What motor oil should I use. It has a flat tappet cam that I just replaced because of a wiped lobe. I here todays oil has less zinc then it used to. Any sudjestions?
Tester
I’m surprised a 2000 has a problem with modern oils. Was the failed cam a stock one?
It was the stock cam.
Then in my opinion it was defective, or the oil wasn’t maintained correctly. No modern car should require special oil just to protect the cam.
Did you run the engine @ 2000 RPM’s for at least 20 minutes to properly break-in the new camshaft?
Tester
I’m surprised it had flat tappets instead of rollers.
Why would Jeep install expensive roller lifters in their engines?
Tester
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Same reason most cars have them now. As far as I know it is a variety of reasons, fuel economy, lower zinc in oils, longer engine life, and better overall performance. I may be wrong, but…
Roller lifters are aftermarket components.
Not stock in most engines
Tester
The Chrysler V-8 engines had roller lifters starting in 1985. The 4.0 L Jeep engine had flat tappets until the end of manufacturing in 2006. I suspect that old block design would require a redesign to be able to fit guides for roller lifters.
Thank you, I was under the impression most pushrods engines had switched to rollers.
Yes. I also had a high zinc break in oil in it. new cam is fine. I’m just looking for the best oil for flat tappet cam so I don’t wipe out another cam.
Then you’re good to go.
Once the cam/lifters have broken in, use the oil specified on the oil cap.
I think new cam/lifter break-in has to be the most nerve racking event to have to go thru.
Tester
Stock in GM pushrod V8’s since 1986. Stock in pushrod Ford engines since about '88 or so. My 2000 Honda S2000 had roller cam followers as did my 3 valve Ford 4.6 and my DOHC 5.0. I’d say most modern engines have roller followers now.
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Tester, what was the date on the article you posted? This one claims no flat tappet cams on any car sold today.
Add a break-in additive to your oil on every oil change. For the life of the car, unfortunately.
Modern oils are not formulated for flat tappet cams anymore.
On a 2000 model car?
You can’t use break-in oil all the time.
The high phosphorous content will eventually damage the catalytic converter.
Tester
The original cam lasted 9 years, are you planning on keeping this car 9 more years? If I was and it was my car I would use a 50/50 mix of 15W40 Mobile Delvac diesel oil and 5W20 of what ever brand you like.