Oil weight

[69RunnerMike]

I bought a 69 runner with a 383 with 105k miles that was sitting since 1984. Motor runs well with very little blow by. I was planning on using a full synthetic oil and was wondering what weight oil to use. I was thinking of using Castrol GTX Full Synthetic 5W-20W with a WIX 51515XP XP oil filter. I'm in West Virginia with average winters and hot summers . Any recommendations?

 

[V.R.D]

use ether 15 w 40 rotella t conventional oil with a zink additive NOT a synthetic it is to thin and will leak when the conventional will help seal i use a 20w50 race oil with surfer and zink witch you will hurt the cam shaft if you don't

 

[quikbird]

5 20 too thin. 100 k miles means motor from that era has some wear internally. agree with vrd that need zinc to keep cam and lifters in good shape.

 

[69RunnerMike]

I forgot to mention that I was going to use ZDDPPlus ZDDP Engine Oil Additive Zinc & Phosphorus. Is using synthetic motor oil in general a bad idea on these engines or was it just that 5w 20 was to light or both?

 

[quikbird]

Synthetic itself not an issue if you supplement with zinc additive. Older engines with 100k miles have some internal wear and need a thicker oil. vrd suggestion 20/50 a good one. remember these cars were starting to be considered worn out at that mileage. Unlike modern engines

 

[Ranger]

You guys are starting to worry me. What's wrong with Rotella T5 10W30 and a bottle of ZDDP Plus?

P.S.
Found this pretty interesting.

Shell Rotella T4 vs T5 vs T6 (Dec Updated)

In the engine oil business, Shell has been a pioneer and one of the superior and successful manufacturers. Their engine oils are produced using the most

comparemotoroils.com

 

[V.R.D]

it all depends on how the engine was built . a 100 thousand mile engine needs heaver oil than a fresh build. i have always used 20w50 as i beat the hell out of mine when raced. i use it now as insurance as Florida is hot.

 

[Ranger]

OK, you guys have convinced me. After studying the numbers in the link I posted, I'm going to Rotella T5 15W40.

 

[Coyote]

IMO Any of the quality brands of diesel 15w40 are more than adequate if used with an additive for cam longevity. I use the Comp Cams break in additive EVERY oil change in my flat tappet engines . I autoX and drag race my “toy” cars and have NEVER had a lubrication related failure, they still carry decent oil pressure afer years of severe usage.

I’ve seen some negative opinions on using diesel oil in gas engines. IMO any oil that can tolerate diesel compression ratios is more than adequate for me!

 

[69hemibeep]

IMO Any of the quality brands of diesel 15w40 are more than adequate if used with an additive for cam longevity. I use the Comp Cams break in additive EVERY oil change in my flat tappet engines . I autoX and drag race my “toy” cars and have NEVER had a lubrication related failure, they still carry decent oil pressure afer years of severe usage.

I’ve seen some negative opinions on using diesel oil in gas engines. IMO any oil that can tolerate diesel compression ratios is more than adequate for me!

Who asked for your opinion

 

[quikbird]

I have never been able to get him to stop opinionating.

 

[69RunnerMike]

I'm going to use Valvoline VR1 Racing Synthetic 20w-50. It's supposedly a high zinc and phosphorus formula, but should I add ZDDP Plus as well, or is too much of good thing not a good thing?

 

[Coyote]

IMO, I wpuld probably add a half bottle of Comp Cams additive to be safe and sure the cam/lifters were protected. Hemmings also sells an oil that is supposed to work for flat tappets. Additive would be extra insurance. If one wipes a cam or lifter(s), hunks and pieces go throughout the entire engine. Rebuild time! That ain’t cheap! ‍

 

[Russ69Runner]

EZ zinc additive comes in a small bottle what my engine guy recommended to use in my 383. 15-50 T4 Rotella. These motor's do run warm. The oil dose thin out at higher temps. Good luck and have fun.

 

[road robert]

I use Lucas Oil Motor Oil 10W40 Conventional (High Zinc) - you can get at NAPA, Amazon, Summit Racing, etc. When I Google T5 Rotella it says for Diesel engines?

 

[mr4speed]

Just dump some oil into it and run the piss out of it stop worrying so much!!!!!!!!!!!!!!

 

[Ranger]

I use Lucas Oil Motor Oil 10W40 Conventional (High Zinc) - you can get at NAPA, Amazon, Summit Racing, etc. When I Google T5 Rotella it says for Diesel engines?

Specification Chart:​

Specs	Rotella T4	Rotella T5	Rotella T6
Oil Type	Conventional	Synthetic Blend	Fully Synthetic
Engine Type	Gasoline/Diesel	Gasoline/Diesel	Gasoline/Diesel
Viscosity Grade	SAE 15W-40 SAE 10W-30	SAE 10W-30 SAE 15W-40	SAE 0W-40 SAE 5W-30 SAE 5W-40 SAE 15W-40
API	CK-4, CJ-4, CL-4 PLUS, CL-4, CH-4	CK-4, CJ-4, CL-4 PLUS, CL-4, CH-4	CK-4, CJ-4, CL-4 PLUS, CL-4, CH-4
ACEA	ACEA-E9	ACEA-E9	ACEA-E9
Price	$12 for one Gallon	$18 for one Gallon	$30 for one Gallon
Oil Change Frequency	Up to 3000 miles	5000 to 7500 miles	7500 to 15000 miles
Additives	Anti-wear, Advanced multi-functional Dispersant additives, Detergents, Antioxidants.	Anti-wear, Dispersants, Detergents, Antioxidants.	Anti-wear, Detergents,

 

[Russ69Runner]

My mechanic suggested to put in a 4 oz bottle of Zdp. Over what the T4 Rotella has in it. Said it is well worth the money and won't hurt a thing.

 

[4134]

Synthetic in a 50 year old 100k mike engine is a bad idea, not what it was meant to use. Think it over Again. Before using it.

 

[insidegroove]

15w 40 rotella