Flat tappet vs roller

[RevTheory]

Check out their .903 stuff

[Mark O'Neal]

First...why would you pay 800.00 got Ford link bar roller lifters. I sell American made lifters for 550.00 retain all day long.

Second...why does a motor with link bar lifters need a retrofit roller?

[frnkeore]

I think I asked my question backward. I think I should have said: Why can't the hydraulic roller be much more aggressive than a .875 HFT cam.

Would it have to do with jerk limitation?

Check out their .903 stuff

.903
.050 .200 lobe
228- 148- 0.353

Yes, I've looked at that but, even more impressive are the 1" lifter ramps, they beat most of the high rate rollers, up to .440 lobe lift.

[CamKing]

Why can't the hydraulic roller be much more aggressive than a .875 HFT cam.

They can be, and in many cases they are. My most aggressive HR cams are more aggressive then my most aggressive Hyd F.T. cams.
The only issue some companies have, is the higher the acceleration gets off the base circle, the tighter the negative radius gets on the flanks of the hydr roller profiles. Those companies that aren't equipped to machine inverse radius cams, can run into problems maching the high acceleration rate roller profiles. Flat tappet profiles are "max velocity" limited, by the radius of the flat follower.
Roller profiles are "Max Acceleration" limited by the radius of the grinding wheel, used to grind the profiles(Roller radius and B.C. radius also play a part.

[David Redszus]

Why can't the hydraulic roller be much more aggressive than a .875 HFT cam.

They can be, and in many cases they are. My most aggressive HR cams are more aggressive then my most aggressive Hyd F.T. cams.
The only issue some companies have, is the higher the acceleration gets off the base circle, the tighter the negative radius gets on the flanks of the hydr roller profiles. Those companies that aren't equipped to machine inverse radius cams, can run into problems maching the high acceleration rate roller profiles. Flat tappet profiles are "max velocity" limited, by the radius of the flat follower.
Roller profiles are "Max Acceleration" limited by the radius of the grinding wheel, used to grind the profiles(Roller radius and B.C. radius also play a part.

Good explanation, Mike.

[frnkeore]

Yes, Thank you.

[n2omike]

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.

THIS. Lucas has a very similar oil, their break-in 30wt. Very similar additive package, and can be purchased through places like Summit for around $31 for a 5 quart jug. Best deal in break-in oil. Moly is not a good additive in a break-in oil, but some still use it.

I LIKE solid flat tappets in 289/302 Ford engines. These engines like to REV, and the solid tappets work great for that. With the small displacement and decent heads, they don't really need a solid roller. Plus, if you're revving it over 6k rpm, a solid flat tappet will often work better than a hydraulic roller, anyway... and less expensive.

I've had great luck with solid flat tappets. Nowadays, I'd be tempted to use the lifters with the oiling hole in the bottom. Camking sells these... as do others. He likes the ones with the larger holes in the bottom. Says they are less likely to get clogged. (I had some included with a cam purchase from him)

With a warmed up 289/302, it's hard to beat a solid flat tappet for performance and cost.

Good Luck!

[Old School]

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.

THIS. Lucas has a very similar oil, their break-in 30wt. Very similar additive package, and can be purchased through places like Summit for around $31 for a 5 quart jug. Best deal in break-in oil. Moly is not a good additive in a break-in oil, but some still use it.

Why is moly not a good additive for break in? Is that not what all the grey paste that we used for years was?

[donsboy]

First...why would you pay 800.00 got Ford link bar roller lifters. I sell American made lifters for 550.00 retain all day long.

Second...why does a motor with link bar lifters need a retrofit roller?

I did a quick google search for lifters and thats the price I found. Havent researched them properly I guess. I was under the impression you need a reduced base circle cam. Am I wrong or can I use any roller cam with a link bar lifter?

[n2omike]

Why is moly not a good additive for break in? Is that not what all the grey paste that we used for years was?

Read the break-in thread... Total Seal did a couple videos on break-in, and were not a fan of moly when breaking in engines.

[steve cowan]

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.

THIS. Lucas has a very similar oil, their break-in 30wt. Very similar additive package, and can be purchased through places like Summit for around $31 for a 5 quart jug. Best deal in break-in oil. Moly is not a good additive in a break-in oil, but some still use it.

Why is moly not a good additive for break in? Is that not what all the grey paste that we used for years was?

i am confident to say that moly lube probably gets thrown on cylinder walls eventually and or mixes with oil and might not help with ring bedding in so to speak,moly paste has been used for decades on cams and lifters with good success.
last year i broke in 2 aggressive SFT cams using EDM lifters and i like to mix Joe Gibbs assembly grease with 30 BR oil mixed as a runny type paste,145 seat 380 open using 1.3 breakin rockers,both survived with no issues,lots of street miles.

[David Redszus]

I would suggest that if one has to worry about break-in oil to help seat rings, they should go back and
properly hone the cylinder walls.

[steve cowan]

I would suggest that if one has to worry about break-in oil to help seat rings, they should go back and
properly hone the cylinder walls.

Are you saying you can use any engine oil if you have the correct hone job for the ring pack?
Can you expand on your explanation please

[F-BIRD'88]

The MolySlip E oil additive does not effect ring seal.
Thousands of engines use it. Moly is on Moly piston rings.
It improves ring seal and ring life .. It extends life of cams lifters and lifter bores and pushrod tips etcetc.
Total seal gapless piston rings are a lot of hype..
No oems go near them for a reason.

[n2omike]

These little 289/302 engines LOVE/NEED to spin some rpm to make power, and spinning 6800-ish rpm does NOT hurt them at all. That's past the safe zone for inexpensive, standard issue HR stuff... but prime territory for a SFT. These small displacement engines don't really need all the open area they can get when fitted with decent heads. A SFT is generally plenty, and when using the EDM lifters and a good break-in, an engine set up properly for that rpm range will last YEARS with only a 'once per year' lash adjustment. It will also run circles around a 'standard issue' HR above 6k rpm.

Sure, you can get the 'good' HR lifters, special lightweight springs, and all the parts that cost a fortune... but a 6800 rpm SFT setup is stone simple, reliable and inexpensive. It will buzz good rpm, and last a LONG time in the process. The engine in my mustang was in the car 12 years before it broke a rod bolt. The 289 headed engine it before that was in there just as long... and had THOUSANDS and THOUSANDS of street miles. Both wrung out to 6800 rpm multiple times every time it came out of the garage.