Roller Cam Questions

-
Valkman

Valkman

Well-Known Member
Joined
Sep 13, 2012
Messages
954
Reaction score
293
Location
NC
I'm working on putting together street-able engine build using a '71 360 block with big valve stock J heads and making it a 408. In considering a hydraulic roller cam I've read about some possible issues and changes that may have to be addressed. So my question goes to all of you that have a done this, what needs to be done?

Some of the concerns and questions I come up with so are as follows:

Will the lifters bore be too short?, Are there certain brands of lifters the work better then others?

Can you use the stock stamped shaft rockers arms?

Do you need a special oil pump/distributor drive gear?

Do valve spring pressure requirements differ from flat tappet cams?

I'm looking to get as broad a torque curve as possible, and yet have a good low end response, with a fairly smooth idle. High RPM power is not my goal, but I still see some benefits from using a roller.


Thanks for you help!
 
If you have money to consider a roller cam conversion, I would first consider some better heads.
Roller cams are nice, but IMO, for you,decent heads trump roller cam
The whole reason for the roller cams existence runs contrary to your stated build. A better set of heads, designed with your goals in mind will be worth one or two cam sizes over using the J-heads, and that means a flat tappet cam is seriously in the game for you. A properly matched smaller flat-tappet cam will make the long flat powerband you are envisioning.The smaller cam has smaller springing requirements which leads to less worries about cam and lifter life, which was a good argument for the rollers.
408s process a lot of air. J-head exhaust ports have a little trouble with that. Especially with headers designed to fit in the A-bodies.
 
Last edited:
Valkman said:
I'm working on putting together street-able engine build using a '71 360 block with big valve stock J heads and making it a 408. In considering a hydraulic roller cam I've read about some possible issues and changes that may have to be addressed. So my question goes to all of you that have a done this, what needs to be done?

Some of the concerns and questions I come up with so are as follows:

Will the lifters bore be too short?, Are there certain brands of lifters the work better then others?

Can you use the stock stamped shaft rockers arms?

Do you need a special oil pump/distributor drive gear?

Do valve spring pressure requirements differ from flat tappet cams?

I'm looking to get as broad a torque curve as possible, and yet have a good low end response, with a fairly smooth idle. High RPM power is not my goal, but I still see some benefits from using a roller.


Thanks for you help!
Click to expand...
You can get a retro-fit cam kit from a reputable cam grinder such as Lunati or several others that will include all the matching valve train stuff. If you call their tech line, they can help you address any remaining concerns for the upgrade.
 
I not really looking for high end power, which I would think where a better flowing head would be the most beneficial. I looking more toward a broad power band. I'm not going race'n I want smooth reliable street performance with a bit of a punch:D.
 
The better flowing heads bennifit both aspects.
 
I don't want to stray too much off the main question here, "what does in take to convert to a roller came?"
 
About the same amount of money as a good set of heads. And the heads will make the torque. If you put the torque in the heads, you can run a smaller cam and get the smooth idle,and the broad torque curve you are so interested in.
Roller cams are designed for fast action and higher lifts. They pick up where flat tapped hydraulics leave off. Sure there is some overlap. But for you the only advantage would be the peace of mind knowing that the cam lobes are gonna stay on the cam.You can buy an awful lot of high-quality oil for the price of a roller cam conversion. Probably 10 to 20 years worth of oil.As a compariso, my 367 has had the same flat tappet 230*cam in it now since about 2004, with just three tappet adjustments in the first 5000 miles. I use no special oils, and it gets just one oil-change each year. So that totals about 14 oilchanges, or under 300 bucks Canadian.So for me the breakeven point to a conversion kit would be 56 years or so. If I was willing to buy the Top-quality oil at double or triple the price what I'm paying, I suppose payback would be correspondingly shortened. But why would I mess with what is working for me? And you are thinking about an even smaller cam.
I wonder if they even make as small a roller-cam as you might be considering.

MRL makes the lifters you need.
 
Last edited:
I'm curious why you just don't build a stroked Magnum 360? I love mine.
 
With the LA block I thought there were some modifications required for proper oil flow. Chrysler, at one time, had a kit to take care of this.
 
if you keep the stock shaft mounted rockers then you want solid pushrods. your rocker oiling system wont change. even if you went to magnum heads, only difference is oil through rods and lifters. i want to say just retrofit roller lifters, roller cam, and solid pushrods should get you where you want to be.

i just bought a hughes engines roller cam and retrofit roller lifters. was like 800$ for everything. but after replacing a tappet cam twice now due to wiping, definitely worth the money
 
AJ/FormS said:
About the same amount of money as a good set of heads. And the heads will make the torque. If you put the torque in the heads, you can run a smaller cam and get the smooth idle,and the broad torque curve you are so interested in.
Roller cams are designed for fast action and higher lifts. They pick up where flat tapped hydraulics leave off. Sure there is some overlap. But for you the only advantage would be the peace of mind knowing that the cam lobes are gonna stay on the cam.You can buy an awful lot of high-quality oil for the price of a roller cam conversion. Probably 10 to 20 years worth of oil.As a compariso, my 367 has had the same flat tappet 230*cam in it now since about 2004, with just three tappet adjustments in the first 5000 miles. I use no special oils, and it gets just one oil-change each year. So that totals about 14 oilchanges, or under 300 bucks Canadian.So for me the breakeven point to a conversion kit would be 56 years or so. If I was willing to buy the Top-quality oil at double or triple the price what I'm paying, I suppose payback would be correspondingly shortened. But why would I mess with what is working for me? And you are thinking about an even smaller cam.
I wonder if they even make as small a roller-cam as you might be considering.

MRL makes the lifters you need.
Click to expand...

You do make a good point, but there's a reason why the OEM car manufacturer's went rollers a while ago. If look at some of the available roller cams you can get a lot more lift and duration and yet have still have same streetable manners. I'm just asking what it would take to go roller? anyone out there that's done this give some advice?
 
FWIW:

Will the lifters bore be too short?, Are there certain brands of lifters the work better then others? It appears to be just dependent on the individual block. Some have tired 2-3 brands and ended up with the same issue, and so have gone to solid rollers to get around this issue. It don't think anyone can tell you if your particular block will have issues. You can measure the distance from the lower edge of the deepest chamfer to the cam center line and perhaps compute it out. Some blocks have deep chamfers and some don't. Your lower lift will help you.

Can you use the stock stamped shaft rockers arms? How much lift are you planning? The feature of a roller for your use would be higher lift with limited duration. That kinda works against stamped rockers. IMHO, you oughta get away with it with lifts under about .450"; that is a pretty mild roller aftermarket cam.

Do you need a special oil pump/distributor drive gear? Check into steel billet cams

Do valve spring pressure requirements differ from flat tappet cams? Yes from what i have seen listed, presumably for the higher valvetrain weight and or the more aggressive ramps. Since you will be limiting RPM, that makes the spring requirements less. The cam mfr will have recommended springs regardless.
 
With your heads I'd just put a flat hydraulic in it and run the stamped rocker arms. Engines are nothing more than air pumps, the more air in the more power they are capable of making. IMO a roller cam with stock heads does as much good as pi$$ing on a forest fire.
 
justinp61 said:
With your heads I'd just put a flat hydraulic in it and run the stamped rocker arms. Engines are nothing more than air pumps, the more air in the more power they are capable of making. IMO a roller cam with stock heads does as much good as pi$$ing on a forest fire.
Click to expand...

Again why would mother Mopar spend the engineering and money to convert to roller if there was no benefit?

I'm building this to be a driver, but I want to be able to eat some of the cake as well. I want torque down low and still make good power up to 5 or 6 grand. From what I've seen ( Voodoo Retro-Fit Hydraulic Roller Cam - Chrysler 273-360 270/279 - Lunati Power ) a roller can do this for me.
 
Cause the catalytic converter required by EPA were effected by the zinc and prosperous in the oil....flat tappet cams require the zinc and prosperous
 
OEM manufactures changed to roller lifters cause of the change in the oil formula required by the EPA......roller cams and lifters make the engines more expensive to build and the bean counters dont like that..

valve springs are going to be dictated by the roller cam...oem magnums run roller cams and they a have wippy springs...but the roller cams are very mild and probably not very aggressive......pick a cam manufacturer and ask them what springs are needed to make it work...
 
IMHO, the better lift to duration ratio of a roller will tend towards a wider torque range, which is what the OP is after. This is the same reason that hydaulic flat cams have been ground with steeper and steeper ramps, like the Voodoo and XE's. So the reasoning is sound IMHO.

However, with all those cubes as proposed, IMHO, going to 6000 RPM with real power is going to be unlikely with those heads unless they are opened up to breathe better. So, the Voodoo cam given above is a step higher than I would go. I would be thinking 5000-5500 RPM max and choosing to work on the lower RPM end. Especially so with the question on using stock rockers; the lift required is going to push those pretty hard.
 
70aarcuda said:
OEM manufactures changed to roller lifters cause of the change in the oil formula required by the EPA......roller cams and lifters make the engines more expensive to build and the bean counters dont like that...
Click to expand...
Mmmmm, I'll respectfully disagree. The movement to rollers started 10-15 years before the EPA mandated reductions. Fuel mileage and the required engine efficiency across a wide RPM range drove the change. Damn the accountants!
 
Valkman said:
You do make a good point, but there's a reason why the OEM car manufacturer's went rollers a while ago. If look at some of the available roller cams you can get a lot more lift and duration and yet have still have same streetable manners. I'm just asking what it would take to go roller? anyone out there that's done this give some advice?
Click to expand...

A cam- 300 or more $$$
Roller lifters- 300 or more $$$
Springs - 120 or more $$$ "If you don't get too aggressive with the profile and hang around .600 or less lift you can use the K-MOTION K800 springs for 120 bucks or less".
Last but not least once you have it together with springs checked and rockers mocked and an adjustable push rod "check all four corners when checking for length!"...PUSH RODS-120 to 190 $$$
Hyd or solid?
 
started in 1994....roller available in 85 318,,,

found another source..

magazine article says oil change in late 80s...
 
Last edited:
Roller lifters have a clear advantage over flat tappet cam in every aspect except initial cost. That is why the factories went to them. Less friction and a better more efficient cam profile= better fuel economy & lower emissions along with more power. The zinc/ catalytic converter issue didn't become a problem for another decade after hydraulic roller lifters were making their way into production engines. To say the oil caused the manufacturers to use them is like saying hot dogs were invented because of mustard.
To get back to the OP's original question, the depth of the lifter bores is an issue with the higher lift cams that can cause the lifter grove to rise high enough out of the bore to cause loss of oil pressure. Probably not going to be an issue with a lower lift cam you might select based on your desired RPM.
However, I wouldn't plan on using the stock rocker arms for any serious cam swap, flat or roller.
Plan on getting a good set of roller rocker arms & a set of custom length pushrods because you'll need to correct any valve train geometry issues. Also valve springs and any machining of the heads to make sure the springs fit properly.
While a better set of heads will most definitely improve your combination & power, the cost isn't ever as simple as buying a set of heads & putting them on OOTB. They will still need to be gone through as most have valve guide clearance issues and less than desirable valve jobs done, and they still may need the spring seats machined. All costs to consider. When you consider that all said and done a set of heads will cost you amounts approaching $2000, the hydraulic roller may be the better option.
 

x2
why bother with the headaches with the lifter bores chamfering issues as their are many posts regarding this ! solid flat tappet or solid roller all the way .
 
You must log in or register to reply here.
-

Similar threads

C
(3) cam regrind questions.
Replies
10
Views
491
Bewy
B
mopowers
Converting Hyd Roller Lifters to Solid
2
Replies
47
Views
2K
Cuda416
Cuda416
mopowers
Cyl Head Experts - Valve Spring Setup Question
Replies
12
Views
552
mopowers
mopowers
S
318 Magnum Cam in 360
Replies
5
Views
407
Garrett Ellison
Garrett Ellison
E
Valvetrain Geometry
5 6 7 8 9
Replies
200
Views
6K
Earlie A
E
Back
Top Bottom