A hydraulic roller FE turning 7500 rpm....

[xb-60]

I haven't looked at SBF developments in detail for some time, so are you saying that 7500 rpm is easily available with hydraulic rollers?

[blykins]

Yes. That was the driving motive behind all of this. The LS crowd can hit those rpms easily, as well as the Gen 3 Hemis, SBC's, BBC's, SBF's, etc.

[66AC]

Brent:
Thanks for the info about the high RPM FE.
With no adjuster on the lifters, how does one set or specify the OAL of the lifter rods?

The higher RPMs brings to mind one thing... what limitation does that reveal? In other words, what part of the engine design modification is next? Head design for instance?

In general, I pretty much never get above 5K rpms in my use of the Cobra.
Would this design coupled with titanium as the material even get higher RPMs?

Thanks for sharing.

[blykins]

Originally Posted by 66AC

Brent:
Thanks for the info about the high RPM FE.
With no adjuster on the lifters, how does one set or specify the OAL of the lifter rods?

The higher RPMs brings to mind one thing... what limitation does that reveal? In other words, what part of the engine design modification is next? Head design for instance?

In general, I pretty much never get above 5K rpms in my use of the Cobra.
Would this design coupled with titanium as the material even get higher RPMs?

Thanks for sharing.

You have to measure for pushrods. It’s the same method as when you use factory non adjustable rockers.

The rockers themselves will not make an engine pull higher unless the engine is already cammed for it and the valvetrain simply won’t let it get there.

Obviously not every FE needs to be a 7500 rpm engine but I did that to prove that FEs can get up there and to prove that my rockers are stout enough to support it.

The rockers would make a nice choice for any FE. Not having an adjuster makes it lighter and eliminates another part that can fail.

[Kit Coyle]

Many thanks to Brent and all the other professional mechanics who contribute
their time and knowledge. For me, the very best part of this website are these
mechanical tutorial threads.

[blykins]

Morel, Crower, Jesel, Isky.

[Whodeeny]

Originally Posted by blykins

Morel, Crower, Jesel, Isky.

Thanks Brent.

Comp Cams has a mechanical roller lifter (96836B-16, $1000 for 16 lifters!) that replaces the needle roller bearings with a bronze bushing. Any experience with using this lifter?

[blykins]

I don’t run Comp lifters.

If you don’t plan on being over 6000-6500, there is no reason to run a solid roller on the street and take the risk.

[Kit Coyle]

My Cobra has a 1970 BOSS 302 Cleveland engine with a solid lifter cam and
lifters built in 2006 with new pistons in 2012. This thread has raised solid lifter longevity concerns so I thought I would run this by everyone to see where I stand. The block, crank, rods, heads and intake manifold are 1970 BOSS 302.
The pan is Milodon road race with windage tray. The cam is a Chrane solid
roller with duration 230/238 @ .50. Adv. duration is 280/288. Intake @ .50
opens 8.0 BTDC closes 42.0 ABDC. Max lift 107 duration 230. Exhaust opens
56.0 BBDC closes 2.0 ATDC. Max lift 117. Duration 238. Spring pressures
145 closed 345 open. Trick flow pushrods. Harland-Sharp roller rockers.
17,000 miles on engine with new pistons at 12,000. I am told heads must
be removed on this block to access lifters to check them. No bad noises
using stethoscope. Very strong engine. How radical is my cam and where do
you see my vulnerability and what can I do to mitigate future problems.
Thank you very much.

[RockBit]

Great job Brent. Your ME education is showing. I’m sure there are lots of guys that will take advantage of this.

Whenever I get close to 6,000 in mine, its time to change my underwear.

[blykins]

Wear some depends and keep your foot in it.

[redmt]

Originally Posted by blykins

Wear some depends and keep your foot in it.

An old time buddy of mine and I used to spend a lot of money and time building these engines. His statement most every time I would blow one up was "Didn't you hear the noise". My reply was usually something like "F'k the noise, by the time you hear it it's already too late" I NEVER took my foot out of it.

[redmt]

Hey Brent, back in the day I had a pull truck FE go over 9k when the oil pump shaft broke and then it made a really big noise, and immediately disassembled itself.
Seriously though, we tried everything we could think of for more RPM. 62-6800 was doable but the valve train available to us at that time wouldn't hold up. It's great that you were able to take a good idea and using todays technology come up with a solution to a long standing problem.

[cycleguy55]

Brent:

I appreciate your FE knowledge and experience, and this example only reinforces that.

On a related topic, what would be the rev limit for a 385 series with a similar setup - properly profiled hydraulic roller cam, light but strong rocker arms, etc.? Other critical components (e.g. titanium retainers)?

[blykins]

Originally Posted by cycleguy55

Brent:

I appreciate your FE knowledge and experience, and this example only reinforces that.

On a related topic, what would be the rev limit for a 385 series with a similar setup - properly profiled hydraulic roller cam, light but strong rocker arms, etc.? Other critical components (e.g. titanium retainers)?

I would expect the same and it's more than likely easier to get to that result. Studded rocker arms are generally more stable than shaft mounted rockers and there are lots of rockers to choose from for the 385 series.

Biggest help is the cam lobe shape, correct spring pressures, and light as possible valves.

[cycleguy55]

Originally Posted by blykins

I would expect the same and it's more than likely easier to get to that result. Studded rocker arms are generally more stable than shaft mounted rockers and there are lots of rockers to choose from for the 385 series.

Biggest help is the cam lobe shape, correct spring pressures, and light as possible valves.

Sounds good. Thanks!


Merry Christmas!

[blykins]

I answered your question up above.

[blykins]

Kit, your cam is not radical and your spring pressures are light. You didn't mention what lifters you're using, but I would be doing a lifter inspection or even a replacement at your mileage level.

In the future, if you do a rebuild, there is absolutely no reason to run a solid roller for this type of build. What you have could have been easily accomplished with a hydraulic roller that could go 100000 miles without issue.

[Kit Coyle]

Thank you Brent. The lifters are Crane "Vertical Guidebar Roller Tappets"
circa 2006. If the heads have to come off to inspect the lifters then I might
consider putting in new. Or maybe think about a hydraulic cam and lifters at not a heck of a lot more money. Too bad there isn't an easier way to get access
to the lifters in this block, but such is life. I also might mention that this engine
has MPG port plates installed...both intake and exhaust. I don't know how
much difference they make but there is no mid-range flat spot. With such a
light car I wouldn't think there would be anyway. Thanks again, Brent.

[Whodeeny]

Originally Posted by Kit Coyle

Thank you Brent. The lifters are Crane "Vertical Guidebar Roller Tappets"
circa 2006. If the heads have to come off to inspect the lifters then I might
consider putting in new. Or maybe think about a hydraulic cam and lifters at not a heck of a lot more money. Too bad there isn't an easier way to get access
to the lifters in this block, but such is life. I also might mention that this engine
has MPG port plates installed...both intake and exhaust. I don't know how
much difference they make but there is no mid-range flat spot. With such a
light car I wouldn't think there would be anyway. Thanks again, Brent.

I am curious as to why the heads must come off to inspect the lifters on a Boss 302? I had a 351C and the lifters could be inspected without removing the heads.