# Fluids



## chadd925 (Jun 5, 2016)

Got the 400 back in my '67 after being rebuilt due to a spun bearing. Machine shop told me to run Penn Grade 20w50. Curious if that sounded right to you guys? I'm out here in CA. 
Also a buddy of mine recommended adding posi lube to my Muncie m20. I plan on using 85w90. Any thought/suggestions would be appreciated.
Thanks


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## PontiacJim (Dec 29, 2012)

chadd925 said:


> Got the 400 back in my '67 after being rebuilt due to a spun bearing. Machine shop told me to run Penn Grade 20w50. Curious if that sounded right to you guys? I'm out here in CA.
> Also a buddy of mine recommended adding posi lube to my Muncie m20. I plan on using 85w90. Any thought/suggestions would be appreciated.
> Thanks


Never heard of adding posi lube to a 4-speed. New one to me. I would not, just go with the 85w90.

Oil selection is often an opinion. It really depends on several things, namely your bearing clearances. Original GTO, Pontiac recommended 30 weight oil. 15w-40 and 20w-50 are racing oils. I have used them all in my older cars, and personally never seen any differences or problems. Those of us with "fast cars" always used 20w-50 racing oil because we had racing cars, right? 

In summer heat, I feel the 15w-40 might be a good choice only because heat thins the oil. In winter, I'd use 10w-30, but I am originally from New England where it gets cold for a longer period of time. 

I think oil choices are up to the individual. What you do want is an oil with zinc in it, unless you have a roller cam set-up. I assume by "Penn Grade" oil you mean Brad Penn oil? It has the correct zinc in it for older engines - so it is a good choice over adding zinc through an additive. You can go with 20w-50 oil if he recommended it. I might question him and see of 15w-40 would be ok. Thinner oil gets to places better as it is not as thick, and you want oil all over that engine. So I would ask him just so you don't have a peeing contest with him should anything go wrong with your engine and him use the oil weight as the cause.


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## chadd925 (Jun 5, 2016)

Thanks Jim, you're always helpful. Talked with my machine shop guy and he actually recommended Brad Penn 10-40 (I could have sworn he said 20-50). I told him I was going to use the Brad Penn 30w Break in oil to start out and he agreed that was a good choice. Maybe I'll switch to the 10-30 when it gets warmer here. 

10-4 as far as the posi lube in the transmission, I'll hold off on that. 

Finished installing my new-to-me power steering stuff, I planning on running the ATF dexron 3 non-synthetic stuff in that per my research.


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## PontiacJim (Dec 29, 2012)

chadd925 said:


> Thanks Jim, you're always helpful. Talked with my machine shop guy and he actually recommended Brad Penn 10-40 (I could have sworn he said 20-50). I told him I was going to use the Brad Penn 30w Break in oil to start out and he agreed that was a good choice. Maybe I'll switch to the 10-30 when it gets warmer here.
> 
> 10-4 as far as the posi lube in the transmission, I'll hold off on that.
> 
> Finished installing my new-to-me power steering stuff, I planning on running the ATF dexron 3 non-synthetic stuff in that per my research.


Glad to help, 10w-40 sounds better after the break-in oil. :thumbsup:


ATF Dexron III is what you want. Apparently the IV & VI are synthetics.


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## 64GTOConvertible (Aug 28, 2016)

Posi fluid will not help anything in a manual gearbox. It is used to add grip to the friction plates in the posi (or slip, I can't remember clearly) I do remember the original additive was created with whale oil and was better than its eventual replacement.


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## 64GTOConvertible (Aug 28, 2016)

Also back in the day we used straight 30 in the summer and recommended our customers switch to straight 20w in the winter. Obviously, this was before multi-viscosity oils were introduced. I run 20w-50 Valvoline Racing in my GTO, unless I come across a stash of old 30w oil. And yes, I know where there is a stash. Hands off!!!


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## chadd925 (Jun 5, 2016)

Couple more q?s for y?all. Machine shop gave me an Elgin RxEmedy with ZZDP for the cam break in. I was watching some videos on the Brad penn 30 break in oil I?m going to use and penn grade oil recommends on not using additives with their oil because it could be detrimental to the oil itself and break in process. Any thoughts?
Also as far as the coolant, should I complete the break in without the thermostat or with? Thanks


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## PontiacJim (Dec 29, 2012)

chadd925 said:


> Couple more q?s for y?all. Machine shop gave me an Elgin RxEmedy with ZZDP for the cam break in. I was watching some videos on the Brad penn 30 break in oil I?m going to use and penn grade oil recommends on not using additives with their oil because it could be detrimental to the oil itself and break in process. Any thoughts?
> Also as far as the coolant, should I complete the break in without the thermostat or with? Thanks


No Zinc additive. Too much is not good. "It is important however, to keep in mind that more zinc is not always better for break-in oil. At a certain point, too much zinc can create a surface condition where the rings will not be allowed to seat. On the other hand, too little zinc may promote excessive wear during break-in. Brad Penn stresses that their formula of ZDDP, a specific detergent package, and Pennsylvania Grade Lubricants base stock results in a break-in oil that works synergistically together to prevent wear. Furthermore, it is not recommend that other additives be used with Brad Penn products." https://www.performancebyie.com/blog/brad-penn-break-in-oil-faq/

Thermostat in.


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## bustac (Oct 21, 2013)

*oil*

My machine shop swears by rotella oil for break-in.


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