This is by far the most thorough investigation of the mysterious lifter issues we hear about constantly. Nice job! The recipe for my cam success' are as follows. Lifter bores checked & honed. Crower Cam Saver lifters are used each time which have a .0015" deep flat spot milled into the O.D. of each lifter & lets a jet of oil bypass the lifter bore & blast the cam lobe. Each lifter is checked for crown but nowhere near as precise as what's in this video. I simply put each lifter on our perfectly flat quartz kitchen countertop (shhh!) & confirm that it rocks on its center high spot. I measure each cam lobe to confirm .003"-.004" taper. Plenty of break in Grease on cam lobes and lifter face but ONLY light oil in lifter bores as to facilitate easier rotation on initial start up. I then fully assemble valve train & put a bright colored magic marker stripe on the top of each lifter. I prime the oil pump, remove spark plugs and jave someone turn the key so I CAN WATCH EACH LIFTER SPIN. Only then will I install the intake manifold & complete the job. I break in the cam with Driven BR-40 oil. If this is too much trouble, it means you enjoy gambling. I Do Not Gamble. 👍

I can give you a bit of insight as to how this used to be in the late 80's and well into the late 90's. I used to own a speed shop, and as you can imagine I sold tons and tons of cams and lifters. I used to be a Crane Cams and a Norris Cams Master Warehouse Distributor. A lot of the V8 engines that we sold cams for were really old 60's/early 70's engines. By that time they were already close to if not 30 years old. I must have sold thousands of cam and lifter kits in close to 10 years in business and not once did I ever hear back from a customer that they had a cam/lifter failure. Now, these engines are now 50 years old, but the reality is that most all of these engines, at least the ones in "high performance use" have not really been daily drivers for probably the last 40 years or more. Even in the 80's and 90's most of the cars we were selling cams and lifters to were not daily drivers, unless they were a 5.0 Mustang, which most of them had roller lifters anyways. What I am trying to say is that yes a lot of these blocks have now been in use for 50+ years, but they have been in very light use for probably the last 30+ years. The real wear on these blocks happened in the first 5-10 years of their existence when they were used as daily transportation. After probably 20 years most were not daily transportation and were only used occasionally. I don't believe that most of these blocks have much more lifer bore wear than what they had 20 years ago. For example, I have a 1972 Olds 442 convertible Factory U code 455 car that has 78,000 original miles on it. When I bought it 20 years ago it had 74,000 miles on it. So, it has ran 4,000 miles in 20 years...

When considering the need for lifter rotation the lifter bore clearance is very important. A tool I never thought was necessary was the little slide hammer lifter removing tool. It was supposed to be for sludged up lifters. How many of these were used to force a mushroomed lifter out. Dragging the damaged lifter out the mushroom burr could gouge a lot of metal out of the lifter bore.

The key is that crown is present. (s/b .002-.003 ideal) That should be equal to the lobe taper on the camshaft used. Light springs and correct break-in procedure should then spell success. If not, probably a metallurgic issue. B.T.W. It was common in the 80s, 70s and earlier to reuse flat-tappet cams and install new lifters. Hardly any failures. Go figure...

My experience has been that break in oil and lobe placement positions on the core are major factors. The lobe c/L has to be behind the lifter bore c/L by .030" to .045" for good lifter speed. Ive never had soft cams or lifters Tested submerged cam and lifters- with excellent results Oil film strength is crucial- break in oil is deficient for flat tappet interface.

didnt know the mellings were so bad. good info

If you read the astm test procedures for cam & lifter wear [IVA & IVB tests], note the engines specified for each is overhead cam design - they are not testing on pushrod style engines, so maybe api spec means something, maybe it doesn't. I tend to think api spec [as seen at the parts store] is window dressing: real engineering criteria is locked down in an NDA by auto manufacturers when they get an oil company on board for being the recommended product on new engines. The recurrance of problems despite a number of people going out of their way to check hardness leans towards the complex - a blend of issues are in hand. Old blocks with lifter bore problems, weak or detergent overloaded oils [a seeming evil in dealing with low tension rings of modern engines], and lifters ground to some spec that may not be a match for lobe taper probably top the list. Complicating things at present is the ongoing [unreported] recession: in tough times, oil companies may pull back on some additive package quality, just so people will/can buy - that can be both a help and a problem at the same time. Nice to see lifter numbers, but they do remain unqualified absent taper. 25 or 30 tenths seems weird, but if taper complements, might be just fine. I do not have an inspection plate so I cannot measure my lifter crown properly right now, but I could mic an old lunati cam lobe: about 0.0025" worth of taper. Doing the trig on that was a little on the guesswork side because distance between measurments suffers from being eyeballed [roughly 0.450"] - that came out to something near 0.33 degrees. I know there's error in that - maybe 10%, because a taper never is a nice concentric or parallel place that a typical mic prefers. I only wish I had a proper plate & probe as used in the video to finish the lifter half to get a handle on peak oil film load radius from lifter center - there's a tangent in the puzzle I just can't get at on account of tools.

Awesome info As always.

Thank you for covering that...as long as there is a flat-head motor out there being built ... I'm sure there always be a flat tappet cam being there for build assembly....good content and thanks

After watching your testing of crown, I did the same test on a new set of Comp hyd flat tappet lifters, but after zeroing out the dial indicator I measured the outer edge at noon, 3 o'clock, 6 and 9. My lifters have an "oval crown" on them. I also found on Comp's website that they had lifter bore grooving tool to give the bore a small groove to allow oil to spill onto the lobe before it gets pressure to the lifter. Have you ever tried one ? your thoughts please.

What taper matches what crown?

Love your series on these FT camshaft issues. Your testing methods seem sound to me. Following, as always! RB

Just sent back a set of Howards lifters that had more peaks and valleys than West Virginia!! Worst shit I have ever seen! Going to use a set of Isky lifters I have on hand and have them re-ground for the camshaft I'm using. Also, you have to go around the entire perimeter of the lifter. The set I had was all over the place from .001 to .0025, with a couple over .003. Howards claims to use a 4060" radius, but it's a radius, not just some pointed peak in the center.

shouldn't the measuring base be on the granite also?

I have never heard of this but, I'm curious, Do you know if mfgs. make an oversize lifter, and can you machine lifter bores to correct for wear?

I absolutely believe lifter bore trueness is one of the culprits behind all the failures. Most blocks have been through thousands of heat cycles and the bores can definitely become egg shaped. Plus, we take these blocks to the engine shop and they always hot tank them. So, more heat. This is why I always tell the shop to HONE the lifter bores. It only costs a few dollars and it's cheap insurance. Also, check the lifter bodies for correct spec. When a lifter hangs or rotates poorly in a bore, bad things are gonna happen! Best solution....just go roller cam and sleep well at night. 😁👍

I question puting your dialgage fixture off to the side, insted of on the surface plate. Great video's!!!

Should cam and lifters be bought as a kit? To assure a match? And what about “cool face” lifters?

I don't understand why roller lifters are so much more expensive than flat tappets. I understand there is a little with the roller part of the lifter and the link bar. But some roller cam sets are in the $1k+ range. Why?

I have 16 lifters, new, Melling, in the Melling boxes for a small block Chevy. No sense talking about what they match, I wish I knew.I got them for the Melling Z-28 second design off-road cam they grind. I purchased these about the time the lockdowns started and purchased them from Auto Zone, they were shipped to my house. They all look great. In fact, I took known Johnson lifters and compared them by taking one each apart and measuring everything and there is no appreciable difference other than the crown. I may have posted this below one of your videos. They are machined by a blind guy that used a bench grinder in my opinion knowing it is a Melling product. I now think they are Purchased from Melling and Melling grinds the face. They are flat, angled, low crown and some with crown a .003 crown. I doubt 2 are alike. If you would like to measure them just to prove me wrong or to see for yourself, I can ship them to you if you will do a video on them. You don't have to mention my name or where I am from and I prefer this. All I ask is that you ship them back at your expense. I finally settled on Crower supplied Johnson lifters and am satisfied with the measurements. I did not waste time to evaluate the chamfer but I know Melling now supplies lifters with no quality control. I checked them for hardness with Japanese hardness files and all meed the correct range. It is the crown that is horrible. There are very few machine shops that have equipment that put a crown on a lifter. Unless you find a job shop that can sharpen tooling and is willing to do the job, automotive machine shops normally lack this equipment. Winona Van Norman makes a machine that puts an actual crown on a lifter. There is a video on KZfaq that Winona Van Norman has covering how the TRX grinder works. It can produce 8, 000 properly ground lifters per day. doesn't take up any more space than a valve grinder mounted on a cabinet. Many of the older lifter grinders some shops have put a flat taper from the center to the edge. If you want the new TRX grinder, expect to pay over twenty thousand dollars and is it profitable for a small shop? I did find a small job shop in my vicinity and have not spoken with him with lifters in hand to find out the cost. Due to the time I have owned these, I have not investigated if I can return them but if the job shop is out of my budget, I will jump all over Auto Zone if need be. The machine shop I used to work at in Baltimore used to purchase Johnson lifters by the gross and they came in a dark blue cardboard box with cardboard dividers and it was 2 tiers of lifters. Talk about heavy. Back then, we could get them for one dollar a piece, late 60's. Time have changed and so has quality control.

Anytime u want to share what u know. 👍

You talked about progress. Right in front of you is real progress for us. That is the DLC lifter. DLC stands for Diamond Like Coating. This is a plasma coating right from the top of the aerospace world. I had a cam go flat after 1.5 years so I upgraded to a Comp Cams cam and lifters, standard lifters. The first 3 went flat in 5 minutes. Then I watched a video about DLC lifters and their tests. I already had the 4th replacement cam from Summit at the house. I called Summit and asked if I could exchange and pay the difference for the DLC lifters. They said OK. Since then I have had no problems. DLC is almost as hard as a diamond and since made of carbon is very slippery. I have since looked at the lifters 2 times and the cam. The lifters look like they were never used and the cam looks like it is micro polished. Save your money, only use DLC lifters. I called Summit with the success and suggested they advertise this. Two weeks later on You Tube I see Summit ads for DLC lifters. I was very happy as I do not want other people to blow away mass money on roller cams, lifters, and pushrods if there is an easy way out and DLC is it. Go read the tests that Comp Cams did on the Spintron. No matter the spring pressure, rpm, or abuse they did not care. The problem is obviously materials. DLC is the best solution to the problem especially for those who do not have endless money.

Having followed this video series, its got me concerned about my own flat tappet cam & lifters. I didn't know all this stuff when i slapped it ('63 292) together. I might not even run with the cam and swap it out with a roller before breakin. Not sure, whats another 1k on roller cam, lifters, and rockers in a 3.5k block. 🥲 Joking mostly aside. What i will do though is pull the lifters and have them measured as they are super easy to acces. While ive got the rockers loose I'd replace the rocker studs with threaded ones as my spring pressure went up from 190 to 230.