camshaft

[idrivejunk]

That ^^^ is why my thought is to  cap run of the mill lifters with precisely made face wafers. Thick enough that the radius is fully included on the precise piece. Obviously a proper lifter face is a lost art so adequate quality is no longer available. Ceased to exist. Maybe in 7 or 800 years we will discover how again. Like with Ulfberht swords.

Seriously the solution is probably not unlike what Leno did just to drive a Sprint6 Firebird around a little... redesigned and re-engineered and made a dozen custom maybe cnc billet cam followers. Because the originals weren't good enough and aren't available.

Like when you go to Peru and the most astonishing masonry is at the bottom of walls. Them who came before us were better at some things. People die, knowledge is lost. Like how to make lifters.

[idrivejunk]

So are these old news? Require using Snake Oil, maybe?

https://www.compcams.com/high-energy-dlc-hydraulic-flat-lifters-for-chevrolet-small-and-big-block.html

[Pete]

Someone commented that lifter/camshaft dimension, clearance and compatibility is a lost black art.
Not so yet. There are many shops across the country that still know how to do it right with the right parts.
You just have to seek them out. You also have to educate your self on what works for the application you seek.
Pick people that have ACTUALLY DONE THE WORK and have raced and won, to research. If they have an engineering background, that helps.

I didn't look at the video because I have seen it all over the 71 years I have been in the cam business.

When collecting parts for a build, stay with USA made parts that have a known reputation of success.
If nothing is available, find out what others are using and if it is working 100%. Sometimes you have to do it yourself.

When it comes to hydraulic lifters I can say I have never had  one fail. That is because I have never built an engine with them in it.
Hydraulic lifters CAN be reconditioned. Candidates for reconditioning should be selected carefully. The face should be smooth, shiny and with no lines, marks or noticeable wear pattern. The body should be checked for diameter within spec. When assembling the engine, the lifter to bore clearance should be checked carefully.
The internals should be CAREFULLY checked for wear.
The face should be checked for hardness and should be at least 55 Rockwell C.
The face should be reground with .0002 taper. This is a TAPER, NOT A RADIUS as some people think. If you think about this, if it was a radius you would have a pinpoint contact area and the unit pressure would be extremely high resulting in almost immediate failure.
The taper on lifters and cams will vary slightly between OEM manufacturer's but .0002 will work ok.
An easy way to check this is put 2 lifters together face to face and rock them. If you can see light at the edge it will be ok.

After market offshore cast iron cam cores are noted for very poor heat treat. Hard spots and some spots dead soft.
If a soft spot is on a lobe nose, failure will be soon. Likewise for the gear area.
Some 49 to 53 flathead Ford cam cores had this problem.
Very few cam grinders ever checked this.

USA manufacturer's haven't all been lily white over the years
but for the most part when they had a problem it was fixed quickly.
In late 1956 Ford put out a factory bulletin to all dealers that they expected in excess of 3% of all cams in 1957 312 engines to fail within 500 miles due to lobe wear. (bad heat treat)
Their estimate was pretty close. There was never any info release on why this happened.

To the person that suggested a hard face material on lifters, it has already been tried but found not necessary and WAY too expensive for production use. John Deere tried facing lifters with carbide for awhile. While they would last forever, it was just too expensive to do.

[Land Yacht]

Are there any US based flat tappet hydraulic manufacturers left?
It sounds like most of these failures are from off-shore companies, that sell through Summit, other online outlets. And mainly the failures seem to be via bad machining, wrong crown angle etc. Not hardness failures.

[rumrumm]

This article provides some insight on flat tappet cams.

https://www.chevyhardcore.com/tech-stories/engine/tricks-to-increase-the-quality-of-life-for-flat-tappet-camshafts/

[jaybee]

That's one of the best articles I've seen on the topic.

[chimp koose]

Thanks for the link  

[Pete]

As usual in tech articles. Some good info, some bad info, some left out.

They barely touched on the MAIN reason lifters rotate, lobe offset to centerline of lifter.
They mentioned shimming the cam fore and aft..That can get 1 or 2 rotating but screw up others in the process. Sometimes a new block is called for.

A LARGE percentage of cam lobe failures are due to poor production process. Most production cores are induction hardened. If the process is not done absolutely perfect the hardness will NOT be consistent throughout the length of the core. Some areas will be as they should be, some will be rock hard and others will be dead soft. A good example of this is the flathead Ford cams up to 1948. They were excellent. 1949 to 1953, not so much.

They talk like chilled iron lifters are a recent breakthrough.. Isky had them in the 50's.

Pressure oiling the lifter face is nothing new either.

Think about the millions of engines over the years that ran their total expected life with no problems. The small percentage of early failures due to cam and lifter problems are the ones you hear about though. Makes ya wonder if they were end of shift type or maybe cutting corners type or just done at home with used parts type.

In any event it is good tech articles like this that keep up my interest in gardening.

[jaybee]

I'd say that induction hardening is a strong suspect in the failure problem along with improperly machined lifter faces. Shows that there are "experts" everywhere, and you can't necessarily believe those who claim to be experts.

I'm no expert, but I've said my share of things that just aren't right. On the other hand, I've seen multiple people who claim to be experts say there's no way it can be a soft lobe, because they're all ground from the same blank. That includes a guy who does YouTube videos now with a Mopar focus, but once wrote magazine articles with a drag racing focus and was very active in the AHRA.

Here are a couple of links I found about camshaft hardening. They confirm that the faces are hardened further after grinding to avoid brittleness.
https://patents.google.com/patent/US4720311A/en
https://performancewholesale.com.au/blogs/news/camshaft-heat-treatment-explained 

[idrivejunk]

https://www.roadandtrack.com/car-culture/a33179/the-secret-story-of-tuckers-failed-massive-engine/