Hey Guys,

So I have spent lots of money and time building a 1970 Corvette and put together a replica LS6 with a crane blueprint ls6 camshaft. The solid lifters were also made by crane. I put the engine together and purchased Brad Penn break in oil. I started the engine and break in went ok. I changed the break in oil to Brad Penn 10w40 with plenty of zinc in it. About 100 miles later, I heard a tap through the passenger side pipe. I pulled the valve cover off and Exhaust on #2 had a 1/2 inch of valve clearance. The oil was glittery. I pulled the intake and looked down through the lifter valley and noticed the lobe gone. I pulled the oil pan off and took a rod and main cap off. The bearings had deep grooves in them along with metal shaving embedded in the bearing. I took the oil pump off and opened it up. The oil pump gears had been gouged from metal particles. The bottom of the lifter was mushroomed and pieces of it was in my oil!!! I pulled the engine out of the car and took it down to bare block. My crank was scratched severely and had to be taken to the machine shop. I have built many engines over the years and never had this happen. I have always used crane solid or hydraulic cams and never had a failure. I am having to spend a lot of money to fix this issue along with lots of time. This time I am going to a roller setup and never will go back to flat tappet again. I have posted pictures of the devastation. Please think twice before going flat tappet with today's cheap parts. I have contacted Chris Straub and he is going to send me a roller cam a lot like the LS6 cam. I can run regular oil and not worry about losing a lobe again. I should have done this in the first place, this was an expensive mistake that will never be made again!! Please chime in on comments or similar stories.

 

Thanks for the honest informative story. Sorry you had this bad luck.

I read a lot of forums . I've no experience at all building an engine .

Seems to me there are a lot of failures of cams ....no matter how careful and experienced the builder .

Basically I ve concluded , what you mentioned , "Cheap parts " or rather what I believe is **** poor iron and materials .

I think I would pay stupid money to buy a NOS GM cam if I were rebuilding a vintage flat tappet engine. I don't trust the cam companies anymore.

I have not read of many issues with an Isky cam .....wonder why?

Are cams being made in China

I read so many of these horror stories, I think I d just buy a factory assembled engine, taking an engine in and out us no fun .....in these cars.

 

I won't use a flat tappet cam nor will I use a carb again. I have seen 2 of my flat tappets go away in under 5k go away and another one go away in under 2K miles. I like you did all the right things but they still rounded off lobes.

 

Yeah, when i did my top end rebuild i was thinking tappet. But after seeing the advantage of a roller cam, i could justify the extra 600. I got a nice Howard's roller cam. I haven't put a bunch of use on it, but it runs well and it's made in the U.S.

 

That sux man! That's the decision we all have to make when building a new engine... Penny up the $2k for a roller upgrade, or roll the dice on the $300 flat tappet stuff and hope that you don't lose the $3-5k you just spent on the rebuild.

About 3 years ago we rebuilt my dads 327/350hp and he wanted to stick with a HYD flat tappet. We used a Crane Z274 and crane lifters, broke the engine in on a run stand and used the break in oil, additives, everything thing you can think of. So far after 2k miles, it's still holding up but I worry about getting that call some day from him that it's ticking.

Recently we just built a 65' 396 and I wasn't going to take the gamble this time, so Straub set us up in a full roller package and now I don't have to worry about rebuilding a $10k engine due to a cam failure.

I will not likely ever use a flat tappet again. (Although we still have 5 cars with flat tappets in them with no issues)

 

I wiped a lobe last spring on a rebuilt engine with ~3k miles on it. I was bummed and let it just sit most of the summer. My buddy that helps me with mechanical stuff happened to show up and we pulled the engine and replaced the cam. Didn't touch the bearings etc and so far all is well, but after reading this I am pretty worried I am in for a total tear down at some point

 

This happens all the time even with the correct oil. It seems it is a roll of the dice everytime. Sorry about your loss. I built a 1970 LS6, correct and date coded down to the bolthead markings and used that same cam you did for authenticity. Correct lifter to bore clearances and removing the inner springs on break in is critical, along with all correct break in procedures. If you miss one thing, no matter how insignificant it might seem that can take it out. That Crane Blueprint cam has slow rams compared to modern lobe profiles and Crane is top quality. Surprised you lost a lobe. I am betting a lifter bore to lifter clearance issue. If someone wants to use a flat tappet I also recommend EDM lifters and nitrided cam or P55 cores but the solution to the problem is a roller cam hands down.

 

This is good to hear that your engines are still holding up. I think the older stuff is better quality and should be ok if the right oils are used. I will never again use flat tappet.

I'm sorry to hear you wiped a lobe also. It is a gamble if your bearings are still good. Depends on how quick you caught it and how much metal went in your engine. I will post a picture of some bearings after the failure later on.

I am hoping I like the new roller cam setup. I hear that Straub makes some really good camshafts that make a lot of power. All the other lobes on my cam looked really good. It was the one lobe up towards the front of the engine. I am running a factory windage tray which I am unsure if this caused any oil supply problems to the front cam lobes. If I was going to try flat tappet again, I would buy the lifters you recommend but I am too scared to wipe a lobe again and cost me all this money. I am 100% sure to make the switch to roller which I should have done in the first place.

 

Im curious why our cars suffer, but modern OHC engines run valves off the cam (no lifters obviously) but are essentially flat tappet solids...anyone have an answer why they dont have issues with modern oil?

D

 

In bold are the things that came to mind for me too. Sorry to hear about your bad luck. Good luck with the new one.

 

I am thinking you have a bypass on your oil filter and that let all the crap through into your motor.

I would ditch the bypass. They are helpful if people never change the oil filter, but if you have no bypass and an oil pressure gauge , and actually look at it, you will start seeing a fall off in oil pressure indicating that metal was clogging the filter before it could ruin an engine.

Get a bypass eliminator.

Doug

 

I recently rebuilt a 1970 L46, stock spec's, the motor builder insisted on installing higher pressure springs as well as others. I had him change the springs too a stock spring by lying to him that I would change the springs after break in. It seem that all cam mfg suggest higher spring pressure. Than required for stock cams.

 

I have heard that our engines suffer when the zinc additive is not in between the lifter and cam lobe. The zinc is like a "pillow" and keeps metal to metal contact from occurring. You are correct, the new engines are basically the same thing without a pushrod. I am assuming spring pressure is lower or better metals? I am clueless on this one.

 

This is a great idea! This would show an oil pressure drop with the bypass eliminator. I did have a the bypass on my engine and all that metal went directly to my bearings. The problem was also the fine metal shavings that were in the oil that might have not been picked up in the filter.

 

I’m sorry to hear about your failure, but at the same time, I am not surprised by it at all. And I seriously doubt that Crane would agree that you were using cheap parts. Just assuming the parts are bad because you don’t know what else to blame, is no way to troubleshoot the failure and draw a meaningful conclusion. Worse yet, making assumptions like that will generally result in a completely WRONG conclusion. Then posting WRONG information on the internet only perpetuates people getting the wrong idea and believing MYTHS that only hurt them in the end.

Wiped lobes do NOT sometimes happen even with correct oil, if you are using reputable parts and the engine is properly assembled. They get wiped for a good reason. And I see a couple of glaring mistakes you made, that almost certainly caused your failure. They are:

1: Your choice of using a motor oil labeled Break-In oil.
So-called Break-In oils are nothing more than a marketing gimmick to sell oil to gullible consumers that they do not need. No engine needs so-called break-in oil to safely break-in. Nearly every break-in oil I have tested, provided poor wear protection capability, because they were formulated to allow wear, not prevent wear, even though they were loaded with zinc. Only Amsoil Break-In oil actually provided good wear protection. So, your choice of oil to use during break-in immediately put your engine at risk. No matter what anyone tells you, you cannot prevent an engine from breaking in, no matter what oil you use. And countless thousands of brand new factory engines have proven that over the years, with the use of synthetic 5W30 Mobil 1. Engines break-in just fine with this oil and come with a warranty. And this oil is in the top 10 motor oils for providing the best wear protection in my Engineering testing of 145 different motor oils so far. So obviously, even synthetic oils providing excellent wear protection still allow engines to break-in fine, proving that so-called break-in oils that provide poor wear protection, are NOT needed.

2: Your choice of using Brad Penn for your normal oil after break-in.
In my motor oil Engineering Tests, all the Brad Penn oils I’ve tested, provided poor wear protection capability, even though they have a high zinc level.

And here is additional information from a Racer who used Brad Penn oil:

An oval track dirt racer (his class is extremely competitive, so he asked that his name be left out) on the SpeedTalk Forum runs a 7200 rpm, solid flat tappet, 358ci Small Block Chevy motor, with valve spring pressures of about 160 on the seat and 400 open, that are shimmed to .060” from coil bind. The rules and the combination of parts, were causing him to experience repeated cam failures while using high zinc, semi-synthetic 10W30 Brad Penn, Penn Grade 1 motor oil. Lab Report Data from testing performed by Professional Lab, “ALS Tribology” in Sparks, Nevada, showed that this oil contains 1557 ppm zinc, 1651 ppm phosphorus, and 3 ppm moly. In spite of this being a high zinc oil, that most folks would “assume” provides excellent wear protection, he experienced wiped lobe cam failure about every 22 to 25 races.

A race consists of one 8 lap (a lap is typically 3/8 mile) heat race and one 20 lap feature race, plus any caution laps. If you add it all up, 25 races only total about 281 miles at the point of cam failure. So, that is a perfect example of what I’ve been saying all along about high zinc levels being absolutely NO GUARANTEE of adequate wear protection. And my test data on this 10W30 Brad Penn, Penn Grade 1 motor oil, shows that it produces a wear protection capability of only 71,206 psi, which puts it in the MODEST wear protection category, and it ranks a very disappointing 107th out of 145 oils tested so far. That means of course that there are 106 different oils I’ve tested that provide better wear protection.

So, my test data ACCURATELY PREDICTED EXACTLY what he experienced during racing. And that is, that this oil does not provide high enough wear protection capability to provide a sufficient margin of safety for this engine’s operating conditions. Looking at my “Wear Protection Ranking List” and choosing a much higher ranked oil, would have prevented all those cam failures. Repeatedly suffering cam failures in motors with so little time on them, may have been considered by some folks to be a normal consumption of parts back in the ‘60’s or ‘70’s. But, in the 21st Century that we live in now, by any measure, that is for sure premature failure. We no longer have to accept that as the cost of doing business, because we can do far better now.

So, he switched to the super micro polished billet lifters from PPPC and the cam life went up to 40 races, which was an improvement since he could now go 450 miles between failures. But, that was still clearly unacceptable. Then later on, he started using “Oil Extreme Concentrate” as an additive to the 10W30 Brad Penn, and he’s never lost a lobe on a cam since. Adding the “Oil Extreme Concentrate” completely eliminated his premature wiped lobe cam failures. Now the motor has now gone 70+ Races without issue, and is still doing fine. This “Oil Extreme Concentrate” is one additive that actually works as advertised, and makes low ranked oils far better than they were to begin with. And that is PRECISELY WHAT MY MOTOR OIL TEST DATA PREDICTED as well.

Here’s how. I also added “Oil Extreme Concentrate” to 10W30 Brad Penn, Penn Grade 1 semi-synthetic, as part of my motor oil “Dynamic Wear Testing Under Load” research. And with 2.0 OZ of “Oil Extreme Concentrate” added per qt, which is the amount intended for racing, its wear protection capability shot up by a BREATH TAKING 56%, to an amazing 111,061psi, which puts it in the INCREDIBLE wear protection category, and now ranks it a jaw dropping 6th out of 145 oils tested so far. So, it moved up a whopping 101 ranking positions, just by adding the “Oil Extreme Concentrate”. This totally accounts for the reason all his cam lobe failures were eliminated.

So, this is an example that PROVES once and for all, that my test data EXACTLY MATCHES REAL WORLD RACE TRACK EXPERIENCE, and that my test data is the spot on REAL DEAL, just as I’ve said all along. This completely confirms that my test results WILL ACCURATELY PREDICT what we can expect from motor oils in running engines on the track or on the street, EVEN if those oils are high zinc oils. So, that should be more than enough proof to satisfy anyone who was skeptical of how well my test data compares to the real world.

Bottom line, your flat tappet cam and lifters had poor wear protection from the beginning, because you were NOT using the correct oil, no matter what anyone tells you. So, it is no surprise at all that you wiped the lobes. I could have told you that was likely before you ever fired it up. If you had chosen a highly ranked motor oil from my wear protection ranking list, no matter how much zinc is in it, you almost certainly would never have had this failure. And with a highly ranked oil from my ranking list, you wouldn’t even need to worry about performing any special break-in procedure. The whole idea of performing specialized break-in procedures, is simply a crutch to hopefully keep poor performing high zinc oils from wiping lobes. Yet people are so brainwashed to think every high zinc oil is wonderful, that they never even realize that you shouldn’t need to go through all that, if you are using a truly good oil in the first place.

The whole idea that you need high zinc levels in your oil is only an Old Wives Tale MYTH that you absolutely cannot count on, which your failure proves that yet again. Relying on an oil just because it has a lot of zinc in it, is simply playing Russian Roulette with your engine. Because some high zinc oils provide good wear protection, while other high zinc oils do not. And this is exactly what I have been saying for the past few years. What matters is an oil’s film strength load carrying capability, which is what my Engineering Tests measure, not how much zinc is present.

Wiped flat tappet lobes still happen all too frequently, while using high zinc oils. So, how many engine failures will it take for people to wake up and realize that they cannot blindly count on all high zinc oils to protect their engines? My Engineering test data is the real deal, and is the only information you can count on when it comes to being able to tell which oils provide desirable wear protection, and which oils don’t?

In contrast to what you experienced, here is an example of a flat tappet High Performance Street Hotrod engine operating just fine with low zinc oils, just as my Test Data predicts. A buddy built a 500 HP, flat tappet, solid lifter, 383ci small block Chevy for his '69 Corvette several years ago. He asked me what oil he should use to break it in and to use later on as well. He wanted to use a conventional oil at that time, that was affordable, and readily available. So, I suggested he use conventional low zinc 5W30 Castrol GTX, API SN, that provided 95,392 psi in my testing, which put it in the OUTSTANDING wear protection category.

He used that oil from day one with no elaborate break-in procedure at all. He just drove the car. It is his only car, so it is his daily driver, which he always drives like he stole it. And he has never had any issue with his cam or lifters. Then maybe a year or so ago he decided he wanted to switch to a synthetic oil that was affordable and readily available, so I suggested he go with low zinc synthetic 5W30 Mobil 1, API SN, that provided 105,875 psi in my testing, which put it in the INCREDIBLE wear protection category.

He has used that oil ever since and still has not had any issue at all with his cam or lifters. He has tens of thousands of hard Hotrod miles on that cam and lifter combo, which is far more miles than most weekend only Hotrods will ever see, and he has never suffered one bit from not using a high zinc oil. So, this is yet another example of the fact that high zinc oils are NOT needed for sufficient wear protection, even in flat tappet engines, and not even for break-in. The only thing that matters, is an oil's film strength load carrying capacity. And that is precisely the data my Motor Oil Testing ranks.

If you really want to save your engine, see the link below.

540 RAT

Mechanical Engineer

U.S. Patent Holder

Member SAE (Society of Automotive Engineers)

Member ASME (American Society of Mechanical Engineers)

Motor Oil Tech FACTS, NOT MYTHS:
The independent and unbiased Engineering testing I perform to establish motor oil wear protection capability, is a dynamic friction test under load, similar to how an engine dyno test is a dynamic HP/Torque test under load. Both tests show how their subjects truly perform in the real world, no matter what brand names are involved, no matter what outrageous claims may have been made, and no matter what their spec sheets say. You can see my entire 140+ motor oil “Wear Protection Ranking List”, which is "proven" by the Physics and Chemistry involved, and EXACTLY matches real world Track experience as well as High Performance Street experience (test data validation doesn’t get any better than this), along with additional motor oil tech FACTS, by going to the Blog link below.

This Blog now has over 75,000 views worldwide. Of course simply listing the number of views by itself, is not intended to indicate validation of the test data (validation is shown throughout the Blog). But, indicating the number of views does show that an enormous number of people worldwide recognize the value, understand the importance, and make use of the motor oil test data FACTS included here, that cannot be found anywhere else. And as a result, they are posting and sharing links to this Blog, all over the world. See for yourself.

The Blog includes:

Section 1 – Motor Oil Wear Protection Ranking List

Section 2 – Motor Oil Viscosity Selection

Section 3 – Motor Oil Thermal Breakdown Test Data

Section 4 - Component Quantity Lab Test Results

http://540ratblog.wordpress.com/

 

I believe, without looking further, they have a much more favorable design using ; "buckets" or "followers", larger diameter camshafts and "buckets", they may very well have a much better oil supply beyond just splash oiling, plus lower spring pressures.

Our antique architecture has a very small and narrow lobe with small diameter lifters - (which must also rotate or they self destruct) , and we know about increasing spring pressures the higher the performance that the cam is !

You can design a very nice lobe profile if you'd have the size of a Oldsmobile .921" diameter flat tappet lifter, but the OHC engine designs have it all over them also !

 

Saying "The only thing that matters, is an oil's film strength, load carrying capacity." is ludicrous when the highest point seen in any of the testing before the film strength is broken is 115,000 PSI and a stock, mild flat tappet hydraulic cam sees loads in excess of 200,000 PSI. The ONLY thing preventing metal to metal contact at the lode/lifter interface is the thin phosphorous sacrificial layer deposited on the highly loaded surfaces after the film strength is broken and the ZDDP is sheared at that extreme pressure highly loaded contact point.

I am betting you had a lifter not rotating correctly from the start. If it was an oil issue why would one fail completely and the other 15 be perfect.

 

http://www.cylinderheadsupply.com/fl...fter-bore.html

 

Wow, what an excellent write up on this issue. I am in agreement with you on this part of the failure because this is the first time ever have I used Brad Penn oil. I have always always used Valvoline oils but was told the zinc is much lower than what is was a few years ago. I then decided to go with Brad Penn. I figured this would have helped but I am assuming it made it worse. Thank you for taking the time to write up this large amount of data. I am still so skeptical of going with a flat tappet now that this happened and I will be using roller next time but will be using my Valvoline oils again.

 

A great point here as well with only one lobe failure. I think partly that the oil had a role in this along with other things. The lifter might have quite rotating at some point but what would have caused this? They were spinning during initial break-in because this issue didn't happen until after the first oil change. The break-in oil looked really good after I drained it. The entire thing is just aggravating and wish none of it happened.