Selection of the right oil for Flat Tappet engines

[widman]

There is a lot of misinformation floating around about additives and oils for flat tappet engines like my Corvair.
Here is a link to a paper I put together to guide people through that maze and some of the whys and why-nots.
Hopefully I've explained away enough of the old wives' tales, but I'm sure there are more.

I repeat, this is written for people with the need to reduce wear in sliding parts, such as the valve trains in Corvairs and many of the older cars. I'm sure the new oils work fine in the average car.

Selection of the Right Motor oil for Flat Tappet Engines

Feel free to comment here or use the link for questions and feedback.

 

[TallPaul]

Just took a very cursory review and it looks wonderful. Thanks for putting this together. Would love to see Valvoline VR1 in those charts.

 

[Johnny]

Richard,

Excellent write-up.

 

[mechtech2]

Many modern overhead cam engines are also flat tappet type - they are called 'buckets' or 'followers'.
Many other conventional engines have non-roller tappets that slide, also.
Most cars are flat tappet type.
I think the problem is when there is extra load [like high spring pressures or high and aggressive aftermarket cam profiles], or extra heat [air cooling can be a problem].

 

[brandontyler65]

so zddp can be bad if too high aswell. lol just goes to show you that everything has to be in balance

 

[bruce381]

Originally Posted By: widman
There is a lot of misinformation floating around about additives and oils for flat tappet engines like my Corvair.
Here is a link to a paper I put together to guide people through that maze and some of the whys and why-nots.
Hopefully I've explained away enough of the old wives' tales, but I'm sure there are more.

I repeat, this is written for people with the need to reduce wear in sliding parts, such as the valve trains in Corvairs and many of the older cars. I'm sure the new oils work fine in the average car.

Selection of the Right Motor oil for Flat Tappet Engines

Feel free to comment here or use the link for questions and feedback.


Just a quick look but it this looks to be VERY well done and I see NO bad info good job.
bruce

 

[TallPaul]

Originally Posted By: brandontyler65
so zddp can be bad if too high aswell. lol just goes to show you that everything has to be in balance
Now I missed that part of the article. Do you remember why they said too much zddp was bad?

 

[boxcartommie22]

i believe too much zddp thickens like a gel..correct me if iam wrong.

 

[bmwtechguy]

"Reduced engine cleanliness, higher engine temps, and more deposits." Also, too much ZDDP can increase oil consumption as well as cause more wear over time. Going over 2000 ppm can cause camshft spalling

Goes to show you that too much of a good thing CAN be bad.

TallPaul, can a whole bottle of SLOB cause me to be over 1400 ppm in an SL (not CI-4) oil?(5 quarts) How about an SM 10W-30?

 

[TallPaul]

My VOA of slob showed 4800 ppm zinc (it's on this site). My last OCI had one bottle SLOB in SL Maxlife. I would predict about 1350 ppm zinc in that mix. For some reason my UOA came back indicating 1700 ppm zinc (also on this site) and it was a very good lab. Maybe I should ask the lab about that?

I recommend half a bottle SLOB in SL oil; a whole bottle in SM.

I do have a UOA on this site (series or several UOAs actually) where I ran a load boosted to about 2300 ppm zinc.

 

[widman]

Those variations are among the reasons to not play formulator, just buy what someone has already tested and certified.

I see real weird combinations and wear with homebrews.

 

[Greaser]

My HDEO shows excellent wear from UOA's in my old tractor motors so thats what I'm using.Like the way the 0W-40 poured out of it's container in the cold test