebuild had nothing wrong with it, and was only freshened on the bottom end because I found a couple of pistons that were questionable for use with the blower. Oil pressure in the boat with all the same parts ran about the same (75-80 PSI).

**Edit Again** Oil pressure was measured (at initial priming) with an Autometer Pro Comp mechanical gauge.

Any thoughts? Thanks in advance!

TZ

The mercruiser stuff may be restrictive enough that it's opening the dump valve on the oil pump. You did put the #30 bypass valve in the oil filter pad, right? I'm no mechanic but just shooting ideas at you here. I had a problem with only getting 40 pounds of oil pressure that sent me changing all of the mercruiser lines out, buying a bigger oil cooler, etc. Turns out it was a bad sender, lol. $20 and 10 minutes later I was getting 80 pounds.

My first thought is, run engine and put on a mechanical gauge on the engine to verify pressure readings. Your dash gauge could be off. You did well by using a K&N filter.....or you could use a Wixx. I like to run 20w-50 VR1 Racing Oil conventional Valvoline. That will spark off a debate that will lead this thread in a oil discussion, which will totally throw this in the dump. But that is my initial thoughts. Good luck. I am sure you will get opinions, but most of them will be about oil weight....lol

What are the bearing clearances?

I'll check it this weekend with a mechanical gauge to rule out the sender/gauge. Not thinking that's the case though considering it worked prior to pulling the engine out AND it's doing the same thing as it was on the primer.

I didn't think to change the bypass valve... never had a problem with it prior so ran it as is. This is a MK-IV block.

Not wanting to get into the whole oil debate, but the Rotella was for break-in purposes. Hoping the filter was the issue really (have seen some discussions around this).

This. Also, what oil pump? I'd be pretty certain you've opened up your bearing clearances inadvertently and now, with the added demand of the oil system in the boat, the pump just isn't up to the task.

I don't have my notes in front of me but they were in the middle of the spec. I want to say .0025 on the mains and .0022 on the rods. I'd have to dig up everything at home.

Reused the factory pump. It was cleaned, clearances checked, and verified perfect. Like said, there was nothing wrong with the engine when it was refreshed. The bearings were perfect, and the engine had great oil pressure. I don' think I ever saw it dip below 50 PSI when we were running it before we took it out to have the transom rebuilt.

Was the crank polished at all?