Technical Do Solid Lifter Cams go flat?

I have adjusted a few while running, but not recently.

Back in the 60's one of the local mechanics in my hometown had what I think was a homebuilt tool for adjusting valves while running. I don't recall exactly how it was put together, but I know part of it was a spring-loaded screwdriver deal that kept the blade engaged in the adjustment screw. The blade moved up and down with the valve, but the handle remained steady in his hand. I'm pretty certain he just adjusted by sound, on a fully warmed up motor.

 

My roadster's engine was only part of what I was spending, as I was building almost from scratch from an incomplete Brookville "rolling ch***is" I bought from a friend who lost interest in it.
All of it together meant that by the time I was building the engine, my budget didn't permit a roller cam and lifters. So I went solid flat tappet with the EDM hole in lifter face.
I've been playing with hot rods and race cars for about 65 years, and yes, many were OHV with solid lifters.
As someone said earlier, with shaft mounted rockers and their lower oil flow, adjusting hot and running is OK. That is unless it's go a radical cam that idles at an rpm too fast for accurate setting while running.
Then for those, as well as those with pedestal rockers like sbc and sbf, I use the EOIC method, cold, while allowing for heat expansion.
Interesting, but seldom mentioned, is that for engines with aluminum heads and cast iron blocks, and more so for both aluminum block and heads, is that valve clearance actually increases as the engine warms up. This is due to aluminum having a higher coefficient of heat expansion than cast iron or steel.

 

Can solid lifters be used a hydraulic cam?? Why not?

 

I've successfully used Crower solid lifters on a Crower 60919 Hyd camshaft in a Pontiac 462 I once had. I put well over 25,000 miles on it with no issues.. By the way the engine ran so much better with less duration. I would of been much better off with a smaller duration camshaft like the Crower 60918 (068)..

 

Yes, since the actual cam core material and heat treat are the same there is no inherent incompatibility there.
You have to run it at very tight lash, since the hydraulic cam lobe shape has no gentle lash take-up ramp... you're trying to find a lash spec that so when the valvetrain is up to temp and hot you end up as close to zero lash as possible without heat growing it past that point and holding the valve off the seat which leads to loss of power and burning the valve up.

If you run it with typical solid lifter lash spec it will pound the valvetrain and beat things up....pushrod tips, rocker tips, valvesprings, the valve tip.

This is best left to a limited use drag engines/pulling truck deal, or maybe circle track qualifying engine deal.....not a street friendly thing for sure unless you know what you are doing, especially with a modern fast lift rate hydraulic. Results are better with old schol hydraulic grinds.

The EngineMasters Program on MotorTrend recently did this test, on a hydraulic roller cam, putting solid roller lifters on it. Episode was "Hydraulic vs Solid lifters: The Redux!"

 

I do remember the lash on the intakes was different then the exhausts and it was real tight, maybe .003 or .005.. I do NOT remember what the actual setting was. I got the lash settings from Pontiac engine builder in Brooklyn named Nunzi.. He suggested I get the RIGHT camshaft and thought it was silly that I would risk ruining a nice motor over a hundred dollar part.. This guy knew his **** when it came to Pontiacs..
Another guy who really knows Pontiacs is Cliff Ruggles the Quadrajet guy. I bought a nice 462 off him once and that motor lasted me 80,000 street miles without issue.. As a matter of fact my TH-400 is in the photos in his TH-400 build book he brought out a few years ago.. Cliff is a cool dude who knows engines and transmissions well..

 

There are some current "theories" that hydraulic roller lifters survive better for that very reason.
The thought is if the roller stops turning during the hundreds of degrees of crank rotation when there is valve lash, when things start liftin', the roller and maybe even the needle bearing skid for a little bit, which is BAD news for any kind of rolling element bearing.

Conversely, I can picture a hydraulic flat tappet might have an issue with the "never any gap" operation.

But I think mostly V-8 cam and lifter face oiling is a hit or miss, hope and pray issue.