View Full Version : Valve Train Failure

06-13-2008, 07:47 PM
My lifters and cam are shot after less than 6000 miles. All precautions were taken. I will get to the bottom of this. One or the other I think is soft. The right oil was used. No valve noise was present, 3 lifters were not spinning, however, the worst lifters were. The ones that were not spinning are some of the least damaged ones. I intend to have cam and lifters Rockwell tested, and then, I'll take legal action, if necessary, if either is soft. If neither is soft, I will look at the valve springs, which are supposed to be stock.

06-13-2008, 07:59 PM
What cam was it? What lifters? Do you have cam bearings? What rocker and what ratio?

My questions are only to get a feel for your set up.

06-13-2008, 08:20 PM
Well, I will talk about who's later. The cam supplier has backed off his earlier statements. It appears that the lifters are the problem, as some of the damaged lifters do not appear to have damaged the cam, indicating the lifter most likely failed first. As for the rockers, they are stock, along with the valve springs. As for the cam bearings, what does that have to do with lifters and lobe being torn up? Rockwell testing will tell the story.

06-13-2008, 08:52 PM
That stinks a whole lot! Sorry to hear about your problem. I hope that you get to the bottom of it and that Graham and I don't have the same cam and lifters.

06-13-2008, 09:38 PM
I feel your pain SearcherMan. I had a set of soft lifters start to fall apart with less than 1000 miles. Camshaft was not damaged at all. So far the new, supposedly hardened lifters, have lasted about 3k miles. They were all still spinning when I looked for you the other night. Its still a nagging worry in the back of my mind though.

Just after the new century mark there was a rash of soft lifter as US companies stopped making solid lifters and all the manufacturing was shipped to the pacific rim. It took about three years for US companies to get back into production. The largest market affected was the Hot Rod V8 crowd but our lifters were equally affected. It would have been nice if suppliers would have junked all the soft stuff, absorbed the loss and started over but they didn't.

Good luck with any legal action. I don't think you'll get far and it could end up costing you more than sucking it up. No malice meant by that statement either. Go for it if you really want to. The most you can probably get are new lifters. Which may or may not still be too soft.

06-13-2008, 11:15 PM
Thanks for your concern. I have received new lifters from BPNW, they are in a sealed package, AE brand. I have never got anything with AE on it that was not first class. I have also got a new cam, CP, 150 HP, from BPNW, Neumann brand. Swift, who's lifters do you have now? I will most likely cleanup tomorrow, and then start putting it back together. As I said above, some of the lifters that are just starting to fail, there is no damage to cam. In fact, the only visual damage is to the 2 worst lifters. I will call the supplier tomorrow. What really upsets me, I remember the conversation, "I have a few more sets from the original manufacturer, after these are gone, they aren't going to make anymore", and I paid almost twice as much. Who's lifters came apart on you Swift?

06-14-2008, 04:11 AM
It's deja vu all over again.

06-14-2008, 07:14 AM
What were the symptoms? How did you know things were going bad? Now I am getting worried, hate to pull the engine apart the middle of touring season.

06-14-2008, 11:41 AM
3 Lifters/pushrods not spinning while engine idling.

06-14-2008, 11:50 AM
3 Lifters/pushrods not spinning while engine idling.

Interesting... Though, as you said, "3 lifters were not spinning, however, the worst lifters were. The ones that were not spinning are some of the least damaged ones."

06-14-2008, 11:53 AM
Swift, who's lifters do you have now?

Who's lifters came apart on you Swift?

I have AE's now, the ones that failed were from Moss. Bought in 2000, right in the midst of the 'soft lifter invasion'. I've seen three other failures from lifters in engines built around the same time. A few wiped out the cams as well. One or two lobes on the cam damaged but 8-9 out of 12 lifters showing failure. The lifters related to the failed lobes were the worst.

Moss knew about all the failures, they appreciated the feedback and offered replacements but I sourced parts from elsewhere. Probably why Moss is now offering the new hardened lifter set. Soft lifters were an industry wide problem for a while. Its taken some time to re-adjust and replace those already in the supply line.

As much as you'd like to blame the suppliers, it's really not their fault. They ask for items made to correct specifications, strive for the lowest price, and don't know the stuff is sub-standard until it starts to fail and we as consumers tell them about it. If they attempt more stringent quality control the prices can go way up and then the consumers complain about prices. For every one person who tells them that they would be happy to pay higher prices for quality parts, there are ten that complain about high prices. It sucks at times but is the game we have to play. In the small world of LBC parts it's sort of a co-operative between consumers and suppliers.

The big cam companies that were still attaching their names and reputations to the sub-standard parts are the ones that were hurt the most and brought some of the manufacturing back here and raised the quality control. The companies like Erson, Crane, Lunati, etc... with huge distributors like PAW, Summit and Jegs make our LBC community look frightfully small.

06-14-2008, 12:03 PM
3 Lifters/pushrods not spinning while engine idling.

Interesting... Not surprising, really. Having the lifters turn just optimizes their life, kind of like rotating your tires. Even with the lifter not turning, it should last 50,000 miles or more. But turning is no panacea against early failure due to other factors (like soft lifters).

I'm curious though, did "all precautions" included running the engine at fast idle (no revving) as soon as it fired, for about 15 minutes ?

Also, I assume you used plenty of assembly lube on the lobes & lifters, but was it a moly-based lube ?

06-14-2008, 12:24 PM
Yes, Yes, Yes, Yes. Now, get a load of this, I put both the cam I just received next to the one I just removed. Boy, what at shocker, the lobes are in such different locations. I put the new cam in the engine. The lobes are all over the place. Example, one lobe mite be centered on the lifter bore, some others toward the front of the engine in regards to the lifter bore, however, some lobes, the edge of the lobe is centered in regards to the lifter bore. This cannot be correct, so, it goes back to the supplier. Now, I called the motherland, there is a cam blank problem. I was going to order one of theirs, they said they were out. One has to wonder are they out, or, do they know I will check the lobe location and they don't want to sell to me? They did say I would be better off with a regrind, as long as I used an original factory profile. Richard indicated a week or so ago, he was aware of the lobe location problem, now he has backed off of that statement. We can talk about motor oil all we want to, but, its a combination of errors, lobe location, soft lifters, higher lift, spring tension. Once again, I think Rockwell testing will tell the story on the lifers, and camshaft. If there is no accoutability, what incentive do suppliers have to sell acceptable parts?

06-14-2008, 12:46 PM
As much as you'd like to blame the suppliers, it's really not their fault. They ask for items made to correct specifications, strive for the lowest price, and don't know the stuff is sub-standard until it starts to fail and we as consumers tell them about it. True enough; but then why does it take YEARS between when people start to complain, and the vendor actually does something ?

Answer : Because they buy the stuff in bulk, and unless the return rate reaches 50% or so, it's cheaper to sell the defective goods and take the returns. And given the way most LBC folk operate, the return rates almost never get that high. Lots of people won't bother to try to return a defective part (especially in a case like this, where it's not clear which part was defective). Plus I've got parts I bought 20 years ago and haven't installed yet !

Not picking on any particular vendor, just stating the situation as I see it. We went through the same thing with synchro rings a few years back; someone had a huge lot of them made that didn't work very well. But since no one could apparently identify the exact problem, and most of the rings worked well enough, the defective rings continued to be sold until the lot (I heard it was 100,000 rings) was gone.

At least with lifters, we know what to look for.

06-14-2008, 12:49 PM
As I understand it, the lobes are supposed to be off-center to the bores, to encourage the lifter to turn; and not all in the same direction (to reduce force along the camshaft axis). But I can't say I've checked that.

06-14-2008, 01:30 PM
I used the lifters from BPNW part number CF339BT with the oil drain holes, I've only got 300 miles on them yet so not sure how they will stand up. Tthis is what BPNW say about them.

"These are Heavy Duty Tappets for a TR250-6, Spitfire 67-80, 1500 Midget. They are tuftrided for long life and heavy duty use. Every batch of tappets are tested when they arrive from the UK. Each tappet will have a minimum hardness of Rockwell 58. The industry standard is 50 for tappets. We have never had a bad batch of tappets like other companies and never will because of our dedication to dealing with only quality suppliers."

06-14-2008, 03:25 PM
Those are the ones I'm using in my rebuild -- except, of course, they're the ones for TR3/4. I sure hope they're as good as BPNW says. It'll probably be another 1 - 2 months before I can fire it up...

06-14-2008, 03:46 PM
this is why I am very reluctant to rebuild the engine in My TR6 so as long as it doesnt burn oil or smoke like my grand father, I think I will leave well enough alone


06-14-2008, 04:59 PM
this is why I am very reluctant to rebuild the engine in My TR6 so as long as it doesnt burn oil or smoke like my grand father, I think I will leave well enough alone


<span style="color: #990000">I am with you Hondo.
I will be ever so happy if my stock engine quits
breaking down all the time. </span>

06-14-2008, 05:01 PM
Well, I got burned on the sychro ring deal also, had to do the trans all over again. However, I don't see how the lobes being where they are now will work for long term. I mean, 2 lobes, the edge of the lobe is in the center of the lifter bore. Another one, the lobe is centered. This can't be right. And, the suppliers, at least some of them, they know about the lobe problem. The problem I have now is where to get a cam. I'd like to have the measurements on a stanpart cam.

06-14-2008, 05:43 PM
I know....I say it over and over again but I still insist that the domed lifter surface is the cause of the cam failures.
Since I grind my lifters dead flat all cam problems disappeared.
The good thing, you can reuse old lifters after grinding.
When a lot grinding is needed to get a good surface then hardening is needed too.


06-14-2008, 05:52 PM
This can't be right.:iagree:

06-14-2008, 07:20 PM
As much as you'd like to blame the suppliers, it's really not their fault.

Gee, let me get out my hankerchief because I think I'm going to start crying for poor unfortunate Moss, et al. :cry: Hey, these guys are businessmen, and if they know something is wrong, they should notify customers. In recent years I have purchased and received lots of crap parts from all of the big three. So, I'm not singling out Moss. I have been fortunate that the defects have been quite obvious, (remember the TR-3 fan with the loose rivets). Not so with critical engine components. Unless you have access to metallurgical testing (which can be expensive) you would never know until you had the unfortunate incident reported here.

Good luck!

06-14-2008, 08:12 PM
But then you could argue caveat emptor - I bought lifters that were hardness tested for just that reason.

They cost quite a bit more, but then you get what you pay for...

That said, I wouldn't wish a messed up cam on anyone.

Dave Russell
06-14-2008, 11:29 PM
With most flat tappet cams, the lobes are ground with a very slight fore-aft taper, around 0.002". The lifters are slightly domed. Usually the lifter centers are slightly offset from cam lobe centers. Lifters should have around 0.002" clearance in their bores.

This all works together to promote lifter rotation which distributes the pressure &amp; wear over the entire lifter &amp; cam lobe surfaces.

A flat bottom lifter on a tapered cam lobe would only contact the lobe on the highest portion of it's taper. Contact pressures would be high but the lifter would rotate &amp; work if the parts are hard enough.

A nontapered lobe with a non domed lifter would still have the desirable rotation if the lifter centers were offset &amp; lifter diameters were larger than cam lobe width. ALA mushroom lifters. Old Ford flatheads, maybe some others.

The original engine designers were careful to get a combination of these variables which would give long cam &amp; lifter life.

After market cams &amp; lifters may or may not be correctly designed &amp; manufactured to work together &amp; be optimum.

This is in addition to having correct cam &amp; lifter hardness. Most good shops have a hardness tester with which they can easily check hardness on the Rockwell "C" scale. I personally never install a cam &amp; lifters unless they measure RC55 or greater. It's important to check ALL lobes &amp; ALL lifters. A lot of the aftermarket parts won't pass this test. Don't take the seller's word for it.

Lifters should have about 0.002" clearance in their bores. Check for free rotation &amp; free vertical travel before assembling the rest of the engine. If the lifters don't have enough clearance, hone the lifter bores.

When you first fire a new engine for cam break in, observe all pushrods for rotation. If some are not rotating, a push with your finger to start rotation will usually do the trick. Sometimes several pushes will be needed. If any still refuse to rotate, there is no use in continuing to run the engine. Pull it down as far as needed &amp; correct the problem.

I would check for rotation frequently during the first hours of engine operation. No need to mention proper cam &amp; lifter lube during assembly &amp; using an oil &amp; or additive with sufficient ZDDP.

Just some observations from an old guy who has been building all types of race engines for 55 years.

06-15-2008, 04:56 PM
Hi Dave,

what you write is an absolute perfect explanation of several cam and lifter designs.

I have cams from about 4 manufacturers here and non of them has a tapered lobe. They are parallel to the shaft axis.

But all lifters you can buy has a very high dome.
End of story is, that the lifters don't rotate properly on most of the cams.

I have NOS lifters from Standard Triumph and they are dead flat. So I started year 2006, after several cam failures, to regrind the lifters to a flat surface.

The best tuning I ever did to that engine.

Chris (who has done today some suspension setup tests on the autobahn crossing)

06-15-2008, 07:18 PM
Interesting Chris, some have told me I am wrong but the ones I got from Goodparts were flat. I could actually wring them together like precision gage blocks. Machinists will know what that means.

06-15-2008, 08:15 PM
MadMarx, it is my understanding, TR6 lifters and cam were flat and not tapered. I would like to know, the 4 cams you have, if you put them side by side, do the lobes line up? The lobe location is what make the lifters spin in a TR6.

06-16-2008, 09:15 AM
The lobe is offset to the lifter bore at a 4 engine.

06-16-2008, 04:30 PM
Thats the problem, the 2 new cams I have, some do not appear to be offset, most are, some way more than others. If you put the 4 cams you said you had, side by side, do the lobes line up?

06-16-2008, 04:33 PM
FYI MadMarx is talking about 4-cylinder cams, not 6 cylinder cams, two seperate families of engines (and not just in cylinder count) so I am not sure how accurate the info from one would be to the other. It might be, but it might not.