1996 Corvette LT-4 M1 5W-30 and S1300 15W-40

[XS650]

Engine Oil
Vehicle: 1996 Corvette Lt-4 5.7l V-8 6-speed
Oil analyzed: M1 5W-30 / Delvac Super 1300 15W-40
Lab: Blackstone
Drain Interval: 2950 / 6410 miles
Total Vehicle Miles: 48,860 at finish
Make-Up Oil: 0 qt
Oil Filter: Fleetguard LF3554 (synthetic media)
OEM air filter
Sample dates: 8/23/04 / 7/17/04
Conmments: See below

Vehicle driven. 90% + highway. From Freeway to extended twisty road driving. Very little city.

Oil temps generally run 200F to 230F with rare excursions to 240F range, Never over 250F

Note, newest to oldest left to right.
ALUMINUM 7/7
CHROMIUM 1/3
IRON 11/31
COPPER 2/5
LEAD 13/48
TIN 5/11
MOLYBDENUM 38/58
NICKEL 1/2
MANGANESE 0/1
SILVER 0/0
TITANIUM 0/0
POTASSIUM 1/3
BORON 42/120
SILICON 13/29
SODIUM 6/14
CALCIUM 2701/2610
MAGNESIUM 422/7
PHOSPHORUS 1124/687
ZINC 1191/881
BARIUM 0/1

SUS Visc. @210'F 74.5/62.5
Flash 380/435
Fuel Antifreeze 0.0%/0.0%
Water 0.0%/0.0%
Insolubles 0.3%/0.4%
TBN 8.0/3.7

I got the car last November with 39,500 miles on it in excellent cosmetic and running condition. Supposidly dealer maintained. I have no reason to doubt that, for better or worse

The above runs were part of an ARx clean rinse cycle. Clean cycle was done on the M1 5W-30. The last 4,000 miles of the M1 was with ARx, I overdid it because of some trips and other issues.

The rinse cycle was on the S1300 15W-40. ARx details will be posted in the additives forum.

No noticable oil was consumed on either batch of oil. It didn't budge off full on the dipstick.

I think the TBN on the S1300 15W-40 is impressive for a dino oil.

I discovered a slight gap in the intake ducting about the time I put the ARx in. Probably accounts for the 29 Si in the first part.

Lead and Tin are high, Lead a lot worse in the first part. I used 6th gear less in the 2nd part in case it was a lugging issue.

Lead got better, Tin only better proportional to miles driven.

Car now has M1 10W-30 and 5 oz of LC. Next analysis in 6,000 miles.

 

[Silverado]

Great car! I love those LT4's. Many LS1 owners have been shocked as they watch an LT4 walk away from them. May I ask why you went with the M1 10/30?

 

[OffOrWFO]

I am some confused about the way you posted your info. I "think" from your description that you ran the M1 6410 w/4000ARX miles and the S1300 2950 as an ARX rinse? But its posted opposite.
If thats the case it looks like the LT4 engine likes the 40wt a lot better than then 30wt M1. It could be the ARX or the extra silicon, but I would say run a thick 30wt or a 40wt. 4K on ARX is way over the recs. I would run the M1 to 6k then try a 40wt syn at 6k and see how they stack up.

 

[Al]

quote:

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Originally posted by OffOrWFO:
I am some confused about the way you posted your info. I "think" from your description that you ran the M1 6410 w/4000ARX miles and the S1300 2950 as an ARX rinse? But its posted opposite.
If thats the case it looks like the LT4 engine likes the 40wt a lot better than then 30wt M1. It could be the ARX or the extra silicon, but I would say run a thick 30wt or a 40wt. 4K on ARX is way over the recs. I would run the M1 to 6k then try a 40wt syn at 6k and see how they stack up.

---

I had the same questions and agree 100% with what you said-I don't think its the silicon causing the problem though. I think it may the viscosity for this engine. It will be interesting to see the 10W-30 results.

Now I know the temperatures are colder now-but I would not run more than 3 or naybe 4 K miles with this 30 wt. oil. I would be too nervous.

 

[XS650]

quote:

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Originally posted by Al:
I think it may the viscosity for this engine. It will be interesting to see the 10W-30 results.

Now I know the temperatures are colder now-but I would not run more than 3 or naybe 4 K miles with this 30 wt. oil. I would be too nervous.

---

Ambient temperatures aren't what matters when picking an oil viscosity. Oil temperature is. My oil temps rarely get over 230F, never over 250F.

Those are resonable temps for a good synthetic xW-30. Actually, not all that bad for a high quality dino oil with 3k mile change intervals.

 

[XS650]

quote:

---

Originally posted by OffOrWFO:
I am some confused about the way you posted your info. I "think" from your description that you ran the M1 6410 w/4000ARX miles and the S1300 2950 as an ARX rinse?

---

Thanks for catching that! Your interpretation is correct. I'll repost the whole thing next change and see if I can keep everything in the same order.

 

[XS650]

quote:

---

Originally posted by Al:
I think it may the viscosity for this engine. It will be interesting to see the 10W-30 results.

Now I know the temperatures are colder now-but I would not run more than 3 or naybe 4 K miles with this 30 wt. oil. I would be too nervous.

---

Ambient temperatures aren't what matters when picking an oil viscosity. Oil temperature is. My oil temps rarely get over 230F, never over 250F.

Those are normally resonable temps for a good synthetic xW-30. Actually, not all that bad for a high quality dino oil with 3k mile change intervals.

Let's put weather and SAE viscosities aside. What actual viscosity in cSt at actual sump operating temperature (not at 100C) should the oil be in an LT4 engine, and why?

[ September 05, 2004, 10:11 PM: Message edited by: XS650 ]