BBC solid roller lifter failures - a root cause analysis

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BBC solid roller lifter failures - a root cause analysis

Post by 540 RAT » Tue Sep 30, 2008 2:38 pm

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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Post by MadBill » Tue Sep 30, 2008 3:23 pm

Well, %^$#!
Originally I had planned to use Shubeck ceramic lifters in my back-burner BBC project, until reports of grenading grit and ultimately business insolvency arose. Lately, I had pencilled in the Iskys, but now, with the data from RAT's meticulous analysis.... ](*,)
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Post by Unkl Ian » Tue Sep 30, 2008 4:00 pm

How are the OEM hydraulic roller lifters able to survive ?

Less spring pressure ?
Less aggressive profiles ?
Please help make Speedtalk a Troll free zone.

desoto30

Post by desoto30 » Tue Sep 30, 2008 4:35 pm

This appears a major dilemma that big cube BBChev owners face,Solid rollers seem the only performance option,Reliability the main obstacle.I have Crower Hippo's in my (not used yet) 565 thinking the Hippo option is good (can't be bad) I now really have my fingers crossed.BTW You are lucky to be told anything by Isky as I have contacted them (& Crower)several times in regard to their products & am yet to receive a reply!!

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Post by Dave Koehler » Tue Sep 30, 2008 5:05 pm

Whether anything comes of it or not, that's a fine detailed report 540!
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Post by Ted Gerstenslager » Tue Sep 30, 2008 6:28 pm

I have been exclusivley using the Isky 202-96 RH long body (not red zone) for over 6 years. I have not experienced a failure in a race application. BBC 's w/ 280# /700# spring rates. Even my own 580" 284/294 .740 net lift 7600 rpm had over 500 runs before I chickened out and put in a new set. My particular combo has a large amount of main vert. oil (.004) and rod side clearance (.035) so I run a higher pressure in my dry sump (95 cold) than most as after the oil gets hot I lose a little pressure. I just pulled for a freshen , pistons wer a little sloppy and a poor leakdown and the bearings look great for so many runs.
My oil of choice has been rotella 15/40 and Lucas oil stabilizer since the first oil change.
On the other side of the coin I had a customer with a small cam 260/266 street driven BBC that ate 2 of the same lifters. Did not drive it a whole lot around town, but he did the Power tour thing. The spring rates were a lot less around 200 or so. pressure was 35/70

Here is my take on the deal.... not in any particular order.
Valvetrain float.... there is usually no traction on the street so the motor will rev to the moon before anybody can shift to drop the rpm. This will beat the shit out of the lifters.
Lubricity......todays oils are not what they used to be, without additives and such. Add in the rumpity-rump cams of the week that pollute the oil on overlap with unburned fuel that dilutes the already crappy oil.

Idling, combined with lack of lubricity. Most solid roller lifters get their oil to the bearings from splash from the rotating crankshaft. Now a street motor spends the majority of time idling and operating at a much lower rpm range so there is no splash and the oil they do get is fuel contaminated so the needles start to erode.

Failure of direct oil lifters on the street . Lack of lubricity due to the lack of an additive package in the oil and fuel contamination.

I've even had to change hydraulic roller on a few marine apps as the rollers went away . the only thing out of the ordinary I noticed was the fuel (pump gas)smell of the oil. Lets face it , when was the last time you got a Dominator or a hp holley to idle snoot clean .

Thats my take on it. :wink:

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roller lifters

Post by bigjoe1 » Tue Sep 30, 2008 7:02 pm

I have very little( i did not say NO ) roller lifter problems. I tell every body to set their idle speed way up ( as high as they can stand it- slow speed is DEATH especially when the engine is cold. I hate slow idle speeds.

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Re: roller lifters

Post by af2 » Tue Sep 30, 2008 7:09 pm

bigjoe1 wrote:I have very little( i did not say NO ) roller lifter problems. I tell every body to set their idle speed way up ( as high as they can stand it- slow speed is DEATH especially when the engine is cold. I hate slow idle speeds.

JOE SHERMAN RACING
As I agree with and do so why the heck does stock lifteres live at 600 rpm? :-$
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Post by chevyman » Tue Sep 30, 2008 7:18 pm

540 Rat, A few weeks back i experienced lifter failure. I was using the comp solid roller w/oilers. It took out the cam and cylinder wall and ebedded a ton of metal in the piston skirt. I just finished a rebuild and went with the crowers. The lifter that failed only had 127 1/8 mile passes. Now to me that isnt a lot of runs for failure. But this is a race only motor. I sure hope i can get more passes than before w/out failures. This failure wasnt due to lack of oil, you can actually see the galling on the roller almost looked like the metal started flaking off. Its a shame that the companies that we spend our money with cant seem to give us any insight when asked about what problems they have had in the past with products and lead you to believe that all will be fine with no failures. Even NASA has failures and they admit to it. :lol:
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Post by Ted Gerstenslager » Tue Sep 30, 2008 7:22 pm

Stock lifters live because they have little spring pressure ,maybe 100-125 # and NO fuel contamination. Just look at a light truck diesel no gas to kill the oil and no spring pressure cause they turn no rpm, ever. 4-5 hundred thousand miles if properly maintained.

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Post by stix818 » Tue Sep 30, 2008 7:40 pm

I appologize if this is not a related question or out of line, but I just had a lifter failure so I'm concerned. My question is, how do these Isky's you mention along with the Crowers compare to the Jesel KeyWay lifters? I just spent a lot of money on bushing and machine work and hope I went the right route. Sorry if I hijacked your thread!!!

Thanks for the info!!!
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Post by 540 RAT » Tue Sep 30, 2008 7:41 pm

chevyman wrote:540 Rat, A few weeks back i experienced lifter failure. I was using the comp solid roller w/oilers. It took out the cam and cylinder wall and ebedded a ton of metal in the piston skirt. I just finished a rebuild and went with the crowers. The lifter that failed only had 127 1/8 mile passes. Now to me that isnt a lot of runs for failure. But this is a race only motor. I sure hope i can get more passes than before w/out failures. This failure wasnt due to lack of oil, you can actually see the galling on the roller almost looked like the metal started flaking off. Its a shame that the companies that we spend our money with cant seem to give us any insight when asked about what problems they have had in the past with products and lead you to believe that all will be fine with no failures. Even NASA has failures and they admit to it. :lol:
That flaking/pitting of metal that you saw on your failed lifter's roller, is the metal surface fatigue failure I was talking about in my analysis. Yours had the exact same failure, from what you report. I think you meant to say spalling, which refers to flaking/pitting, where galling refers to a scraping of the metal from an oiling failure.

Fatigue failure of the roller OD is worse than at the needles/axles because when the roller goes, it takes the cam, and as you found out, it can also take out the cylinder. Failure at the axle will generally show up as extra lash, and can give you a chance to save the motor, if caught in time.

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Post by 540 RAT » Tue Sep 30, 2008 7:47 pm

stix818 wrote:I appologize if this is not a related question or out of line, but I just had a lifter failure so I'm concerned. My question is, how do these Isky's you mention along with the Crowers compare to the Jesel KeyWay lifters? I just spent a lot of money on bushing and machine work and hope I went the right route. Sorry if I hijacked your thread!!!

Thanks for the info!!!
The Isky EZX's that I mentioned have no needle bearings, they use a bushing instead. The Crowers do use needle bearings, which is why I took them out of my engine. I'm not familiar with the Jesel's you mention, but if they have needles, I would not put them in my motor. Needles are a weak spot in terms of reliability, no matter what any ad copy might say. Only you can decide if you did the right thing or not.

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Post by stix818 » Tue Sep 30, 2008 7:48 pm

Interesting thanks!!!
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Post by s/c 266 » Tue Sep 30, 2008 7:59 pm

I have a deal I did last year that may help you live with a failure. or not

555 BBC drag race only

Healthy Bullet roller and Crane Pro lifters. Stock size.

Roller bearing failure lead to roller dragging and what looked like lobe death. Changed cam and put with the rest of the issue parts. A pricey cam for me so I started looking close and mic-ed the lobe. Hmm bigger than it should be Huuuu??

Shop is meager so decided I'd take my pneumatic die grinder and a large 80 grit flapper and see what kind of damage I could do heee hee Messed with that lobe for maybe 60 min all by hand to the pint it looked fine. Not perfect but fine in the area it needed to be.

Put it back in and degreed it and it was within 2deg of my original degree notes and .002 new lift.

Hey I just bracket race a mid 7 sec dragster so this little diff is no big deal.

The nasty looking lobe was just crapped up with the roller wheel metal.

This is it looked when I moved on to polishing. Don't have a as found or finished.

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