Good video explaining zinc in motor oil

[TJ Hopland]

This video just came up on youtube.  https://www.youtube.com/watch?v=erxjPicpYyw 

Seems like he does a good job explaining several aspects of zinc in motor oil.  Perhaps some of the things he is saying is why there are so many people saying not to add it.  The other people never seem to explain why but what this guy is saying makes sense. Also makes a lot of sense when he talks about different materials in the engines making a big difference. 

I also wonder about the low friction but higher wear aspect when it comes to modern engines. Is it one more way we are being screwed?  We are saving a slight amount of gas but wearing out the over complicated non repairable engines faster?  Seems like the way things work these days, only focus on one aspect and say yay we are saving the environment as long as you ignore a dozen other parameters. We saved some gas and emissions when it comes to driving the car but producing it and shortening its usable life... well we won't talk about that.   

[smokuspollutus]

Interesting video TJ.

I run Rotella oil as it is cheap and available, and is similar to the oils my era cars were designed to run. Nothing has to be added to it to get it up to snuff which is a big plus. I have not had any abnormal wear or failures in the past 30-40k combined miles I have put since switching over.

I had spoken to a mechanic who does a lot of work on Northstars. I didn't know at the time but apparently the first generation Northstars (93-99) were made with flat tappet cams. He said that in almost every one he takes apart, the vehicles have cam and or follower wear. This adds a lot of expense to the head gasket job and he has ended up owning a few of these cars due to that fact.

This was interesting to me as the Northstar showed up at right about the end of the flat tappet era and was probably spec'd for the older oils. But they were in daily service during all of the reformulations. So they likely got fed whatever the shop was buying in bulk which were the reformulated oils that are supposedly backwards compatible.

For now I'll continue running diesel spec oil in my old flat tappets until some regulator finds a new species that's going extinct because of me.

[TJ Hopland]

That's another thing I don't quite understand.  I have been watching a bunch of engine teardown videos on the I Do Cars youtube channel and it appears to me that is maybe half and half rollers or not.  I have not actually started a spread sheet to try and figure out which has what or why but it doesn't seem like its cheap cars vs expensive or a high performance thing.   

Pretty much everything is overhead cam and maybe half of them do have a rocker like setup with a roller that rides on the cam.  The rest of them have what seem to be called 'buckets' which seems to just be a cup that sits over the top of the valve and spring. The cam lobe rides directly over this bucket so it seems to me the exact same thing going on with our push rod engines. 

With push rods there is some leverage action going on with the rocker arm so we get more valve movement with less cam/lifter.  What does that do to the pressure involved?  On these bucket style its running directly on the valve so if they want the valve to move 1/4" that has to be how high the bump is on the cam.  I would assume the pressure would be equal or maybe even more?  When there is a rocker is there still a leverage thing going on?  Or is it just to get a roller in there?  To me it looks like its mostly to get the roller in there.   

And with any of the OHC designs there doesn't appear to be any sort of hydraulic lifter sort of thing going on.  How are they getting away with that now but in the olden days you had to do constant valve adjusting with solid lifters? 

[klinebau]

I think rollers are only needed when the ramps on the cam are pretty dramatic.  I think flat tappets seem to work fine for normal applications.

[The Tassie Devil(le)]

You also need rollers when the valve spring pressure is very high to stop valve float and bounce at high lift and high revolutions.

Bruce.

["Cadillac Kid" Greg Surfas 15364]

Roller lifters allow for a much more aggressive cam ramp and longer actual full flow (past the open valve).
Things that are necessary when you are trying to wring 350 Hp out of a 2 litre 4 cylinder motor.
Greg Surfas

[TJ Hopland]

I assume multi valve means you can get the desired increased flow with a less aggressive ramp and lift not to mention a lighter mass thats easier to move quickly?   So why the just modest performance engines don't need rollers?

It does look like some of the bucket style units may have a hydraulic aspect to them but it sort of looks like those are the minority and I don't see anything that looks hydraulic on the roller ones so it would seem like a majority of modern engines don't have any sort of hydraulic component to the 'lifter' component.

Did anyone catch the bit about that they changed the type of zinc too?