UltRoadWarrior9

DON'T EVEN RESPOND IF YOU ARE ABOUT TO SUGGEST A SOLID ROLLER...

I have a 383 build nearing completion and I'm always doing alot of research into the high dollar parts going into this build. That's a bit of a lengthy build thread, so I decided it was wisest to start a new thread. I have almost everything nailed down except pushrod length and the hydraulic lifters. I will determine the pushrod length after I receive the 1.6 Scorpion RR's.

At the beginning of this project I'd purchased a new set of 'LS7' lifters for about $124 after some amount of initial research. I thought they would be satisfactory. Maybe my goals were different back then too... Been a year

I guess I've finally realized and am starting to worry about what I've learned and the point that I'm at in my build. That is the 7000RPM range I'm aiming for and the valve spring pressure that will be required.
Here is my build so far, all machine shop work has been done to the block. Last week I asked them to swap the valve springs. They also installed new locators with shims and checked the bind height. Everything is a GO:

1)Chevy Performance Parts 383 clearanced block. Bored and machine shop clearanced to 4.030" x 3.75".
2)Internally balanced and forged bottom end by Scat including Crank, 6" H-Rods and Mahle flat pistons. Pistons have 5cc valve relief.
3)292XFI cam. .242/.248 @.050 113LSA .584/.579 lift.
4)AFR 210 65cc heads, competition ported w/titanium retainers. PAC-1934 double springs w/damper have replaced the AFR-8000 solid double roller springs that came with the heads. The PAC-1934 springs, as measured by my machinst, are about 175lbs on the seat and are close to 400 open spring pressure. Very close to the advertised rates. He also installed new locators under all springs, very tight fitting for the inner springs. Also, extra .015" shims under all the intake valve springs for the extra weight of the larger valve.
5)Scorpion 1.6 Roller Rockers
6) Going with Manley pushrods .120" wall thickness. Still have yet to determine pushrod length. Hopefully length will fall into .120" wall thickness availability.

So, back to this: "At the beginning of this project I'd purchased a new set of 'LS7' lifters for about $124 after some amount of initial research. I thought they would be satisfactory. Maybe my goals were different back then too... Been a year"
I've narrowed it down for 3 choices on the critical Hydraulic Roller Lifters. As I mentioned, I purchased a set of Part #12499225x16 about a year ago for around $130 from CPP. I need to make sure nothing bad happens close to 7K:

1) Chevy Performance Parts Part # 12499225. $163 from Summit. OEM replacement
2) Comp Cams Part # 875-16. $227 from Summit. Advertised as Reduce Travel
3) Comp Cams Part #15850-16. $464 from Summit. Advertised as Short Travel

ETA: Corrected Title.

Vanilla Ice

How far above 7k rpms? 7000 isn't a lot. I personally ran a stock LT1 bottom end to 6800 RPM with very little valve train upgrades.
Did you get NSA rockers or SA?

Stock lifters too.

AlkyIROC

Intended purpose of the vehicle? Street, street/strip, road course, drag race only?

The 292XFI camshaft you list only has an operating range of 2200-6200 so pushing it over 7000 is a few steps backwards.

As for the lifters, the 12499225 and 875-16 are not designed for highly aggressive lobe ramps. They're more of a stock replacement style lifter. The 15850-16 is the best option from those 3 choices. The roller is exposed and there's no chance the body will contact the lobe with an aggressive ramp of an aftermarket performance camshaft.

If you want a lifter that will easily survive high lift cams and repeated high rpm usage, spending between $900-$1000 for a set of lifters is expected. I use Crower HIPO lifters in my race engine.

86LG4Bird

iTrader: (1)

Agreed, your 15830-16 option is the ONLY one I would even consider.

skinny z

I've used (and am using) Comps 15853 short travel lifters to RPMs of 7000. That's not a shift point or red-line but an upper RPM limit (self imposed).
There has been no trouble after hundreds, perhaps thousands, of max RPM shifts with cams in the 288 advertised duration range with lifts via 1.6 rockers in the .57X range.
Keep in mind, (and this you may already know), that the short travel lifters intent is to mitigate the effects of component separation due to inadequate valve springs or other factors which contribute to the loss of valvetrain control.
PS. I hope you're well versed in calculating the correct pushrod length. There is a lot of BS on what's right and not right and how to get there.

Orr89RocZ

iTrader: (20)

Ls7 can do it on that cam and better believe it will want a 7000 rpm shift atleast

If it was me i would lean towards morel 4602's. I ran them to 7200 with 180/450 seat, much bigger cam and 30 lbs of boost.

I have done 7 in a ls7 lifter deal with a 286/230 lobe .603 lift. So you should be fine at 175 seat 400's open, esp if spring is shimmed so its less than .100" to bind

UltRoadWarrior9

Street/Strip...
Nasty SOB on street, but rarely seen or heard...

The operating RPMs of this cam as advertised I think are lower that what it's capable of. Just like their recommended Torque Converter stall speed from what I've read, absolute minimum of 2500. A few here have rec'd 3500+ stall speed converter with this cam selection.

Thx for y'alls input

UltRoadWarrior9

Re-read this article:http://www.hotrod.com/articles/ccrp-...-roller-power/ . Thought I would post it here for anyone else to follow.
Makes me think if I was going with the 15850's that I should've kept the 220lb springs that came with the AFR's. Ah well...
My cam's lift is only .584/.579, so I'll take Orr's suggestion and keep the LS7's since there will be no anticipated interference problems with the rollers. But I think I'll borrow my buddies borescope, take the oil pan back off, and try to see if those rollers are really tracking those lobes.

Orr89RocZ

iTrader: (20)

Afr valves are lighter than most sbc due to using lsx style 8mm stems

175 seat if thats what they measured should be plenty. Close to 400 open should also be ok. Surprised the heads didnt get set up with pac's smaller diameter spring, the 1.27" roller spring that were 155 ish seat at advertised install height and 420 open at max lift. Those can be shimmed .030 to 170's lb seat and be good to .615-.620 lift still

UltRoadWarrior9

Been doing some research on crankshaft coalition and speedtalk.. I figured I'm in debt close to 3K at this point in the build, why not make it 3K? (and have before next august to pay it down before interest)

Also, cutting corners is not logical at this point in the build. I've wanted this engine design to last a reasonable amount of time. I'd rather it break a trans or diff than have it self destruct. I'm getting the 15850's. Final decision.

Regarding finding correct pushrod length... I'll start a new thread for that topic after parts come in.

86LG4Bird

iTrader: (1)

Wise choice. I cringed at your post above where you were going with LS7 lifters. You would have been lucky to sneak by with them.
Plus, with the 15850's and your seat load, you'll pick up some hp as a bonus.

I've seen firsthand the limitations using stock style lifters with an aggressive HR grind. Here's an autopsy on my last HR motor:
http://ls1tech.com/forums/lt1-lt4-mo...alvetrain.html
Posts 14 and 16 in that thread talk more about the valvetrain

UltRoadWarrior9

Thanks for posting!
I'm not done reading your thread over there, but something I did see, reminded me of something I've read on speedtalk regarding hydraulic lifters during one of my searches over there. Had to do a with marine Mercruiser BBC valvetrain collapse when using hydraulic lifters. This was a boat with a BBC that traveled up the Colorado river, with RPMs at a constant maximum output. After some hours, they lost the hydraulic valvetrain. The reasoning behind the failure was aerated oil had collapsed the lifters IIRC.

Orr89RocZ

iTrader: (20)

Sounds like stability problem with the valvetrain. Spring dynamics and stiffness in the system. Pushrod diameter and wall thickness as well. Not sure i would blame the lifters there

86LG4Bird

iTrader: (1)

Good point you make. But with this one, I really don't think that was the case.
Complete valvetrain including stiff pushrods was spec'd by and purchased from Advanced Induction......EXCEPT for the lifters They strongly recommended upgrading, but I declined. I ended up spinning that motor higher than planned based on the extended power curve I was seeing.
I think Ult's comment about the lifters collapsing due to aerated oil was a STRONG possibility during roadcourse use with the high g loads in all directions intermittently uncovering the pickup. Even with the Accusump, I wouldn't rule out sizeable gulps of air entering the system.

Orr89RocZ

iTrader: (20)

Indeed sustained high rpm use, oil draining and windage are concerns. Theres alot of differences in getting things to live in that environment vs a drag race pass


I like using good quality stuff. I think ls7's work well in most applications but the ultimate hyd roller setups do use other styles

I also would recommend shaft rockers for ultimate stability. Deflection in the system makes it difficult to control but a shaft system greatlt reduces those effects.

A big 3/8" pushrod, shaft rockers, good lifters, and light valves/springs/retainers with correct geometry is how to get hyd rollers performing. I was able to spin a big heavy valve to 7200+ under big boost with a .640" cam using this system. Hyd rollers can definately get the job done, just have to have everything matched and setup correctly

Another thought is use a slightly less aggressive lobe design. A high lift magnum lobe can make the lift with a little less ramp rate for abit more stability and not sacrifice much power

skinny z

I'd like to hear what others have to say about that subject. I hope I catch the thread when you post it.

skinny z

One thing has been demonstrated regarding OEM lifters and RPM. They don't do the job once RPMs get north of 6000 or so. It's been documented that this is due to cast lifter body distorting under the stress and a subsequent loss of oil pressure. The step up here, and I'll think you'll find this to be true, is to use a lifter body made of tool steel such as Morels or Comps short travel lifter. Weight and valve train stability notwithstanding, this is a common failing when guys start to spin their OEM equipped small blocks (or big blocks I would imagine) to higher revs. Most blame it on valve springs or something other than the lifter itself. We've been there, done that, saw the results, made a change, and moved on.

Orr89RocZ

iTrader: (20)

The cam lobe is important. Stock ls7 goes to 7000, and most ls motors in the car platforms make power over 6000 just fine. My stock ls1 went to 6300 shifts.

But yes lifters, and thus performance, can be improved

skinny z

I should have clarified that the problem was associated with the 1st generation of OEM rollers. Probably mid to late 80's IIRC.
I can't comment on the Gen III or IV SBC stuff although by many accounts (yours included) they seem to be a step beyond that early model.

89gta383

iTrader: (5)

I am using the morel 5315's they are the standard sbc roller lifter replacement:
http://www.straubtechnologies.com/53...es-to-present/

skinny z

Copied for Straub's website.

100% Made in America
Fully machined from 8620 Tool Steel
Bodies, Axles, and Wheels are Centerless Ground
Body OD is held to .0003” +/-

Looks like a solid part. Notice the tool steel construction. That's what makes the difference.

UltRoadWarrior9

Just looks like your standard LS7 lifter replacement. Not impressed by any means. Should've unshrouded the rollers like 15850

skinny z

It's more the material it's made of that was the point there.

UltRoadWarrior9

Ok, so you Canadians are bragging you guys have better metal? WTF? Explain

Orr89RocZ

iTrader: (20)

Tool steel body is stronger/stiffer and machined to tighter tolerances than any oem lifter. Thats where the difference is

UltRoadWarrior9

...Got in the 15850 lifters, took a side by side pic of a used LS7 lifter and a 15850. Look at the pitting on that used roller on the left! Got the used lifter set from a member here on TGO. Will try to find origin and usage...

UltRoadWarrior9

Damn camera... Here's another angle. Measured about a .050" wider roller contact area on the 15850 compared to the LS7 part. Same 'main body' widths @ .842", relatively same heights @ 2.59" -2.62".