We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Flat tappet vs roller

General engine tech -- Drag Racing to Circle Track

Moderator: Team

donsboy
New Member
New Member
Posts: 11
Joined: Sat Mar 26, 2011 1:55 pm
Location:

Flat tappet vs roller

Post by donsboy » Tue May 12, 2020 7:27 pm

Good afternoon gentlemen. I'm bored silly during this pandemic and found some free parts on Facebook. I'm going to build this sbf for the street nothing radical just good street performance. Is it worth the cost to convert to hydraulic roller lifters? Is there enough performance gain to spend $800+ for just lifters plus the cost of a custom reduced base circle cam? I found a 70s 302 block for a giveaway price should I just find a later roller motor or just use the flat tappet cams? Do I need zinc at every oil change or just during the cam break in period? Thanks for all your help to a middle age guy that loves cars but needs guidance.

frnkeore
Member
Member
Posts: 194
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Flat tappet vs roller

Post by frnkeore » Tue May 12, 2020 7:56 pm

If you can provide the roller cam, .050 timing, lift and duration, I might be able to help.

donsboy
New Member
New Member
Posts: 11
Joined: Sat Mar 26, 2011 1:55 pm
Location:

Re: Flat tappet vs roller

Post by donsboy » Tue May 12, 2020 8:12 pm

Havent decided on any of that yet. Will a low use hot rod benefit enough to justify the cost

jeff swisher
Guru
Guru
Posts: 1084
Joined: Wed May 23, 2007 11:13 am
Location: yukon ok.
Contact:

Re: Flat tappet vs roller

Post by jeff swisher » Tue May 12, 2020 8:41 pm

I have access to free camshafts. Lifters I must buy. I have good roller lifters on the shelf of my own and I still like using flat tappets better.

maybe because I am using old heads and am not worried about making that extra 20HP and I have seen way too many failed roller cams come into the cam shop to have faith in them.

Good oil with either type of cam is a must for me.
For flat tappet cams I use Crower cam saver lifters and Gibbs Driven break in oil.
Then use their Hot rod oil or VR racing oil.

If you are after those last 20 Horses and wish to run short duration like 218-230 @ .050 and get the lift up in the mid 500's like 550" or so then a roller is the way to do it.
If you are running under 500" lift and duration like the above I say keep with the hydraulic flat tappet.

I have ran a roller but it was almost identical to a flat tappet and Not any real power difference to speak of.
Both would rev clean to 7000 rpm Roller was 228@ .050 .492" lift on a 110LSA.
Flat tappet was a 230@ .050 .480" lift on a 110 LSA.
12 second 3600lb car with a 350" with that flat tappet.

Decide what your goal is with the car.

Flat tappets do not scare me and I pull my boat with the above 12 second car..High 12's.
Buddies 6.0LS ate his roller cam from over revving it with too little spring pressure.
Lasted less than 4 months. 130 seat pressure and 304 open pressure Beehive PAC spring 313 rate .557" lift.

I ran the same springs on my roller cam which is the same grind but I have gen 1 and 1.5 rockers.
7200 rpm I have seen many times with my Gen 1 roller his LS 6.0 did not work well with those springs.

Just information that your bored silly brain may like to use.

frnkeore
Member
Member
Posts: 194
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Flat tappet vs roller

Post by frnkeore » Wed May 13, 2020 2:13 am

Since 218 to 230 @ .050 cams have been mentioned. I'll use a ~220 @ .050 cam profile, for comparison.

First, your fortunate that you have a Ford, with .875 lifters to begin with. What I will compare are Howards .875 hydraulic FT profile, with their most aggressive standard hydraulic roller profile.

---.020 - .050 - .200 - lobe lift
HR 248 - 221 - 138 - .317 x 1.6 = .507 lift
FT 244 - 220 - 138 - .339 x 1.6 = .542 lift

In this case, the FT is the clear winner. All the off the shelf cams, are ground for .842 (SBC) size lifters.

You have to order the .875 cam, as a custom cam. Howards sells the custom FT cams for $159. You supply your own lifters or buy with cam.

F-BIRD'88
Guru
Guru
Posts: 7541
Joined: Tue Mar 27, 2007 6:56 pm
Location: Ontario, Canada

Re: Flat tappet vs roller

Post by F-BIRD'88 » Wed May 13, 2020 4:20 am

I use this Moly additive in my oil for flat tappet wear reduction
MolySlip E Oil Additive. google it.
an altrernative is Liqui- Moly (additives and motor oils.

These are alternatives to using specialized racing motor oils
like Brad Penn / Driven brand that contain moly and zinc.
I use Shell Rotela T 15w40 oil. along with the MolySlip E.
Either way works.
The MolySlip E Oil additive contains both Moly and some Zinc..as effective anti wear anti scuff motor oil additives.

If you want to build a high reving (6500+ rpm)302W motor consider a solid flat tappet or solid roller cam set up (street roller)
say if with a single plane intake that likes rpm.

My427stang
Expert
Expert
Posts: 789
Joined: Fri Sep 09, 2005 11:04 pm
Location: Omaha, NE
Contact:

Re: Flat tappet vs roller

Post by My427stang » Wed May 13, 2020 7:50 am

donsboy wrote:
Tue May 12, 2020 7:27 pm
Good afternoon gentlemen. I'm bored silly during this pandemic and found some free parts on Facebook. I'm going to build this sbf for the street nothing radical just good street performance. Is it worth the cost to convert to hydraulic roller lifters? Is there enough performance gain to spend $800+ for just lifters plus the cost of a custom reduced base circle cam? I found a 70s 302 block for a giveaway price should I just find a later roller motor or just use the flat tappet cams? Do I need zinc at every oil change or just during the cam break in period? Thanks for all your help to a middle age guy that loves cars but needs guidance.
It's hard not to recommend hyd rollers for a street engine, for the most part, there are more options in the lobe catalogs, you don't have to worry about break in, etc, and after the initial cost it's really a no-brainer especially on a 302. We say no need for special oil, but the engine still needs good oil, and in some cases like Morel, they like a specific viscosity range, but super-easy to meet (they won't fail but behave better)

On the flip side, once flat tappets break in, yes they need the correct oil, has some additives, mostly zinc, that keeps them alive, but the biggest thing is proper assembly, parts choice, and break in until they burnish (mate, polish, break in etc) and then they need less. I actually run flat tappet on my own in my signature, mostly because I am cheap and don't pay myself well, LOL, but they do work. Spring pressures are generally less, etc.

In the end though, when someone comes to me for a street/strip non-class engine, I will do either, but when comparing the cost difference, I ask them to consider the loss of a lifter or cam lobe, especially if I ship or the engine sits around. 800 for rollers, minus the 300-400 for flat, then add a disassembly and cleaning and replacement of the flat tappet (if it doesn't damage anything else), for the mainstream motors, it's tough NOT to go HR based on risk
70 Mustang, 489 FE, TKO-600, Massflo SEFI, 4.11s
71 F100 SB 4x4, 461 FE, 4 speed, port injected EFI, 3.50s

CGT
Guru
Guru
Posts: 1969
Joined: Sun May 10, 2009 12:29 pm
Location:

Re: Flat tappet vs roller

Post by CGT » Wed May 13, 2020 8:43 am

My427stang wrote:
Wed May 13, 2020 7:50 am
I ask them to consider the loss of a lifter or cam lobe, especially if I ship or the engine sits around. 800 for rollers, minus the 300-400 for flat, then add a disassembly and cleaning and replacement of the flat tappet (if it doesn't damage anything else), for the mainstream motors, it's tough NOT to go HR based on risk
I agree, the only benefit to the flat tappet is initial cost, but consequential cost could be much higher. I guess I could see some merit in a flat tappet, if the desired duration and lift, spring pressure etc was so small that the roller couldn't add area....but who does that? Also with hot rods, that see only occasional use, I think that is the worst scenario for keeping a flat tappet alive...months on end of all the residual oil running off of the lifter faces and lobes until startup.
There are basically two types of people. People who accomplish things, and people who claim to have accomplished things. The first group is less crowded.
Mark Twain

Golf is a good walk spoiled.
Mark Twain

Walter R. Malik
Guru
Guru
Posts: 4838
Joined: Tue Jul 24, 2012 11:15 am
Location: Roseville, Michigan (just north of Detroit)
Contact:

Re: Flat tappet vs roller

Post by Walter R. Malik » Wed May 13, 2020 10:12 am

donsboy wrote:
Tue May 12, 2020 7:27 pm
Good afternoon gentlemen. I'm bored silly during this pandemic and found some free parts on Facebook. I'm going to build this sbf for the street nothing radical just good street performance. Is it worth the cost to convert to hydraulic roller lifters? Is there enough performance gain to spend $800+ for just lifters plus the cost of a custom reduced base circle cam? I found a 70s 302 block for a giveaway price should I just find a later roller motor or just use the flat tappet cams? Do I need zinc at every oil change or just during the cam break in period? Thanks for all your help to a middle age guy that loves cars but needs guidance.
Tie-Bar type hydraulic roller lifters are available from almost anywhere to fit that application and are well under $500.00 not to mention that any replacement standard base circle camshaft can be used with them.
http://www.rmcompetition.com
Specialty engine building at its finest.

User avatar
CamKing
Guru
Guru
Posts: 9531
Joined: Wed Aug 08, 2007 4:05 pm
Location: Denver, NC
Contact:

Re: Flat tappet vs roller

Post by CamKing » Wed May 13, 2020 10:59 am

It really depends on the RPM you want to run. If you're not going over 6,000rpm, a hydraulic flat tappet cam will be plenty dependable, and you would probably never notice the power difference between it, and a hydr roller.
Mike Jones
Jones Cam Designs

Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449

User avatar
BOOT
Guru
Guru
Posts: 1781
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: Flat tappet vs roller

Post by BOOT » Wed May 13, 2020 11:29 am

One advantage to roller is if you plan on swapping cams you don't have to break it in each time and buy new lifters. Course you could buy a few flat tappet cams & lifters vs one set of just the tie bar roller lifters since it's not oem roller block.

I like cheap mild flat tappet cams or oem roller, I've read/herd a few times above .480 lift the advantage goes to a roller cam but as some mentioned in here it's prob more bout duration. As always no simple one answer works for all, just depends on your app
Channel about my projects https://www.youtube.com/user/BOOT350V

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!

frnkeore
Member
Member
Posts: 194
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Flat tappet vs roller

Post by frnkeore » Wed May 13, 2020 1:04 pm

So, in the end, you can pay $220, including shipping for a hydraulic FT cam & lifters or $500 for a roller. If there is any performance advantage it would go to the FT, using .875 lifters.

As far as brake in goes, there is really no issue for springs under 300#, you just install with the supplied cam lube use a high zink oil, start it and run for about 20 min at ~2000 rpm, then go down the road, with normal break in rules, for a new engine.

I would add that you should set the collapsed lifters @ about 3/16 (.188), then prime the oil system, before starting, to avoid a lot of clatter, when doing the initial start up and 20 min run.

Roadknee
HotPass
HotPass
Posts: 152
Joined: Sun Nov 18, 2007 9:31 pm
Location: Washington

Re: Flat tappet vs roller

Post by Roadknee » Wed May 13, 2020 5:33 pm

I recently bought a Jones HFT for a mild BBC build. Comparison to an ISKY HR below. Note I only have a 8" degree wheel so my Jones Cam numbers might be off a little. Isky numbers are directly from their catalog.

Duration Jones Isky

@0.050" 228 228

@0.100" 196 196

@0.200" 139 139

@0.300" 66 61

lobe lift 0.330" 0.325"

I personally don't think the Isky HR would make more power.

User avatar
CamKing
Guru
Guru
Posts: 9531
Joined: Wed Aug 08, 2007 4:05 pm
Location: Denver, NC
Contact:

Re: Flat tappet vs roller

Post by CamKing » Thu May 14, 2020 11:21 am

Roadknee wrote:
Wed May 13, 2020 5:33 pm
I recently bought a Jones HFT for a mild BBC build. Comparison to an ISKY HR below. Note I only have a 8" degree wheel so my Jones Cam numbers might be off a little. Isky numbers are directly from their catalog.

Duration Jones Isky

@0.050" 228 228

@0.100" 196 196

@0.200" 139 139

@0.300" 66 61

lobe lift 0.330" 0.325"

I personally don't think the Isky HR would make more power.
But, that's not the fault of it being a hydr roller. That's the designer's fault.
Compare those 2, to a 228@.050: HR of mine
228 @.050"
198 @.100"
147 @.200"
84 @.300"
.340" Lobe Lift

Even if you look at one of my mild HR profiles, you can see an advantage
228 @.050"
198 @.100"
141 @.200"
70 @.300"
.330" Lobe Lift
Mike Jones
Jones Cam Designs

Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449

frnkeore
Member
Member
Posts: 194
Joined: Wed Dec 25, 2019 3:06 am
Location: Oregon

Re: Flat tappet vs roller

Post by frnkeore » Thu May 14, 2020 1:20 pm

This is Howards, HFT .875, 228 @ .050 cam:

--------------.006-.020-.050-.200 lobe lift - lash
HF2283497A 275 -252 -228 -146 - 0.350 - 0.000

Howards doesn't list the .300 lift, it's 1° behind @ .200 but, has .010 more max lift.

How is it that a .875 FT lifter can come so close to a roller?

Post Reply