[Formulas]

the main point of my comment was roller size change on the same roller lobe effect on duration it could be very little as .700 to .750 isnt that drastic of a roller change iam not thinking duration would change much either

in theory as its obvious you couldnt actually do this in a pontiac if you changed the roller size to 1 inch it would be rolling up the ramp earlier and or faster in the cams rotation and that translates to duration


to possibly understand what iam saying take it to the extremes a roller lobe under a razor blade the ramp has to travel further to get under the blade to lift it conversely put a roller lobe under something as big as a tire the tire would be elevated a longer amount if degree lobe rotation

thus a change in roller diameter has to effect duration of tappet lift catagorically

i never said it would be earth shaking game changing from .700 to .750

[Formulajones]

I'm more surprised that no one is asking about possible longevity affects or possible better durability affects given the fact so many here are scared of rollers. I'm not even the least bit concerned a .750 wheel may add about 1 degree of duration over a .700 wheel.

[Dragncar]

I have always wondered what a good cam guy could do with a sft 55 mm cam and .904 Mopar lifters in a IA2 block. Cam would be very expensive and who knows if the oil band would line up.
But with that big circle of the 55mm and the .904 lifter you would think a good cam guy would be able to take advantage of it vs a std. journal cam and .842 lifters.
Would make a nice high end street or bracket race engine with the right parts. And no needle bearings to worry about. Billet ft cam would have a hard time going flat.

[Jim Moshier]

I was thinking that the quality control issue that is heard about on here and seen and heard, with its sloppy fitting metering and noisy lifters via QC. These new lifters have a sealed plunger which should eliminate the noisy, sloppy-fitting plunger and now it's just a mechanical movement of the lifter following the cam. Am I wrong in seeing it this way? Please share that the Shaver lifters at one time were pretty good lifters if I remember correctly.

I was just asking if anyone else has actually used them yet and what their opinion was. I have purchased them already and will share my experience with them when I do get to my build but I have a full plate right now and don't know when that will be!

[tom s]

Most of the hyd roller issues come from street driven cars.The cost is already too high for street engines IMO.Tom

[Formulajones]

$670 doesn't seem out of line. Isky is over $800 and Comp's short travel lifters are $720. Even Comps standard hydraulic roller retrofit lifter is $600. There aren't many that are even under that price point anymore. Some are $900 now.

Everything is expensive right now.

[Tom Vaught]

I personally see little benefit to installing a Hydraulic roller camshaft in a "street car"
(that actually is run on the street) with a non-oem lobe profile.

So agree with Tom S, the cost is too high as well as the failure point too low if the vehicle is driven much.
But, there are some who take trips with the stuff. Some designs are more robust vs others.

My only failure of a Pontiac valve train part was caused by a failed aftermarket lifter after a long trip.
I had to tear down the whole engine to clean up the metal in the engine from the failure.

Not a fan of modifiers making the roller cam parts in their rented out shop in the Detroit area. Too many issues for me.

Tom V.

[Lee]

These have been available for several months now. I got one of the first sets back in January. I had to wait on some other parts, so just recently finished the motor and got it on my test stand. I used HS 1.5's and 8.800" pushrods. There was a tiny bit of noise with 1/2-turn preload. Pulling a few rockers, the contact pattern was a tad past center. I took the preload to 1-full turn, and the motor doesn't make any noises that my stock rocker HFT 455 doesn't make.

https://youtu.be/r6veuoS6vqY

[Formulajones]

I'll probably use a set on a little pump gas SBC I'll be doing.

[jhein]

Originally Posted by Tim Corcoran

I was told by someone a very reputable Pontiac engine builder that the best hyd roller for Pontiac currently on the market are made by Johnson Lifter, not Hy-Lift Johnson but Johnson. They are expensive most would not be willing to pay that much for lifters, but you get what you pay for.

I originally had a set of Morel HR lifters for my motor but before it went together, Butler got the new Johnson (not Hylift) reduced travel (.093) lifters in stock so I got a set. I only have a couple hundred miles on the motor so far but I'll say that at least they are VERY quiet.

[tom s]

Just because I have a hyd roller cam in my drawer im going to try a set of the Comp Evolution hyd rollers in my next build.Tom

[Jim Moshier]

Tom,

Which Roller cam do you have? Looking forward to knowing the outcome!

Jim

[tom s]

Clay Smith 234-246@50 on a 112..348-360 lobe lift.Tom

[Half-Inch Stud]

Sold my 0.442" roller for peanuts. Cost of springs, Lifters, pushrods, bore bracing is stoopid for Same or less DURATION to what Flat Tappets i've been running now. More duration would be interesting, with the "improved idle", but I got too much cam as it is now.

Dave Vizard has a recent video showing the flat lifter is capable of more lifted area under the curve up to 0.200" all day long, without devastating sideloads. Thus more TQ, HP. High-Rev maybe not addressed.

After 0.200" lift the Higher Duration Rollers can open the valve quicker than the big duration Flat tappet.....but go figure that Duration and "quicker" matter at Opening and Closing.

Longk ago, I ran parameters on Roller and Flat and concluded we need >.951" or Mushroom Lifters to advance optimal HP Street/Strip with good BSFC.

Leave Rollers for > 469 CID Race going beyond RPMs that Street drivers ever need. My 68 GTO will pull strong ( like the strongest in rush-commute with the fancy cars) when cruising set at 2500 RPM at 75 MPH. Like a friggin ping-free slingshot in OD to 100 MPH. Go figure what 5000 RPM brings.

1 fella (an executive) at work had a 100 hp/cyl 4-CYL and we talked about the driving culture on that main highway. He says its nuts but admits he takes the offramp at > 100 MPH. A buddy would take his VW Turbo-Diezel wagon at about 90 (me in it). The GTO could muster pretty well in the 80s. i never got a good read as ya gotta watch the road. Seen many vehicles that left the road on that offramp. Huntsville has its speedsters and wrecks.

Oh, cams, duration and rollers: What Duration roller is better than my cam mentioned in the Low-Compr Signature below, and remains Ping-Free?

[Formulajones]

Originally Posted by tom s

Just because I have a hyd roller cam in my drawer im going to try a set of the Comp Evolution hyd rollers in my next build.Tom

Me too. Let me know if ya beat me to it. I'd be happy to share my experience as well when I get to it.

[tom s]

I’m just getting a 455 out of the shop.Need to get it on the run stand and off to the restoration shop.Then the block will go to the shop.Tom

[77 TRASHCAN]

I'm think about calling Ripley's Believe it or Not....
Tom is building a run-of-the-mill Pontiac 455!!!

[tom s]

I have built 2 455s with STOCK 48 heads!My next build will be my FIRST round port engine ever!Tom