2mnyvets

The machine shop is recommending I use coated cam bearings in my Mark IV big block, I am going with a Lunati roller with .575 lift, .221 intake duration @ .050 and 229 exhaust duration @.050 and dual springs. Any thoughts?

427Hotrod

They are a "nice to have"....but not needed...especially with a cam like that. It's pretty mild and will use lighter springs. My cam bearings have been in my 555" for 18 years now with solid roller cams neat .800" lift and stout springs spinning 8000+ RPM. Gazzillions of runs down the track, street and cross country miles. They still look brand new and they are not coated.

JIM

Pop Chevy

I agree with Jim. Coated brgs are not needed for that application.

NewbVetteGuy

Can someone provide a quick high-level overview of what the coated bearings actually protect against vs. a standard bearing?

My understanding is that they're simply insurance against VERY short periods of oil starvation (while starting the engine after it's been sitting a while, or under extreme driving conditions that your oil system really isn't designed to deal with).
Are there other benefits/times in which coated bearings offer relevant protection?

2mnyvets

I think he suggested the coated because I leave my cars set for long periods of time.

427Hotrod

Coated bearings help to give you a little insurance in the event of low oil flow and metal to metal contact. You've still got the problem and it's going to come apart some day...but the coated bearing might save it the first time or two it happens and allow you to fix the problem,

I don't use them in my stuff and have had no issues. I don't think there's anything wrong with them...as long as the coating stays in place...but if I'm not having issues I'm not going to add another variable that might not be reliable.

JIM

427Hotrod

Mine do too. If it worries you..use some Brad Penn oil...it's some sticky stuff (and I say that admirably) and will remain in place and not run off when you shut it down.


JIM

OldCarBum

I've heard of Brad Penn oil and it's supposed to be great oil for performance builds.
Someone recommended it as a break in oil.
Is it good stuff and would it be a good break in oil?

leadfoot4

I would think that they also offer a SLIGHT reduction of friction, as the coating tends to make the bearing "slipperier".

Brad Penn oil has a higher level of ZDPP content, like oils of 20 years ago, therefore not only is it a good break-in oil, for engines with flat tappet cams, it's a good oil to use at all times, in a flat tappet engine....

v2racing

I have coated rod and main bearing as well as my piston skirts in my 406. It sits for months without starting up here in the north. I don't think it's a necessity but I think it helps protect things at startup. I've used coatings in a lot of race applications too. I found it extended the life of valve springs in severe conditions. It also worked really well with tightening up the clearances on mechanical fuel pumps for nitromethane injection upping the pressures and extending pump life.

Mike

OldCarBum

Brad Penn oil has a higher level of ZDPP content, like oils of 20 years ago, therefore not only is it a good break-in oil, for engines with flat tappet cams, it's a good oil to use at all times, in a flat tappet engine....[/QUOTE]

What about in a hydraulic roller engine?

leadfoot4

What about in a hydraulic roller engine?[/QUOTE]

The most critical "place" for lubrication, in an automobile engine, is the camshaft/lifter interface, as there is no direct lubrication. This interface is oiled by "splash", and with a flat tappet camshaft in place, the contact there is by "rubbing", so the lubricant, and it's make up, is critical. ZDPP in the oil, is what makes that "rubbing friction" survivable for the cam and lifters. With any kind of roller camshaft, the friction at that point is SIGNIFICANTLY reduced, so the chemical makeup of the oil can also be significantly different. However, using an oil that's higher in ZDPP content, in a roller cammed engine, will certainly not hurt anything.

dmaxx3500

cant hurt,and are pretty cheap

2mnyvets

My car is complete and I am just closing out all the items you provided me information on. I went with the standard bearings mainly because i had them and didn't see the need to buy new ones. I went with Joe Gibb Racing Break in oil and will switch to Mobil 1 10W 30 since I have a roller cam.

Jebbysan

I have never personally installed coated cam bearing in anything. One of our builders at the shop built a 565 Tunnel Rammed Merlin screamer that used them.....but only because it was wet sump with over .900 lift and "Maskalloy" springs from Dart that were pretty heavy.......
I do recommend Dura-Bond for cam bearings as they seem to tap in the block better with a nice wide taper.

Jebby