POLL: which oil do you use ?
 

what oil do you use in your stock big block ?? let the :argue: begin.

If you use FULL synthetic,, what weight ??

Re: POLL: which oil do you use ?
 

Valv Race 40

Re: POLL: which oil do you use ?
 

both engines very fresh. pennzoil 30 in one, Mobil 1 15w50 in the other, temps the same now, Ill see how things look next winter.

Re: POLL: which oil do you use ?
 

Castrol GTX Racing straight 40 weight

Re: POLL: which oil do you use ?
 

I don't use any

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Wow looks like that slik 50 test didn't work out for ya...

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That is UGLY !! :eek:

Re: POLL: which oil do you use ?
 

P.S. what weight are you Mobil 1 guys using ??

Re: POLL: which oil do you use ?
 

Mobil 1 15w-50

Re: POLL: which oil do you use ?
 

Old 500EFI and Current 496HOs
Mobil 1 15w50

Re: POLL: which oil do you use ?
 

I use 20-50. I would like to go to Mobile 1 but I hear so many worries about going to synthetic oil. I also hear on a full roller motor to stay away from the synthetic because it does not work with the extra tolerance our motors have, it is also so slippery that the rollers may not roll and develop flat spots. I have 502s with the HP kit, full roller (crane gold) and Dart intake. What do you guys think? I was told this by a very reliable engine builder.

Re: POLL: which oil do you use ?
 

That is a myth. I heard the same things too Mitch and it is an old engine builders wives tail. If the roller didn't roll because it was so slick that would be fine with me. It would be riding on a thin sheen of oil and cause no wear. If your roller lifters are hanging up then you should have a talk with the manufacture. The only time I ever lost a roller cam was when it broke. Thank you Iskenderian

The only time you shouldn't use it is during engine break-in when piston rings need more friction than normal to properly seat. Also in leaky engines synthetic oil can exploit those leaks and be worse.

Roby

Re: POLL: which oil do you use ?
 

The main difference synthetic motor oil has versus a conventional motor oil is at the molecular level. Synthetics do not have the waxes, ash, etc and other impurities that conventional motor oils have, and their molecular structure is uniform compared to conventionals. These impurities that conventionals have burn off a different temps or contribute to deposit formation.

Mobil 1, for example, is the factory fill motor oil for many higher-end production cars, most of which have roller or OHC valvetrains. Do you think GM would put Mobil 1 in Corvettes if it were going to cause unusual valvetrain wear that they would have to address under warranty? Actually, even in automotive apps with conventional motor oils, roller tipped rocker arms have a tendency to slide over the valve stem rather than roll, especially under higher vlave spring pressures. But you're only talking about a movement of 1/3 of 11/32 of an inch(typical in a GM engine). The late John Lingenfelter even pointed this out in his engine book, and I have seen this myself while setting up valve trains. Of course my observations occured while rotating the engine by hand, which is entirely different than an engine operating at thousands of rpm.

I see or hear people say all the time how marine engines have extra clearances in comparison to automotive engines, but that's not really true. It's a good idea to consider the fact that most marine engines perform at a lower operating temperature which may affect piston to cylinder wall clearance due to the fact that the cylinder block doesn't get as hot and wrist pin clearances due to potentially higher piston temps as a result of running under load for extended periods, but other critical clearances such as main and rod bearings, valve guides, etc are the same as automotive applications. If you open the clearances up too far out of tolerance, then you lose oil pressure and oil film strength. Metal to metal contact results.

The cylinder walls and pistons/rings and wrist pins are primarily lubricated and cooled by oil splash. As long as the cylinder walls are machined appropriatelyfor the piston ring, i.e. moly, excessive oil consumption is not a problem. It used to be said that you shouldn't break an engine in on synthetics because the rings wouldn't seat as well, but with modern honing techniques even that is not a problem. The only drawback synthetics have compared to conventionals is their increased cost.

Re: POLL: which oil do you use ?
 

My engine builder ( Innovation Marine ) says to use in my 502/500hp Mobil 1 15/50w. When talking to them about this they said after testing on the dyno..Mobil 1 worked best and gave 10hp over straight weight.

Re: POLL: which oil do you use ?
 

I know this had been debated to death, but there is always some GOOD information that comes out of these threads... I was thinking of going with castrol 20-50 synthetic BLEND, I now have 12 hours on a new 496 H.O. The blend seems like the best of both worlds..

Re: POLL: which oil do you use ?
 

Got basically the same motor, 509 cu in, full roller crane gold, even have the dart intake. For the 2 years I ran Red Line 50W Race, the past 2 years Mobil 15W50. No problems after many hard hours.

Re: POLL: which oil do you use ?
 

Thanks for the info, I am going to Mobile 1, my engine has about 40 hours or so on since rebuild so the break in is done. I have a cool oil change system on this boat, lines from the drain plugs go to a T and then to a pump on the bulkhead. The T has valves so you can isolate each engine, put a 5 gal bucket on the ground (long line from pump to bucket, but a siphon effect helps pump fast) and you are done, I have a 5 gal with a lid and a small hole for the hose. I can dump a pan in about 2 min. I can even reverse it to pump in but that makes no sense. I am off tonight to buy 20 qrts :) Although more costly, the extended life of the oil will offset this cost....by a bit, I change every 50. Thanks for the tech info, like said, why would Corvette use this from day one if it was not the best.

Re: POLL: which oil do you use ?
 

royal purple.........

Re: POLL: which oil do you use ?
 

I have a 540 w/871 blower at 5lbs of boost. No intercooler. I've been told to use Kendall Racing 20/50. What do you think?? (I change the oil every 10 hours)

Re: POLL: which oil do you use ?
 

My engine builder recommended it in the beginning. Since I change it about every 10 hours, Im told it's ok. They don't recommend synthetic.

Re: POLL: which oil do you use ?
 

how bout castrol racing 10w60????? . what are your thoughts?

Re: POLL: which oil do you use ?
 

Mobil 1 15w50

Re: POLL: which oil do you use ?
 

The only concerns with blends is that the ratio of synthetic can be very low. If you want a blend take 3 quarts of synthetic Mobil-1 15w50 and add 2 quarts of Mobil conventional 10w40. That is what my neighbor uses in his 18' Donzi 350. Works great as he buys a 4 quart container of each at Walmart. About $ 3/qt. It's an older motor and he is worried about seal leaks. The reason seals can leak with a synthetic is because of the increased fluidity of synthetic oils. That's the only reason. The 496's are GM proven on synthetics in trucks. I would not worry a bit about a synthetic in them at all.

Here is a good representation of how conventional oils shear down in the presence of heat and in this case Redline ( and most quality fully synthetics) do not. It shows for example that you can start with a 20w50 conventional and under heat and shear (piston movement) it can go down to a 10w40 viscosity and is comprimised. A conventional 10w40 can shear down to 5w30. The Redline synthetic 10w40 stays a 10w40 and is not comprimised. That's why I use a good 10w40 synthetic in place of a conventional 20w50. Under normal operating conditions they are the same viscosity in essence but more sludge can develop with the conventional's increased volitility and boil off. If you want a 20w50 to stay 20w50 use what Merc supposedly uses in it's big blower motors Amsoil Series 2000 20w50 it will remain a 20w50 under heat and shear forces as will Redline and RP and Mobil-1 to a slightly lesser extent. I think this graph is worth a thousand words. With conventionals you need "thick" because you end up with "thin". Premium synthetics can take the heat and shear forces and remain virtually unchanged. Still change at normal intervals in the marine environment.

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I wouldn't extend the change intervals, the acids still build up in the oil and although the oil will not break down it is not good for the bearings. I was told to keep the 25 hour change interval on my motors.

Walmart has 5qt bottles for $19.

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I've used Mercury 25w40 since day one. Oil pressure is dead on perfect. I use mercury race filters and change every 10-15 hours. The drive gets changed every 25 hours with merc. hi perf drive oil. :D

Re: POLL: which oil do you use ?
 

Mobile 1 15-50 @ Walmart $18.95

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Mobile 1 15W50 - 496HO's

Re: POLL: which oil do you use ?
 

I've got 110 hours on a Sterling rebuild of my 800SC's. They suggested Mobil 1 15-50 Synthetic on a 15 hour cycle. Doug told me that Mercruiser sets their blower motors up "fat" so I should watch for dilution based on how I'm running it. He suggested I do the following immediately after shutting down. SMELL the oil. If you smell gas, change oil filter. Oil level may drop if running hard or raise ever so lightly if lots of idling which is immediate signal to change it. I was running AC PF35's at the time which he thought was cool. I change tranny fluid every 5-6 hours and drive fluid in the #5's every 20 hours. I don't go on plane until oil temperature has stabilized. Probably overkill but in four seasons, the only non-maintenance failure I've had under the hatch is a sheared stud on the power steering pump and two failed battery chargers. For what it's worth

Re: POLL: which oil do you use ?
 

I meant oil AND filter!

Re: POLL: which oil do you use ?
 

cen-pe-co!

Re: POLL: which oil do you use ?
 

Since you are a "Mercury Man" and that's certainly fine! You may be interested in knowing that Mercury has a Synthetic Blend 25w40 for it's 4 Stroke Outboards. I was told the conventional 25w40 wasn't holding up as well in that application and they came out with this new product. The synblend goes for $ 4.95/qt.

Re: POLL: which oil do you use ?
 

Today, I just bought a few 5 quart bottles of Mobil1 for $18+change each at Wal-mart.

G

Re: POLL: which oil do you use ?
 

The most important thing you can do is let the oil show temp before going on plane. Like Lmarth said, it will make a huge difference. I do a lot of idling and I have not seen any sign of fuel in the oil. Thats a good thing. :) Bought 4 5qt 15-40 M1 for 18. each also. :) Now lets talk about disposal. I found dumping it offshore left a horrible oil stain on the hull, if I idled it collected on the stern. Now I just dump it in the woods. :) NOT. :) :)

Re: POLL: which oil do you use ?
 

Mitch, pour it in the neighbors yard. Thats what I do!!!........NOT!! :rolleyes:

Re: POLL: which oil do you use ?
 

Mobil 1 15w-50 in a Dennis Wells built 454

Re: POLL: which oil do you use ?
 

Mitch--Thanks for the feedback. Forgot to mention that I never start the motors without cranking them on the starter until I have oil pressure. Perhaps simplistic, but starters are cheaper than an expensive and complex prelube setup. Boat (1998) had a prelube setup on it at one time. Don't know why it was removed, but my technique seems to have worked and the starters haven't failed so far. Lou

Re: POLL: which oil do you use ?
 

What filters are you guys using? I was ripped off by west marine on some Frame filters....$14.00, I can get the same at wall mart for $4. Why do I always do things back wards? Now I have to take them back. I bought NAPA Gold. Are these OK, they are longer than stock which can't hurt? I am changing the oil for the first time tonight. How many quarts does a 502 hold? I have 15 quarts of Mobile 1, thats 7.5 each....with my luck I will need 8 :rolleyes: How do you crank the engines for oil pressure without them starting? Pull the tether? Mine start right away, maybe 3 cranks and BOOM, Merc/Gills start barking loud.

Re: POLL: which oil do you use ?
 

Mitch-- I believe it was Hydrocruiser who had an interesting thread on oil filters a few days ago. I suggest you check that out. The AC Delco, Amsoil,etc were quite good. I've always run the long version of the AC Delco brand in my BBC's. Just personal preference. My 800SC's don't start unless I give them 1-2 strokes of the throttle so I can easily crank to get oil pressure. I'm sure you've heard about wiped cam lobes with BBC's with High lift cams. I hope I didn't mislead anyone with my prior comment. Pulling the tether is one way of doing it. -- Lou

Re: POLL: which oil do you use ?
 

Oh I do know about taking cam lobes out. I did this on a 454, the biggest reason was water from the risers getting into the oil. I have to give it a goose also when cold so I will try this also. Thanks Lou. The first time is always a B, then you know what to expect and it is easy, just need to take my time. :)

Re: POLL: which oil do you use ?
 

Mitch- Hang in there, you'll be just fine. The biggest threat to a BBC cam is when a brand new cam is first run. What I usedto do was to mark the rotor and distributor housing before teardown. Then when I assembled the heads I'd use only the outer springs. Then I'd spin the oil pump with a drill to get oil pressure. Then I would fire it up and keep at 2000 to 2500 RPM's for twenty minutes. Then add the inner valve springs/dampers, fresh oil/filter and retorque heads. Now all you had to do was check the timing and run it. The worst thing you can do to a new,hot cam is to fire it up and let it idle @ 800RPM. At the marina I'm at I've seen 3-4 cam wipe-outs in the last year or two. Common thread-New cam, start it, idle off tto try it. Next day, missing and/or backfire through carb. It got to the point where you could tell whether it was an intake lobe (miss) or exhaust lobe (backfire). For what it's worth- Lou