1969 Pontiac

[Rhymingmechanic]

I have a 400 that was rebuilt with the "high pressure" pump. With fresh bearings and a polished crank, it makes around 20 psi at hot idle and 80 cold. Pressures were about the same with 30W and 10-40. I don't know what the stock pressure was, because I didn't add a gauge until after the overhaul.

Rotella 10-30 or 5-40, as recommended earlier, are what I'm considering next time I put the car on the road.

 

[Merkava_4]

Originally Posted By: 69P
Why choose 5w over 10w ?

Also im hesitant to run Quaker State oil. Ive always heard about quaker state and a notorious grey buildup. Have you guys heard or experienced this?


If you want, I can give you the name of an automotive machinist that's been in the business for well or 20 years and he just so happens to own a '69 Pontiac Lemans. I'd take his word for gospel if it was me.

I can guarantee you he'd never recommend 5W-30 in a million years.

 

[Hollow]

Originally Posted By: 69P

Also im hesitant to run Quaker State oil. Ive always heard about quaker state and a notorious grey buildup. Have you guys heard or experienced this?


Nonsense.

 

[spasm3]

Like JHZR2 said , spring pressures matter here. If you have heavier valve springs, you do need more zinc. The lucas stabilizer is diluting the add pack of any oil you use, so don't use it. SL rated oils like the high mileage oils should have enough zinc. Although expensive, motor cycle oils have tons of zinc. Amsoil HDD ( heavy duty diesel) would work here. its a heavy 30wt oil, probably close to a 40wt.

 

[aquariuscsm]

Instead of using GTX 10W40 w/Lucas,how about straight GTX 20W50?

 

[Merkava_4]

Originally Posted By: aquariuscsm
Instead of using GTX 10W40 w/Lucas,how about straight GTX 20W50?


Man I hope you got your flame suit on.

 

[Chris142]

if it has not ate a cam yet then it probly wont.i would go with a hdeo myself.

 

[aquariuscsm]

Originally Posted By: Merkava_4
Originally Posted By: aquariuscsm
Instead of using GTX 10W40 w/Lucas,how about straight GTX 20W50?


Man I hope you got your flame suit on.

You got my back brother? We can take em on!

 

[Clevy]

Lucas is doing nothing more than thickening your oil and diluting the precious zddp you think you need,as well as diluting the oils additive package.
So drop the Lucas and go thicker.
I'm not a fan of the 50 grades simply because of drag. But it seems if you are running a 10w-40 with a quart of Lucas you are already heavier than a 50 grade.
If you want high zddp look at a v-twin oil. I'm no fan of mobil 1 however iirc their v-twin oils have in excess of 1600ppm zddp,which is 50% higher than most commonly available diesel oils.
I'm not convinced you need extra zddp though. That cam isn't really high lift so unless the spring pressures are really high it may not be required.
Adding zddp will shorten the oils useful life because the tbn will be affected. I'd rather use mos2 based on my experience with it but there are some here who don't like it. If it's not a daily driver I may hold off on the mos2 idea based on potentially dropping out of suspension.
So forget the Lucas. A simple diesel oil should be more than ample. A 15w-40 should give you good hot pressure,similar to what you've got now.
I do like M1 0w-40 though. Very high tech and a fantastic high performance oil. And inexpensive.

 

[69P]

As far spring pressures go, Im pretty sure stock pontiac springs have an average load of ~275-300#, and seat pressure is around 100#.

This car is my hobby car, and it gets driven tops once a week. More like every 2-3 weeks.

Im also concerned with using a synthetic oil in an old motor. I have always been told not to use synthetics in old cars, but I know the synthetics have more potential. Do any of you have insight on synthetics in old OHV motors. I heard their seals arent made for it all the way to the pushrod, lifter, cam setup arent made for it.

 

[901Memphis]

Most over the counter synthetics are group 3+ hydrocracked anyways. Shouldn't have any seal issues that the conventional oil wouldn't. Try Mobil 1 0W40.

 

[Clevy]

Originally Posted By: 69P
As far spring pressures go, Im pretty sure stock pontiac springs have an average load of ~275-300#, and seat pressure is around 100#.

This car is my hobby car, and it gets driven tops once a week. More like every 2-3 weeks.

Im also concerned with using a synthetic oil in an old motor. I have always been told not to use synthetics in old cars, but I know the synthetics have more potential. Do any of you have insight on synthetics in old OHV motors. I heard their seals arent made for it all the way to the pushrod, lifter, cam setup arent made for it.




As far as mechanically it's an absurd notion to believe that synthetic oil can do any harm. In fact they are better in service.
And how is a cam made for a synthetic or conventional. I'd love to hear the theory on that one.

So yes at one time syns would expose leaks in older engines. Considering you've said this engine was rebuilt I assume they used modern gaskets and not rope type,so there shouldn't be any reason not to use a synthetic oil.

I'd love to know how a cam or lifters or springs can be "set up" for synthetic oil. It's oil man,just a more pure form.

 

[901Memphis]

Originally Posted By: Merkava_4
Originally Posted By: 69P
Why choose 5w over 10w ?

Also im hesitant to run Quaker State oil. Ive always heard about quaker state and a notorious grey buildup. Have you guys heard or experienced this?


If you want, I can give you the name of an automotive machinist that's been in the business for well or 20 years and he just so happens to own a '69 Pontiac Lemans. I'd take his word for gospel if it was me.

I can guarantee you he'd never recommend 5W-30 in a million years.


Old timers are the worst, especially ones who think they know best. I bet he's a 10w40 for everything guy.

 

[69P]

Originally Posted By: ThirdeYe
I'd use Rotella T6 Synthetic 5W-40, personally. Nice car! Can we see some pics?

Maybe I will if I can motivate myself to upload a picture to a site LOL

 

[Merkava_4]

Originally Posted By: 901Memphis
Old timers are the worst, especially ones who think they know best. I bet he's a 10w40 for everything guy.


He's 6 months younger than me; so if you're calling him an old timer, that makes me one too.

 

[69P]

Originally Posted By: 901Memphis
Originally Posted By: Merkava_4
Originally Posted By: 69P
Why choose 5w over 10w ?

Also im hesitant to run Quaker State oil. Ive always heard about quaker state and a notorious grey buildup. Have you guys heard or experienced this?


If you want, I can give you the name of an automotive machinist that's been in the business for well or 20 years and he just so happens to own a '69 Pontiac Lemans. I'd take his word for gospel if it was me.

I can guarantee you he'd never recommend 5W-30 in a million years.


Old timers are the worst, especially ones who think they know best. I bet he's a 10w40 for everything guy.


That old timer would be smart to recommend a 10W40 oil for it. At least he wouldnt have recommended a 0W oil for it, that wouldnt be a good idea. I would like to hear what he has to say.

 

[Nick1994]

Originally Posted By: 901Memphis
Originally Posted By: Merkava_4
Originally Posted By: 69P
Why choose 5w over 10w ?

Also im hesitant to run Quaker State oil. Ive always heard about quaker state and a notorious grey buildup. Have you guys heard or experienced this?


If you want, I can give you the name of an automotive machinist that's been in the business for well or 20 years and he just so happens to own a '69 Pontiac Lemans. I'd take his word for gospel if it was me.

I can guarantee you he'd never recommend 5W-30 in a million years.


Old timers are the worst, especially ones who think they know best. I bet he's a 10w40 for everything guy.
69P, take Merkava's oil recommendations like a grain of salt, I'd never recommend his oil recommendations in a million years lol.

 

[Merkava_4]

Originally Posted By: 69P
That old timer would be smart to recommend a 10W40 oil for it. At least he wouldnt have recommended a 0W oil for it, that wouldnt be a good idea. I would like to hear what he has to say.


If I know him like I think I do, he'd probably recommend 15W-40.

I'll be talking to him tonight or tomorrow night. I'll ask him what he thinks.

 

[69P]

Originally Posted By: Merkava_4
Originally Posted By: 69P
That old timer would be smart to recommend a 10W40 oil for it. At least he wouldnt have recommended a 0W oil for it, that wouldnt be a good idea. I would like to hear what he has to say.


If I know him like I think I do, he'd probably recommend 15W-40.

I'll be taking to him tonight or tomorrow night. I'll ask him what he thinks.


Thanks man, I appreciate it!

 

[aquariuscsm]

Originally Posted By: 69P
Originally Posted By: Merkava_4
Originally Posted By: 69P
That old timer would be smart to recommend a 10W40 oil for it. At least he wouldnt have recommended a 0W oil for it, that wouldnt be a good idea. I would like to hear what he has to say.


If I know him like I think I do, he'd probably recommend 15W-40.

I'll be taking to him tonight or tomorrow night. I'll ask him what he thinks.


Thanks man, I appreciate it!


Alot of hotrod forums recommend 15W40 HDEO's on built muscle cars.