Technical Reusing old cam & lifters

Ok so I pulled the cam, lifters, and top half of my SBF off years ago. Figured I'd get a new cam & lifters, so I didn't keep track of which lifter mates with which lobe. Finances dictate that if I want to get the motor running soon, I'm not spending money on a cam/lifters. Can I reinstall the cam & lifters using the appropriate procedure one would use for a brand new cam (proper break-in lubes, etc) and expect it to at least run for a while? Thanks!!!!

 

Get a new cam and lifters!!!!!....

 

That's the response I was expecting.... I really need to spend the $$$ on new rod/crank bearings and a carb, which shoots the budget. So I was wondering if I can save the cam/lifters by re-breaking them in (if there's such a thing). So let me rephrase the question: can I re-breaknin a used cam/lifters if I treat it like a new cam install? If not, just say so....

 

Oh, and bonus points to the engineer who can explain why it wouldn't work (why can't a cam/lifters be reused).

 

As a 20 year old dirt poor kid. I bought a used very low mile .030 / .030 SBC cam from a buddy. On his advice I installed it with NEW Chevrolet solid lifters. Worked fine and only had to run the valves once a year afterwards. As I said, I had no money and it was barely affordable but it came out fine. Wouldn't repeat
it again though.

 

It’s not best practice, things that wear as a pair have mated to some extent. Swap the parts around and you get rapid wear as they mate again. On a cam that’s not so great. Obviously you can assemble it and it will run, but....

 

It's my understanding (haven't tried it) new lifters on a used camshaft is acceptable though not the other way around.

You could try "mix and match" used lifters on used cam. Let us know if it works. I guar-antee it's been done, but it's not the way to bet.

 

It will run for a while. You can change it out later. It’s easy enough to put in a new cam and lifters.

I’m not sure how your budget is that tight though. Cam and lifters aren’t that expensive. It will cost a lot more doing it this way in the long run because you’ll need to buy gaskets twice. Antifreeze, etc. Then there’s the value of the commodity more valuable than money can buy: time. Even billionaires like Steve Jobs can’t buy more time.

You will get the response “buy new cam and lifters” because it’s the correct answer. It doesn’t take an engineer to see that.

Scrounge up a few bucks and get it done. It will actually be much cheaper, even considering interest on a credit card, than putting it in later. You’ll also have peace of mind.

Or, just do it and post back on this thread after 30,000 miles. I’m curious.


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See if you can find somebody that can resurface the lifters used to be acceptable

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If you had kept track of the lifters by lobe position you would be in good shape to reuse it all. If you mismatch the wear pattern things will wear out pretty quickly. Using new lifters with the used cam would be the best bet if you can't replace both the cam and lifters.

 

While I understand and agree with the comments about why it isn't good practice, there may be a bit more to consider.

I would bet that any of us who found themselves challenged 'with their back against a wall' would consider reusing the parts. Examine the base of the lifters and see how evenly worn they appear to be. Same for the cam lobes. If they are scored or show uneven surface wear....there is your answer. If they look 'good', and you are willing to assume some risk about the outcome....proceed with your plan.

 

Years ago I tried to save a few bucks and did the same thing, take it from someone that has been there and done that, your wasting money using a old cam and lifters, it will cost you more money in the long run. HRP

 

If you must reuse the lifters, get some fine crocus cloth and a piece of glass and polish the lifters using a figure eight pattern.

 

Sounds like you don't clearly understand the Cam and Lifter relationship. I'll do my best here to explain. A new Cam has lobes that start out machined square on the sides. The new lifters are Not flat on the bottom, they are in fact domed to the center. The lifter bottom design is to rotate the lifter as it goes up and down. As they ware together the dome slightly goes away and the square shoulders go away but the lifter still keeps turning. They become a matched pair. All 16 ware at a different rate. When you miss match them the lifter contact can stop the lifter from turning thus causing them to become a Grinder to each other. Use a straight edge on the bottom of the lifters and if you have any at all cupping on the bottom and it don't go back on the matting lobe You are Screwed. Also if you did a valve job and increased your spring tension at all, now you have sped up that process. Now make your decision and let us know how things work out. Keep in mind that the very fine material being ground off the cam train is now passing through your Oil pump and right through your new Bearings.

 

Pist-n, I usually agree with much of what you say but must disagree on this, it has always been my understanding that a flat tappet camshaft's lobes are angled very slightly and the lifters are perfectly flat.....the slight angle on the friction surface of the lobe causes more contact on one side of the lifter causing it to rotate and in theory reduce wear.....

 

As a kid I put new lifters on used cams.Got away with it.Engine oil was designed for flat tappets back then,and im sure thats why it worked ok.If you do this now add Zinc,and run the rpms above 2,000 for 25 minutes like you would breaking in a new cam.As an old guy I would just save for another month,and get all new.Wont say time has made me smarter,but it has given me patience.

 

Lifters are crowned on the bottoms. We used to buy used solid lifters from a NASCAR team. Yes, used. They spent hundreds of hours matching sets of lifters for weight, height of the plunger and then correcting the dome and heat treaded to their specs. They blue printed each lifter to have a perfect crown to it. Might have ben a set from a dyno session or a set that was not weight matched to their specs. We bought them 20 sets at a time to run in claim engines in IMCA modifieds and stock cars. Never had a single cam/lifter failure running a set of those lifters and still have about a set and a half left of them. Talking to the seller we dealt with, he made the promise that what they blueprinted and ran was still more perfect than anything a cam manufacturer sold new. They saw no problem running their "slightly used" lifters on a new cam. It worked.

That said, I would NEVER run a stock style used lifter with a ton of miles on them and expect it to live very long. Just asking for trouble and I think it's a false economy to do it. You might shop around and find a set of new lifters and run them on your old cam but ONLY if the cam is in perfect condition. That seems to work OK.

The cam/lifter interface fails and you will have a junk engine. Metal in the bearings, scuffed pistons, crank scratched and garbage entirely thru the engine. Is it worth it? Not to me. Shop around for a cam/lifter kit and save a lot by spending a little.

JMO,
SPark

 

Tappets will have a convex surface where the lifter meets the camshaft lobe. The lobe will have a slight angle. I recall finding some real good illustrations in the past, but this is all I could find quickly.

https://www.crower.com/media/pdf/cam_book.pdf

 

No engineer will be able to convince you of the proof you are asking for...

I'm not an engineer with a degree hanging on the wall, but I've experienced several brand new cams and lifters going bad right out of the box and I did EVERYTHING right! Proper break-in, proper oil with zinc additive, proper oil changes, cleanliness during assembly, everything!

I liken this question to a brand new wheel bearing. NEVER install a new wheel bearing on an old pitted or worn race. Your asking for trouble with accelerated wear.

That's another reason why I NEVER rotate my tires either. It wears them out much faster than normal.

But in a pinch, you might get lucky! At the worst case scenario, you'd have to buy a new cam and lifter set!

 

Speaking from experience, it doesn’t take long to wipe a lobe and lifter. If that happens your engine will need a full tear down to clean out the metal filings. Expect to replace bearings, gaskets, cam, lifters, possibly push rods and oil pump too. Suddenly, a cam and lifter kit doesn’t really sound too expensive does it? At the very least, replace the lifters if you use your old cam and follow proper break in procedures like it was a new cam.

 

You can get a mild performance hydraulic cam and lifters from Competition Products, Elgin Cams for $103, or Summit brand for $115.....pretty stupid to risk mixed used lifters on a used cam.

Even new lifters on a used cam is a risk, cam doesn't like being wear mated to a second set of lifters, it is only designed to wear mate one time.

If you want to be really tight budget, and the used lifters you have are in decent shape, still have some crown left on them.....then do the crocus/emery cloth on a flat surface plate or piece of glass and sand the bottoms of the lifter moving them across the paper in a figure eight pattern, this action naturally produces a crown finish. You're looking to produce a .002-.004" crown, you can eyeball it with a straight edge and feeler gauges.
Put those refinished lifters on a new cam, $60-75 from the sources I posted.

 

Remember new cam = new bearings and cam/ lifter lube.

 

Okay Guys, I get it. Lot's of info out there so here's what I will say. I am No cam grinder or Lifter refacer. King ford may in fact be right. Some motors may have the machine surface reversed however a crown somewhere is necessary, at least from my experience. So, Here I have a new out of the Box 302 small block Ford flat tappet lifter as in Never before run before.

I take my pocket 6" machine ruler and put across the face on center. Please excuse me for not sticking a feeler gauge in between the two. I'm fresh out of surgery Friday and working with only one hand.

I can tell you that bottom is Not flat and if I were to guess there is about a .003 to .005 crown on it. I was a little shaky with the camera but it's the best I can do today.

 

New cam doesn't automatically mean new cam bearings are needed....cam bearing wear is extremely low on typical street applications, if you don't damage them taking the old cam out you can run a dozen different cams on the same cam bearings. Typically 100,000 mile bearings are capable of being re-used....just often get replaced because a hot tank will eat their surface, so they have to be replaced in a fully machined new build, ....but otherwise, replace only as needed.

 

Just to clarify a couple of things:
1 - Flat tappet lifter faces ARE TAPERED, not spherical, domed, crowned or any other type of curved surface.
They are tapered about .0002. (that is tenths)
2 - The cam lobes are tapered. Usually about .0001 to .0002. (that is tenths)

This leaves a FLAT surface meeting a FLAT surface.
This is to cause the lifter to rotate and wear even. Eventually the tapers wear away and the 2 surfaces are full mated.
By then, everything being mated the lifter will keep rotating because the lifter bore is offset from the lobe centerline.
Original Ford flathead lifters were ground flat BEFORE the war. Main reasons they got away with it was very low spring tension, very lightweight STEEL, and, the face was heat treated to 65 Rockwell C.

"Been in the cam business 65 years"

 

I can only comment from personal experience, so here goes. In the early days, myself and friends with tri-five Chevys would frequently replace stock cams (solid lifter) with what we called Duntovs. Later referred to 30-30 cams. We would pull the old cam and lifters, throw in the new one, dip the lifters (in no particular order) in STP and shove the whole mess together. The performance results always fell short of expectations, but I don't ever remember a cam or lifter failure. During my 65 years of wrenching, I have mixed and matched about every possible combination of new/used/cam/lifters and never wiped a cam. Now, these were not high performance engines (by today's definition) and were primarily vintage parts and old school oil. These days things are different but I know it can be successfully done. Remember, there were many many things done back in the day that are not approved of today.

 

You can reuse the cam, but you need new lifters.

The cam is harder than the lifters. Break in is wearing the lifter surface to match the cam lobe.



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They will eat each other and spread metal all through your engine....no bueno.

 

A lot of blanket statements here. How about info like this:

Several camshaft manufacturers we interviewed for this article (Crane & Howards Cams) told us they are now grinding more taper on their flat tappet cam lobes to improve lifter rotation. Spinning the lifters reduces friction and spreads the wear out across the bottom of the lifter to reduce both cam and lifter wear.

On some older engines, such as vintage 1957 to 1966 Buick Nailheads, the original cams were designed to work with flat bottom (no convex) lifters. On these engines, lifter rotation was achieved by offsetting the lifter bores with respect to the center line of the cam lobes. That’s important to know if you are rebuilding one of these other engines and want to correctly match the cam and lifters. Using modern convex bottom lifters with a vintage cam designed for flat bottom lifters will create a mismatch and likely lead to cam and lifter failure.

Likewise, you should never use flat bottom lifters on a cam with tapered lobes that is designed for convex bottom lifters. Flat bottom lifters will ride on the edge of the taper, creating very high loads that will lead to rapid cam failure.

NOTE: A “flat” bottom lifter may actually have a small amount of convex (maybe as much as .005?). By comparison, a modern solid or hydraulic lifter with a crowned bottom will have .0008 to .0015? of convex across its surface.

That was taken from this article:
https://www.enginebuildermag.com/2011/08/inside-flat-tappet-camshaft-andlifter-technology/

It's not one answer fits all applications. Best answer is to put a new cam and lifters in it but then you have to be sure the valve springs are correct. It's a never ending circle.

SPark