flat tappet vs. roller
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Instructor
Joined: Sep 2006
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flat tappet vs. roller
Once I get my tranny rebuilt and back together I should have my car back down the road with a temporary motor (spun 3 bearing on the previous one 
)
I will then start rebuilding the blown motor and I would like to take my time and put good parts into the new motor so that it will potentially have more power but more importantly be very drivable and reliable.
I will probably need to have the block bored over a bit and I plan to get the holley commander 950 TBI kit instead of carburation.
My next thought for this new motor is building a full roller setup. i'm already running Crane full roller rockers, but would like to know the advantages/disadvantages of going with a hydraulic roller instead of flat tappet hydraulic setup.
I know that it could give more power and durability as there is less friction between the parts.
I'm of course looking at about $400 for a set of roller lifters as apposed to about $80 for regular hydraulic lifters... so would it be worth over quadruple the price?
)I will then start rebuilding the blown motor and I would like to take my time and put good parts into the new motor so that it will potentially have more power but more importantly be very drivable and reliable.
I will probably need to have the block bored over a bit and I plan to get the holley commander 950 TBI kit instead of carburation.
My next thought for this new motor is building a full roller setup. i'm already running Crane full roller rockers, but would like to know the advantages/disadvantages of going with a hydraulic roller instead of flat tappet hydraulic setup.
I know that it could give more power and durability as there is less friction between the parts.
I'm of course looking at about $400 for a set of roller lifters as apposed to about $80 for regular hydraulic lifters... so would it be worth over quadruple the price?
Last edited by ram100987; Apr 30, 2007 at 11:00 PM.
Drifting
Joined: Aug 2004
Posts: 1,883
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From: Lubbock TX
BINGO! With more and more oils removing zinc and other contact-wear additives, you'll see more and more flat tappet cams with lobes going away, even after years of service. One defective lobe on a flat tappet cam will cost a good bit more than going roller in the first place - engine removal and tear-down, bearings, new cam and lifters, yada yada. Roller is the only way to fly, IMHO, and you can have better performance and driveability at the same time.
Last edited by L88Plus; May 1, 2007 at 07:47 AM.
Safety Car
Joined: Jul 2002
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From: St Louis MO
I'm still not convinced the cost of the full roller valvetrain is offset by power gains over a similar flat tappet setup. Does anyone have any hard numbers on this? Me thinks it's hard to beat a good solid flat tappet cam with a roller anything.
Drifting
Joined: Aug 2004
Posts: 1,883
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From: Lubbock TX
One of the car rags did an article a few years back titled "The Lash Word" that compared the four different types of cams. See if you can find it on the web, it demonstrates the power differences. I'll agree that a good solid flat can make impressive power, even above a hydraulic roller due to higher rev ability, but the solid roller is clearly the king of the pack due to it's insane high lift ability. With the newer rollers with pressurized pin oiling, they're becoming more and more streetable and durable. I'm going to go with Isky's new bushed rollers and about .725 net lift and shaft rockers. I only want to build this thing once and have had the "I wish I'd have ..." enough to know that it's cheaper in the long run to go ahead and build the biggest and strongest possible, I generally end up there anyway after spending money on the lesser parts.
Le Mans Master
Joined: Apr 2007
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From: Graceland in a Not Correctly Restored Stingray
The only push-rod engines with flat tappets in any serious form of racing are either there by rule, because of a lack of available parts or funds, or due to a lack of experience. Just a simple fact.
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Burning Brakes
Joined: Mar 2006
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From: Lima, OH -- 69 L71 427/435hp
How much lift you plan on running? Unless you plan to race it often or running a radical cam with high lift, then flat tappet will be fine for romping it around town...not to mention flat tappets have a distinct sound. 
Safety Car
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From: St Louis MO
Brett
Le Mans Master
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hydraulic roller would be nice over a hydraulic flat tappit, cost
will be four times as much you may gain another 25/35 hp.
New Z06 coupe costs $25,000 more then a regular coupe and
the HP differance is only 100 HP.
will be four times as much you may gain another 25/35 hp.
New Z06 coupe costs $25,000 more then a regular coupe and
the HP differance is only 100 HP.
Last edited by Little Mouse; May 1, 2007 at 04:19 PM.
Le Mans Master
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From: Graceland in a Not Correctly Restored Stingray
Sorry, I didn't understand that question about performance as having been qualified by a "bang for the buck" factor. But, I'll concede that if you're on a tight budget, that's certainly a consideration.
Even so, although I've been happy with the solid flat tappets I've run on the street in the past, I'll never go back. Just wipe a lobe and you may become a convert, as well.
And, solid rollers sound good, too.
Even so, although I've been happy with the solid flat tappets I've run on the street in the past, I'll never go back. Just wipe a lobe and you may become a convert, as well.
And, solid rollers sound good, too.
Last edited by TheSkunkWorks; May 1, 2007 at 04:23 PM.
Safety Car
Joined: Jul 2002
Posts: 3,770
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From: St Louis MO
Also, most lifter peddlers now market a lifter with a laser-hole in the face to improve lubrication at the lobe/lifter interface. I got the Crower Cool-Face lifters when I did my cam swap years ago. That cam is still alive and kicking in my big-block and gets a steady diet of high-zinc diesel oil. Valve adjustment on my solid cam happens every spring and they're never more than .001"-.002" off. Of course, you never have to adjust hyd lifters but they don't sound nearly as cool as solids!
Brett
Burning Brakes
Joined: Dec 2004
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From: Nederland Texas
Hey Brett,
When I started my engine I used the Rotella but now it is being made with low-zince content. What do you plan to run? I have a roller cam so it's not as critical but I really liked that oil.
-Patrick
When I started my engine I used the Rotella but now it is being made with low-zince content. What do you plan to run? I have a roller cam so it's not as critical but I really liked that oil.
-Patrick
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From: St Louis MO
Team Owner
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From: All humans are vermin in the eyes of Guru VA
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Advanced
Joined: May 2005
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From: '70 Coupe - SoCal
I like solid flat tappets myself. My concern is tie bar reliability. You will never see a flat tappet motor be destroyed if the lifter turns 90 degrees. Do a search on roller lifter failures & you'll see what I mean.
Safety Car
Joined: Jul 2002
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From: St Louis MO
Not to mention bearing failures. Not much can fail inside of a solid lifter.
Burning Brakes
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From: Lima, OH -- 69 L71 427/435hp
I plan to break engine in with Rotella, then run Royal Purple, if you check oil analysis RP is up there far as zinc/moly count, but it's $7-10 a quart.