Need help choosing the right viscosity

[jjwalker]

I own an 88 s15 with a 2.8L v6. The engine is fairly new and only has 30,000 miles on it. It doesnt burn any noticable amount of oil.

My problem is choosing the right multigrade for it. When I drive it hard the oil thins to nothing and the lack of pressure makes me nervous. But, on the other hand when it is chilly ouside the oil takes a second to make it up on the topside of the engine and I get alot of valve train noise (in the winter, summer is ok).

Currently I am using Castrol GTX 10w30. I was thinking of maybe going to a 15w30 or 20w40 for the summer. As for the winter, I am lost.

What are yall's suggestions?

 

[sbc350gearhead]

I would probably try delvac 1300s 15w40 for a conventional. IIRC, it actually meets 10w cold temp pumping specs. If you still have problems in cold weather, then use a 10w30 in the winter. Rotella T syn 5w40 would be a decent compromise, and its not that expensive.

 

[jjwalker]

Thanks, I appreciate the advice.

 

[jorton]

Does Delo 400 pump like the Delvac 1300? I am using Delo in a 90 Nissan and I would switch if Delvac is better.

 

[Al]

quote:

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Originally posted by jorton:
Does Delo 400 pump like the Delvac 1300? I am using Delo in a 90 Nissan and I would switch if Delvac is better.

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Delo pours at -38F and Delvac -30F . At 40 C the Delvac is 123 cSt (thicker) and Delo 116 cSt (thinner)

jjwalker : have you done an oil analysis to verify the oil "thins out" This is very subjective and you shouldn't trust what you see in terms of thinning. All oil is "thin" when hot.

Do an oil analysis

 

[jjwalker]

I do understand an analysis would tell me alot, but what I was basing the "thinning" from was the dramatic loss in oil pressure associated with heat, and high stress put on the engine.

Normaly, pressure stays at 20 at idle and 40-50 above 2000rpm.

After some hard driving the idle pressure is 5-8 and 20-30 over 2000rpm.

I dont know, maybe I am just getting too worked up over it, but for an engine with 30k on it, 5-8 at idle sounds way low.

Also, another question. What is a good oil filter? I always hear bad things about fram and supertech is scary cheap. any suggestion is appreciated, even if you suggested fram or supertech.

[ July 03, 2004, 02:24 PM: Message edited by: jjwalker ]

 

[TallPaul]

I assume the 20 psi idle and 40-50 above 2000 rpm is hot pressure, meaning you drove at least 15 miles. Given that, it seems the hard driving is heating the oil pretty badly to lower pressure as much as you note. An oil temp gauge might be useful here. You may want to try synthetic oil which would take the heat better, probably Amsoil, Mobil 1, or Redline. It should thin less. See if that works, or maybe an oil cooler is in order. What is the factory spec for oil pressure on your engine? Motorcraft, Purolator, Wix are good filters.

 

[widman]

I would go with the Delo. I haven't had any issues, easy starting and quick response at -20C. In general I don't see running the thinner oils in anything from the 80's. My Check-chart book for the 88 year shows 15W-40 or 20W-50 for almost everything, with a few recomendations for 10W-30 in below -18 C.

 

[Al]

quote:

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Originally posted by jjwalker:
Also, another question. What is a good oil filter? I always hear bad things about fram and supertech is scary cheap. any suggestion is appreciated, even if you suggested fram or supertech.

---

SuperTech is actually a good filter. Go with the larger version. Best Oil filter is K&N IMHO) Another good compromise is STP orBosch. Other good ones out there. Wix is good. Amsoil. Mobil 1 is good but may be too restrictive.

 

[labman]

quote:

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Originally posted by jjwalker:
snip...Also, another question. What is a good oil filter? I always hear bad things about fram and supertech is scary cheap. any suggestion is appreciated, even if you suggested fram or supertech.

---

What are we talking here, something common and cheap like a PF 52? If it is anything you can get for less than $4 for the AC at Advance Auto or somewhere like that, go with it. It took me a while to get up the guts to put an ST on my truck. If you just can't quite do that, and the OEM is hard to find, an STP or Purolator should cost about the same as a Fram. The ST, STP, and Purolator all have about the same guts.

I agree the Fram is crap, but there isn't too much hard data proving your truck needs more. Still why chance it when as far as I know, everything else is better?

 

[jjwalker]

TallPaul:

Yes, that is after the oil is warmed. The pressure before the oil gets to temp stays at 75 and doesnt move. I am not sure what the stock oil pressure should be. I must point out that I custom built it to take higher pressures. I want to keep as much thick oil as possible between the crank and bearings under hard acceleration. The last engine that got built (I didnt do it) went dry one day as I had it at WOT. If you can imagine what horrible things happened next, I wanted to make sure they didnt happened again.

But anyway, The reason i havent considered synthetics is because I keep a strict 3000 mile OCI and it doesnt seem economical to use it without an extended oil drain. As far as the supertech filter goes, I might have to take a look at those. I havent heard anything bad about them, I just got a little nervous about using one due to the very low price. As far as the frams go, I am not picking side in the Everyone VS. Fram war. The way I see it, I am not going to use a filter that is under constant debate and has no known (to me anyway) factual info regarding its strengths and weaknesses. I think I am leaning toward trying out Castrol GTX 15w40
for the now due oil change, and go take one more good look at the oil filter analysis.

Thanks for the suggestions, they have been very helpful. I havent made a set decision on what oil to stick with for the rest of the engines life, the castrol is just going to be a test. Any more comments or suggestions will be very helpful.

 

[jjwalker]

lol, I appologize. I guess that info before would have been alot more helpful.

It isnt highly modified, slightly modified performance wise, and the rest is all durability related. I can say it definately isnt in the ballpark for racing oils, just something that will take a real good beating and thrashing

 

[Gene K]

quote:

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Originally posted by jorton:
Does Delo 400 pump like the Delvac 1300? I am using Delo in a 90 Nissan and I would switch if Delvac is better.

---

Delvac 1300 - 6000 cp @ -20C
Delo 400 - 6400 cp @ -20C

Not much difference but Delvac has slightly better cold pumping numbers.

Gene

 

[jjwalker]

I remember reading somewhere on BITOG that Diesel oils shouldnt be used in gasoline pushrod motors.

Is Delo approved for both Gasoline and diesel engines?

 

[Gene K]

quote:

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Originally posted by jjwalker:
I remember reading somewhere on BITOG that Diesel oils shouldnt be used in gasoline pushrod motors.

Is Delo approved for both Gasoline and diesel engines?

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Yes, both Delo and Delvac carry the latest SL Service Rating (Gasoline) and CI Commercial Rating (Diesel).

Gene

[ July 05, 2004, 02:48 PM: Message edited by: Gene K ]

 

[haley10]

JJ, now you tell us that the engine is not stock and you have modified it.

That's a horse of a different color, entirely.