Hot Rodders - The death of the flat tappet cam.

[DuckRyder]

News coming out of PRI Show is that the last remaining supplier of cast cam cores will discontinue production.

This means that unless and until a replacement supplier arises, there wont be any flat tappet cams unless you want to have one ground on a billet core ($$$ might as well go roller)

 

[supton]

For some reason, when I hear "flat tappet" I think of the non-hydraulic lifters. But this is really for both, any flat tappet/lifter that doesn't have a roller, right? hydraulic or otherwise?

Nobody else is casting? They just went out of business, one by one? I thought Comp Cams, Edelbrock, Isky, Crane... way more others... were still in business? Just slowly moving towards being "foundry-less" in operation over these years?

 

[OVERKILL]

For some reason, when I hear "flat tappet" I think of the non-hydraulic lifters. But this is really for both, any flat tappet/lifter that doesn't have a roller, right? hydraulic or otherwise?

Nobody else is casting? They just went out of business, one by one? I thought Comp Cams, Edelbrock, Isky, Crane... way more others... were still in business? Just slowly moving towards being "foundry-less" in operation over these years?

It's the cores, not the grinders. Cast cores have gone the way of the Dodo. The last cam I ordered was on a billet core (and was roller).

 

[RDY4WAR]

Comp, Edelbrock, Isky, Bullet, etc... don't make cam cores. They buy the blank cores and grind them to the desired profile.

Flat tappet cams/lifters can be solid or hydraulic. The same for roller cams.

This will have a big impact on sportsman racing where many classes require engines be true to era. Many NHRA stock eliminator engines have flat tappet cams. The same for stocker oval track engines.

 

[supton]

Solid, that was the term I was forgetting, thanks.

 

[DuckRyder]

Yup it's the Cores Texton CMC was the last outfit and they sold under 2 names they would sell anything from a blank to a finished cam to the customers specs (not one offs, like to Summit or Jegs or Melling and such.) Word is they got a large OE contract and need the resources...

And yes Solid and hydraulic flat tappets. Gonna be a problem for classes that require flat tappet, everyone else i guess will go roller.

Assuming its true, but ive herd it from enough sources i'm pretty confident it is, also explains why a lot of stuff is going "not available" ...

 

[Jetronic]

News coming out of PRI Show is that the last remaining supplier of cast cam cores will discontinue production.

This means that unless and until a replacement supplier arises, there wont be any flat tappet cams unless you want to have one ground on a billet core ($$$ might as well go roller)

you can go more agressive profile with a flat tappet cam, so if a build is that advanced I'm sure the money can be found.

 

[Astro14]

you can go more agressive profile with a flat tappet cam, so if a build is that advanced I'm sure the money can be found.

I thought it was the opposite. Rollers allow a steeper profile.

 

[Jetronic]

I thought it was the opposite. Rollers allow a steeper profile.

no once you go too steep, the force is acting sideways on the roller. the flat tappet always gets hit on top.

 

[Astro14]

no once you go too steep, the force is acting sideways on the roller. the flat tappet always gets hit on top.

Why is that not the case with the flat base of a flat tappet, either hydraulic or solid?

I guess I would need to see a picture - I suppose that the "foot" of the flat tappet is only moved in the vertical direction, though with steeper profiles, the sliding friction goes way up...

 

[Jetronic]

Why is that not the case with the flat base of a flat tappet, either hydraulic or solid?

I guess I would need to see a picture - I suppose that the "foot" of the flat tappet is only moved in the vertical direction, though with steeper profiles, the sliding friction goes way up...

yes friction goes up.

I can do better, there's a video about it from David Vizard.

i think it's this one:

 

[DuckRyder]

it's possible, it's also difficult to directly compare without a cam doctor because the contact patch on a roller is a straight line and the contact patch of a flat tappet is not (is a semi circle..)

Lots of talk about this sort of thing as a result to the cam challenge. if interested check out Daniel Powell (Powell cams/Powell machine) Bent Lykins (Lykins Motorsports), Brian Salter and others on tube of you.

But the vast majority of flat tappet cams sold are street cams, to make one faster than a roller your talking expenseive stuff like ceramic lifters and DLC coated cams and that's assuming you are even able to control the valves at the velocity. (more high dollar stuff.)

Id say it's an extraordinarily small sample of people wha are going flat tappet because it can be faster. One place this would come into play is something like an NHRA Class that required "stock lift and duration" where they want to get the valve open to the "stock lift" and keep it there as long as possible...

Super fast is not really what you want on something other than a race car it is hard on parts ...

 

[JeffKeryk]

you can go more agressive profile with a flat tappet cam, so if a build is that advanced I'm sure the money can be found.

Much faster ramps on the roller. More area under the curve for a given lift and duration.

 

[chainblu]

I already own the next 3 (maybe 4) cams I have planned for my next builds. What I'm hearing in other groups is that there have been some quality issues with lifters coming from 'overseas'. Hopefully we won't be seeing this with the cam cores in the future.

 

[Astro14]

Much faster ramps on the roller. More area under the curve for a given lift and duration.

That was my understanding, too, but the last time I bought a cam was, well, about 1988, and it was a Competition Cams 252 for an Olds 350…

Flat tappet of course. The block was a 1970, and the engine in a 1977.

 

[marc1]

If you want to read about the company, history and process:

https://www.kautex.com/en/mobility/cwc-textron-castings

Writing has been on the wall for about 2 or 3 years now sadly. I have a limited and small inventory and have already given up cams to friends in need etc. I can't predict what cars I am going to own in the coming years so I don't know what to stock up on. For example; I was medium serious about buying an AMC Javelin just recently, I have never owned an AMC and I have nothing in inventory for AMCs. One thing I stopped doing a while ago is getting rid of good condition used cam and lifter sets. I now keep all my used cams with the matched lifter set. I have let go of a ton of OE vintage classic grinds and aftermarket (Crane, Comp, General Kinetics, etc.) classics and modern upgrades in my time, both new and good used, that I would give anything have back now facing this new challenge. The $50 - $75 I got at the swaps meets isn't worth it now. To be clear, this post pertains to older American V8 muscle car engines. I do not know the state of parts on the newer domestic engines eg. LS series, Coyote etc.

 

[Tman220]

Lets not fool ourselves. Roller lifters can handle a much more aggressive lobe profile. A roller cam/lifter combo will lift the valve quicker, keep it open longer, all with less friction.

The key to making power is getting as much air in as possible in the precious few milli seconds the valve is actually open.


I run a hydraulic roller cam/lifter combo in my 355 CI Lt1 for the camaro, duration at .050" is 228 int / 234 Exh. it has .617" lift both intake and exhaust it's on a LSA of 108 degrees.

It makes enough vacuum at 825 rpm to run the brakes and hvac doors. It makes great low end power, makes peak power at about 6500 and maintains it all the way out to the 7000 rpm limitation of the stock PCM. It's basically a stock sbc (lt1) with ported stock heads good for 500 hp (430 wheel) These are good numbers for this engine configuration. Not possible with flat tappet components while still making power across the whole rpm range.

 

[DuckRyder]

and it was a Competition Cams 252 for an Olds 350…

That's a relatively tiny cam and an ancient design its probably a "lazy" lobe.

Theing to remember about flat tappets is they aren't actually "flat". the bottoms of the lifters are crowned and the cam lobes are tapered this is what causes the lifters to rotate.

This thread drift on Faster fast tappets is a bit of a theory vs reality thing. In theory it is possible, in reality its a very small subset of people trying to do it and they are doing it for some reason like a class rule...

The lack of cast cores is going to affect precisely the cams like your Comp 252..

Also i think it was golds garage that did a comparison of a regular cam and a cam for a super stock or something.

 

[Astro14]

That's a relatively tiny cam and an ancient design its probably a "lazy" lobe.

Theing to remember about flat tappets is they aren't actually "flat". the bottoms of the lifters are crowned and the cam lobes are tapered this is what causes the lifters to rotate.

This thread drift on Faster fast tappets is a bit of a theory vs reality thing. In theory it is possible, in reality its a very small subset of people trying to do it and they are doing it for some reason like a class rule...

The lack of cast cores is going to affect precisely the cams like your Comp 252..

Also i think it was golds garage that did a comparison of a regular cam and a cam for a super stock or something.

Absolutely it was a mild cam. The car had a turbo Hydro Matic 400, stock converter, and relatively tall rear end at 273. A cam with more lift and duration would not have been the right fit. That cam was just about perfect. The torque curve created by that cam match the weight, gearing, and stall speed perfectly.

 

[CheezWhiz]

thought i read somewhere that a flat tappet could accelerate the valve faster just off the base circle but after that the roller has it hands down.