Lifters? Hydrualic roller, solid flat tappet?

[Paul G]

I would assume they all have there special uses right? Hydraulic flat tappet is the standard lifter we use.

It is said that the lifter bores wear out over time. That allows oil to bleed by the lifter body, pressure is lost and the lifter wont pump up correctly. Is that correct?

It has been said that using a hydraulic roller lifter is not a good idea unless the lifter bores are bushed. Theory is the sloppy lifter bores allow oil bleed by and will not allow the lifter to stay pumped up at higher RPM's. Why would the lifter bores need to be bushed for a hydraulic roller lifter, and not a traditional flat tappet hydraulic lifter? Is it that a hydraulic roller lifter in this case would be intended for higher spring pressures and higher RPM than a standard hydraulic lifter, rollers used more for a high performance engine build where as the standard hydraulic lifter would not?

Lots of engine builders are recomending to go with hydraulic roller lifters, no mention of bushing the bores. Is that strictly to eliminate wiping the cam lobes from low zinc oils?

So what does that say for a solid roller lifter? No hydraulic problems from loose bores to deal with? Requires periodic adjustments which are very easy.

Thoughts?

[John_Kunkel]

It has been said that using a hydraulic roller lifter is not a good idea unless the lifter bores are bushed.

Who's saying that?

[green69rt]

It has been said that using a hydraulic roller lifter is not a good idea unless the lifter bores are bushed.

Who's saying that?

This is a big thread on the subject.  Just info, I'm not knowledgeable about this.

http://www.dodgecharger.com/forum/index.php/topic,111208.0.html

[Challenger340]

It has been said that using a hydraulic roller lifter is not a good idea unless the lifter bores are bushed.

Who's saying that?

I think I did john.... not EXACTLY that way, more that..... some added attention to actual lifter bore "clearance" might be highly recommended with HR's in BB Mopars, due to the higher V/spring pressure/lifter Bleed down on the "short" bores.

For myself, after far too many rpm problems on the Dyno with HR's with BB mopars....
I now just default to "bushing" the Lifter Bores with BB Mopar HR applications.... a product of chasing my tail on the Dyno with HR's as "drop ins" on 45 yr old blocks ... poor rpm capability, bleed down, too many problems for me.... which brings the added costs associated with HR's on the short mopar lifter bore heights into question as "drop-ins" for me, versus actual power increase vrs cost over a Solid Flat Tappets ?

By all means, if anybody else feels it is fine to drop HR's into 45 year old "short" Lifter Bores, bump your V/Spring pressures to 150# to 175# Seat pressures on 400# rates to gain all that Power & Torque some of these newer HR profiles offer ?? .... then good luck to you, fill yer boots !
Maybe they are luckier/better than I ?
just say'in
for me personally, I've experienced too many "less than stellar" results and problems, related back to factory "short" and "worn" Lifter Bores on 45 yaer old BB Mopars, that I now don't consider HR Lifters as a "drop-in" for BB Mopars.
everybody's entitled to their opinion.... they can do as THEY wish... I would love to see their actual Dyno Sheets ?

[Challenger340]

It has been said that using a hydraulic roller lifter is not a good idea unless the lifter bores are bushed.

Who's saying that?

This is a big thread on the subject.  Just info, I'm not knowledgeable about this.

http://www.dodgecharger.com/forum/index.php/topic,111208.0.html

The 428 FE Ford referenced in the above thread, was taken and assembled by the Shop(we just did machining), and then was indeed Dyno'd using it's HR Cam, with the reccomended V/Spring pressure, using the supplied HR lifters used "drop-in", and with the exhibited lifter Bore clearances ranging from .0014" to .0018", and "normal" wear/taper on the 45 year old bores. Pretty normal for a 45 year old block.

It managed a whopping 425 hp, and peaked at 5100 rpm with it's 240's @ .050" duration HR Cam, Edelbrock RPM Aluminum Heads and 10.3: C.R.
The Customer is pretty dis-appointed
Sounds GREAT though.... and he can tell his friends he has a ROLLER !

[Paul G]

Let me restate the questions, two of them.

Would the lifter bores still require lets say "work" in order for a standard hydraulic flat tappet lifter to operate correctly at higher rpm and under higher spring pressures?

Is this lifter bore problem negated by using solids of roller or flat tappet design?

Sorry to ask so many questions. I am trying to get my head around this situation. I tend to over think things sometimes.   

[BSB67]

It has been said that using a hydraulic roller lifter is not a good idea unless the lifter bores are bushed.

Who's saying that?

This is a big thread on the subject.  Just info, I'm not knowledgeable about this.

http://www.dodgecharger.com/forum/index.php/topic,111208.0.html

The 428 FE Ford referenced in the above thread, was taken and assembled by the Shop(we just did machining), and then was indeed Dyno'd using it's HR Cam, with the reccomended V/Spring pressure, using the supplied HR lifters used "drop-in", and with the exhibited lifter Bore clearances ranging from .0014" to .0018", and "normal" wear/taper on the 45 year old bores. Pretty normal for a 45 year old block.

It managed a whopping 425 hp, and peaked at 5100 rpm with it's 240's @ .050" duration HR Cam, Edelbrock RPM Aluminum Heads and 10.3: C.R.
The Customer is pretty dis-appointed
Sounds GREAT though.... and he can tell his friends he has a ROLLER !

I'm sure there is more to the story, but with what you have shared, it is not particularly convincing that the root cause of the low power is the lifter bore.

Paul, anyone that says they know the answer to your first question is either misleading you, or they have made a considerable amount of assumptions about your build and part selection.  The short comings of a HFT and a hyd roller are about the same.  They just become more pronounced with faster ramps and higher valve spring pressures sometimes used with hyd. rollers or fast ramp hyd. FT.  If you use a true street roller with relatively gentle ramps, and reasonable spring pressures, higher oil pressure and higher viscosity oil, you'll likely be fine.  The quality and tolerances within the hydraulic lifter itself plays a huge (if not the largest) part in whether it will hold true lift and duration at higher rpms.  The short of it is, there are a lot of variables.  As you might know, there are cases where the fast rate HFT fail to perform at high rpm as well.  And honestly, I have not seen a lot of evidence that they do perform well at higher rpm, but some claim they do.  Is the issue the bore?  Only if the lifters are not getting sufficient oil pressure.  Said differently, If the lifters for #1 cylinder are getting 60 psi oil pressure, the bore is not the problem.  Personally, I would never bush a block to run a hyd cam.  Just pick the right parts.

I would not call it a "lifter bore problem".  It is simply a matter of appropriate tolerances/clearances between the lifter and bore for the intended purpose.  Excessive clearance, for whatever reason (manufacturing tolerance or wear), is problematic for any motor, and the valve train is not the main concern.  

Lifter/bore clearance does not figure into the performance of a solid lifter.  The cam events are directly transferred to the valve irrespective of the oiling conditions.

If you are not concerned about wiping a lobe, don't need/want an aggressive lobe, and are on a budget, get a hyd. FT

If you want hydraulic cam, but are worried about wiping a lobe, budget is not an issue, get a hyd roller

If you are not concerned about wiping a lobe, want a fast lobe, and are on a budget, get a solid FT

If you don't want to leave any power on the table and budget is not an issue, get a solid roller.

Personally, because I don't like to leave power on the table, or potentially leave power on the table, my preference is to go solid.  This way, there is no question if the cam events are being transferred to the valve.  That being said, people have made tremendous power with hydraulics.  It is a personal choice and you will simply need to decide.

[Challenger340]

Here's how I see it.... as related to the problems and dis-appointments in "expected" HP performance, that I have personally experienced on the Dyno with HR Cams/Lifters as "drop-ins" in BB Mopars, and other old/worn short lifter bore blocks, WITHOUT bushing the Lifter Bores.
and,
why at our Shop we recommend bushing the lifter Bores when we use HR Cam/Lifters in BB Mopars.

No wars wanted... obviously here, Anybody can believe what THEY wish, based upon their experience, and as I said I would LOVE to see their Dyno data.

Hydraulic Lifters, it matters not Flat Tappet or "Roller"... rely upon lifeblood Oil Pressure to maintain their internal "pump up", in order to transfer the Cam Lobes motion up to the Pushrod/Rocker Arm.
The "resistance" pushing back down against the Lifters trying to transfer this Cam lobe "motion", is Valve Spring Pressure which causes internal lifter Oil leakage responsible for transferring less motion, reducing motion transfer down from 100% of Cam lobe motion.

The weak link in this "Transfer of Motion" system, is internal of the "Hydraulic" Lifter.... being the maintenance of a "leaky" chamber internal of the Lifter that relies upon Oil PRESSURE entering this chamber to keep it pumped UP in order to transfer the "motion", which it NEVER DOES, again here, as Oil is constantly being pushed OUT of this chamber through Internal Lifter "clearances" on the Chamber by Valve Spring pressures...
and,
It also relies upon actual clearance around the Lifter Body EXTERNALLY in the "Bore"..... to direct the Oil PRESSURE INTO the Lifter to maintain it's internal "Pump Up" described above.. versus time... to replenish.

In a perfect world....
the Hydraulic Lifter would indeed RE-FILL sufficiently when on the Cams base circle(after bleeding down somewhat against spring pressure during cycle), to be "pumped up" again and prepared for it's next motion transfer "cycle" against the Valve Spring Pressure, in transferring 100% of the Lobes motion, which it NEVER transfers 100% anyways due to the aforementioned internal leakage.
Now add into the equation;
*  Higher and higher V/Spring Pressures ? to keep up with faster "Roller" Lobe "motions" (more internal leakage... further down from 100% motion transfer)
* Higher rpm's further reducing the "nanoseconds" for lifeblood Oil Pressure to enter and MAINTAIN the "hydraulic" Lifter motion transfer.
and my issue....
* 45 year old "Sloppier" Lifter Bores, that are "short" (because they were never designed to "seal" that much), further increasing the path of "least resistance" for leakage out and around the Lifter Body rather than INTO it.

So why do HR's seem to work just "fine" in other brands with equally OLD & worn lifter bores ?
let's examine that ?
The first Engines to employ HR's from factory were SB Ferds back in the 80's
What's the first thing Ferd "engineers" did to revise/prepare the 302 Engine Block for HR useage ?
Answer: redesign to LONGER TALLER Lifter Bores.
Theoretically to "increase" the path of "least resistance" for Oil to escape around the Lifter Body in the Bore, and direct more INTO the Lifter.

OK,
but why then do the "retro-fit" HR's still work just fine in other brands WITHOUT the longer taller revised HR lifter Bores ?

My answer this one is going to hurt, because we like to think of our Mopar LARGER lifter diameter, or surface "area" being a massive .904" as an ADVANTAGE... which it is.....or WAS until Oils went away.... with Flat tappet Cams, for being able to run FASTER ramp Cam Lobes with greater "area" to spread the pressure around.
But lets come back to that actual DIAMETER as it relates to external Lifter Body leakage OUT and AROUND instead of going INTO the Lifter with an HR Cam shall we ?
Chevy Lifter Diameter  .842".....  with the SHORTEST path from Oil gallery to "leakage"..... .830"
Ford Lifter Diameter   .874"..... with the SHORTEST path from Oil gallery to "leakage"..... .910"(even further with late HR 302)

Mopar..... .904"..... with the SHORTEST path from Oil gallery to "leakage"..... .625"  

Anybody doing the "math" here ?
If we have 3 lifters,
one each of the above brands,
and all with the same .0015" Lifter Body to Bore clearance.....
and all with the same 60 psi Oil pressure....
Which one is going to LEAK lifeblood Oil Pressure OUT and AROUND the Lifter Body instead of INTO it .... the WORST ?

again, just the way I see it... you do as YOU wish.

[BSB67]

Here's how I see it.... as related to the problems and dis-appointments in "expected" HP performance, that I have personally experienced on the Dyno with HR Cams/Lifters as "drop-ins" in BB Mopars, and other old/worn short lifter bore blocks, WITHOUT bushing the Lifter Bores.
and,
why at our Shop we recommend bushing the lifter Bores when we use HR Cam/Lifters in BB Mopars.

No wars wanted... obviously here, Anybody can believe what THEY wish, based upon their experience, and as I said I would LOVE to see their Dyno data.

Hydraulic Lifters, it matters not Flat Tappet or "Roller"... rely upon lifeblood Oil Pressure to maintain their internal "pump up", in order to transfer the Cam Lobes motion up to the Pushrod/Rocker Arm.
The "resistance" pushing back down against the Lifters trying to transfer this Cam lobe "motion", is Valve Spring Pressure which causes internal lifter Oil leakage responsible for transferring less motion, reducing motion transfer down from 100% of Cam lobe motion.

The weak link in this "Transfer of Motion" system, is internal of the "Hydraulic" Lifter.... being the maintenance of a "leaky" chamber internal of the Lifter that relies upon Oil PRESSURE entering this chamber to keep it pumped UP in order to transfer the "motion", which it NEVER DOES, again here, as Oil is constantly being pushed OUT of this chamber through Internal Lifter "clearances" on the Chamber by Valve Spring pressures...
and,
It also relies upon actual clearance around the Lifter Body EXTERNALLY in the "Bore"..... to direct the Oil PRESSURE INTO the Lifter to maintain it's internal "Pump Up" described above.. versus time... to replenish.

In a perfect world....
the Hydraulic Lifter would indeed RE-FILL sufficiently when on the Cams base circle(after bleeding down somewhat against spring pressure during cycle), to be "pumped up" again and prepared for it's next motion transfer "cycle" against the Valve Spring Pressure, in transferring 100% of the Lobes motion, which it NEVER transfers 100% anyways due to the aforementioned internal leakage.
Now add into the equation;
*  Higher and higher V/Spring Pressures ? to keep up with faster "Roller" Lobe "motions" (more internal leakage... further down from 100% motion transfer)
* Higher rpm's further reducing the "nanoseconds" for lifeblood Oil Pressure to enter and MAINTAIN the "hydraulic" Lifter motion transfer.
and my issue....
* 45 year old "Sloppier" Lifter Bores, that are "short" (because they were never designed to "seal" that much), further increasing the path of "least resistance" for leakage out and around the Lifter Body rather than INTO it.

So why do HR's seem to work just "fine" in other brands with equally OLD & worn lifter bores ?
let's examine that ?
The first Engines to employ HR's from factory were SB Ferds back in the 80's
What's the first thing Ferd "engineers" did to revise/prepare the 302 Engine Block for HR useage ?
Answer: redesign to LONGER TALLER Lifter Bores.
Theoretically to "increase" the path of "least resistance" for Oil to escape around the Lifter Body in the Bore, and direct more INTO the Lifter.

OK,
but why then do the "retro-fit" HR's still work just fine in other brands WITHOUT the longer taller revised HR lifter Bores ?

My answer this one is going to hurt, because we like to think of our Mopar LARGER lifter diameter, or surface "area" being a massive .904" as an ADVANTAGE... which it is.....or WAS until Oils went away.... with Flat tappet Cams, for being able to run FASTER ramp Cam Lobes with greater "area" to spread the pressure around.
But lets come back to that actual DIAMETER as it relates to external Lifter Body leakage OUT and AROUND instead of going INTO the Lifter with an HR Cam shall we ?
Chevy Lifter Diameter  .842".....  with the SHORTEST path from Oil gallery to "leakage"..... .830"
Ford Lifter Diameter   .874"..... with the SHORTEST path from Oil gallery to "leakage"..... .910"(even further with late HR 302)

Mopar..... .904"..... with the SHORTEST path from Oil gallery to "leakage"..... .625"  

Anybody doing the "math" here ?
If we have 3 lifters,
one each of the above brands,
and all with the same .0015" Lifter Body to Bore clearance.....
and all with the same 60 psi Oil pressure....
Which one is going to LEAK lifeblood Oil Pressure OUT and AROUND the Lifter Body instead of INTO it .... the WORST ?

again, just the way I see it... you do as YOU wish.

I agree with it all.  But 60 psi is 60 psi irrespective of the leakage.  Of course,  if the leakage is great enough then you will not be able to maintain the 60 psi.   And the popular, although wasteful choice of using a high volume pump will likely take care of that.  The lifter is the greater issue.

[Mike DC]

 
IMO hydraulic rollers would seem to have an advantage on paper for lower RPM motors.  Faster valve openings from the steeper ramps, without tackling the problems that higher RPMs bring. 




Has anyone started making a real distributor gear for a roller cam?  Something that doesn't need to be constantly changed out? 

[Challenger340]

[/quote]

I agree with it all.  But 60 psi is 60 psi irrespective of the leakage.  Of course,  if the leakage is great enough then you will not be able to maintain the 60 psi.   And the popular, although wasteful choice of using a high volume pump will likely take care of that.  The lifter is the greater issue.
[/quote]

I agree that 60 psi system pressure, SHOULD be is 60 psi everywhere ?, except "closest" to those points where it actually "escapes" the system being gauged, because closer to "where" it is dropping to ZERO .... is linear back into the systems integrity ?

In this case oil pressure is dropping rapidly down from the 60 psi system pressure, as it "escapes" around the "leaky" Lifter Bore ? ... with very short travel from the oil gallery to "freedom" on a BB Mopar ?

[fy469rtse]

I agree with a lot said ,
but challer340 has hit all the relevant points in my book,
its your engine paul,
but the best money spent is at the prep and machining work to any block , the valve train is one of those area's as car guys playing and modifying things , we are putting more demands then the factory ever intended to area's like this , good insurance to do this area if you intend to go hydraulic roller , 

[John_Kunkel]

This thread begs the question "why hydraulic lifters at all in a performance application?" 

They run quieter....so who here's gonna object to a little clatter?

They don't need frequent adjustment...c'mon, isn't wrenching on cars what it's all about?

[Ghoste]

Agreed John.

[c00nhunterjoe]

Got severL solid cams over here. They get checked annually and have not required an adjustment in years. All still in spec.

[Challenger340]

This thread begs the question "why hydraulic lifters at all in a performance application?"  

They run quieter....so who here's gonna object to a little clatter?

They don't need frequent adjustment...c'mon, isn't wrenching on cars what it's all about?

Well stated John, an oxymoron if there ever was one,  "High Performance"...... used in the same sentence with  "Hydraulic" Lifter Camshaft ?

Ray Barton wrote an interesting article many years ago about the same frustration, I'll see if I can dig it up.

[Mike DC]

 
I always thought the clatter of solid cams sounded kinda cool. 

   

[Paul G]

I have a much better understanding of the situation.

Bob, as always I have to read your explanations more than once to fully grasp the meaning. You sir pack a lot of information in to a small package. 

When rebuilding a worn out engine it only makes sense that wear is going to have opened up the tolerances, that's why it needs a rebuild. Cylinder bores, bearing clearances, etc., the lifter bores are no exception. They two will have an equal amount of wear. I found it puzzling that reconditioning the lifter bores is seldomly mentioned by re builders. (other than on this forum)

If I understand this correctly, there are two ways around worn lifter bores:

Bush them and regain the correct bore sizing, oil loss around the lifter body will be back to factory spec. The hydraulic lifter will maintain internal oil pressure and lifter pump up will be at full capacity of the design of the lifter.

Use a mechanical lifter that is not dependant on oil pressure to work "correctly". Oil loss around the lifter body is not a concern since there is no internal oil pressure to be maintained inside the solid lifter.

There has to be a point where lifter bore wear is outside of the acceptable range even for a solid lifter? That is where we are still dependant on the machinist who is doing the rebuild.

For those of us who chase every last ounce of power, it sounds like solids are the way to go. A little more upkeep is well worth the extra effort for some of us. Adjusting lifters is not very hard to do at all.   

As for solid rollers, or any roller cam/lifter combo, the benefit is faster ramp rates, and longer valve opening times. Correct? Along with that is higher spring pressures to keep the valve under control. If I have this correct, the higher spring pressure is what reeks havoc on the hydraulic lifter. It seems to me that a roller cam, even a mild grind, will have a benefit over a non roller design. I guess the key is to stay with a mild grind.

This must be why the engine builders I have spoken to push for roller cams? A mild roller cam will have many benefits over a flat tappet. No zinc issues, better performance in all but the higher RPM range (which most people never see), no maintenance.

Do I have all this correctly?     

[fizz]

My question, being Unknowing, is the cost of bushing lifter bores that expensive? In the big picture, spending 10-15 thousand on an engine in a car that we may have 50+thousand in is, for a lot of us, a once in a lifetime toy. And machine work is machine work, if it needs it it needs it. So if bushing the lifter bores is a grand, for instance, I would spend it, I could name a lot of stuff on this car that cost as much for far less value. A bigger question though, in another thread they talk about warm up and thermal stabilization. I am not willing to take the time, just would not drive the car. Does a relatively mild street roller require this? I realize this means I will never be the fastest guy.

[Challenger340]

 
As for solid rollers, or any roller cam/lifter combo, the benefit is faster ramp rates, and longer valve opening times. Correct? Along with that is higher spring pressures to keep the valve under control. If I have this correct, the higher spring pressure is what reeks havoc on the hydraulic lifter. It seems to me that a roller cam, even a mild grind, will have a benefit over a non roller design. I guess the key is to stay with a mild grind.

This must be why the engine builders I have spoken to push for roller cams? A mild roller cam will have many benefits over a flat tappet. No zinc issues, better performance in all but the higher RPM range (which most people never see), no maintenance.

Do I have all this correctly?    

Yep, I'd say you have about pretty much nailed it Paul

Some final distinctions to Camshafts, just some food for thought when selecting;

The FASTER.... and FURTHER..... you can whack the Valve open with a Cam Lobe(and accurately close it again), is just more POWER pure & simple !
But obviously here,
the faster your "open and close" the Valve for power with a given Cam Lobe TYPE... the more Valve Spring Pressures are required to keep up ?
and there are limits as per different Lobe "type" applications
by things like acceptable Valve Spring pressures, and acceptable parts WEAR.... acceptable parts STRENGTH.... for each Lobe TYPE... over "time" for longevity.

From "Lowest to Highest" power potential, and typically "Lowest to Highest" acquisition/parts costs

* Hydraulic Flat Tappets are the slowest/ least power.... but quite running and less accurate because of the "hyd"(leakage) Cam Lobe motion transfer. Cheapest parts.... 100# - 120# Seat pressures... usually sub 300# over the nose V/Spring Pressures.

* Solid Flat Tappets are a little faster/ more accurate/ more power .....  but still within an F.T. 's "area" for face friction limits(.904"), and somewhat noisier, still cheap because F.T., typical V/Spring Pressures as the Hyd above 100-120# and sub 300#, but some can be extended to ~150# seat pressures and 350# over the nose for faster ramps(Hughes, etc., and faster big lifter .904" Mopar areas). Hence the REAL Mopar cams we used to LOVE prior to zinc Oil troubles, etc. but still pushing the F.T.'s useable .904" area service life.

* Hydraulic "Rollers" are faster yet being a roller.... which should be more power because a "roller", and quiet because "hydraulic".... but inaccuracy(leakage) to the faster Cam Lobe motion transfer, can be compounded by more reliance on even greater V/Spring pressures to keep up with the faster Roller ramps vrs Oil Pressure.(as discussed here on some applications).
From the V/Spring Pressures required... we can see that the only HR's typically capable of potentially MORE power utilize the 150# seat pressures and ~350# to ~450# O.T.N. pressures
(but reliant on HYD Lifter leakage for accurate Cam Lobe motion transfer to make extra power)
Alot more Money than the F.T.'s !!

* STREET "Mechanical" Rollers..... fastest yet and accurate.... but still within reasonable limits for extended Street Driving usages without killing parts/pieces/Valve Springs over time. Somewhat noisier being "solid", but reasonably quiet, BEST power thus far, BEST accuracy to Cam Lobe motion, Real Roller costs... but very close or closer to HR costs than below.

* RACE "Mechanical" Rollers... the absolute fastest ramps & best power.... but requiring the MOST Valve Spring Pressures to keep up, HIGHEST pressures on other Valvetrain Parts so the STRONGEST Parts are required, HIGHEST parts costs by far, and here is where the "confusion" sets in for useage of RACE Rollers on the street by LAYMEN ... the amount of Maintenance and Continuity required for Owners attempting to run them in a "street" environment.
Average people just are NOT prepared, or educated enough, to even realize how to "maintain" the checks/balances necessary to make them live in the street driven environment. The RACE stuff is "on the edge"..... keeping it there is critical, or things can go south($$$$) REALLY quick. It can be a very long and expensive learning curve for most to get "street" driving a RACE Roller profile right.... and even once they do, most discover just NOT worth it !
210# and HIGHER seat pressures... 550-600# over the nose and HIGHER !

Just my thoughts, very tough trying to explain this stuff, and there are always exceptions, but above are the basics.
The above explains why.....
we were trying for "decent" power using cheap/inexpensive/innaccurate F.T. Hyd Cams in those "lowly 440" Engines ?

It would have been very interesting to test the 545 hp /565 ft lb "284H" Hyd F.T Cammed Engine...... using even a "Street" Mechanical Roller Cam ?... just for shits & giggles ?.... but it just didn't fit the budget intent on cheap engines !
and YES,
exactly why Engine Builders will immediately push for any "Roller" Cam, as far easier for them to make the same power.... with far less work or attention to detail for THEM, albeit more "parts" cost to YOU.
A Roller Cam can wring more power out of a "lesser" Engine... but who cares really, "X" HP is "X" HP to a customer.... PRICE is all they typically care about ?
The problem later can be... a poorly built Engine at the same "X" HP might not stand the test of time ?
We prefer to "overbuild" the Engine... then "under" utilize the potential and last forever.

[BSB67]

It seems to me that a roller cam, even a mild grind, will have a benefit over a non roller design. I guess the key is to stay with a mild grind.

This must be why the engine builders I have spoken to push for roller cams? A mild roller cam will have many benefits over a flat tappet. No zinc issues, better performance in all but the higher RPM range (which most people never see), no maintenance.

Do I have all this correctly?    

As Bob pointed out, those are generally the rules on hierarchy.  I would say that there are exceptions particularly where the hydraulic roller overlaps with the solid flat tappet.  A decent solid flat tappet will be faster off the seat to 0.050" lift and about the same to 0.200" than a hyd. roller.  At some point in the lift the hyd roller will pass the solid FT and that is why it has more lift for a given duration.   To me, this is very important. If you have a street car that you care about idle quality, a good solid FT can idle better and make as much power as a hyd. roller.  

IMO, the main reason a guy would be pushing a hyd roller is that he does not want the risk of the motor coming back due to a wiped lobe.

You should spend some time in the master lobe catalog of some cam manufacturers.

[Challenger340]

It seems to me that a roller cam, even a mild grind, will have a benefit over a non roller design. I guess the key is to stay with a mild grind.

This must be why the engine builders I have spoken to push for roller cams? A mild roller cam will have many benefits over a flat tappet. No zinc issues, better performance in all but the higher RPM range (which most people never see), no maintenance.

Do I have all this correctly?    

As Bob pointed out, those are generally the rules on hierarchy.  I would say that there are exceptions particularly where the hydraulic roller overlaps with the solid flat tappet.  A decent solid flat tappet will be faster off the seat to 0.050" lift and about the same to 0.200" than a hyd. roller.  At some point in the lift the hyd roller will pass the solid FT and that is why it has more lift for a given duration.   To me, this is very important. If you have a street car that you care about idle quality, a good solid FT can idle better and make as much power as a hyd. roller.  

IMO, the main reason a guy would be pushing a hyd roller is that he does not want the risk of the motor coming back due to a wiped lobe.

You should spend some time in the master lobe catalog of some cam manufacturers.

YEP, what HE said  
Always exceptions across different Cam profiles/types.... I was merely trying for generalized power "assumptions", versus Lifter "types".

We're Bushing the Lifter Bores on a 440 Block right now for an HR Cam ....
I just couldn't chance it at .0015" with bottom wear in the Bore, been stung before so now I just do it.
I'll post up the Dyno data when done

[fizz]

So I found Wydendorf package of 16 oilite bushings with reamer for $400. That plus machine shop labor to install and opening up an oil passage would seem to be under a grand, so why not for a performance hydraulic lifter engine. I also noted some discussion about drilling an oil passage for lifter lubrication. I don't exactly live in Mopar country here, Anything in general I can pass along to my machine shop? You just can't beat advise gained from experience if you an get it!

[ws23rt]

This has been a very interesting and informative thread

It got me thinking again about a question I posted about sometime back.
On my motorcycle project the engine block is not drilled for oiling the lifters (It's a KB alum block). That fact is something I missed when I ordered the cam and hydraulic lifters. (The cam is a stock hemi grind.)  The engine is all assembled with alum. roller rockers and not been started yet.
My question was/is---- Is their a solid lifter out their that can take the place of my hydraulic ones?  It was recommended that the cam I have be changed as it would/may not last long with solid lifters.

The engine in my application will never see full power or many miles  Changing the cam is not such a big deal but I'm still interested in the question and what is the difference at the cam lobe that make them different?

[six-tee-nine]

I'm not an axpert by all means on building V8 engines and I mostly only read this stuff because it is really interesting stuff.

So I read alot of storys about guys popping lifters beacause of lifter failure or bleed down. Would'nt it be better to build an engine on the safe side to put in solid rollers for instance? Not thinking about money now but its just a form of insurance when you misshift your 4 speed rpm's can bump up pretty nasty.
Its not that most of us run that many miles a year. So checking the valve clearance once a season will probably do just fine.
OK I'm a mecanic on lots of industrial diesel equipment, so valve adjustment jobs is something I could almost do blindfolded, but then again its something a average home mecanic can do just fine.