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  #1  
Old Sep 30th, 08, 12:45 PM
540 RAT 540 RAT is offline
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Default BBC solid roller lifter failures - a root cause analysis

Like everyone else who is interested in BBC solid roller lifter failures, I wondered just what is really causing all these failures. Everyone talks about the problem, and some have ideas how we can make them live as long as possible. But at the end of the day, most all of them are going to fail, no matter what you do to try to help them, at a time/mileage that most of us consider premature. Yes, there are some reports of long lives, but that is mostly luck of the draw and not something that you can count on with any regularity.

As far as I know, no one has ever done an actual root cause failure analysis on these lifters to see what is really going on. So, in an effort to preserve my own nearly finished 540, I decided that if I wanted that info, I'd have to do it myself. So, I thought I'd post my findings for others who might be interested as well. I managed to get my hands on failed std diameter .842 solid roller lifters from 3 different BBC's. I would have liked a wider sampling, but these 3 motors spanned the spectrum from relatively mild to relatively wild. The specs are:

1. 408ci BBC, 243*/249* at .050, .663"/.655" lift, .018/.020 lash, 210/567 lbs spring pressure, Chevron Delo 15W40, Isky Redzone lifters failed at 3,000 nearly all street miles.

2. 540ci BBC, 266*/272* at .050, .678"/.688" lift, .016 lash, 260/650 lbs spring pressure, Redline 20W50, Crower HIPPO's failed at 5,000 nearly all street miles.

3. 632ci BBC, 277*/292* at .050, .848"/.824" lift, .026/.028 lash, 325/875 lbs spring pressure, Mobil 1, Redline, and Royal Purple Racing 20W50, Crower HIPPO's failed after 1 1/2 years. Mileage and driving style not documented.

So, I took them apart one at a time for careful analysis. I figured to get to the bottom of it all, if needed, I'd also Rockwell test the parts and send them to a metallurgy lab for detailed analysis. As it turns out, no matter what the cam, lash, springs, or oil used, they all suffered from the exact same mode of failure, in the form of extensive surface pitting on the axles and needles, which is also called spalling (no indication of an oiling problem such as galling was found at all). The axles were the worst in all cases, which make sense, since they are softer, which allows for the swaging at their ends which holds them in place. All this pitting is caused by metal surface fatigue failure. And this is brought on by the part being overloaded for its size, which sends the stresses of the metal so high, that its fatigue life is lowered to an unacceptable level. Since this failure was totally obvious, much like a bullet wound through the head, the cost and hassle of further analysis was not necessary. That being the case, there is essentially no defense against this fatigue failure with .842 lifters. They are just too small for the job we ask of them. If they are made bigger, and of course some are available a bit bigger (though they may not really be big enough for acceptable fatigue life), then the stresses can be lowered, thus increasing fatigue life. Using .842 lifters is just convenient for use in existing lifter bores, but this size is not what engineers would design from a clean sheet of paper, or a blank computer screen, for an application such as this. All most can do is closely monitor things to see when they start to go. And hope you can replace them before they take the engine with them. The other thing that was very bothersome about all 3 sets of failed lifters, is the fact that the roller OD's all showed the same fatigue failure pitting. Some had totally failed, and some were just beginning to fail. And with all different oils, cams and spring pressures being used, showing the same problem, there is really no defense against fatigue failure here either. This failure is actually worse than a needle/axle failure, because with close monitoring, you can usually catch the needle/axle failure before it takes anything else out. But with a roller OD failure, by the time you see it show up in terms of extra lash, it is almost guaranteed to have already taken the cam lobe with it, and perhaps even more. Not a very comforting thought.

Since I now see that the needle-type solid roller lifters for BBC's are basically hopeless, I pulled the new Crower HIPPO's out of my as yet un-fired brand new 540, and replaced them with newer Isky EZX bushing-type roller lifters, since they are more or less the only game in town for that type design. By all accounts that I've come across, these EZX's are much more durable than the needle-types, with respect to the needle/axle problem. So I'll give them a try, even though I really don't like some of their other design aspects. I suppose overall, they can't be any worse than the needle-types, and will hopefully be much better. But, unless those EZX's have better material being used for the rollers, than the basic Redzones, then they also can only last as long as the roller OD's, no matter how well the bushing/axles hold up.

For those who might be interested, here are some things I came across when installing those Isky EZX's in my Dart Big M block with its Comp Cams billet custom solid roller cam:

1. The diameter was larger than Isky told me they would be, thus reducing the lifter to bore clearance to less than I'd really like, but the motor was built already at this point, so honing the bores was not an option. It should be OK, but it is at the minimum, so it does concern me a bit.

2. The pushrod seats were about .040 higher than were the seats in my previous Crower HIPPO's, so I had to get another set of shorter pushrods to maintain the rocker geometry that I had ever so carefully setup with my AFR 335cc CNC heads. So, that cost me even more money, even though Isky told me there would be no change in that regard.

3. Isky's so-called high pressure bushing oiling holes are horizontal holes just above the axle, in the front to back direction, and do not get oil through a passage from the pressurized oil band up above like the Crowers and other lifters do. These Isky bushing/axle oiling holes hang below my lifter bores when on the base circle, where they get no oil at all half the time. Those oil holes will see some oil when they are up in the lifter bores, where there is some oil pressure, though restricted by the amount of lifter to bore clearance available. And they will also see a shot of actual pressurized oil during the relatively brief time (maybe 90* camshaft, give or take), when the holes reach the block's lifter oil galley at max lift. But the way the bushing/axle gets most of its oil, most of the time, is because there are oil holes above the roller, shooting oil onto the OD of the roller. The spinning rollers will throw the oil off and outward just like water off a spinning tire in the rain, but it hits the underside of the lifter body, and then comes back down the sides of the rollers onto the axle, where it can sort of work its way into the actual bushing/axle interface. Overall, I don't like this poor oiling design. Though it does apparently work well enough to get by. But, having the bushing/axle area get consistent fulltime oil directly from the oil band like other lifters do, would be far superior.

4. The lower thrust surface below the large oil band, is really way too short. It doesn't wrap somewhat around the roller like the Crower HIPPO's do, which is a much better design altogether. Some of the Isky's I took apart, showed excessive wear on that shorter thrust surface below that oil band. This is also an inferior design aspect that I don't like.

5. The precision outer diameter surfaces of the lifters were not machined high enough, which I didn't expect to have to look for originally, and so I had 3 lifters stick in their bores. All they had to do was machine about another .100 higher, and it would be no issue. My original Crowers were machined correctly, but the Isky's were not.

6. The one good thing I found with the EZX's is that the large pressurized oil band is lower than they were on my previous Crower HIPPO's, so they don't try to restrict oil flowing through the lifter oil galley like the Crowers would at max lift.

All in all, I was not very happy with my $1,000.00 Isky purchase. But considering the solid roller lifters available, they apparently are the lesser of evils. So, I'm crossing my fingers and hoping that they will hold up better than the rest. I guess guys like us who insist on running solid rollers on the street are a bit crazy………..
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  #2  
Old Sep 30th, 08, 01:00 PM
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Steve69SS396 Steve69SS396 is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

I've run a solid roller in my car since 2000 with lots of street miles. The best advice I can give is to do proper maintenance by checking the lash regularly.

Most importantly keep a log book of everytime you check the lash and which valves need adjustment. If a particular valve needs adjustment twice in a row pull the intake and inspect the lifter, pushrod and rocker for wear. If the roller on the lifter is loose replace the entire set of 16 lifters.

By doing this you will catch the problem before there is any damage.
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Old Sep 30th, 08, 02:34 PM
zdld17 zdld17 is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Just 2¢'s here. I noticed you mentioned that the roller was only getting oil at max lift? Was this because the recessed lifter oil band was not in line constantly with lifter galley?

I got into this issue or close to it when running a small base circle cam with the same rollers that were run on a large base circle. I pulled back and front galley plugs to ensure that this lifter oil band was in constant view of the lifter galley. I see how this can become an issue.

I have always questioned solid rollers on the street for hi mileage vehicles or long distant cruisers. I have taken it as a rule , not to do this. But I hear of some that have gotten by.
Something that I have seen is bronze bushed lifter bores and in addition to , oil lifter bores tapped to provide additional oiling.

I will last say that the Shafiroff 540 motor we got, we used the Hippo rollers but this was a race motor only. Lifter bores were drilled and bushed to center roller on the cam.

You really researched this topic. Good topic.
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Old Sep 30th, 08, 04:44 PM
pdq67 pdq67 is offline
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Smile Re: BBC solid roller lifter failures - a root cause analysis

I have followed Schubeck's bullnose solid lifters and his axle-less solid roller lifters that oil like a main bearing and think BOTH are a great idea IF they actually will work over the long haul and don't cost more than three pounds of flesh!

That said, the Isky needless bearing jobbers are probably the next best there is.

And I have to say that I flat won't run a solid roller cam b/c of worrying about when I will eat a lifter and spit my engine out UNLESS it is a low-lift, milder numbered jobber??

I bugged UDHarold for quite a while to make me a solid lifter copy of CC's great old 288AR solid street roller and he did!

Spec's are 278/249/161, 110/106, .618" gross lift and it need's .018" lash on both sides!

I think that the MOPAR/AMC lifter dia. is way better than our small .842" and IF I had the $Bucks, I would use them and a more aggressive solid lifter cam to combat solid roller lifter issues! BUT I also realize that this can only be done up to a point and then the stresses get carried away unless you surface harden both the cam to the max as well as the lifter feet!

Sorry, no real world experience, but please consider all this too.

pdq67

PS., and I'm onna those odd-ball guys that think synthetic oil just may be too slick, which allow's roller wheels to slide and thus brinnell/surface fatigue/pit like was mentioned.
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Old Sep 30th, 08, 06:26 PM
zdld17 zdld17 is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Paul, one thing I forgot to ask here on this subject, Do you think that the cause of these roller lifter problems could be the absence of a rev kit? My thought is that with out constant roller / cam contact, there is a lot of slamming of the roller off or on the lobe, due to the lash setting. If the spring loaded roller followed the lobe all the time then the lash would be at the rocker / valve stem. Make sense?
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Old Sep 30th, 08, 06:35 PM
ace's68 ace's68 is online now
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Default Re: BBC solid roller lifter failures - a root cause analysis

kinda skimmed the whole thing...I'm assuming you used a thrust button, nothing good can come from cam walk...
I noticed A LOT of race engine manufactures are paying special attention to the lifter bores recently. Using copper O rings with oil holes punched in them in the lifter bores (holes for oil). Kind of like non floating rods vs. floating.
Reher-Morrison does this... A lot of hard passes and most never see any cam problems, mostly something catastrophic if anything.
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Old Sep 30th, 08, 07:12 PM
ssscamaro ssscamaro is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Great read. Do you have any pictures of the ezbushing and the hippos comparing height and oil hole/ band locations? I would love to see them if so. Curious what cam brand you are running? i ran into something similar with uncovering the oil hole years ago when assebling a friends mk 4 bbc using comp roller cam and comp roller lifters. there quality control was terrible holes drilled sideways and in different locations. they would get uncovered at max lift and some on base circle. He purchased a set of crane pro series and no problems. Car went mid 9s at 3700 lbs 150 passes few thousand miles. Never had lifter problem with them.
Anyway i would love to see those pictures if you can provide.I am seroiusly considering the isky ezbushing lifters for my zl1 race motor.
Thanks
Ryan
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Old Sep 30th, 08, 07:59 PM
Doug F. Doug F. is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Nice info but the total analysis could/needs to go deeper. You indicate the wear is from an overload condition, understood, but from what would be key. Difficult to say for sure, but is it from spring force, valve train instability caused by profile, lash? I've never really heard of that issue with a hyd roller and some people run some moderate spring pressues with them.

I ran a small solid roller for 10k+ miles, swapped to a bigger cam and the lifters looked like new when I pulled them out. This also had well over 500 passes on them as well. I ran low spring pressures as was recommended.

I've got about 200 passes on my std red zones in my BB now and they looked good this winter albeit there was a lot of thrust wear on the lower band as you mention I didn't care to see.

I've seen lobe profiles kill springs in one dyno pull, so I have to wonder what are the actual causes of the excelerated fatigue of those lifters.
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Old Sep 30th, 08, 08:42 PM
Z15CAM Z15CAM is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

540 RAT: I too am concerned about Mechanical Roller Failure. You have a very interesting post with and a fair amount of work and I say well done.

I run a 73 10.1 Static Compression 454+ .030”, modified 781 Heads with the Cast Core 288AR-10, (244-244 @.050” / .623-.623”, 110 LSA), Crower Hippo’s with the CCA-929 148 Seat and 437 lb’s open. I also run the Donovan Cam Gear Drive which really locks the cam end play to with in .004” and use Chevron Delo LE 15w40 oil. The Drive train is a M22 to a 12 Bolt Posi 3.08. I don’t rev over 6000 rpm but the engine sure want too.

This is my 1st experience running a Solid Roller on the Street; but HWY is my intention and want that explosive acceleration )).

The Donovan Anti-Cam Walk device is a preventative measure for me. I drilled a 1mm hole in the Psgr Tappet Gallery Oil Plug to ensure the Gear Drive gets Oil. Cam Walk is the result of inaccurate Lifter Bores in blocks originally designed for FT and will exert forces on the ends of the needle bearings around the ends of the Rollers Shaft much more so then in blocks designed for Roller Tappets and subject to failure as you describe. This is why I choose to use Oil with relatively Hi-ZDDP content. My present spring Pressures are low compared to your examples and I am sure I would be asking for trouble, if I went over 200 Seat/500 lbs Open using a Cast Core Cam; however, depending how this works out I would like to run, say the Crane 138551 Billet with Cast Distributer Gear (238-246 @ .050 / .595-.615”, 112 LSA) and use more spring pressure and get into Higher Revs with a 3.31 gear ratio. The cam’s not cheap at $360 USD.

I would say with any block designed for FT, you should have the Lifter Bores Trued and Oversized to run a Hippo Type Roller Lifter with larger diameter Pin Shafts. Truing the Lifter Bore should nullify the Cam Walk Forces exerted on the Roller Pin Needle Bearing and Shaft, but then again you looking at considerable expense.

I’ve no advice for anyone attempting to run Solid Rollers on the Street other then “X” your fingers, hope for the best and stay On-Top of the Tappet adjustment. So far after some 2000 miles my Tappet clearances have remained constant.

This is the first time I've heard or looked at the Schubeck EZX solid axle-less roller lifter and must say the design impresses me and I'll be giving them serious consideration in the future - man - his engines are worth over $45,000. One thing I must say is that CROWER has a very reliable service and will rebuild your lifter set at a very reasonable cost. I had a spare set of used SBC Hippo's serviced and converted to the BBC Link Bar costing approx $150 including shipping; plus, CROWER included a warranty. For the price I would say it is worth to send your lifters to Crower for inspection, during the time your car is off the road for the winter months or for some other reason. In event of lifter failure, I imagine, their warranty covers their lifters but not your engine.

I think we are rather a sick lot who enjoy pushing the limits of what we can build and drive; and man, Solid Rollers sure Rev-Freely.

If you have any advise or other experiences to relate, I am all for it ))

Great Topic.
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Old Oct 1st, 08, 10:02 AM
540 RAT 540 RAT is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Quote:
Originally Posted by ssscamaro View Post
Great read. Do you have any pictures of the ezbushing and the hippos comparing height and oil hole/ band locations? I would love to see them if so. Curious what cam brand you are running? i ran into something similar with uncovering the oil hole years ago when assebling a friends mk 4 bbc using comp roller cam and comp roller lifters. there quality control was terrible holes drilled sideways and in different locations. they would get uncovered at max lift and some on base circle. He purchased a set of crane pro series and no problems. Car went mid 9s at 3700 lbs 150 passes few thousand miles. Never had lifter problem with them.
Anyway i would love to see those pictures if you can provide.I am seroiusly considering the isky ezbushing lifters for my zl1 race motor.
Thanks
Ryan
I've never set things up to post pictures on the forum, so I just emailed you the picture you wanted. Maybe you are setup to post it here. If so, I'm sure others would like to see it also.
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Old Oct 1st, 08, 08:04 PM
Eric68 Eric68 is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Good info 540 Rat. Looks like you put some serious time and effort into this project.

What I would like to know is the underlying cause of the spalling. Since there are many who have successfully run similar cams, spring loads, and applications to the ones you tested I wonder what the difference is. If it was a design issue (like size) then it would seem to me that all .842" lifters would fail like this . . . there has to be something else going on here because many run these lifters successfully.

Here are my ideas, but I don't know how to go about proving it short of spintron testing. 1) valve float. If (for whatever reason) the valves float, the bearing and rollers would take the brunt of the impact when cam lobe smacks the roller. 2) improper lash technique. Too much lash causing lifter to impact cam lobe in a violent way rather than hitting the lash ramp. 3) No rev kit. Although controversial, a rev kit in theory keeps the lifter on the base circle rather than bouncing back and forth when the valve is not being opened.
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Old Oct 1st, 08, 10:16 PM
Mark .L.W. Mark .L.W. is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

I have always run rev kits , after talking to guys like Chet Herbert and tech's at Isky they all said the roller lifter will not survive the shocks . I have run the Redzones with my solid roller and have been fine , as stated above keep a log on the lash each time .
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Old Oct 1st, 08, 10:29 PM
Z15CAM Z15CAM is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Take a look at the modern Factory Engines with Lifter Bores and Cam Walk Retainers designed for Hydraulic Rollers. There is virtual no failure. The lifter bores are accurately machined. The lifter bores of our old FT engines are not accurate and some blocks are worse then others. On a BBC say without the Anti-Cam Walk device installed and one or two cylinders mocked up with a valve train, it will take less then 3 turns before the cam has walked forward enough for the next lobe of the cam to strike the adjacent lifter. Now multiply this effect when the entire valve train has been installed. The combined force from the springs create a tremendous energy to push the cam forward and each pin shaft of the Roller Lifter contributes to this force, specifically the ends of the shaft and needle bearings. This force also attempts to rotate the roller lifter in spite that the link bars and Anti-Cam Walk device are installed. I concur that as the revs increase the force of lifter bounce associated with mechanical tappet clearance increases and a rev kit more then likely would add stability and lessen harmonic bounce but then again the kit will increase pressure on the ends of the roller pin shaft and needle bearings which are already vibrating in a rotational direction.

I believe a lot of the Mechanical Roller Lifter failures are associated with the degree of Lifter bore misalignment which varies between one FT Block and the next. If your lucky you might have a block with lifter bores that exerts minimal forces on the Roller Pin Shaft and stand a better chance for success.

I think this theory is compatible with 540 findings and may explain the damage he has found on Mechanical Roller Lifters. A weak Anti-Cam-Walk device and excessive cam back lash would certainly attribute to lifer failure in regards to this scenario.
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Old Oct 2nd, 08, 10:53 AM
Doug F. Doug F. is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Quote:
Originally Posted by Eric68 View Post
Good info 540 Rat. Looks like you put some serious time and effort into this project.

What I would like to know is the underlying cause of the spalling. Since there are many who have successfully run similar cams, spring loads, and applications to the ones you tested I wonder what the difference is. If it was a design issue (like size) then it would seem to me that all .842" lifters would fail like this . . . there has to be something else going on here because many run these lifters successfully.

Here are my ideas, but I don't know how to go about proving it short of spintron testing. 1) valve float. If (for whatever reason) the valves float, the bearing and rollers would take the brunt of the impact when cam lobe smacks the roller. 2) improper lash technique. Too much lash causing lifter to impact cam lobe in a violent way rather than hitting the lash ramp. 3) No rev kit. Although controversial, a rev kit in theory keeps the lifter on the base circle rather than bouncing back and forth when the valve is not being opened.
Eric,
I've seen cam designs kill springs in less than 3 dyno pulls and kill roller rocker arms quickly too. Someone would have to change my mind with a lot of data to tell me that that valve train instability can't hurt roller lifters too. Loads on a lifter are highest at lowest speeds as well, so that is at the opposite end of the spectrum, but I would think can play as well.

And from what I have learned about cam designs if you open up the lash much at all on some cams, you can truly be hammering things even more. Depends on that specific lobe design.

Nobody talks much about lobe profiles because they don't have access to the design data and curves. There IS a lot more to a lobe design than .020, .050, and .200 numbers, although they tell you a little.

Bottom line is you can't make blanket statements. Too many variables.
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Old Oct 2nd, 08, 12:35 PM
540 RAT 540 RAT is offline
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Default Re: BBC solid roller lifter failures - a root cause analysis

Quote:
Originally Posted by Eric68 View Post
Good info 540 Rat. Looks like you put some serious time and effort into this project.

What I would like to know is the underlying cause of the spalling. Since there are many who have successfully run similar cams, spring loads, and applications to the ones you tested I wonder what the difference is. If it was a design issue (like size) then it would seem to me that all .842" lifters would fail like this . . . there has to be something else going on here because many run these lifters successfully.

Here are my ideas, but I don't know how to go about proving it short of spintron testing. 1) valve float. If (for whatever reason) the valves float, the bearing and rollers would take the brunt of the impact when cam lobe smacks the roller. 2) improper lash technique. Too much lash causing lifter to impact cam lobe in a violent way rather than hitting the lash ramp. 3) No rev kit. Although controversial, a rev kit in theory keeps the lifter on the base circle rather than bouncing back and forth when the valve is not being opened.
Hey Eric,

The failed lifters I inspected all suffered a text book case of metal fatigue failure as I mentioned. This is caused by the amount of load being applied to the size of the part in question, or in other words the material's stress in psi, and its number of pressure cycles. How all that combines for a given part, along with the particular material used, determines that material's fatigue life. Size in terms of diameter in our case here, is what's important because larger diameters allow room for larger rollers, axles and needles. This reduces stress psi on the parts, since the load is spread out over more material, and will extend fatigue life. But of course there are limits to how large we can physically go in a given engine, and then increased weight of the parts also becomes an issue. If you can run larger lifter diameters than .842, by all means do it, because it's a good thing in terms of lifter life. All other things being equal, the std size .842 lifter will fail first because of its higher stress psi.

Fatigue life considerations:
Less load and the resulting lower psi, for the same size part, with the same number of pressure cycles, will give a longer fatigue life. Same load but a larger part and the resulting lower psi, with the same number of pressure cycles, will also give a longer fatigue life. Less pressure cycles, with everything else being constant, will extend fatigue life. So reducing the stress by reducing the load, or by increasing the size, will work in your favor, as would simply reducing the number of pressure cycles. However, this may not always be easy or even possible with any given engine situation.

Dedicated race engines may see hard use, but in terms of the total number of pressure cycles involved, which you could measure as the number of total revolutions turned (this would take into account the rpm's involved and not just mileage put on), will pale in comparison to even occasionally driven weekend street cars. That is consistent with the fact that street driven BBC's typically see solid roller lifter failures much more often than race cars do. Though there is not really a shortage of racers reporting lifter failures either. But like everything else in life, things are not just that simply cut and dried. Many other commonly considered things come into play such as valve train stability, valve float, lash, lobe design, spring pressure, etc. In addition to that, if you look at any part failure analysis, you'll see a resulting spread called a bell curve. This shows the distribution for the failure of identical parts. The majority could be fine for a long time, while others fail quickly, with no real explanation as to what the difference is. Call it luck of the draw perhaps. I saw this in some of the failed lifters I inspected. Out of the same motor, some lifters looked like brand new, while maybe only one or two were completely destroyed. You wouldn't really expect night and day differences in what the lifters experienced inside the same engine, so that bell curve spread appeared to come into play. The cause most likely is due to minor manufacturing differences. And is no doubt why some guys see good service out of their lifters, while other guys have engines destroyed when they prematurely let go.

I consider my root cause failure analysis of the failed lifters, which now seems to be becoming an epidemic, as Phase 1 in my search for an answer. Now I know "how" the lifters themselves are failing, which is the first thing you need to know. If we could run lifters with say maybe 1.5 or 2.0 inch diameters, if weight and actual fit were not deal breakers, then the stress psi would be so low that the lifters could have a more or less infinite fatigue life, much like stock lifters do in stock motors. Then all the lifter fatigue failure problems would be solved and we could go on our merry way. But since that is not possible, then our search must go on. Of course the easy way would be to run overhead cam motors, but that's not what most of us run. So phase 2 of the search for the rest of the answer to prevent that fatigue failure, assuming there even is a practical solution, will not be easy…………...
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Team Camaro Tech > All Generations > Performance      Current Topic: BBC solid roller lifter failures - a root cause analysis
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