Flat tappet failure

[71Demon540]

I have done more than 25 flat tappet cam break in's, the last 10 years, most of them Mopar but some of brand X, and no failures, the right oil, lube on cams and lifters, if its a dual springs i pull the inner out, and want i think is really important is the engine must start right away, no grinding on the starter trying to get to fire. If the spring pressure was to high that could be a big problem, and 1 more thing, i have not used anything Comp is 20 years i learned about that product and never again.

I respect the fact that there are lots of flat tappets out there. But you couldn’t pay me to put one in another engine, let alone my own engine.

For clarity, I’m not angry at what happened in my scenario. I knew it was a risk when we put it in. But at the time that’s what the budget allowed for. I remember thinking “millions run hydraulic flat tappets, it should be fine”. Well, famous last words lol.

 

[Ottmundr]

looks like the lifters were soft.

That is some serious wear for what sounds like less than full break in time.
What was the cam grind?

Here’s one after 1/2hr run time on the dyno.
Hylift Johnson lifter, Melling cam, SBC
The other 15 were perfect.

View attachment 1716416662

These days, FT cams in high rocker ratio big blocks seem to be particularly hard to get to live.
Slow, smooth lobe designs that will survive with pretty modest spring loads should help.
And you’ll more than likely need to break it in with very mild springs(solidly under 120/300).
I think solids with edm oiling have a better chance of surviving.

That's what i bought. Took a year to get them from Hughes too, which did not impress me. We'll see how they work when i get my little 360 put back together.
Getting married really kills an engine build budget.
Kills it DEAD IN IT'S TRACKS!

 

[Ottmundr]

Nuthin like a stout big Chebbie.

Nuthin like a stout big chubby...

 

[71Demon540]

That's what i bought. Took a year to get them from Hughes too, which did not impress me. We'll see how they work when i get my little 360 put back together.
Getting married really kills an engine build budget.
Kills it DEAD IN IT'S TRACKS!

Lmao

 

[Jeremiah (jd)]

That'll just buff-out?

JB Weld Steel and run it!

 

[Jeremiah (jd)]

I just checked comps website and the mopar dlc coated lifters are in stock now. I hope these flat tappet lifters are a solution for the problem with flat tappet failures. I have not tried them yet. They are priced reasonable. Comp seems to be all in on these lifters and it looks like they are available for most applications now. If anyone has any experience with the dlc coated lifters let us know please.

TAPPET, DLC HYDRAULIC FLAT TAPPET .904" DIA AMC & CHRYSLER APPLICATIONS SET 8 CYL - Set of 16 - COMP Cams® https://share.google/2awEYj2Af67SovNIC

$112/set is reasonable $$$ too. I'll be interested to see how these work out. Until then all of the lifters I use will have a roller on the bottom.

 

[RustyRatRod]

Nuthin like a stout big chubby...

View attachment 1716417369

Ewwwwww

 

[Cal Tonsley]

I can’t comment on current FT cam & lifter metallurgy & engineering beyond what I see online but I can comment on my experiences back in the 80s & 90s working in the high performance industry and specifically in my time working for the Crane Cams distributors here in Australia. Even back then, cam lobe and lifter wiping was definitely an issue for a number of customers. Good engine building and run in practices were always employed by everyone else. This included proper run in procedure, zero mechanical interferences, correct spring pressures (including removal of inner springs during run in), identifying and correcting lifter rotation issues by the retruing of lifter bores & using the right oils / assembly lubes.
FWIW, we’d regularly test failed cams / lifters and I’d never seen any parts from that era fail a Rockwell test so I wonder how they’d fare now? While there definitely appears to be a big question mark regarding the quality of current day parts I do also think that as Rusty said, this can now be amplified greatly across the world by the use of social media and online forums.

 

[Bewy]

Chrys foresaw the problems that could arise from high spring pressures & tried to do something about it with the 440 6bbl & Hemi engines. The cam taper was less with these engines & the lifter radius was greater; result was more contact area between lobe & lifter to reduce wear.

 

[Bewy]

To that dope Killer 6: I never said BB Chevs didn't eat cams, just the opposite in fact. I said the reason was NOT because of lifter bore alignment, which is what you claimed in post #7.

 

[Bewy]

For those interested, you should go the Small Block section of this website & see what Engle, of Engle cams says about today's lifters: huge problems

 

[Cal Tonsley]

Chrys foresaw the problems that could arise from high spring pressures & tried to do something about it with the 440 6bbl & Hemi engines. The cam taper was less with these engines & the lifter radius was greater; result was more contact area between lobe & lifter to reduce wear.

That’s interesting given that NASCAR flat tappet cams in the 90s were employing more taper (>.002”) to promote lifter rotation with high spring pressures!

 

[RustyRatRod]

That’s interesting given that NASCAR flat tappet cams in the 90s were employing more taper (>.002”) to promote lifter rotation with high spring pressures!

I've read two differing versions for the low taper reason. One is as our friend Bewy says for reduced wear. The other is to pick up some extra power and torque from reduced friction. Perhaps a little of both? Remember, the Six Pack and Six Barrel engines were rated at 490 FT LB of tourqe at 3200, while the Hemi was the same, but at 4000. Who knows?

 

[71Demon540]

That’s interesting given that NASCAR flat tappet cams in the 90s were employing more taper (>.002”) to promote lifter rotation with high spring pressures!

Ya nascar is a whole other ball game from what I understand.

 

[Sr4440]

How much is that to get new lifters rebuilt and resurfaced? Is it cost effective?

$3.25 each Rebuilt lifters - classic cars, trucks, agricultural, Industrial - Mizpah Precision Manufacturing

 

[mopowers]

$3.25 each Rebuilt lifters - classic cars, trucks, agricultural, Industrial - Mizpah Precision Manufacturing

And that's for a roller lifter. I wonder what they do to rebuild a used roller lifter. Their list says $3.00 for a non-magnum lifter. I assume that means "flat tappet?"

 

[Killer6]

To that dope Killer 6: I never said BB Chevs didn't eat cams, just the opposite in fact. I said the reason was NOT because of lifter bore alignment, which is what you claimed in post #7.

And You are still wrong, w/a serious reading comprehension deficiency....

 

[fishmens67]

I believe too much spring pressure and the recommended varying rpm kills them.
Sig recommended a constant rpm back in the day 2000rpm was the sweet spot.

 

[junkyardhero]

And You are still wrong, w/a serious reading comprehension deficiency....

don't even bother, it's like trying to have an intelligent conversation with a brick wall only with less personality and a highlighting problem.

dude lives in the upside down world. i mean who picks an arbitrary year as "the year lifters went bad"?

clown shoes MF'ers, that's who.

 

[Killer6]

don't even bother, it's like trying to have an intelligent conversation with a brick wall only with less personality and a highlighting problem.

dude lives in the upside down world. i mean who picks an arbitrary year as "the year lifters went bad"?

clown shoes MF'ers, that's who.

Lol, I was going to post a link to a Lifter Tru fixture some posts ago, but -F- it........today, with a lot of CNC machines out there, the only ones using those fixtures are the old school guys who've been using 'em. In My limited Chevy-Guy sphere, they have all been 396's, the couple of guys running 454's w/tunnel rams & big sticks did not have a fail over the time I knew them......yellow/black '68 SS/RS mini-tubbed & '70 Nova.

 

[RustyRatRod]

I believe too much spring pressure and the recommended varying rpm kills them.
Sig recommended a constant rpm back in the day 2000rpm was the sweet spot.

I'm sure you've seen the opening scene in Christine. THAT'S how they used to start new cars back then. Bust um off, a few revs to the redline and park um out back.

 

[Bewy]

Hero,
I would try & explain it to you but you are too IQ compromised....

 

[junkyardhero]

Hero,
I would try & explain it to you but you are too IQ compromised....

IQ compromised? that's what you're coming with? mister selective reading over here trying to be cute.

i asked for sources in post #27, which... *gasp* crickets, as per usual from you.

but here, i'll quote it for you:

explain to me the reasoning for the specific year and how it's not totally arbitrary.

please cite any sources you have and present any data that may be pertinent.

so for the edification of those following along, please enthrall us with your selective reasoning on the matter.

present data, display facts, produce evidence. and be sure to cite sources. highlighting is optional.

i'm not expecting much, so please don't let me down here.

 

[Bewy]

Here is as clue: maybe you have noticed lifters are not date stamped....

You must lead a boring, lonely life....to follow me around on this forum.

 

[junkyardhero]

Here is as clue: maybe you have noticed lifters are not date stamped....

You must lead a boring, lonely life....to follow me around on this forum.

you're the one that put a date on it. so i guess we can add selective memory to your list now too.

as usual, you've got nothing to back up your wild assertations and you fall back on name calling and *waves hands around* whatever this is.

ohhh... i'm lonely because i followed up on your malarkey? ohhh... i'm boring for the lone reason that i want to hold somebody accountable for spreading misinformation?

so again, where's the proof? where's the data? you know those niggling little details like facts and evidence?

what happened did your highlighters dry up?

as always, you never fail to disappoint.