minxguy

Can't speak about other oils because I don't use them, but Spectro Oil's full synthetic is still a group IV PAO, no group 3 at all. Ken

o2man98

AMSOIL is also still a Group IV with adds of V with the exception of the XL line of car oils.

http://www.amsoil.com/products/motor...spx?zo=1132530

Hydrocruiser

The old Series 3000 and 2000 were GRP IV. I understand.

I am not switching to a GRP IV. personally over this.

If I see a flashpoint drop on a brand then I would be alerted to a possible concern. To date I do not see this happening.

Amsoil..M-1..Redline..RP...etc are all good.

Rage

Attached is chart of Blackstone Lab analysis of Mercury 25W40 and Mobil1 20W50 V Twin used in my Mercruiser 496.
It is not a good A - B comparison because the 25W40 was run 90 hours in a dead stock 496HO (425hp) and the Mobil 1 20W50 VTwin oil was then run 80 hours after the same engine had been converted to a Gen1 HP3 (~525hp) except the 5150rpm rev limit remained. Both were driven exssentiall the same. The only changes were HP3 heads, HP3 cam and HP3 valve train (except a lower load valve spring was used in lieu of the high load Nascar valve springs) and addition valve relief was added to the stock pistons (while still in the engine). The lower end of the engine was not dissassembled.

That being said I am still more than a bit surprised by the dramatic increase in wear versus the Mercury 25W40 and what appears to me to be generally high wear numbers with the Mobil1 20W50 VTwin oil versus the Blackstone "UNIVERSAL AVERAGES".

Comments/thoughts on these results are solicited.

sleeper_dave

So you ground a valve relief into the pistons while they were still in the motor?

I'd figure a lot of your wear metals are from doing that. Did you do an oil change shortly after the modifications, or is that v-twin oil the stuff you put in when you got done hopping it up? I would think that the new cam and valvetrain would result in more metal in the oil.

Fuel is high and flashpoint is low, though. Tune issues, maybe? Or maybe the extra 100 hp just takes a lot out of a motor?

Hydrocruiser

Good observation.

The reason the universal average is higher is because increased detergency specific to the product frees up sludge and metal particles thereby increasing "wear metal content" from a long time back.

We have known this for a while.

Hydrocruiser

FYI..I checked my sources and a trend is that there is a blending of PAO III. (highly refined) and IV. basestocks occuring to various degrees. Some synthetics are 100% GRP III. and some 100% GRP IV.

This does not worry me for the most part as synthetics still have the edge and the products are continuing to perform well vs. non-premium conventionals.

I suspect based on oil tests that it is safe to say that the more a product costs on average.. the more GRP IV. is in the formulation.

I would not "diss" a premium oil such as Mercury 25W-40 or Kendall 20W-50 as they work well and conversely would not say all "synthetics" are "equal" either.

As far as synthetics go the rule is the more it costs the better the product performs. You do get what you pay for.

phebus

I've followed this thread for some time, and I'm more confused then ever. I don't care what an oil change costs, if I can extend engine life, but I don't know what the best oil would be.

Hydrocruiser

Amsoil Premiums/Mobil-1 EP & V-Twin/Redline/Royal Purple

Pick the right viscosity and you are good to go.

If you are paying $6-9/qt you got the good stuff in the crankcase.

berns29scarab

so your recommendation for a pair of 280 hour 502 mpi's would be what...this thread is confusing as hell...lmfao going to change out whats in there now when i winterize her with a basic 10/40...then in the spring (i already have wix filters) you'd use which...