I see that there may be differences between aftermarket heads for hydraulic roller vs flat tappet. What’s up with that ??
Difference between heads hyd flat vs roller
- Thread starter Brooks James
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fully assembled aftermarket heads - the difference will be in the valve springs
I’ve seen heads listed as flat tappet and hydraulic roller.
is that the only difference?
Want to check if they oil through the head or up the hollow push rods like the '90 318 roller engines.
I answered in post 2. When ordering a set of aftermarket heads, you get a choice. Roller version or flat tappet version. The spring is the difference.
Professor Fate
Push the button, Max...
Cut to the chase- call the supplier and ask them.
Yes will do. Thanks
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Hydraulic roller lifters are heavy compared to a FTH. It takes more spring to control that heavy lifter at rpm. I can't say for sure but I have heard that retro rollers for LAs are the heaviest.
I have heard quite a few guys here on FABO complaining about roller lifters. And
have heard a few guys extolling solid rollers.
_____________________
I've been running the same hydraulic FTH lifters since about 2004 when I installed a Hughes HE 3038AL cam with specs of 276/286/[email protected], 230/[email protected], and lifts of .549/.571 (1.6 arms) using Hughes 1129(IIRC) dual springs. I've been shifting it at up to 7000/7200. I got no complaints.
jus saying.
I have heard quite a few guys here on FABO complaining about roller lifters. And
have heard a few guys extolling solid rollers.
_____________________
I've been running the same hydraulic FTH lifters since about 2004 when I installed a Hughes HE 3038AL cam with specs of 276/286/[email protected], 230/[email protected], and lifts of .549/.571 (1.6 arms) using Hughes 1129(IIRC) dual springs. I've been shifting it at up to 7000/7200. I got no complaints.
jus saying.
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yellow rose
Overnight Sensation
Like any other hydraulic lifter, they are RPM limited by the hydraulics, not lifter weight.
Why put a squishy shock absorber in the valve train if you want performance?
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I run my squishys at near-zero preload, so if or when they pump up, they behave like a solid. Since my pushrods have never fallen out, and the minor ticking never changes after a blast; I have to assume that the lifters have never been squishified. The proof, I think, is in the 93 mph Eighth-mile, with that smallish 230 cam
Biomedtechguy
Well-Known Member
For "general principle" and especially "dem kinda" RPMs w/FTH lifters, I bestow upon you a heartfelt
DOUBLE thumbs up!!
Now that's a term for FTHs I've never heard...
"squishified" ....Is that like nitriding, or treating hot forged steel to some liquid inert gas specialty performance or strength enhancements? No WONDER they rev so high! Lol.
I'm running hydraulic roller lifters and cam in the built-for-performance 421 Tripower in my wife's 65 GTO. The builder picked the cam and lifters from CompCams, and given the RPM range, hand ported smallish valve factory iron heads, they are perfect for that application.
In the 541 stroker I'm planning with a Mopar builder, using a new Bill Mitchell aluminum block as the foundation, but BIG, FLAT, TORQUE as my primary goal, not a towing motor, but for the street and 1320 action, unless they come up with an exceptional argument to do otherwise, I think solid flat tappet lifters are going to be PERFECT for that build. The larger diameter of the Mopar/AMC lifters allow for a "roller-esque" ramp profile, and without the weight and complexity of hydraulic roller lifters, and without the fear factor of stop and go and stop, creeping along in traffic in hot weather of solid rollers, and no need to tear down and rebuild. Just a slug of steel in the bronze lifter bushings, and springs that have enough pressure to handle the cam profile.
I don't even expect to have to check or set lash that often, but I definitely won't have any neuroses about the lifters doing something bad...
AJ/FormS
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YR started it, He makes perfect sense tho; I just rolled with it,lol.
furrystump
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There might also be more clearance between retainer and valve seal, but just spit balling. People run more lift with roller usually.
MichiganRay
Active Member
The big thing is that the roller lifters are taller. This changes the angle of the pushrods going through the heads and will bind and scrape in the tubes of the heads. Edelbrock makes heads with that clearance. At least this is the case with the LA heads. I had to modify mine. I was too cheap to by new made for roller cams. You have to be careful not to cut into the intake runners.
Post some videos.
spring pressure required for the lifters are different
Scody21
Just send it
I’m diggin the air cleaner scoop. Would ya post a few more pics?
j par
Well-hung Member
Roller lifters are heavier so they need stronger springs to keep them from bouncing (floating) off the cam..
About as simple as I can explain it...
About as simple as I can explain it...
yellow rose
Overnight Sensation
I disagree. Lifter weight has a LOT to do with spring selection, especially when you consider the inertia of the lifter at high RPM. It will take a lot more spring to control a heavy lifter, than a light weight lifter (one of the reasons high RPM engines need light valvetrain components)....think about it critically for a moment, I'm sure it will make sense.
Simple illustration: Shake a can of soda at a steady rate of 5 shakes per second, now try to do the same with a gallon of milk....it will take a lot more force to control the milk because it weighs more (more inertia). Now imagine the magnitude of a small increase in weight at 7000RPM....I hope that helps.
MichiganRay
Active Member
The front. This is 3/8 thick. I believe 1/4 inch thick would have been much easier to work with/bend. My wife was heating the top and I heated the bottom. Used a Harbor Freight break to bend it. It fits tight to the hood. It was very important to use two heat guns. We also heated the break as we heated the Lexan so it wouldn't be sucking all the heat out. We didn't take any pictures while doing it. I will make a separate post of it..
MichiganRay
Active Member
The front. This is 3/8 thick. I believe 1/4 inch thick would have been much easier to work with/bend. My wife was heating the top and I heated the bottom. Used a Harbor Freight break to bend it. It fits tight to the hood. It was very important to use two heat guns. We also heated the break as we heated the Lexan so it wouldn't be sucking all the heat out. We didn't take any pictures while doing it. I will make a separate post of it..
yellow rose
Overnight Sensation
Ok. But there has been so much testing on this it’s ridiculous and redundant. Weight on the pushrod side of the valve train has very little consequence as far as performance and such are concerned. That’s a well known fact.
The valve side of the system is where you need to save weight. Simple as that.
You can (and must) run more spring load with a roller lifter because of the shape of the lobe. It’s how aggressive the lobe is that requires more spring load, not the weight of the lifter.
That’s an issue with hydraulic lifters of any type. One is you put a shock absorber in the system. That’s bad. And two, the hydraulics won’t take much spring load. That limits RPM. Too much spring load and the hydraulics collapse.
I’ll say it again...lifter weight is not a function of spring load.
In fact I have another example of pushrod side weight stupidity. When I first started doing this stuff guys were running pushrods there weren’t much stiffer than a noodle. Most guys still don’t run a stiff enough pushrod. One of the first things I learned was a 3/8 pushrod is pretty much worthless with any kind of a decent roller lobe. Will it run? Yes. Is it right? Nope. I went from some high dollar 3/8 pushrods to 7/16 pushrods and gained a bit over 500 useable RPM and something like 12 HP everywhere. I gained more going to a double taper (3/8-7/16) pushrod when all the whiz bang’s in gym shorts said it would be a power loser.
Lifter weight (within reason) is insignificant.
MichiganRay
Active Member
Here is the porting I did. You can see how the push rod tubes interference. Opening them you have tobe very careful in the runners & in the tube. You can see them on the top of the whole head. The holes at the top close to the outside.
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