camshaft

[enjenjo]

watch these videos and give me your thoughts

[chimp koose]

Makes me scared to try breaking in my new lunati . I bought it and the lifters directly from lunati as I thought they would be more careful with the lifters they sent with a cam they are providing warranty on . I hope I am right . The lifter face video has convinced me to check the crown on mine before even using them .

[Crosley.In.AZ]

I have watched several videos this year on this.  I have a flat tappet camshaft in my 327 chev in my 1948 Simca.. The engine has not turned a lick in 2.5 yrs , so I worry about it even tho the camshaft was fully broekn in and run several passes on the drag strip before its hibernation..

I do not have the $$ to swap over to  a retro roller camshaft set up. You have cam , lifters , pushrods to change

[jaybee]

I've watched quite a few of these videos, and it seems to be everything. Soft lifters, soft cams, not enough taper on the cam lobes, improperly ground lifter faces, too much or too little lifter clearance to the bore, too much clearance between the plunger and the lifter body...anything. Someone can make a very rational argument, with evidence, for any of those things. No wonder there seems to be an epidemic of failed cams, and builders who control for one thing get bitten by something else. The lifter faces in that bottom video, though, when the light hits them it looks like a geodesic dome, a whole bunch of flat faces instead of a smooth face.

[idrivejunk]

Had this realization around 2007. The curtain done fell on the flat tappet show a long time ago. Seems like a business opportunity where someone would step up with good lifters but that doesn't happen because money. If the cost of a make-do hit-or-miss brand fits ten times inside the price of a sure-fire top-notch brand... of air drill, speaking in my terms, I'll take my chances on having to buy ten drills. Everybody does. Thats the issue but not the only one. Waning interest / demand. Racing isn't a household word anymore and design advancements left lope lovers in the dust. Them engine guys are swallowing some hard nasty facts. I chose bodywork but nowadays the technology is nonsensical beyond comprehension for collision guys. The USS Flat Tappet is sinking. Mine were not lookin good a couple years back.

My take is we are on borrowed time, pretty much.

[tomslik]

i pulled the lunati cam out of my rambler a couple of weeks ago, looked like new. replaced it with a Mellings RV cam and broke it in with rotella T1 and mellings cam lube...fwiw

[idrivejunk]

What might be interesting to see is a comparison of machining precision on flat tappet vs roller lifters made at the same plant.

Would it mean anything if proper dimensions with less variation were found on the roller product?

A manufacturer's assumption must be that a buyer wants only the least expensive version of a product which in a picture appears to be like the desired item. (actual product may vary)

Is anyone asking these overseas plant managers or whatever if, for a higher price, a usable quality level product could be made available? Could it be as simple as not knowing the right sentence in a foreign language?

Could we pay half again more but not go roller for a stock smoggo build? Roller conversion was presented to me as an only option for a Pontiac that one might realistically put a hundred thousand miles on a decade ago.

Thats the while root meaning of I drive junk. There has to be a camshaft and it has to be the modern kind or stay home.

[jaybee]

Interesting comments, Matt, as usual. It reminds me that General Electric at one time intended to close all their operations at Appliance Park, Kentucky. That was the high point of manufacturing being outsourced from the USA. It didn't work out that way.

What they discovered is that some things lend themselves to outsourcing far more than others. Low tech products which don't require extreme precision, absolutely. What they didn't have luck with was products which require much skilled work, great precision, very tight controls on material quality, or were in active development with frequent spec changes.

It wasn't just about availability of skilled workers, because the USA certainly isn't the only place in the world where people are capable of excellent craftsmanship. The more important thing was communication. When engineers and quality control experts have to communicate to factory managers 13,000 miles away, in a different language, with 12hrs time zone differential more or less, quality suffers.

[idrivejunk]

Whatcha wanna bet theres a slippery coating solution for this that will never be explored. Theres such thing as piston skirt anti-scuff coatings. Nitriding is best left to HF drill bits that wouldn't make the first hole without it.

Aren't computer controlled electronic or hydraulic valve actuators already a reality? Direct injection is.

Again, money twarts efforts. First generation V8s are not given the advantageous design attention. Because while it may take decades more for users to admit obsolesence, manufacturers know that the dead horse won't suddenly snap to life and win races no matter how much whipping is done.

[jaybee]

I have to wonder if some sort of anti-friction coating on the cam lobes or lifter faces would help. It could help keep the lifter and lobe from digging into each other until the parts work harden sufficiently to be operational. It could lower friction until the lifter fails to rotate and makes the problem worse. It may prevent oil from getting into the tiny crevices of the metal and cause problems that way. I sure don't have the technical expertise to know.

[idrivejunk]

I'm devoid of that as well. 

The jist of what I caught onto was that it is less about materials than dimensions.

I assume methods exist for truing / sleeving lifter bores in tired blocks and that that is a contributing issue with antique castings that will never improve.

Heres one for our residents who know their way around a machine shop:

If a guy was to take a set of common oh, say $300 flat tappet lifters, take .125 off the faces and install (thats my question, how to install) precisely machined caps on the faces, and could sell those for under $600 and consistently create lovely break in patterns when used in a fresh block or checked and corrected seasoned block's lifter bores... might that be a thing?

Tackling that manufacturing step here might allow adequate QC of lifter faces while using existing overseas castings. There may not be .125 of meat on existing faces so a body casting revision might be needed.

Lobes are one thing to worry about but the nitty gritty of what goes on at lifter to lobe interface that the guy in second vid explained has me thinking just about the lifter faces. Seems like thats what it boils down to. So make perfect faces, attach to milled down plain lifters, and if the caps didn't create other issues that'd be half the battle. Double the price but thats half of a roller conversion.

Just meandering thoughts that I am certain have entered minds of those who make livings on engines.

[jaybee]

This link has some interesting thoughts on it. There's been a lot of attention paid to metallurgy, but what  if it's other changes to engine parts? Cam lobes have higher ramp angles now, even when the measured timing remains the same. Spring pressures are higher now, and more consistent. higher rocker ratios present higher pressure at the cam lobe.

But what about failures with stock replacement parts? Again, I don't know. Maybe these stock replacements have been massaged in ways that don't quite show up in the specs? More aggressive ramp angles are so common now, maybe they're being incorporated in stock replacements. A lot of stock performance engines, like the Ford 5.0 HO engines from Fox bodied Mustangs suffered premature valve float which can be remedied with more spring pressure. Maybe some of these changes are in the "stock replacement" boxes?

https://www.camcraftcams.com/some-thoughts-on-cam-and-lifter-wear/

[Crosley.In.AZ]

My random thoughts on the oil , lifter , camshaft wear :

When oil specs reduced the ZZDP and related additives for the catlytic converters... OEM manufacturers wwent to roller camshafts.

Us olde pharts with flat tappet camshafts started using ZZDP additives, diesel oils , specialty oils, etc.  THings seemed fine till:  It appears the camshaft - lifter manufacturers forgot how to build flat tappet cams and lifters?

Decades ago, when I broke in a new flat tappet camshaft..  I coated the lifter base and cam with the thick goo like everybody did.  I also used a GM oil additive called EOS aka Engine Oil Supplement.

So: what happened?

 

[kb426]

I have 2 thoughts to add to this: the 1st is about 5.0 engines. When I put my 32 together, I used LS springs. In talking to the Ford Performance people and telling them how high it would rev, they were surprised. The stock springs are good for around 4300 rpm. I believe that is about friction loss and cafe fuel milage. The 2nd: are all lifters the same. Absolutely not. I have some NOS lifters for a sbf. If you measure the crown on them, it's very obvious what is there. When you take the white box units and compare, you will notice the difference. There's so many factors involved in this that I don't think you will find one problem. I'm aware that there are way more failures than when I was young. I wonder if we used the same parts from 50 years ago and used today's oils and additives if we would get different results?

[chimp koose]

I have read about people sending out OLD lifters to get them re ground as they do not trust the metallurgy of the new stuff. Looking at the video of the guy grinding down lifter faces it is obvious there is a problem with the contour of the face . I wonder if it is being done on a machine that is not adequate for producing the proper contour . Many years ago I had projects where I had to dress a specific radius into a grinding wheel with a diamond dresser set to that radius . I would then surface grind that contour into hardened steel parts . I wonder if this could be done in a valve re facing set up . One problem with that would be dressing the stone to the right radius .