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Re: roller vs mechanical flat tappet cam?
[Re: gsmopar]
#1260953
07/03/12 10:20 AM
07/03/12 10:20 AM
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Joined: Jan 2012
Posts: 2,646
Stuttgart, Arkansas
rickseeman
master
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master
Joined: Jan 2012
Posts: 2,646
Stuttgart, Arkansas
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I've lost count of how many blown up roller cam motors I've bought in the last 35 years. Can't remember buying any blown up flat tappet motors. The lift you are asking for doesn't take much spring pressure over stock. It should last forever. Flat tappet motors also make their power at a lower rpm, which makes for a longer life engine. Nearly all drag racers think they have to have a roller cam. What a joke. You can make over 800 HP with a low rpm, low spring pressure flat tappet that will last a long time.
2011 Drag Pak Challenger
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Re: roller vs mechanical flat tappet cam?
[Re: sshemi]
#1260956
07/03/12 04:21 PM
07/03/12 04:21 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
I think that a roller is better for power in every way but i have seen a few roller lifter bearings fail and its not pretty.
And in most cases(not all) the spring pressure was
too light OR the springs wore out... some cases the
roller lifter was just a inferior product ...JMO
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Re: roller vs mechanical flat tappet cam?
[Re: gregsdart]
#1260958
07/04/12 02:01 AM
07/04/12 02:01 AM
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Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
jyrki
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master
Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
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I converted to a roller in a street car around 1994. The reason was that I wiped out three MP cams during a short period. I have used dozens of different cams since then in different build ups. In my opinion, there isn't an absolute truth here. There really is a reason why the OEM manufacturers use rollers nowadays too, it just makes more power than a similar flat tappet. It also accepts way more aggressive grinds, which requires and can use way stiffer valve springs etc. That of course stresses the other valvetrain components alot more than a flat tappet will ever do. However, a similar flat tappet would kill everything + itself there immediately. In a race car with frequent checking and maintenance, I would say go for it. And with an aggressive race grind. In a streeter, if you pick a "street roller" that doesn't require extreme spring pressures etc., I would say that the relaibility is at least as good as with a flat tappet, but the manners and power better. The real question is, that is the advantage for you worth the 1000$ or so you have to spend upgrading?
Plynouth VIP '67 TT IC EFI
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Re: roller vs mechanical flat tappet cam?
[Re: gregsdart]
#1260959
07/04/12 02:07 AM
07/04/12 02:07 AM
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Joined: May 2009
Posts: 511
Temperance, MI
68 HEMI GTS
mopar
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mopar
Joined: May 2009
Posts: 511
Temperance, MI
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rollers work well, you just gotta suck it up and send the lifters back for a rebuild every few years. especially, if they don't oil the needle bearings directly. i send my comps back every 2 years that are in my Hemi, but it also see's tons of street miles and some stop and go traffic. think i idle'd more yesterday going 30 miles (one way) than i did all last year.........
68 Dart GTS "HEMI" 10.30 @ 131 pump gas street car 3780#
69 Roadrunner 511 six pack 10.92 drive to track street car
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Re: roller vs mechanical flat tappet cam?
[Re: rebel]
#1260961
07/04/12 04:48 AM
07/04/12 04:48 AM
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Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
jyrki
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master
Joined: Jan 2003
Posts: 2,932
Finalnd, Perkele
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I believe it was 100-150$? I have never done that, for the very same reason
Plynouth VIP '67 TT IC EFI
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Re: roller vs mechanical flat tappet cam?
[Re: jyrki]
#1260962
07/04/12 11:07 AM
07/04/12 11:07 AM
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr
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master
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
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ive been reading along...and if i base my conclusion on what has been stated here ...I would come up with the complete wrong impression of a roller cam. the tradition for rollers in racing in the beginning was to fill the need for going ultra agressive...so that created the roller cams reputation.. however...if you get a cam turned for your specific application. then throw this montra out the window "roller cams are best suited for high rpm application" that statement/mindset is misleading. the roller lifter opens up the valve lift profiles to dimensions not avail in a flat tapit. this means Torgue ..you can build in torque..you can build in low lift or low rpm performance. id venture to say...take what you can do with a flat tappet for whatever your application...and add a %20 better results with the roller lifter over what you did with the flat tappit...its geometry and mathmatics plain and simple... the only negative factor to add (as stated) is lifter weight...but honestly that only applies in higher or extreme applications...and can be designed around.. for what your doing...you will see definate gains..just dont base your new roller cam choice on flat tappit profiles...get a roler profile that best suits your heads flow graph and valve lift limitations.. fwiw..  my advice with your sinario is get a set of doug herbert roller lifters and do up a roller cam for your application get oil pump drive ..use the springs herbert recomends. .and go faster than you went last yr.... 
365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
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Re: roller vs mechanical flat tappet cam?
[Re: cheapstreetdustr]
#1260965
07/04/12 01:16 PM
07/04/12 01:16 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
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master
Joined: Oct 2003
Posts: 7,506
Az
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The OEM's went to rollers to be able to meet the EPA standards ( and a good portion of that was to cut friction losses ), not for performance reasons. Street grind flat tappet cams can easily duplicate roller performance with a lot less valve train stress - and BTW, those high load valve springs needed with rollers affect valve train longivity at ALL rpm's - all the time. That equates to not only higher initial valve train $, but higher $ throughout the entire life of the valve train( and only the valve train if you are lucky ). The point I have been trying to make here is not that rollers are a bad thing, but that they are mismarketed by many cam manufacturers ( for obvious reasons - $$$ ) and sold to the ( to be kind ) less knowledgeable as a major performance gain when in most street and mild performance appications they are not. JMO. My suggestion is that before you pop for a roller cam, take a good look at your particular application. Don't just jump in to a roller because " all performance engines gotta have one".
Last edited by Crizila; 07/04/12 01:19 PM.
Fastest 300
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Re: roller vs mechanical flat tappet cam?
[Re: Crizila]
#1260966
07/04/12 01:59 PM
07/04/12 01:59 PM
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Joined: Jan 2012
Posts: 323
A57_RT
Parts Problem
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Parts Problem
Joined: Jan 2012
Posts: 323
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Its funny this comes up every so often. For years now ive been using the Beck/SM solids in both the std and leightweight version. Even there heavy one is lighter then most anything offered. On cams under .650 lift I can use modest (far less then a roller needs) springs, good quality rockers and pushrods and run to the chipped 7600 limit, one set is on the 5th cam, testing/dyno now in a car so that makes the cost worth it imo vs comps pig heavy edms thay call lightweight. I do have one motor with the comp edms, never broke the cam in as by the book, just used rot. one can of old stp and I use a hp spring in the pump with the thoughts the edms will oil more at idle???? Never an issue if the lifter will spin in the bore, if the lifter is tight, try a different hole, if its the hole hone it. When I was younger and took blocks to one of the better shops I used they always wanted the lifters and the pistons I was going to use, each time the block came back with a small cross hatch pattern in the lifter bores  Who knows.
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Re: roller vs mechanical flat tappet cam?
[Re: Crizila]
#1260967
07/04/12 02:05 PM
07/04/12 02:05 PM
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr
master
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master
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
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Quote:
The OEM's went to rollers to be able to meet the EPA standards ( and a good portion of that was to cut friction losses ), not for performance reasons. Street grind flat tappet cams can easily duplicate roller performance with a lot less valve train stress - and BTW, those high load valve springs needed with rollers affect valve train longivity at ALL rpm's - all the time. That equates to not only higher initial valve train $, but higher $ throughout the entire life of the valve train( and only the valve train if you are lucky ). The point I have been trying to make here is not that rollers are a bad thing, but that they are mismarketed by many cam manufacturers ( for obvious reasons - $$$ ) and sold to the ( to be kind ) less knowledgeable as a major performance gain when in most street and mild performance appications they are not. JMO. My suggestion is that before you pop for a roller cam, take a good look at your particular application. Don't just jump in to a roller because " all performance engines gotta have one".
i dont mean to digress but HUH?
frictional losses at the lifter ? = emission output?
more like valve events..that allow for a longer burn cycle to take place before exhaust valves open sending incomplete combustion gases out the tail pipe. that constitutes emissions..
holding the valve closed longer in degrees of crankshaft rotation extends the burn cycle..then having an opening ramp rate faster so the valve opens to the same lift rate later in crank rotation..achieving the same or more optimal max open rates in relation to crankshaft degrees..is more likely...
or Intake valve events that prevent reversion and egr issues.
seems more likely the causation..
now if we where talking oem extending the oil changes to 10,ooo miles.because of rollers..you may have causation to justify that one...?
365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
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Re: roller vs mechanical flat tappet cam?
[Re: cheapstreetdustr]
#1260968
07/04/12 03:29 PM
07/04/12 03:29 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
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master
Joined: Oct 2003
Posts: 7,506
Az
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I think we are kinda saying the same thing here re the emission thing - although a part of it was to cut friction losses. Extended oil changes came about by mostly better oil ( synthetic in particular ).
Fastest 300
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Re: roller vs mechanical flat tappet cam?
[Re: Crizila]
#1260969
07/04/12 04:52 PM
07/04/12 04:52 PM
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr
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master
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
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you get more valve lift or gain a broader span of valve control across the lobe with a roller trunnion than you can physically achieve with a flat tappit..
so saying you can do the same thing with a roller just doesnt compute.
you can have a steeper ramp which speeds up lift.
or you can move the valve lifter earlier or later in the lobe position in relationship to crankshaft degree of rotation..fwiw..
there is an advantage here..you cant utilise with a flat tappit...
granted a .904 diameter lifter affords us mopars more options..but no where near what a roller offers...fwiw.
365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
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Re: roller vs mechanical flat tappet cam?
[Re: cheapstreetdustr]
#1260970
07/04/12 04:59 PM
07/04/12 04:59 PM
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr
master
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master
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
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its not just more lift..thats simple..its more lift earlier (intake lobe/tapit) or later (exhaust lobe/tapit) at points you cant achieve with a flat tappit...
you can get aggressive loge ramps with a flat tappit but at some point you put too much side load on the lifter..
and the lobe sweep across the tappit face you will find a numb spot...where the lobe moves/crankshaft degree of rotation moves..ie piston moves..
but the valve no longer does...
this is why the roller is superior.
365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
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. Should have known better. This car runs the 1/8 and we shift at 5500 and runs 7.20 consitantly or should I say ran... Its just a 440 that had a .590 purple shaft. Ran good and consistant had no complaints with performance. We dont really wanna turn that many Rs because we dont wanna spend the money to do so lol. So it sounds to me like unless we wanna turn mor RPM stick with the flat tappet and just keep the cam lube in stock. 
