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Roller Cam or Flat tappet?

Roller or Flat tappet?

9K views 57 replies 24 participants last post by  Reelysalty 
#1 ·
After reading the Maxima oil thread, and the comment about "who runs a flat tappet here" compared to "who has a car with a catalytic converter". I am very curious to know that answer.

I would like to have a MJ built roller but during my restoration the budget was already stretched, so I have a flat tappet.
 
#2 ·
Mike, it took me a while to save for the MJ bullet, and yeah, I paid for and wanted Mark to set up the roller valvetrain.

My 427's solid cam was NEVER an issue. EVEN after I tried to run it in with .100" lash on both #1 valves. ( i kid you not, I have no idea how I screwed up) 30K , TWO break-in procedures as my engine stand rolled one day and all the lifters hit the garage floor ( F-bombed for two days on that one) had Delta regrind the faces, ran her in again and still ticking. No problemo.

So even a hapless idiot like me can run a 7500 rpm solid flat tappet cam successfully. And not a lazy L88 cam either, a really intense modern lobe cam. (same 200" durations as L88 with like 35-40 less seat!) using Isky 8005a springs, and Ti retainers. ( which are not really neccessary)


APPROVAL VOTING is a balloting technique we should use in all our single winner elections. Its really simple, vote for all acceptable choices. The math does a great job of finding a winner, in a large enough sample size.

But most polls, like our antiquated system of real voting, don't allow this.

I vote for BOTH flat tappet and roller.
 
#3 ·
The Org. born with engine in my LS-5/M-22 Camino has been running Pennz Oil since new. Now for the last 15/20 years I have been using " Brad Penn racing oil."
My 70 ( FRAUD SS-454 Sta. Wgn.) driver has a 468 with 44.000 miles on the engine. All of the miles are with the Brad Penn Racing oil. Both of my 70s are flat tappet and both use Brad Penn. I have no intention of reinventing the wheel. My flat tappet B.Blocks will use Brad Penn until I no longer own them.
Bob
 
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#8 ·
Back in the 1980's , US Army's SF groups had a "keep it simple" motto borne from real combat experience. It has real merit. ( now they all wired up and digital).


The other thing Tom ( DZ), and I know you do all your own work, but if I am going to pay a pro like Mark Jones, 1.) I'll do what he recommends, and 2.) that may be the time to add the $1000+ extra, as I did. ( I saved some $$ by reusing my Crower steel rockers. )
 
#6 ·
MOST of my engine experience over the past 55+yrs has been with flat tappet cams. And I have NEVER had an issues with any of my flat tappet engines.
Although, I will concede that a roller cammed engine, compared in every identical way to a flat tappet engine, will produce more power. PERIOD. BUUUUUUUUUUUUUT, does the added expense of a roller cam package (usually about $1000) justify the added gains? That is a personnel call. We recently built a roller cammed, flat top piston SB400 for my son's 73 Vette and he absolutely loves it!
 

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#9 ·
Some of my personal thoughts on the matter:

1) there are still a lot of GM/Chevy trucks on the road that came from the factory with flat tappet cams and lifters....running whatever oil you dump in them.

2) the problem that you run into TODAY is where do you buy decent flat tappet lifters?

3) I don't have the empirical data to back this up, but I have a hypothesis (not a theory) that the success rate of roller lifters in SBC motors is very high.
The second part of this theory is that BBC roller motors have significantly higher failure rates than the SBC, whether the lifter is Morel or whatever brand you like.
I opine that the inconsistency of push rod length in the BBC world is the primary cause of this.....meaning that a lot of amateurs and hobbyists are using the wrong length pushrods in their roller BBC motors and wind up paying the price.

Just my two cents..........
 
#10 ·
For the past several years, I have gone to Walmart and bought Rotella 15-40 in 1gal jugs. That's what I've been using in all my engines----------------------- ZERO issues.
I use synthetic 5-30 from Walmart in 5gal jugs for the 04 Impala SS and 12 Tahoe. Both have over 100,000mi.
 
#12 ·
In my opinion you need the same good oil with a roller cam as you do with a flat tappet.
And if you have a flat tappet with the same duration and same lift as the roller which one will be better.
Neither in my book.
I like my flat tappets much more than a roller cam.
Crower cam saver lifters for my Hydraulic flat tappets and Howards EDM for my solid flat tappets.

Driven BR oil for break in.
VR1 after that or Driven or as DZAUTO stated the Rotella in some types is still decent.

I also got away from valve springs with dampers in them. Beehive Ovate springs now with small light retainers.
 
#13 ·
I haven't built a flat tappet motor in many years and when I left the machine shop 80% of our engines were roller. We had camshaft rule circle track motors we did with flat tappets so they had no choice. But I am not even sure today how much of the issue lies in oil. Granted oil is a helper but I think with the metal makeups being used the parts are failing no matter what oil you use.
 
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#14 ·
I don't remember anyone mentioning stagnant usage, or starting your engine once in 4 months or so. I doubt I'm unique in that I've got too many cars that just sit, can't drive them all and I'm a busy man. Does a roller cam make more sense in that case? I've got a few ft cams and only had one lobe go south many years back in a 355 that I just ran Shaeffer semi syn. which has descent zinc/phos numbers, but nothing like BP or VR1. I have 2 rollers here, one solid, one hydro., and they both make noise that I don't care for.
 
#15 ·
I don't know that I would start them if they are just going to sit. I think I would let them sit and only start them when its time to start using it. Its just as bad letting a roller motor sit for long times with an oil with a low cling ability. The rollers are all dry and unnecessary starting is not good. You are better priming it first, or just starting it and going. My race engines used to sit all winter, but I would change the oil in the spring and pour it down over the cam and lifters before initial start up.
 
#18 ·
I voted flat tappet but have gone with roller in the past. They certainly run better then a flat tappet. You can have the same power or better and have better vacuum and better driveability BUT!. First the retro kits are expensive. Second with the fast ramp design they stress out engines designed for flat cams so you will need to beef up your valve train, full roller high quality rockers, screw in studs, guide plates etc. You are easily looking at over a grand. With my car today and being number matching I was forced to stay stock (but that hot flat tappet sure does sound nice) but if I was building a car I would probably go to an better design later Chevy block (6.0 LS) with roller everything and fuel injection. Direct injection even better! With all that said I just sold my 2014 Gt500 with 662/631 hp/tq and that extremely streetable engine was very docile until you hit it then it scared the hell out of me. New England twisty roads can't handle a car that goes sideways at 100mph:laugh:
 
#20 ·
If I could be guaranteed that a $4-5-6k+ build would not be destroyed using a FT cam I would consider one.
 
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#23 ·
while gone on many deployments my wife would start start the cars once a month and let them idle to warm-up and give some cycles of the throttle.



1975 Chevy Dually mostly stock 454 w/stock cam. My daily driver for 14 years. Furthest it has ever been torn down was to replace head gaskets. Didn't even replace the rods or lifters when the intake came off. Still going at 376,000 mi.




Idle time is the worst time for a Flat tappet cam. It needs splash oiling.


376,000 miles stock cam 454 from 1975..Good job there and I bet money it has the Delphi hard foot lifters in it and very minimal spring pressure.
It's life began and continued for a long time with oil that was probably in the 1400 PPM ZDDP levels.
 
#24 ·
Now put some dual springs in there, a stiffer cam with some lift and rev it out on a regular basis...that's IMO what exposes cam issues whether its cam/lifter related or block related.:crying:
 
#30 ·
I agree with parsons and a few others. I am a semi retired automotive maschinist and also a proponent of f/t cams. Years ago we never had a problem and if there was it was rare. I know all the arguments and have chimed in on most both here and tc.how ever i have to say this , throughit all the problems seemed to be with two particular brand cams and then a third. Most of the problems were with the fast ramp stuff but those 3 had all around problems. I personaly believe most of it was overseas inferior quality cores an garbage lifters and the lack of zdp . On the oil thoughthe additive pkg should take care of all previous specifications .that being said during this whole debacle how come there were never any cam failure posts on iskenderian engle crower clay smith schnieder howards erson and a few others . They sold cams and lifters all during the time and they seemed not to have a problem . This leads to the question were the other three pushing the cam design envelope too far did greed for higher profits fuel buying inferior overseas parts. To date i still use ft cams isky rev lube vr-1 motor oil silver bottle and wont buy a cam from any of those three with the original problems . I would also saythat the only decent lifter you can buy is the pro topline johnson lifter as gm no longer makes thier own ft lifter. To date with proper oil and break in like parsons i have had no problem . Good stuffis always good stuff and most times you get what you pay for. In closing one company offers a hardening service for thier cams that adds a hefty price to the cam. If your product is good why does it need to be hardened isky dont harden nor do the others and no problem alex
 
#38 ·
Radical is a misplaced word, more lobe intensity, sure.

What I didnt include in my " I finally saved my nickles and dimes and a had a real pro build my next engine" reply above is that I also told Mark Jones
the only real design parameter was to push out 600 ft lbs. Reely, not to put words in Mark's mouth, but if I had said i'd like to see WELL over 600 HP, he may have used a big trad solid flat tappet as likely as a solid roller.

I think Harold's old UD solid FT cam was more intense than the Isky hyd roller in fact. ( PS I'd love to see one of Mark's totally done builds, where he can only choose from amongst the old skool UD Harold grinds. Oh, if I ever won the lottery, the stupid stuff I'd do! )
 
#32 ·
IMHO it's like Chris Straub mentioned about the demand and source for hyd flat tappet lifters not to mention the touchy break in, I broke mine in on my 454 (summit/crane cam & lifter kit) 7-8 yrs ago and it went fine, would I trust that to happen again? 50/50 so I opted for a hyd roller and howards max effort lifters, roughly $600-$650 more but I'll sleep better
 
#37 ·
"they wipe lobes" or "the roller lifters scatter crap all through my engine", you decide.
Those are both concerns for each type, and I'll add, the roller valvetrain is noisy, requires very specific oil, and costs a ton more.
If you're tearing the intake, balancer, timing cover off, probably the oil pan, and resetting your valve adjustment, why is so tough to break a cam in?
 
#40 ·
Say what? Millions of cars are produced each year with roller cams, how many cars are still produced with flat tappet cams?


And if you are just talking a solid roller cam, then you're also not going to make anywhere near the power with a flat tappet cam that you'll see with a solid roller cam.

But hey,, I guess you're forgetting all about the quiet hydraulic roller cams that make excellent power, are easy on parts and last a very long time.
 
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