Oil for old V8

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Dec 21, 2002
I have an old 1987 V8 Holden. It has low kms on it (120,000) but unfortunately, was not been well maintained by its previous owner

When I bought it, the oil looked ok and the engine was quiet. However, when I changed the filter, it was filled with grit and looked like it hadn't been changed in ages. I am guessing it had been used to filter oil that had been overused

Not long after, the pressure relief valve clogged up and caused zero oil pressure

Anyway, frequent changes now have inevitably uncovered some valve noises (either from blocked oil passages or wear) and a rather alarming noise from the engine at startup in the 3 sec before the oil pressure rises at startup.

It blows no smoke.

I have been running dino 20W - 50 since there seems to be no Australian synthetic which is similar to this spec and this is what the engine is meant to use.

I am thinking it couldn't hurt trying Mobil 1 5 - 50.

Thoughts ?
Well for the rest of us North Americans Holdens are Australia's GM's. What size is this engine? 350 small block? I ran 15W50 Mobil 1 for a while in my 350 and had no problems. Started easy even on cold days. Recently went to 10W30 to see if mileage would increase.
It's a small block 304.

I would like to find some synthetic 15 - 50 but I can't seem to find any. Just 10 - 30, 0 - 40 and 5 - 50 formulations and the like.
The holden V8s are pretty rough on caamshafts, most of the 253s that I've owned have worn a few lobes, and cupped the end of the lifter.

Not sure whether it's an alignment issue or a lubrication issue. One had been run on LP gas and Mobil 1 and still had a couple of lobes go south.

And with the oil pump mounted so far about oil level, they clatter pretty badly on start-up also.

So something that gets to the top end quick, and has lots of anti-scuff stuff in it would be the go.
An Auto-Rx clean would be a good start. M1 5W50 probably not a good idea as the elevated VI ain't good. Mobil Super S 15W50 blend a better choice IMO. 10W40 also available.
A full syn would give u better start up protection, just about regardless of its weight.

Even a 15w-50/20w-50 is pletny thin to flow fine in a australian summer.

DO some cleans, Wynns is pretty gentle and widely available in Australia.

Also just pruior to oil change do the "idle w/ quart of ATF" thing.
Thats effective enough to help but gentle enough not to cause potential prpoblems (unlike many kerosense based cleaners).

Too many VI's in M-1, but not in Super S blend??? Can you explain??? So how many VI's are there in a 5-50?
Hmm maybe I got that wrong (1st day back at work). M1 5W50 pretty wide spec but your right maybe 15W50 blend has even more VI. Bit outa my league, anybody care to advise?
Noticed on another thread that Torco make a 20W - 50 full synthetic. I have seen it advertised in Australia too. Will be expensive though.
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