ThisIsLivin

+1

Keith Atlanta

No

In a big block with massive rotational parts and clearances it is crazy... Even when my oil gets old and whipped out a little the engine is significantly noisier when it starts. I wouldnt run anything less than15-40, never 10-30 and probably not even 10-40.

Just my 02. cents in my engine.

ramos45

iTrader: (1)

My .02, before pulling my 454 mags for rebuild I used rotella 15-40. I never had it analyzed but never thought I had too, my oil pressure was always consistent from start up to after running. On my new engines I will talk to my builder about rotella 5-40 full syn. That is what I've used in truck, cars, and track/race sportbikes without an issue.

Black Baja

iTrader: (2)

I've ran valvoline vr1 30wt in my 598 with no problems and I'm not easy on it. If its not wide open its because I'm pulling it off the trailor. I think I'm gonna try something different with the motor over the winter and try a 5w20 in it for next season. If the clearances are right and the oil isn't getting to hot there is no need to run such thick oil. They are running 0w5 in the NASCAR stuff now and they aren't cruising around the track anywhere near 2000 rpm...

jeffswav

I have been running Amsoil 15/40 Deisel oil for many years. Also use a 2 quart oil filter.

Pismo10

VR1 is the best balance of quality and cost. $5-6/qt cant beat it.

SS930

Bringing this back TTT.

I've been doing a lot of reading on oil on Bob's site and agree that thinner oils and synthetics are perfect for automotive use, but there's not much info over there on real high hp offshore engines. In the past I've always used 20-50 or straight 50 dino oil (VR1) in my SC BBC's for marine use. Looking at my cold oil pressures has me rethinking this.

Thoughts on using 5-40, 10-40, 15-50 synthetics for these high HP marine applications???

35fountain

Amsoil Z-rod 20-50 oil

On Time

I have used Merc's 25W-40 in all my marine apps for 30 years. 350s, 350 mags, 496s, 525s, even a Volvo Kaiser V-6 I had in school. Never an oil related problem. First the dino and now the semisyn. Just change it as directed and you'll be fine whatever good oil you choose.

MACDAD260

Second the Amsoil Z Rod 20w-50.