I have a 1998 Cadillac Eldorado with a 4.6L northstar that will be due for an oil change soon. I've been pouring Napa Premium Conventional into the crackcase. But I was informed by several people that because my car has flat tappet cams that I should use an oil with more zinc. And since they took zinc out of oil it'll be hard to find. I've done some research and some say that zinc is good for cams but bad for cats, others say that zinc doesn't protect flat tappet cams anyway. Etc... will it be bad to continue using Napa Conventional or should I try to find something with more zinc? My mechanic says oil is oil most cars don't benefit from synthetic and Napa is Valvoline and he sings their praises. Bottom line, if this was your car and you wanted that engine to last (aside from HG failure) what oil would you use?
Flat Tappet Cams
- Thread starter Timber_Wolf
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You could use one of the Valvoline VR-1 oils like the Racing Synthetic which is rated SL/CF, or use a dual-rated diesel/gas HDEO like Rotella T5 or T6, which have extra ZDDP.
I thought the engine had ohc with hyd lifters.
i would not use synthetic in that northstar they tend to leak and i would also get the dex cool out of there...
OHC flat tappets are not the same issue that OHV tappets are. OHV engines have 2 big valves with higher spring rates, usually smaller tappets and the multiplication effect of the rocker arm. OHV tappets have more pressure load than OHC tappets. Besides your engine is a 1998 model and by that time oil was lower ZDDP anyway and about what it is now.
If you'd feel better about it, use a 10w30 that is dual-rated for both diesel and gasoline engines--it has more zinc. Shell Rotella, Chevron Delo 400 LE, and others.
+1
You have an overhead cam engine, with hydraulic tappets. Use any modern oil. Whoever told you differently was uninformed.
Besides, if you had a conventional in-block cam with flat tappets, if it was standard production it's not a big deal. Going to a more aggressive cam and higher pressure valve springs is when to think differently.
Originally Posted By: mechanicx
OHC flat tappets are not the same issue that OHV tappets are. OHV engines have 2 big valves with higher spring rates, usually smaller tappets and the multiplication effect of the rocker arm. OHV tappets have more pressure load than OHC tappets. Besides your engine is a 1998 model and by that time oil was lower ZDDP anyway and about what it is now.
You have an overhead cam engine, with hydraulic tappets. Use any modern oil. Whoever told you differently was uninformed.
Besides, if you had a conventional in-block cam with flat tappets, if it was standard production it's not a big deal. Going to a more aggressive cam and higher pressure valve springs is when to think differently.
Originally Posted By: mechanicx
OHC flat tappets are not the same issue that OHV tappets are. OHV engines have 2 big valves with higher spring rates, usually smaller tappets and the multiplication effect of the rocker arm. OHV tappets have more pressure load than OHC tappets. Besides your engine is a 1998 model and by that time oil was lower ZDDP anyway and about what it is now.
You guys should have seen the high cam/lifter wear with old V8s and pushrod valve trains.
And this was with high ZDDP oil.
And this was with high ZDDP oil.
FYI there is a site or organization with a site named Petroleum Quality Institute of America. They test oils from all over the country, large and small companies, and publish the analysis of the virgin oil on their website. PQIA.com. You can look at many different oils and make a decision based on what they find and report.
In a 98 model, use a good quality oil and change it regulary. Many conventional oils will meet your needs and not break your budget.
In a 98 model, use a good quality oil and change it regulary. Many conventional oils will meet your needs and not break your budget.
I would "second" using Rotella 10w30 or even Rotella T5 10w30.
What about the Mobil 1 with 1200 plus. I dont remember which flavour but it was high zinc for sure. Or throw some delo 400 in it and call it a day.
Originally Posted By: mechtech2
You guys should have seen the high cam/lifter wear with old V8s and pushrod valve trains.
And this was with high ZDDP oil.
You have obviously had the same experience i have ! Trying to pull worn mushroomed lifters out of a 76 buick 350!
You guys should have seen the high cam/lifter wear with old V8s and pushrod valve trains.
And this was with high ZDDP oil.
You have obviously had the same experience i have ! Trying to pull worn mushroomed lifters out of a 76 buick 350!
Originally Posted By: mechanicx
OHC flat tappets are not the same issue that OHV tappets are. OHV engines have 2 big valves with higher spring rates, usually smaller tappets and the multiplication effect of the rocker arm. OHV tappets have more pressure load than OHC tappets. Besides your engine is a 1998 model and by that time oil was lower ZDDP anyway and about what it is now.
That's interesting. I didn't know that. Thanks.
OHC flat tappets are not the same issue that OHV tappets are. OHV engines have 2 big valves with higher spring rates, usually smaller tappets and the multiplication effect of the rocker arm. OHV tappets have more pressure load than OHC tappets. Besides your engine is a 1998 model and by that time oil was lower ZDDP anyway and about what it is now.
That's interesting. I didn't know that. Thanks.
When your engine was built in 1998, the limit for zddp in oil was 1000ppm, according to the SJ specification, and that level was maintained in SL. The limit was dropped to 800ppm with SM. Find an SL oil and run that. Mobil 1 5w30 High Mileage is SL. Castrol Syntec 0w30 is also SL.
That said, I'm not sure that the Northstar engine actually has sliding cam followers. All of GM's current OHC engines have roller followers. Does anybody have pictures?
That said, I'm not sure that the Northstar engine actually has sliding cam followers. All of GM's current OHC engines have roller followers. Does anybody have pictures?
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I've been thinking of pouring Pennzoil Conventional in the Eldo since Shell Rotella is hard to get in 10w30 without bulk ordering....from what I've found the Pennzoil Conventional has a really good addive package and Valvolines is a mystery.
OHC flat lifters are usually not under the same pressure as OHV lifters because they don't have to return the pushrod and larger lifter back into place.
This is why you usually don't read about their failure.
Also, in some cases higher ZDDP didn't make a difference. The 2.0L Pinto engine and Honda CVCC engine frequently flattened out cams, even though there was no limit on ZDDP in the 70s and 80s.
This is why you usually don't read about their failure.
Also, in some cases higher ZDDP didn't make a difference. The 2.0L Pinto engine and Honda CVCC engine frequently flattened out cams, even though there was no limit on ZDDP in the 70s and 80s.
The NAPA oil is good, it is made by Ashland, which also makes Valvoline. Valvoline is good oil, use your NAPA oil with confidence!
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I wonder how Napa 15W50 compares to Synpower 20W50(since they`re both Ashland oils),or Mobil 1 15W50?
I've wondered about the comparison between Napa and Valvoline. With Napa being the cheaper of the two I wonder if its exactly the same as Valvoline conventional or just slightly less as good. My father was a Valvoline or Castrol man and spoke ill of Pennzoil because of their days of sludging engines and sadly I've carried on those prejudices that he had. But after reading more and more about Pennzoil Conventional and its stellar reviews it makes me think that although his reasoning may have been founded in the 40s and 50s, oil technology has improved leaps and bounds and to maintain such prejudice could keep one from making use of a great product. I'm a member of cadillacforums.com and let me tell ya after reading complaint after complaint about worn cam lobes its got me a bit worried. I just don't want to ruin my northstar.
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