Here is a question for the flat tappet cam guys....

[Ceedawg]

I took apart a 383 a couple of years back, a couple of small blocks too. I saved the hydraulic lifters from them just in case I ever get the motivation to have them resurfaced. I made sure each lifter was not failing, none had and abnormal wear patterns.

View attachment 2036558

I set them all on a sheet of glass and NONE of them rocked. Somehow they had so little crown to them, I couldn’t get them to wobble on the glass at all. I don’t have the tools to accurately measure the crown but this surprised me.

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A new set of solid lifters I have here all wobble a bit.

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A couple of months back a FBBO member posted about how lifter crown and cam lobe taper are at their peak when new and that they wear to a point and stop wearing. He was pretty much laughed off as an idiot that didn’t know anything. Was this guy right? This was an odd thing to see.

Every old lifter I’ve removed is flat so by that reasoning they wear in the center. The heel is where it goes flat and crown promotes the turn. Look at the pattern on a healthy used cam.

 

[Kern Dog]

I am just surprised to see that the crown is gone but the lifters didn't get chewed up. How is that possible?

 

[493 Mike]

I am just surprised to see that the crown is gone but the lifters didn't get chewed up. How is that possible?

It maybe "work hardening".
Mike

 

[Wietse]

Once the cam is broken in, what harm is there in idling? The [COLOR=revert-layer] engine[/COLOR] is under no load and there still is some oil being thrown around.

The reason for cams not running to the ground after they were broken is because of the zinc.
Zinc will adhere to metal surfaces, but only with mechanical force applied to it.
During break-in the camshaft and lifters are coated with the zinc, which will build up a protective layer against wear.
If the oil used has sufficient zddp for the application and oil changes are done in time, this protective layer will be maintained by the continues forces applied to the parts that contact.
Oil with too low zddp content may cause this protective layer is not maintained, other oils may have additional additives (detergents, etc) that may also cause the zddp to not maintain the layer and keeps getting washed of before properly forced on the contact surface.

Excessive idling is not good for any engine, old or modern.
The low operating temperature only causes soot buildup.
Thats why a “lazy” engine could use a long highway run from time to time to burn clean again.
Or an Italian tune-up

 

[Ragmanx]

My answer (even if nobody asked). Valvoline VR-1 for my slant six tappets.
Lots of ZDDP.
Steve

 

[Kern Dog]

I'm working on a 340 out back, something that I will probably sell off once I am done.
I bought a flat tappet cam and lifter set for the engine 10-12 years or so ago. During mock up, I marked the lifters with Dykem and cranked the cam over to watch for rotation. Only 5 spun like they are supposed to. I tried some old, used lifters and none of them did which had me wondering if the old lifters had worn off all of their crown. I put in a set of new solid lifters, most of them did spin. A set of used Howards lifters all spun. I figured that the cam was fine but that the new lifters needed to be refaced so I sent then to Oregon cams. For something like $6 each, they are supposed to come back with the proper crown. I'll know once they are back.

 

[493 Mike]

I'm working on a 340 out back, something that I will probably sell off once I am done.
I bought a flat tappet cam and lifter set for the engine 10-12 years or so ago. During mock up, I marked the lifters with Dykem and cranked the cam over to watch for rotation. Only 5 spun like they are supposed to. I tried some old, used lifters and none of them did which had me wondering if the old lifters had worn off all of their crown. I put in a set of new solid lifters, most of them did spin. A set of used Howards lifters all spun. I figured that the cam was fine but that the new lifters needed to be refaced so I sent then to Oregon cams. For something like $6 each, they are supposed to come back with the proper crown. I'll know once they are back.

I think Schnieder Cams did lifter refacing. I don't know if they exist today?
Mike

 

[66 Sat]

Yes Schneider Cams are still around. I've had 3 cams from them for my Poly.
They are based in San Diego.

 

[Ceedawg]

I'm working on a 340 out back, something that I will probably sell off once I am done.
I bought a flat tappet cam and lifter set for the engine 10-12 years or so ago. During mock up, I marked the lifters with Dykem and cranked the cam over to watch for rotation. Only 5 spun like they are supposed to. I tried some old, used lifters and none of them did which had me wondering if the old lifters had worn off all of their crown. I put in a set of new solid lifters, most of them did spin. A set of used Howards lifters all spun. I figured that the cam was fine but that the new lifters needed to be refaced so I sent then to Oregon cams. For something like $6 each, they are supposed to come back with the proper crown. I'll know once they are back.

I’ll be real interested in what you find out!

 

[threewood]

Every lifter I’ve pulled out from any engine, from the 50s till they went roller, has been FLAT, ie worn, no crown. I never looked at them before till this issue came up. Makes me wonder.. Almost every engine had springs around 100 pounds or less closed.

Funny enough. The Hughes cam and lifters I pulled out of my GTX (about 8 years old) had worn in flat lobes and flat lifters. One lobe was noticably shorter than the others. They were still rotating. No signs of it from driving that anything was wrong. Used Driven and VR1 oil exclusively.

 

[493 Mike]

Looks like that lobe needed a roller lifter!
Mike

 

[threewood]

Looks like that lobe needed a roller lifter!
Mike

It was smooth all the way across, same as the lifter. But it was running fine. Next cam I have to do will be a solid roller.

 

[DanielSlocum]

Funny enough. The Hughes cam and lifters I pulled out of my GTX (about 8 years old) had worn in flat lobes and flat lifters. One lobe was noticably shorter than the others. They were still rotating. No signs of it from driving that anything was wrong. Used Driven and VR1 oil exclusively. View attachment 2047741View attachment 2047742View attachment 2047743View attachment 2047744View attachment 2047745

Very surprised they were still rotating! Leads me to believe either the valvesprings were very stiff and/or the metal was too soft ?

 

[Kern Dog]

I've had valve covers off of engines and had them running. One 318 or 360 ran fine but not all of the pushrods were spinning.
WE have been told that the lifters have to spin or they will fail. I'm wondering how true this actually is. I'd certainly agree in the case of a higher performance engine with higher spring pressures but what about an old high mileage 318 with soft springs?
There is a member here that has commented that the lifters lose their crown and the cam lobes lose some taper not long after they are broken in. It seems hard to understand but I'm wondering if he was onto something.

 

[threewood]

Very surprised they were still rotating! Leads me to believe either the valvesprings were very stiff and/or the metal was too soft ?

All the parts are from Hughes and I used their cam lube. They do use high spring pressures. 155lbs closed / 415lbs open. Solid flat tappet.

The lifters are enough off center that they promote spin and with enough friction between surfaces it seems to occur.

 

[vance.dykes]

I'm working on a 340 out back, something that I will probably sell off once I am done.
I bought a flat tappet cam and lifter set for the engine 10-12 years or so ago. During mock up, I marked the lifters with Dykem and cranked the cam over to watch for rotation. Only 5 spun like they are supposed to. I tried some old, used lifters and none of them did which had me wondering if the old lifters had worn off all of their crown. I put in a set of new solid lifters, most of them did spin. A set of used Howards lifters all spun. I figured that the cam was fine but that the new lifters needed to be refaced so I sent then to Oregon cams. For something like $6 each, they are supposed to come back with the proper crown. I'll know once they are back.

You are correct there has to be rotation with the lifters if the lifter is not made with a crown it cannot rotate on the edges of the camshaft if you look at where a good camshaft wears it is a bit off center before it gets to the top of the lobe so as the lifter is rotating that's why the high side should not wear into the can in certain areas because it's rotating and the edges are which catching which is where you need your lubricants there's too many people that have too many opinions on lubricants but I've never had a flat tap camshaft failure I've had them come to me failed and had to fix them but I've never had one fail when I've done it

 

[vance.dykes]

Here's two pictures of one of my lifters from my 600 lift mechanical cam these are crane lifters from crane for the cam cuz I had it all special made back in 2000 and I removed it because being on the street and the fuel injection I needed something different if you look close you can see lines actually on the lifter body where it was rotating the base you can also see some areas where the lifter is actually got lines from rotation circles

 

[vance.dykes]

Here is the straight edge that I got from Blue Point otherwise known as Snap-on when I was working at the dealers to check for cylinder head warpage on the newer engines back in the day coming out with aluminum heads it was a true problem so this picture is from putting my lifter did I showed you in the other pictures on this straight edge and you can see the light from the flashlight behind it and actually the lifter looks like it's tilting on its crown