What weight oil should I run

[Print Dad 58]

Hello all,

This is another of those questions that is pretty simple but I am

OLD and not too bright.

 

The car 70 Mach 1 with 351C - 3 speed standard

 

The motor has about 92,000 original miles and runs well.

No major mods to the motor.

 

What weight oil should I be running for summer use?

 

I see lots of "new" oils on the market and don't really know much about them.

 

I am currently running Quaker State - 10/30. The car bruns no oil and the oil is real clean and is changed every 2500 miles with filter.

 

I was curious if I should use something special for this motor.

 

For those of you that read my other post -- - I changed the filter, ordered a new sending unit and the pressure is steady a little over the center of the guage.

 

Thanks for helping this old guy

 

Print Dad

[StephenC 10]

I usually use 10W30 Royal Purple I switched to 20W50 Valvoline racing oil and its raised the compression a little but it feels like it runs a little smoother. Just a personal preference.

[ashleesmach1 28]

Just run 10w40 in summer and 10w30 in winter

[6T9Mach1 12]

Quaker State makes a good oil but since you have a flat tappet camshaft it would be best to run a oil that has higher levels of phospherous and zinc. Several years ago now oil manufactureres started reducing the levels of "zddp" because it was clogging catalytic converteres in newer cars. This zddp is a neccessary anti-wear ingrediant for flat tappet camshafts; the more agressive the valve spring pressures the more important it is. With your stock valve springs an oil with 1200 ppm of zddp would be just fine. An easy off the shelf oil to use is Valvoline VR1 conventional. It can be found at just about any auto parts store and has the zddp you need for flat tappet camshafts. I would probably run 10w-40.

[Max Power 74]

Flat tappet camshafts are fine once they are broken in.

 

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1049812

 

Off the shelf 10/30 or 10/40 is fine.

 

And if you keep posting help threads about your car, you should consider typing up how your car is equipped in your signature. It will save you a lot of time of typing it over every time you have a question. Just a thought.

 

Cheers!

[tony 63C 14]

Good thread Print Dad.

 

Any reason why a 5W30 synthetic (Castrol) may not be the best choice? (1969 351W, mild cam, otherwise stock, ~ 2000mi since rebuild)

 

Regards,

Tony

[6T9Mach1 12]

Good thread Print Dad.

 

Any reason why a 5W30 synthetic (Castrol) may not be the best choice? (1969 351W, mild cam, otherwise stock, ~ 2000mi since rebuild)

 

Regards,

Tony

 

Depends on what the clearances are. Who did the rebuild? If you had someone do it for you I would ask them what weight oil they recommend. These engines generally have fairly loose tolerances, even when freshly rebuilt in comparison to today's engines, which means a heavier weight oil is probably needed.

 

Flat tappet camshafts are fine once they are broken in.

 

http://www.bobistheoilguy.com/forums...Number=1049812

 

Off the shelf 10/30 or 10/40 is fine.

 

Unless all the lifter bores are aligned properly, same spot and angle, then a proper break in never really happens. While that is an interesting read it is going to take more then one internet source to change my mind about whether or not to use an oil with high zddp with a flat tappet camshaft.

[carprojects 10]

Just an FYI, when I picked up a rebuilt 302 mild performance engine, one of the guys there was telling me that the oils are going to even lower zddp concentration. They, of course, told me to add the comp cam additive and to use rotella 10W40 for the first 500 miles.

 

Edit: I forgot to mention this was as of about 1 month ago...

[tony 63C 14]

As with most things in life, I have a tendency to over think them, and the whole ZDDP matter is fertile ground for pondering - so without further adieu:

 

After digging through several older forum threads on this topic it seems that simple good old 10W30 seems to hold its own as a popular choice for summer driving.

 

I happen to have 5 quarts of Amsoil 10W30 sitting on the shelf, but after reading some posts am thinking of taking the unopened containers to my local auto parts and swapping for the Amsoil 15W40 diesel (also approved for gasoline). The latter has ZDDP over the recommended 1200ppm range, while the 10W30 is below this supposed minimum level.

 

These comments from other threads, along with the added zinc has me leaning towards the 15W40 oil. (I haven't been able to find any ZDDP additive anywhere here, otherwise this would probably not be an issue)

 

 

>>> I was reading in Hot Rod a while back that 10-anything is not enough for our cars . . . if you opt for synthetic oil, then 10W is not enough <<<

 

>>> Amsoil says it's for pre 2007 deisels so it should be good stuff, I'd probably use it if I couldn't get the additives cheaper. <<<

 

>>> I use Royal Purple synthetic 20W50 racing oil. It's synthetic, has sufficient zinc without needing additives, and is a great weight for classic muscle. Because of the 50, you'll keep your oil pressure up as well. <<<

 

>>> These old engines were not designed to run the new lightweight oils unless it was oh my god cold <<<

 

Any thoughts?

 

Regards,

T.

[LoneWolf2U 136]

Over think? :blink:

I remember back when the simple oil change was at 15k miles.

As time has passed, the miles dropped down inbetween to 12k then 10, 7500, 6000, 5000, now its 3500 or when ever the car tells you its time to change it. :shifty:

 

Has the oil changed that much, that now it doesn't last as long?

 

Just to show them all....After break in oil runs, I have used a plain 30wt for years.:whistling:

Simple oil/filter every 5k an no oil related failures yet.

[Max Power 74]

 

 

Unless all the lifter bores are aligned properly, same spot and angle, then a proper break in never really happens. While that is an interesting read it is going to take more then one internet source to change my mind about whether or not to use an oil with high zddp with a flat tappet camshaft.

 

Lifter bores is another issue, not necessarily related to ZDDP.

 

Bob the oil guy is a former GM engineer and while the website name seems campy, he is pretty highly regarded. While he is one source, I have noticed that just about every other source promoting ZDDP has some sort of vested financial interest in doing so, or is simply quoting a source with the same interests.

 

ZDDP is probably cheap insurance, and for many, the peace of mind in using it is worth the investment. That being said, I have seen a lot of trends come and go, and a lot of money made off trends like this, and I have to say I have a pretty decent level of skepticism regarding this latest additive.

 

Ultimately, everyone will have to decide for themselves.

[EastYorkStang 63]

Over think? :blink:

 

I remember back when the simple oil change was at 15k miles.

As time has passed, the miles dropped down inbetween to 12k then 10, 7500, 6000, 5000, now its 3500 or when ever the car tells you its time to change it. :shifty:

 

Has the oil changed that much, that now it doesn't last as long?

 

Just to show them all....After break in oil runs, I have used a plain 30wt for years.:whistling:

Simple oil/filter every 5k an no oil related failures yet.

 

 

Great point!

 

I change the oil in the spring after I bring the car out of storage. No problems yet! I don't think I've driven it 5k in a single year...

[tony 63C 14]

Thanks for the added input. To revisit my original questions:

If there is any truth to modern synthetic oils being “thinner” than their mineral equivalents . . . and if so, would a 15W40 synthetic be a better choice over 10W30 synthetic?

(my car is driven only in the warmer dry months, and resides in a heated garage)

Cheers,

Tony

[CandyAppleRed 10]

Great point!

 

I change the oil in the spring after I bring the car out of storage. No problems yet! I don't think I've driven it 5k in a single year...

 

 

You may want to consider changing the oil in fall, prior to storage. Used oil contains acids and condensation. It would be better to get that stuff out and store the car with nice clean, fresh oil.

[6T9Mach1 12]

Synthetics are not thinner then conventional oils; they do however tend to flow better. I have found that I lost 5-7 psi of oil pressure using synthetic oil vs. a conventional oil of the same weight. You will be just fine running 15w-45 synthetic. Personally, I feel that 10w-30 is a bit light for these engines if built with traditional bearing clearances. Mobile 1 15w-50 is another very good synthetic oil that you may want to look at that does contain higher levels of zddp.