[adynes]

Hylift-Johnson's opinion on preload: (see attachment)

According to them, impact forces in short travel hydraulic lifters can reduce roller bearing life up to 70%

I wonder if flat tappets are similarly effected. It's too bad they no longer offer the S lifter for pontiac.

[DiamondJim]

For street/strip performance I’m partial to solid flat tappet cams, specifically those designed by Harold Brookshire. The man flat knew his stuff. A solid lifter is lighter and you know what your getting.

[Cliff R]

"According to them, impact forces in short travel hydraulic lifters can reduce roller bearing life up to 70%

I wonder if flat tappets are similarly effected."

IF the lifters are well made with consistent bleed-down rates they will NOT "hammer" the valve train at all. Matter of fact they will provide a mild "shock absorber" instead as they use fluid (oil trapped under the plungers) instead of metal to metal contact.

The problem we've been seeing in the past 15 years or so relates to poor quality and construction. Inconsistent bleed down rates resulting from poor plunger to body tolerances are the main problem. This is NOT just an "offshore" product problem. I know several engine builder who will NOT use Morel HR lifters because the leak down rates are all over the map with them.

As it relates to this topic for those of you that have Harley Davison twin cam motorcyles they went to Delphi lifters back around 2002 to save money. The Delphi lifters obviously work OK, but are noisy. Companies actually started making "rocker locker" to help combat the noise those engines make in the valve train. The real cure is to order a set of Hylift Johnson direct shot roller tappets and replace the Dephi lifters. I've done exactly that here more times than I can count with perfect results. The Hylifts are much slower bleed down rates and very consistent so they quiet things down considerably vs the stock HD tappets...FWIW.

Anyhow, IF you bought a set of "slow bleed" lifters, for example, and ALL of them were apprx 120 seconds to bleed down then they will pretty much function like solid tappets with the only loss of lift/duration being very slight with each cycle. Since oil is used instead of metal to metal contact it becomes your "shock absorber" on the up cycle of the lifter.

Even a fast bleed lifter, like Rhoads does an EXCELLENT job in cushioning between the tappet and the everything above it and would especially at low RPM's when the fast bleed down rates allow the plungers to take both lift and duration away from the cam profile.

I actually dyno tested Rhoads lifters back to back with HT-951 lifters around 2004 just to see if we lost any power with a "fast-bleed" design. There was no power loss whatsoever and they actually showed a very slight improvement past 5000rpms showing them to be an excellent "high RPM" part. What we did see on the dyno was a solid improvement of 2" vacuum at 750rpm's over stock lifters and noticeably improved throttle response right off idle. We even tightened up the dyno brake to record at lower RPM's and they pulls were still the same, clearly showing that Rhoads lifters are FULLY pumped up by at least 2500rpm's.

Common sense would tell you that anyhow because the slight "clicking" sound from them bleeding off at low RPM's disappears by 2000rpm's or so......FWIW.......Cliff

[Formulas]

The interesting thing about Rhoads lifters is

If the camshaft selected for your engine comes in at the same time the lifters reach full action the start of the power band is VERY noticeable it's like combining two steps at once

The best experience I had with them was on a HC-03 cam 440 cubes #48 heads I was young at the time (1982) didn't realize I did not need them because compression was up there but the lifters and that cam came in at almost the exact same time

[Cliff R]

I ran my first 455 with and without Rhoads lifters. It was part of the testing I did with them. Since my converter flashes to 3600rpms there wasn't any improvement waiting for me at the track since the cycles per second doesn't allow them any more bleed-down that standard lifters at that point.

What I did see was 2" improvement in vacuum at idle speed, and noticeably improved throttle response/power right off idle for "normal" driving. The engine was basically "tamed" slightly, making it act like I put a smaller cam in it for "normal" driving then the same power at WOT. So we do get "variable valve timing" like many modern engines with a pretty simple and inexpensive system.

At that time I was running the Crower 60919 cam, specs out at 304/314/ 231/240@ .050" and 113LSA. I was also using 1.73 ratio rocker arms on it. The engine made 455.4hp with 6X heads and 494hp with KRE's on it. I ran it with the flat cam with both sets of heads for quite a few years and logged a LOT of street miles and track runs with it.

I did NOT experience a lot of noise at idle, even with the engine fully warmed up and heat soaked. The "clicking" at idle was barely noticed with the hood closed. At that time I was using Rotella 15W-40 weight oil.

A few years later I moved on to roller cams in both that engine and the current 455. I used HR lifters in the first one and Crower HIPPO's in the current engine and had no noise or problems with either one of the. The HR engine was RPM limited but it was WAY above the shift point or where the engine was making best power so really not an issue. I never once experienced any sort of RPM limiter with the flat cam topped with Rhoads lifters or the current HR cam topped with HIPPO"s.....Cliff

[Jay S]

When I was about 7 my brother and I both remember riding with my Dad in a 69 Ford pickup chasing down cattle that got out of their pen. One rogue cow got out in the middle of a plowed field, the Ford truck right on its tail with the 360 at full steam screaming across the feild trying to chasing the lone crazy cow. As I remember Dad almost had the cow pointed back the right direction when all of a sudden the engine pulled down a little then it was like the key was shut off, and cow got away. Lol. We asked Dad what happened, frustrated he replied the lifters pumped from floating the valves and made the engine shut down. He waited about a couple minutes, it fired back up and got back on the cows trail.... If he would have had the lifters set at the top of the preload the story would have ended differently. Having the lifters set with almost no preload is the only setting that could have changed the outcome.

The only down side to running the lifter preload at the bottom of the preload is if you do happen to float the valves it has potential to go full stroke and have some valve to pistons clearance problems. Probably less likely to happen with higher bleed rates. The OEM lifters that have longer bleed rates would likely have more risk than a higher rpm lifter and a faster bleed rate.


I know of a builder that has “S” hylift Johnson lifters special made for .904” flat tappets, never seen them for .842” lifters.

The “S” rollers are rock stars to a certain point and then the dyno graph seems to get wonky because the plunger seems to have to much pressure on it and can not control the valves. At least I assume that is what is going on. High rpms the short travel set ups seem to be the best. Short travel sound great until you see the 70% decrease in the service life. Lol

I was not aware Hylift quit making the “S” hyd roller. I thought Hylift has not made any Pontiac lifters for awhile mostly becuase there production line was behind.

[Formulajones]

Originally Posted by DiamondJim

For street/strip performance I’m partial to solid flat tappet cams, specifically those designed by Harold Brookshire. The man flat knew his stuff. A solid lifter is lighter and you know what your getting.

I'm a solid flat tappet fan too. I nitrided the last one and run a lifter with oiling for the lobe. No worries. And with the right lobe and tight lash, they actually run pretty damn quiet. I can't even hear it with the hood shut standing next to the car.

The other car here with a solid flat tappet is a very old Isky grind from the late 60's with I think .026 lash or there about. It's a little noisier but nothing I'd call obnoxious. If you stand outside the car with the hood shut and try to listen for it, you'll notice it. Sitting in the car you can't here it at all.

[DiamondJim]

Originally Posted by Formulajones

I'm a solid flat tappet fan too. I nitrided the last one and run a lifter with oiling for the lobe. No worries. And with the right lobe and tight lash, they actually run pretty damn quiet. I can't even hear it with the hood shut standing next to the car.

The other car here with a solid flat tappet is a very old Isky grind from the late 60's with I think .026 lash or there about. It's a little noisier but nothing I'd call obnoxious. If you stand outside the car with the hood shut and try to listen for it, you'll notice it. Sitting in the car you can't here it at all.

All of these adjustments of hydraulic lifters seems to me that their goal is to make the hydraulic lifter function more like a solid. . Why not just run a solid? Lifters are lighter and very few problems.

[Formulajones]

Originally Posted by DiamondJim

All of these adjustments of hydraulic lifters seems to me that their goal is to make the hydraulic lifter function more like a solid. . Why not just run a solid? Lifters are lighter and very few problems.

I hear ya. I think people are afraid of the old rumors of needing valve adjustments all the time, and they are afraid of noise.

Thing is though with a good rocker setup and good parts, periodic valve adjustments are pretty much a thing of the past. I daily drive one with a solid flat tappet and the only thing I've done is take a few minutes to check the lash once a year. It hasn't changed in 5 years and more than 40k miles.

The noise thing, well like I mentioned the modern profiles and tight lashes hardly make any noise. As we get older we don't hear as well anyway Put some hood insulation on the darn thing like it's supposed to have, and turn the radio up

[JLMounce]

Originally Posted by Formulajones

I hear ya. I think people are afraid of the old rumors of needing valve adjustments all the time, and they are afraid of noise.

Thing is though with a good rocker setup and good parts, periodic valve adjustments are pretty much a thing of the past. I daily drive one with a solid flat tappet and the only thing I've done is take a few minutes to check the lash once a year. It hasn't changed in 5 years and more than 40k miles.

The noise thing, well like I mentioned the modern profiles and tight lashes hardly make any noise. As we get older we don't hear as well anyway Put some hood insulation on the darn thing like it's supposed to have, and turn the radio up

I'm not so concerned with the noise. Well I am, but that's more of an issue that my current valvetrain with the Lunati lifters is exceedingly noisy.

My worry has always been longevity and reliability of parts in a street driven application. Is your 40K mile solid lifter engine a roller or a flat tappet?

[Cliff R]

Cool story about chasing the cow with the Ford truck.

Personally I believe the 360 just got tired and needed a rest. You probably could have continued the chase longer if the truck had the 390 FE option instead!....LOL

Seriously, folks are afraid of solid lifter set-ups and they shouldn't be. The Dodge slant 6 engines were all solid flat tappet to around 1978, and I never knew anyone who even knew that or did the periodical valve adjustments on them.

Ford also had a solid flat tappet V-6 around for a few years, in the little Bronco's back in the 1980's. They never needed any tending to either and pretty much a bulletproof design.

I've been running HIPPO solid rollers set at .005" lash on my Old Faithful cam over 10 years now, with only 4 adjustments and two of those wouldn't have been needed if I had used better rocker arms in the build.....FWIW......

[Jay S]

Originally Posted by Formulajones

I'm a solid flat tappet fan too. I nitrided the last one and run a lifter with oiling for the lobe. No worries. And with the right lobe and tight lash, they actually run pretty damn quiet. I can't even hear it with the hood shut standing next to the car.

The other car here with a solid flat tappet is a very old Isky grind from the late 60's with I think .026 lash or there about. It's a little noisier but nothing I'd call obnoxious. If you stand outside the car with the hood shut and try to listen for it, you'll notice it. Sitting in the car you can't here it at all.

390 we could have caught to cow sooner. And I was only 7. Lol

We are exactly the same way. I have a mix of hyd and solid cams.

Some people just cringe when you say solid cam. Other than inexpensive HFT set ups, after that we go straight to solids on our own cars. My T/A is a solid roller tight lash hybrid Bullet combo. We do SFT cams with EDM oiling when it fits, that is about as tough off combo as there is IMO.

I have dozens and dozens of Diesel engines with solid cams with thousands and thousands of hours on them. Our 97 Peterbuilt has 1.4 Million miles on its SOLID ROLLER cam. My 2002 LS 6 liter with its HR set up started making lifter noise at about 250,000 miles. The Pete’s cam is dead quiet. What do the hydrualic set ups offer over properly designed solid set ups...IMHO.. Nothing

[JLMounce]

Cliff, what kind of spring pressures do you run on that deal?

[Formulajones]

Originally Posted by JLMounce

I'm not so concerned with the noise. Well I am, but that's more of an issue that my current valvetrain with the Lunati lifters is exceedingly noisy.

My worry has always been longevity and reliability of parts in a street driven application. Is your 40K mile solid lifter engine a roller or a flat tappet?

It's a solid flat tappet that has been nitrided, and EDM oiling solid flat tappet lifters.

It's been a bullet proof combo.

[Cliff R]

"Cliff, what kind of spring pressures do you run on that deal?"

I bought the KRE heads from Dave at SD. He told me the pressures but I just don't remember exactly. I seem to remember around 140 on the seat and 350 or 380 over the nose but that may not be correct.

I've built a couple of 455's and one 400 "street" engine with KRE heads using flat solid cams and used the Crower 68405 springs no issues anyplace.

[Steve C.]

Cliff, what valve springs are in use with your Old Faithfull hyd roller and the Crower solid roller lifters ? The Crower 68405 or the Crane 99893 ?


.

[Formulas]

Iam currently running a comp solid XTQ tight lash lobe cam with crower cool face lifters in a 462 took a bit for lash to settle at first but everything in valve train was settling in with stock old but good rocker arms

[rtp]

Originally Posted by Steve C.

Cliff, what valve springs are in use with your Old Faithfull hyd roller and the Crower solid roller lifters ? The Crower 68405 or the Crane 99893 ?


.

Hello folks
My KRE's from Dave are set up at 1.800 with Howard 98445 springs...same as Crane 99893. 360 lobe with 612 at the valve...good to 650 lift max. Every body is happy

[Steve C.]

In the past Dave has often used the Crane 99893 spring.

"...in most applications we use the Crane 99893 valve spring, installed at 1.790-1.810", I set the intakes on the tighter side of the tolerance, I test all the springs and always put the ones with the higher pressures on the intake valves, since the intake valves weigh more and also have the momentum of the charge pushing on the back side of the valve while the exhaust valve if anything has pressure pushing or drawing it closed and the valve is lighter. On my digital InterComp spring tester the seat pressures on a new set of springs will range from 147-157lbs typically @ 1.800" and 380-390lbs @ 1.200" open pressure."

Posted by Dave Bisschop


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[ponjohn]

Comp bought Crane - will the 99893 still be available?