new oil for old cars

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I know this has probably been discussed many many times before, but I am still having trouble with deciding what oil to use in my OLD vehicles. I have a 1980 chevy with a 350 C.I. with about 160k, and never any major work --A 1965 ford with a 200 C.I. 6 cylinder, has been overhauled about 10k ago--- and a 1950 ford with the 239 C.I. flathead v/8. and it has been overhauled about 5k ago. My main concern is the ZDDP content of the oil. I can not decide if they need more than the amount in the newest SN oils, or if since they are all well broken in stock engines, that the modern oils are sufficient. If I need more, I will probably use QS Defy.But they never seem to put that on sale around here anyway, so am wondering if other oils would give plenty of protection to the cams, and I would have more choices. For instance Mennards right now has QS full syn. on sale after rebate, for $1.99/qt.
 
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Seriously how expensive is QS Defy? But QS syn for $1.99 is seriously cheap. So the question is how much ZDDP do you need or want in your older cars. QS Defy 5W-30 has 990 ppm of phos'. Do you actually need that much? My point is you could pick up some QS syn and blend the two oils the the phos' level your happy with.
 
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I use Rotella in all my old engines, and most new for that matter. Your engines specifically I would use Rotella T5 or the original triple T 10-30
 
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I'd also go Rotella. Unlike previous Menards QS rebates the current Quaker State rebate is through the manufacturer, which is less desireable IMO. But for high zddp apps a conventional HD/diesel oil should be competitive on price and a better fit.
 
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Oils from the 50's-60's had very low levels of additives. I should know, I was there, I owned several Fords & Chevys. No multi-vis oils. 10, 20, 30 weights. We bought a new 55 chevy 2 ton stake truck with the 265 cu.in. sb. Had no low end power, wiped out 2 cams before the warranty was up. very poor engine for a truck. We changed the oil every 1000 miles or 1 year. 20 weight in the winter, 30 in the summer. Somewhere in those days a 20W-20 all season oil came out. Just about anything you can buy these days is way better then the best oil of that time. If it were me I would use Rotella T-5 10W-30 as long as the oil pressure is good. I'm currently using it on some OPE's and a 94 2.5L mopar with ~240k miles on it. This is a stout oil and I like it a lot. If the oil pressure is a little low, I would use Rotella T-111, 15-40 or T-6 5W-40 full syn. I run the T-6 in my 94 3.8L van which has somewhat low oil pressure. Works well. If you want to go old school, just use straight 30 weight. That's what we mostly ran back in the day.... I'd love to see your cars... Wayne
 
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Yes a dino HDEO is certainly a cheap option but IMO since Defy is readily available, is semi-syn and comes in various grades from 5W-20 to 10W-40 you'll have no problem selecting an oil of a more optimum viscosity for your application.
 

old1

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So, I guess what you are all saying is that I SHOULD use an oil with higher zddp than the 7 to 800 levels of the sm rated oils of today. Like Defy or the Rotella. Does the Rotella in the lighter weights (like 10/30) have the same zddp as the 15/40 flavor?
 
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Here's the zddp count from 4 recent UOAs ............................ Moly Phos Zinc Rotella 10W30 HDEO 2 971 1193 Rotella 15W40 HDEO 11 960 1051 Rotella 15W40 HDEO 5 1018 1145 Rotella 5W40 HDEO 65 970 1128 The T6 5W40 was in a mid 1990s Subaru
 
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Anything you buy out of everything mentioned so far including any modern PCMO or HDEO should be superior to the mineral oil available when the engine was fresh. Even without boosted ZDDP, modern oils have a balanced mixture of anti wear additives good enough for any stock flat tappet engine with normal spring pressure. I like Mobil 1 High Mileage 5w30 for those applications.
 
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Originally Posted By: old1
So, I guess what you are all saying is that I SHOULD use an oil with higher zddp than the 7 to 800 levels of the sm rated oils of today. Like Defy or the Rotella. Does the Rotella in the lighter weights (like 10/30) have the same zddp as the 15/40 flavor?
As Oldmoparguy1 alluded your cars don't likely require a high ZDDP level oil. I would think 700-800 ppm of phos would be more than enough for the 1950 flat head V8 and likely the '65 6 cyl Ford and probably even the stock '80 V8 Chevy. So yes I would certainly buy the QS syn on sale and depending on the grade use it the Fords. One oil I wouldn't use is a 15W-40 in any of your cars as that is certainly heavier than what was originally specified. I wouldn't use anything heavier than a 10W-30 unless the engines are worn and have oil pressure issues.
 
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In the flathead I would use 15w-40, I have two and thats what I have used for years as they are notorious for low idle oil pressure.
 
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Originally Posted By: old1
So, I guess what you are all saying is that I SHOULD use an oil with higher zddp than the 7 to 800 levels of the sm rated oils of today. Like Defy or the Rotella.
I'd recommend the Defy myself, too. However, that Chevy SB will eat that cam sooner or later, and that's even if you run a race oil. wink So, don't fuss too much.
 
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The other posters don't appear to have any flat head experience as I've never seen one carry more than a couple lbs. at idle. It depends as to how you will be driving your flatty. The guys that only do the parades run 20w-50, mine get run down the road a couple times a year, but idle for hours running the pto, hence the 15w-40. 10w-30 is really light for one of these and the op gauge will scare you warm.
 
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I recommend Mobil 1 15w-50. I been using it in all my vintage cars for the past 15 + years and a cummunltive. 200,000 miles. That s includes over 90,000 miles on two '66 Shelby GT350's. That weight of Mobil oil has plenty of zinc & phosphorus : 1300 ppm zinc and 1200 ppm phosphorus Z
 
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