Flat tappet failure
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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.
Perhaps, but how much of it is due to information being shared worldwide due to technology? Do you know? I sure don't, but I promise you that's a factor.
you know what didn't exist in 1994 1/2? forums like these. so the dissemination of information is much more prevalent today that it ever has been.
that being said, if it was as endemic as people are making it out to be we'd be seeing posts about it weekly. and we aren't.
Exactly.
Hmmmmm, so explain all of the BBC's that didn't eat cams, with the same valves/springs/rocker ratios.......You are an ignoramus.......
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NC Engine Builder
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My experience has been its incorrect machining of the lifter faces. I resurface every flat tappet lifter I use, old or new out of the box.
71Demon540
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Here is what Reher Morrison said about flat tappet cams 20 years ago.
Tech Talk # 43 – The Trouble with Flat Tappets
Here is Powell machines on YouTube who gives lots of good info on today’s flat tappets
Tech Talk # 43 – The Trouble with Flat Tappets
Here is Powell machines on YouTube who gives lots of good info on today’s flat tappets
NC Engine Builder
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Here is a good example. Brand new out of the box, with a very light "touch off" pass, you can see the radius is off center. The lifter was fixtured crooked when it was manufactured
Scody21
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The dlc coating is not going to change the metal that the lifter is made of. The DLC coating will ware off. All it does is make the coated area a little more slick.
71Demon540
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It’s interesting to hear everyone’s different experiences with flat tappets. I have minimal experience with them. But this thread is my experience with them. A close friend of mine who I build a lot of cars with, and build transmissions with, he loves flat tappets. He got us a BBM street engine build and wanted my help. I told him I will only help if the guy is gonna spend the money on a hydraulic roller. If the guy wanted a flat tappet, solid or hydraulic, count me out.
Any engine that comes in my engine builders shop, if they want a flat tappet, he won’t accept their business.
Caveat. Im no expert, or engineer. Just a dummy who loves learning.
Any engine that comes in my engine builders shop, if they want a flat tappet, he won’t accept their business.
Caveat. Im no expert, or engineer. Just a dummy who loves learning.
furrystump
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I have been running comp EDM solids since 2010. Was worried the oil hole in the face would just get plugged up over time, but have been in there a bunch of times and they are always clear. If going flat tappet, I would do the EDM’s again. I run in the window that Dwayne outlined for spring pressures.
PRH
Well-Known Member
Looks like a Comp XE284, which is indeed a fast rate .842” design cam.
It’s a cam that I’d think of as pretty “unforgiving” in a high RR combo, especially one that was using .842” lifters.
The recommended springs are fairly mild duals, but if using those you’d have been wise to remove the inners for break in.
Thats all moot now…….there won’t be any issues with the new HR cam going flat.
That XE284 cam is actually available nitrided as a shelf cam.
I suspect that the nitrided version coupled with the DLC lifters would have resulted in a different outcome.
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NC Engine Builder
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I think you will find that price to be inaccurate. They will be over $100 bucks EACH. Sets of 16 are typically $1600-$1900
PRH
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There does seem to be confusion about the pricing on the new DLC FT offerings from Comp.
They are not priced like the coated or uncoated tool steel lifters(which are $100-ish each).
These new DLC coated Hyd lifters are indeed nominally priced at about $125/set.
https://www.compcams.com/dlc-hydrau...ler-applications-904-dia-310303016.html?gQT=1
They are not priced like the coated or uncoated tool steel lifters(which are $100-ish each).
These new DLC coated Hyd lifters are indeed nominally priced at about $125/set.
https://www.compcams.com/dlc-hydrau...ler-applications-904-dia-310303016.html?gQT=1
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Any failure reports out on the lifters with the oil hole through the center?
71Demon540
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They were actually single springs with a damper. And yes, Tim had talked to me about having my father in law getting one nitrided and DLC lifters. Obviously that didn’t happen lol
thank you for your input Dwayne. Much appreciated
PRH
Well-Known Member
Despite the findings from Powells that the cam & lifter hardness were rarely the “reason” behind a failure…….I still think it would be pretty interesting to know how those failed lifters fared on the hardness tester.
Check the link. You may be thinking of the tool steel dlc lifters like NASCAR was using. I can't speak to the quality or longevity as I have not tried them yet myself. But I have my ear to the ground on these.
Mods need to put the red x back in service
That was one of my birthdays, thanks for the memories
By the time dlc wears off the lifters should have been hardened by heat cycles
NC Engine Builder
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The thing that seems odd, is that price is cheaper than the junk hydraulic lifters they allready sell
ValiantRacing
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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.
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