Hydraulic Flat Tappet vs. Hydraulic Roller

[nonosstang]

I currently have a hydraulic flat tappet cam and wanted to order a new cam today because I'm going to be adding a supercharger in a couple months. So, I was considering doing a retrofit to a hydraulic roller cam.

Would changing over to a roller cam be worth the additional cost? About $400 difference.

 

[steel1212]

I think it would definatly be worth it. A roller cam is going to greatly reduce friction. If you do it right, with the link bar lifters, you will gain a lot of hp and torque from the switch and get a better cam profile as well.

 

[Edbert]

If you are planning on pulling the motor then do the roller-cam. if you intend to install a new cam with the engine in the car then don't. There is monor machining required and it is not a good idea (IMHO) to do such things without a tear-down.

 

[302 coupe]

there is no machining required unless the dogbone and spider setup is used. Link-bar lifters require no machining 99% of the time, any work that light be needed would be due to excessive casting flash in the lifter valley around the lifter bore.

 

[D.Hearne]

I voted no, but this only applies to a flat tappet block. If you have a roller block, roller wins everytime. The cost difference is more than $400 to convert. You already have a cam, you'll have to add the new one to the cost. Plus lifters, pushrods, new valve springs, etc.

 

[nonosstang]

I voted no, but this only applies to a flat tappet block. If you have a roller block, roller wins everytime. The cost difference is more than $400 to convert. You already have a cam, you'll have to add the new one to the cost. Plus lifters, pushrods, new valve springs, etc.

Well, I was figuring $400 in my case. I already have the other stuff. I just need a new cam and lifters. The difference in price from Summit is about $350 since I need to get a new cam anyways. Then, another $50 for the retrofit kit.

 

[thehueypilot]

You also have to take the heads off to install the new vertical bar lifters.

 

[Edbert]

there is no machining required unless the dogbone and spider setup is used. Link-bar lifters require no machining 99% of the time, any work that light be needed would be due to excessive casting flash in the lifter valley around the lifter bore.

I thought the top of the lifter bores needed clearancing, but I know your level of knowlege on such things and I stand corrected.

:SNSign:

 

[rbohm]

yes the difference is worth the price of admission. faster ramp acceleration rates with the same duration, lower friction, both add up to better performance and fuel economy as well.

 

[D.Hearne]

Well, I was figuring $400 in my case. I already have the other stuff. I just need a new cam and lifters. The difference in price from Summit is about $350 since I need to get a new cam anyways. Then, another $50 for the retrofit kit.

Where you going to get a cam AND hydraulic roller lifters for $350 ? Using the factory style lifters in a non roller block also requires using a reduced base circle cam ( that's $350+ there by itself). Using Crane's retrofit lifters ( $425) you can use the std base roller cams ( but a custom blower cam will still set you back more than a std cam will) You will need new pushrods, no getting around that, and those will likely end up being custom jobs too, with all the mixed up parts. You may have done the math, but I've done it too--- several times and fitting a roller cam to a non roller block always came out costing about $600 minimum. Hardly worth the cost differential over a good flat tappet grind. And if you're thinking on using a set of used factory lifters, that's all good, but forget about reving it over 5500 rpms.(just in case you had that in mind)

 

[mustangdave]

I voted no and agree with D. Hearne. To do a retro was going to cost me $700 last time I checked. Maybe something has changed. Besides how much broader of a tq. curve are we talking about; 5-10 lb. ft.? Consider dollar vs. gain. I think it would be better to start with a roller block.

 

[steel1212]

I think we are missing something here. I don't think he is including the price of the cam in as he needs to get a new one anyway.

"price from Summit is about $350 since I need to get a new cam anyways"

So with that theory it would be about 350$ for the lifters, plus another 100 or so for gaskets.

 

[Realmongo]

I was in the process of gathering up the parts for my rebuild including buying a new flat tappet hydraulic cam and lifters. When I discovered my original block had problems, I dragged home a roller block from the junkyard to rebuild in its place. After comparing the differences, I just ordered a new roller cam and lifters even though I could have used the bought and paid for flat tappet hydraulic in the roller block.

 

[D.Hearne]

I think we are missing something here. I don't think he is including the price of the cam in as he needs to get a new one anyway.

"price from Summit is about $350 since I need to get a new cam anyways"

So with that theory it would be about 350$ for the lifters, plus another 100 or so for gaskets.

He'd still need to add in at most another $100 for custom pushrods. Prices on off the shelf flat tappet cams are about the same as std base rollers (for 5.0's anyway) in that case, the lifters cost you $425 for Crane's link bars. Using the factory lifters, requires a reduced base cam, that's going to run hum at least what the Crane lifters cost, seeing as he's going to have to go custom with the supercharger application. I don't see where he figured $350 from.

 

[nonosstang]

He'd still need to add in at most another $100 for custom pushrods. Prices on off the shelf flat tappet cams are about the same as std base rollers (for 5.0's anyway) in that case, the lifters cost you $425 for Crane's link bars. Using the factory lifters, requires a reduced base cam, that's going to run hum at least what the Crane lifters cost, seeing as he's going to have to go custom with the supercharger application. I don't see where he figured $350 from.

All I was asking for was some pros and cons about roller vs. hydraulic. . . not for someone to try to prove me wrong. Also, in my first post and poll question, I specifically mentioned ADDITIONAL cost . . . not the total cost. I already have a built 347 with nothing stock in it. I pulled it so I can change the pistons to drop the compression from 10.4 to 8.5. I was considering retrofitting a roller cam in instead since the motor will be torn down and I need a different cam anyways with less lobe separation.

Ok, custom grind cam from Summit (Comp Cams) is about $250 ($363 directly from Comp Cams). Comp Cams lifters from Summit are $240. Comp Cams retrofit kit is about $50. That comes to $540.

A new hydraulic flat tappet cam and lifters would probably be around $175.

Therefore, the difference is $365, when rounded up $400. Like I mentioned before, I don't need new pushrods, valve springs, etc.

 

[69Rcode_Mach1]

If you are going with the roller you will need new pushrods regardless, in fact you need custom ones. Take it from me I am doing the swap right now, and stuck on trying to get the right size pushrods, I will have to go custom to get them right. What valve springs on what heads are you running? Mine were fine because they were Victor Jr.'s but the ramp rates combined with high lift will kill a normal spring that isn't designed for the application.

 

[nonosstang]

If you are going with the roller you will need new pushrods regardless, in fact you need custom ones. Take it from me I am doing the swap right now, and stuck on trying to get the right size pushrods, I will have to go custom to get them right. What valve springs on what heads are you running? Mine were fine because they were Victor Jr.'s but the ramp rates combined with high lift will kill a normal spring that isn't designed for the application.

Trick Flow heads that I've had reworked. The valve springs are upgraded Isky springs.

 

[classic boost]

I don't need new pushrods.

unless you have a set for a hyd roller cam lying around, then yes, you do need new pushrods.

back to your original question,
pros- more aggressive ramps, higher revs, no break in.
cons- extra cost, removal of head to install lifters.

 

[jbuening]

Maybe someone else here can remember, but there was a recent magazine article with dyno comparisons of a roller and non-roller cam motors with all else being the same and i think it was around 10-20hp difference and it was at a very high rpm, one that wouldn't notice it if it were a street driven car. Can't for the life of me remember what magazine that article was from though but it was written by David Vizard IIRC. Below is a site mentioning some roller conversion lifters for flat tappet cams. Pretty price though

http://www.revsearch.com/dynamometer/rollervsflattappet.html

Aha, found the post that referenced the article : http://forums.stangnet.com/showthread.php?p=5847380#post5847380

 

[302 coupe]

I thought the top of the lifter bores needed clearancing, but I know your level of knowlege on such things and I stand corrected.

:SNSign:

I've never done a spider/dogbone style swap, but I have heard of people having to grind/flatten the top of the lifter bore area for the dogbones to sit flush. Plus, of course, tapping the holes for the spider, unless you do the nut-sert things. Just what I've heard though.

I have only done 2 link-bar style conversions to date, both were Comp solid roller setups with the link-bars, they just dropped right in. Pushrods will need to be checked, and you'll always need stronger valvesprings than you would with a flat tappet cam, but thats about the extent of it.

Roller cams typically make more torque, but there isn't much horsepower difference over a solid flat tappet cam with similar specs. My guess is because of added valvetrain mass and spring tension. Theoretically, the lobe style of the roller cam should do everything better than a flat tappet cam, but thats not quite how it works.