New long block oil recommendation (7.4)

I've got a Gen6 (I think this is also called a L29) 454 of the 2006+ variety. It's a Volvo Penta setup but I know they are all GM big blocks. Volvo originally called for 30 weight but it's impossible to find in my area. I"m wondering if any multi weight would do for a new engine.

The guy slapping it in my boat asked me what I want for oil...my old Crusiaders we always used Dino and 10W30 but this engine is several generations newer with roller cams too.

Haven't heard back from the long block company...they seem to be better pre sale then post sale.

You can use Mercruiser 25/40 or Delo or Rotella 15/40. If the engine has an engine oil cooler you can use lower vis oils but if not then I'd stick to the higher vis oils.

louc said:

You can use Mercruiser 25/40 or Delo or Rotella 15/40. If the engine has an engine oil cooler you can use lower vis oils but if not then I'd stick to the higher vis oils.

Click to expand...

Thank you. I got ahold of my boat mechanic buddy who lives out of state...he's hard to get ahold of this time of the year and he's pretty much right on with you.

He's recommenced I go with Valvoline VR1 20W50 (conventional) race oil for the break in period and then a 25W40 or stay with the VR1 after that in synthetic or Dino. If anyone has any opinions on that I"m all ears as long as their is good logic and/or experience.

Lou steered you right.

If I recall the VR 1 race oil is very good for preventing wear but it may not have the anti-corrosion additives that the marine oils have. I am in salt water that's why I use the Merc marine oil. I know some scoff at that but I had blown head gaskets about 3.5 years ago, salt water in the oil and one cyl. Got the water out fast and when I took it apart I was amazed, no rust at all on the valvetrain. So that convinced me.
take look at these pix....I used the plain old Merc 25/40 conventional oil....look at the rocker arms and pushrods...normally you get water in the oil and you get rust on those parts pretty quick, esp if its salt water...also....I took out all of the roller lifters to check the cam lobes for wear....the lifters and the cam lobes looked like new...no wear...no rust...and this engine was taken apart in 2017, it was 29 years old and had never been taken apart before....
I was able to get all the water out, installed reman heads, new gaskets etc and got her up and running again.