Solid Flat Tappet VS Solid Roller
#2092528
06/15/16 04:23 PM
06/15/16 04:23 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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If I change over to solid FT from a solid roller.. how much difference do I need to add to the FT to equal the roller..I'm gong to a bit smaller cam then what the roller is.. the roller is a 105lsa installed at 105.. 260/270with .640/.640 with 1.5 rockers.. this is in a 416 so IF I change over to a FT how much more do I need to go to come close to the roller... one thing that will change is the LSA..I'm going to a 110lsa for the injection so any help is welcomed.... I know the ramp rate will be slower but if I go larger would it help..I would like stay at about 260-265 duration and about .600-.630 lift thanks guys
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2092540
06/15/16 04:41 PM
06/15/16 04:41 PM
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Joined: Jul 2006
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StealthWedge67
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It seems that you're asking how many apples does it take to equal an orange. Obviously, the difference in two similar spec. cams, FT vs. Roller, will be the lift area under the curve. I don't think there's going to be any mathematical equation that can give the answer to your question, since each cam profile would offer its own variable. It would seem that a FT cam with substantially more lift at the same .050 duration would require faster ramp-rates, and thus may mimic the valve action of a roller, without changing the running characteristics too much, being of the same breathing duration. But by the nature of the pieces themselves, the flat tappet will never be able to approach the ramp-rate of the roller. I'm sure I'm not describing anything you don't already understand though, Mike.
I'd call a reputable cam company and ask to have a conversation with one of their technical experts (not a customer service phone jockey), and see what they have to say.
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2092550
06/15/16 05:01 PM
06/15/16 05:01 PM
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lewtot184
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the more "flat tappet cam" you add the greater the parasitic load to drive the valve train. what's less friction; a skid or a wheel?
some years back i put together a solid roller bracket engine with 750lbs open spring pressure. at about the same time i put together a mild hydraulic flat tappet engine with less than 300lbs open spring pressure. the break over torque for both engines completely assembled was the same 75lbsft. what i'm getting at is adding more lobe and spring on a flat tappet may never equal a "wheel".
Last edited by lewtot184; 06/15/16 06:00 PM.
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Re: Solid Flat Tappet VS Solid Roller
[Re: lewtot184]
#2092572
06/15/16 05:37 PM
06/15/16 05:37 PM
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MR_P_BODY
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I know they will never be equal.. but just something close... if I add a bit more lift and a bit more duration will get get close(to what I am running now)...I can go with a FT at a much cheaper price than a roller.. if I could get the roller cut to a 110LSA I would just do that..but from what I know that isnt gonna happen
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2092594
06/15/16 06:24 PM
06/15/16 06:24 PM
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Joined: Jan 2011
Posts: 4,785 Utah and Alaska
astjp2
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My crane roller is 112 lsa, I a running a small cam at .620 lift and 248@.050, if you do it, have a custom ground 3/7-4/2 swap so idle improves and it will help on the FI parameters. Tim
1941 Taylorcraft 1968 Charger 1994 Wrangler 1998 Wrangler 2008 Kia Rio 2017 Jetta
I didn't do 4 years and 9 months of Graduate School to be called Mister!
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2092619
06/15/16 07:13 PM
06/15/16 07:13 PM
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MR_P_BODY
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I just ordered up a solid flat tapper...from Clay Smith and all the parts to go with it..cam is 110 lsa,I will have to change to my 1.6 intake rockers...no big deal, springs for it with keepers and locks and AMC solid lifters for push rod oiling... should be right inline if not a touch more power due to the 1.6 rockers... George(the owner) is pretty damn sharp when it comes to that stuff.... I was surprised how quick they can get things out the door... this is a custom grind
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Re: Solid Flat Tappet VS Solid Roller
[Re: AndyF]
#2092625
06/15/16 07:22 PM
06/15/16 07:22 PM
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Joined: Jun 2003
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MR_P_BODY
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I don't think you'll be able to get the same lift unless you go with a 1.60 rocker arm.
Comp MM lobes are 263/.606 or 267/.617 or 271/.627 so lift isn't what you're looking for. Correct Andy.. due to the 904 lifter..but yes I have to change over to 1.6 intakes... this gives me a .626 intake if I wrote it down right.... I tried 4 other cam companies with no response...getting pretty fed up with these companies
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2092677
06/15/16 09:27 PM
06/15/16 09:27 PM
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Joined: Jan 2003
Posts: 4,712 Moved to N.E. Tennessee
GomangoCuda
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I just ordered up a solid flat tapper...from Clay Smith and all the parts to go with it..cam is 110 lsa,I will have to change to my 1.6 intake rockers...no big deal, springs for it with keepers and locks and AMC solid lifters for push rod oiling... should be right inline if not a touch more power due to the 1.6 rockers... George(the owner) is pretty damn sharp when it comes to that stuff.... I was surprised how quick they can get things out the door... this is a custom grind Wouldn't it have been cheaper to just buy a new roller cam made the way you want it than to buy a ft cam and all those parts?
In theory, there is no difference between theory and practice. In practice, there is.
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2092679
06/15/16 09:29 PM
06/15/16 09:29 PM
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72Swinger
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Well I was gonna say just have a wider lsa roller ground and have your cake and eat it too.
Mopar to the bone!!!
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Re: Solid Flat Tappet VS Solid Roller
[Re: GomangoCuda]
#2092694
06/15/16 09:48 PM
06/15/16 09:48 PM
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MR_P_BODY
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I just ordered up a solid flat tapper...from Clay Smith and all the parts to go with it..cam is 110 lsa,I will have to change to my 1.6 intake rockers...no big deal, springs for it with keepers and locks and AMC solid lifters for push rod oiling... should be right inline if not a touch more power due to the 1.6 rockers... George(the owner) is pretty damn sharp when it comes to that stuff.... I was surprised how quick they can get things out the door... this is a custom grind Wouldn't it have been cheaper to just buy a new roller cam made the way you want it than to buy a ft cam and all those parts? I wasnt happy with a few things.. cant grind in the 110lsa I wanted plus I wasnt happy with the EDM hole in the rollers.. way to big.... and the cost for the cam was $40 more for a new one over a regrind
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2093019
06/16/16 03:25 PM
06/16/16 03:25 PM
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Joined: Jan 2003
Posts: 9,872 Weddington, N.C.
Streetwize
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Opinions probably vary but when you look at the very peak lift on a flat tappet, there is no truly effective "dwell" for the peak lift flow, other than you need it for the valve to change direction. but with a solid roller at say .650 lift, the "squarer" roller lobe sort of "parks" the valve (i.e., very little change in net lift...of course it IS changing, just not very much from one degree to the next) where a FT has to take the valve up and over to come back down. Let's leave Lash setiings/valve mass and specific "opening/closing rates' out of the comparison for now.....So if you compare the head flow of a .650 roller to that of a higher lift say .700 or .720" lift (same running duration) FT you could say that you MAY have similar duration at .650 lift for both cams and MAYBE that little extra "up and over" between .650 and .720 can yield as much or MORE flow (depending on the head) as the roller "parking" the lobe at or near 650 for the (near) equivalent degrees of duration. But if that was the case, you could ramp up the Roller to .720 and so it becomes a matter of where you wish to draw the line. Advantages of a solid FT, lower cost, weight and less to break/go wrong. Disadvantages would be friction/wear (especially with todays low zinc oils) and the obvious limitations of the flat tappet lifter base diameter...you roughly have 1/2" of the diameter of the lifter to open the valve and the other 1/2 to seat it, even with asymmetrical ramps you have more physical constraints. Whoever came up with the mushroom lifter was obviously trying to address that acceleration (rate of lift) rate. It's hard to get true "apples to apples" but if you compare what you can get your head around, it's somewhat doable.
Last edited by Streetwize; 06/16/16 03:27 PM.
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Re: Solid Flat Tappet VS Solid Roller
[Re: Streetwize]
#2093038
06/16/16 04:12 PM
06/16/16 04:12 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Opinions probably vary but when you look at the very peak lift on a flat tappet, there is no truly effective "dwell" for the peak lift flow, other than you need it for the valve to change direction. but with a solid roller at say .650 lift, the "squarer" roller lobe sort of "parks" the valve (i.e., very little change in net lift...of course it IS changing, just not very much from one degree to the next) where a FT has to take the valve up and over to come back down. Let's leave Lash setiings/valve mass and specific "opening/closing rates' out of the comparison for now.....So if you compare the head flow of a .650 roller to that of a higher lift say .700 or .720" lift (same running duration) FT you could say that you MAY have similar duration at .650 lift for both cams and MAYBE that little extra "up and over" between .650 and .720 can yield as much or MORE flow (depending on the head) as the roller "parking" the lobe at or near 650 for the (near) equivalent degrees of duration. But if that was the case, you could ramp up the Roller to .720 and so it becomes a matter of where you wish to draw the line. Advantages of a solid FT, lower cost, weight and less to break/go wrong. Disadvantages would be friction/wear (especially with todays low zinc oils) and the obvious limitations of the flat tappet lifter base diameter...you roughly have 1/2" of the diameter of the lifter to open the valve and the other 1/2 to seat it, even with asymmetrical ramps you have more physical constraints. Whoever came up with the mushroom lifter was obviously trying to address that acceleration (rate of lift) rate. It's hard to get true "apples to apples" but if you compare what you can get your head around, it's somewhat doable. If I dont like this FT cam I'll go back to a roller but with a wider LSA.. this one has a ton of lope to it.. if not heavy on the brakes it each time it lopes it jumps forward some.. this cam runs real strong but the 105 lsa and the injection dont like each other too well... yeah I can lower the fuel map at idle.... if I dont like the FT cam I'll have a 110 lsa roller made up... but also I'm not trilled with the EDM hole in the bottom of the lifters.. it dumps way more oil than I like.... glad you made comment of the zink.. forgot all about adding that since I havent run a FT in more than 25 years.. and yes I know about the break in and the springs... whats the strongest spring pressure you have ever run on a FT.. I was told by the cam company that 140-145... I was thinking up to 150 but I will try 145 first
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Re: Solid Flat Tappet VS Solid Roller
[Re: MR_P_BODY]
#2093042
06/16/16 04:19 PM
06/16/16 04:19 PM
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Joined: Aug 2011
Posts: 2,853 Pattison Texas
CSK
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I have 155 seat on my small solid ft, but i also have trend tool steel edm lifters.
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: Solid Flat Tappet VS Solid Roller
[Re: CSK]
#2093054
06/16/16 04:36 PM
06/16/16 04:36 PM
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I have 155 seat on my small solid ft, but i also have trend tool steel edm lifters. I'm gonna run AMC lifters on this... I have to oil via the PRs
Last edited by MR_P_BODY; 06/16/16 04:41 PM.
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