Difference of oil type

[duckseatfree]

So I've read up and down the forums and I'm still have a few questions. To set you guys up I have an '86 Supra Sunsport w/ 351 and a little over 500hrs.

What kind of tranny do I have 1:1 or 1:23:1? What is the difference. (I would look but I don't have access to my boat this week)

I want to change the oil but can't find a definite oil type I should use. One manual says any specifically Dexron 3 and another one says Type A, Suffix A, Dexron.

- Could I use Dexron 6 as oppose to Dexron 3...what makes them so different...could the change damage the transmission?

(This is where I got one Manual...can't find the other one for now... http://www.planetnautique.com/CorrectCraftManuals/PCMEngineOwnersManual.pdf )

Last one....for the engine oil it suggests 10W30 or 10W40, what's the benefit of using one over the other? My engine has about 500hrs so would that make a differnce on which type i should use? (the meter stopped working this year so I'm trying to keep track of it myself)

I know I could google all these questions but for one, you can't always trust that information...and two, I know you guys take great care of your Supra's and I would like your take on these questions.

Thanks guys!

[jsandy]

at skiers we always go with 10/50 oil for motor. as for in my 91 sunsport i went with straight 40 weight. our service tech said thats what they always use on the older boats so i went with his advice. as far as trans fluid as long as its new fluid it really does'nt matter. but since you dont know plan on changing it 3 times in a row. such as you drain it, fill it run for a second drain it......... enough to flush out whatever was in there and so you have all new stuff, the problem accures when the new mixes with the old. from what i have read its pretty hard to kill these old trans. for the record i used stander atf fluid. works fine

[beast 496]

For an 86, you should have a velvet drive. 1.1 ratio. Try to get Dex III As for the engine. We use 15w40 synthetic blend in all of our applications from brand new to 60's versions. Basically you need an oil with a high "zinc" content for flat tappet cams such as you engine has. Al

[wotan2525]

beast -- My mechanic has recommended that I start running an oil additive with high zinc content for the exact reason that you just mentioned. Do you agree with this?

[cadunkle]

The two things important for flat tappet cams are zinc and phosphorus. The zinc does the cushioning and the phosphorus carries the zinc enabling it to do its job. Don't worry about using zinc additive. I higher zinc content oil is good but not really necessary.

The only time when high zinc/phos are critical is cam break in. After that, everything is worn together and you'll be fine even with the newer lower zinc/phos oils unless you're running crazy spring pressures. For cam breakin I use Valvoline VR1 which IIRC has 1300/1200 ppm zinc/phos, compared to 500-800 ppm in some of the low zinc oils. Mobil1 varies the zinc/phos content in their different grades of oil, though I have a chart somewhere that breaks that down, as well as info on several other of the big players.

Bottom line though is it doesn't really matter too much after cam breakin.

[Okie Boarder]

Isn't Dex 5 or 6 also a replacement for Dex 3?

I was under the impression you needed the high zinc all the time. I just buy the oil that has it...like Shell Rotella.

[cadunkle]

Okie, do not buy Rotella thinking you're getting high zinc content. They changed it a few years back and it's now well under 1000 ppm zinc/phos. I used to use Rotella for cam breakin, with no additives. I remember picking up some Rotella to break in a cam for an engine I was building for a friend, and thinking "That's odd, the bottle is different". Didn't think much about it until after breakin when the motor had a slight tap. Pulled it out and tore it apart, chewed up a couple lifters on breakin. Checked the zinc content as this was when most oils were going low zinc/phos, sure enough Rotella dropped a significant amount of zinc/phos from their oil. That mistake cost me $250 and a weekend of work to replace the cam.

I now only use Valvoline VR1 for cam breakin. It's a great oil anyway, but very well suited for cam breakin due to the 1300/1200 ppm zinc/phos. The fact that your engine hasn't wiped the cam is a great example of how low zinc/phos content is not necessary after breakin. Must be 4-5 years since they changed the zinc/phos content.

[beast 496]

There are so many differant oils on the market. Here is a link to the brand and type we use, 2% zink content.
http://www.docs.citgo.com/msds_pi/663003002.pdf

[Rusty]

beast -- My mechanic has recommended that I start running an oil additive with high zinc content for the exact reason that you just mentioned. Do you agree with this?

I agree. My mechanic told me the same thing about "zinc" content in oil. He said to use valvoline motor oil- because it has zinc in it.

[cadunkle]

I agree. My mechanic told me the same thing about "zinc" content in oil. He said to use valvoline motor oil- because it has zinc in it.

Valvoline has no more than any other oil. Most are now fairly low zinc and phosphorus. Most of Valvolines oils are too, unless you get VR1. The lower zinc/phos doesn't matter after a cam in broken in though. If you want to run high zinc/phos for peace of mind, don't go buying any old Valvoline oil (or Rotella, or whatever brand) thinking you'll get it.

There is a LOT of misinformation out there about this. You need to look up the spec sheets on the exact, specific oil you plan to run and find the ppm of zinc and phosphorus. The manufacturers will vary it between viscosities of the same line of oil, and it can vary significantly. 5w30 and 10w40 of the same line of oil will likely differ in zinc/phos content. Do your research first if you want to run a high zinc/phos oil. If manufacturers don't make this information publicly and easily available then don't buy their product.

[Okie Boarder]

That's interesting as I've been told Rotella or the VR1 are two good ways to go. How do I find out what the zinc content is?