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MOP
05-14-2007, 12:34 PM
Please lets try to keep this as an oil thing only!
As many know I was on the wrenchs as an OMC and Volvo tech which brings me to the following question! I believe most all of us have noticed how warm our drives get while running on a flushette talking with -0- exhaust going through, I feel most of the temp is due to oil weight. Volvo ran 30wt for a guzillion years with great longevity, the OMC electric shift ran a thinner blend yet also with good gear life but was a crappy drive in other respects. Why do we now run these 70-90wt oils that contribute to drive temps when we have syn oils that are of lighter weights. Just an example Mobil 1 is like water but like other syns does a good job, why can't we run a high quality 30wt syn and get good results life wise and better speeds? Yes I am running Merc HiPo but switching to Spectro for better drive life.

Phil

MOP
05-14-2007, 03:00 PM
Kenny & I have had a few discussions on oils, Spectro is in my stash and in my engine & will be in my drive. I am trying to get a debate going here to get more facts, I worked on this stuff for many years and have real life knowledge of how long these drives survived with light oils. We have some very good oil men up here!

Phil

mphatc
05-14-2007, 09:04 PM
Redline Shockproof . .

thin
all synthetic
proven peformance

Mario L.

BigGrizzly
05-14-2007, 09:15 PM
Phil, in the mid 80 Volvo changed recommendations. they did the 70-90w on the early drives. It was a bulletin. I changed mine, I noticed no change. They said it would help the not going into gear syndrome. I don't know why since the 30w worked well. I am really surprised they didn't go to ATF, like some cars did in their manual trans and rear ends.

Greg K
05-15-2007, 07:05 AM
It has to do more with what type of oil it is and if it's rated SAE or SAE gear.
The "real" viscosity of a SAE 30w and a SAE gear 85W are pretty much the same as shown on this chart.

CHACHI
05-16-2007, 06:02 AM
Greg, I couldn't of said it better. From a viscosity standpoint a SAE 30 ENGINE OIL has the same viscosity as an heavy SAE80W/light SAE85W gear oil. The important thing to remember is that the ratings of oils do not go 5,10,15.20,25,30,40,50,60,70,80,85,90,140, etc.
The heaviest motor oil that the SAE recongnizes is a (out on a limb here)50. (It may be 60).
Any thing above this is considered a "Grade". A Grade 60 engine oil as the same flow rates as an 140 gear oil. Engine oils and gear oils are rated on two different scales. Kind of like inches and millimeters. Same length but a different number depending on the measuring stick.
If an engine oil would work to keep the gears happy, why not use it. Honda did/has for years. With the higher horese power being fed into modern day drives I would stay with an oil with the proper additives for gears. If you want to run a 30wt engine oil product, I would use a 75w90 GL-1 gear oil.

Ken