MRL Roller Lifter Street Durability

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Old Man Mopar

Old Man Mopar

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I am looking for honest realistic opinions on how many miles I can expect to be able
to street drive (goin' cruzin') a 400/470 with the best MRL roller lifters (with the larger
roller wheel) and a mild (approx. .580 - .600 lift) solid roller camshaft before having to
have the lifters rebuilt or replaced. What about valve spring life?

Below are the valve spring specs:

1.550" o.d. dual spring
138 lbs. @ 1.950" installed height
430 lbs. @ 1.250" open
420 lbs. per inch rate
.680" max. valve lift
 
I would contact MRL, I have heard the SB rollers are the best to use. I would still use a good race oil with plenty of zinc even though you may not need it with a roller.
 
I'm not questioning the oil. I would still run the same zink additive that we
use in all of our flat tappet motors. I'm asking about the lifter durability.

What if I decide to go out and get on the interstate for a couple of hours?
Any problems to expect?
 
Old Man Mopar said:
I'm not questioning the oil. I would still run the same zink additive that we
use in all of our flat tappet motors. I'm asking about the lifter durability.

What if I decide to go out and get on the interstate for a couple of hours?
Any problems to expect?
Click to expand...

interested old man, I`ve got a set of them in my 505. sos far so good !
 
OK, here's a little comparison. I've been rebuilding Harley Davidson engines since the '70s. Currently I work for the largest manufacturer of aftermarket H.D. engines in the world. You might have seen some of our engines winning in the NHRA P/S bike class.
Anyway the H.D. valve train is "the most" horrible thing you've ever seen! And it takes lots of spring pressure to keep it stable. If you ever saw the spintron footage of one of these things you wouldn't even want to stand next to one when it runs.
Right now in the production street engines that are being sold it has a 640" lift camshaft and a set of triple valve springs. The installed height is 1.800 with a seat pressure of 170lbs and the open pressure is 450lbs. This is very similar to what you're running.
But my main point here is that these engines run a roller tappet. They have since the '20s and the axle on these tappets is so spindly it's incredible. I believe it's around 7/32's in diameter. But the amazing thing is that these things very rarely fail. Plus I know where theses parts are made and I will go out on a limb here and say that I'm sure that the ones that you're going to run are made to much higher standards.
The bottom line is that I would not worry too much about it. Get out and drive it!!!!!

My 2 cents................Ted
 
400lbs over the nose isn't terribly high, but it's a good amount. Your use will determine the life span. Highways and steady rpms wear things by putting heat into the parts. IMO, any solid roller build should have the bores bushed. Doing so means the longest expected life of the parts regardless of use. You should buy the best springs you can afford, potentially look into a beehive design that would do the same work with less pressure, and make sure there's a good flow of oil over them especially if extended rpms are expected. If it was me, I would want to check the spring pressures on all the springs yearly. I'm less concerned with the lifters as a lot has advanced over the past 10 years and if the springs are doing their job, the lifter's not being overly stressed.
 
I don't know for sure. The one thing I know is what moped was saying.
Overkill on spring pressures or worn out springs will screw stuff up before a roller lifter fails.
As my budy Ted said, Harley used roller lifters since the 20's. I used to put a7K a year on my bike which isn't crud next to some riders I know whipping out as much mileage on there bike as many cars do @ 15K+ a year.

MRL worked with Comp Cams directly to make a better lifter. It took a while to work with them until they finalized the current lifter. Comp now sells the redesigned lifter at a heftier price.

Between a good quality spring and oil, I can not see a reason for failure.
 
I have been looking at ovate beehive springs and will probably use them.

I think that this will be about as low stress as you will find for a solid roller
setup that makes any power.

I used to be a Harley Davidson parts manager and crewed for a top-flite
AMA Dirt Track team (Steve Morehead) for several years. I built the
engines with Hank Scott. Spent time on Jerry Branch's and Carl Patrick's
dynos. I know of where you (DusTed74) speak.
 
only 138# seat and .590" is only 385# open, very light for a solid roller - keep the revs down. is the cam and lifter makers ok with that light a spring? the roller lifters and rockers etc. with bronze bushings is the hot setup
 
Old Man Mopar said:
I have been looking at ovate beehive springs and will probably use them.

I think that this will be about as low stress as you will find for a solid roller
setup that makes any power.

I used to be a Harley Davidson parts manager and crewed for a top-flite
AMA Dirt Track team (Steve Morehead) for several years. I built the
engines with Hank Scott. Spent time on Jerry Branch's and Carl Patrick's
dynos. I know of where you (DusTed74) speak.
Click to expand...

I'm a big fan of the beehive spring. We've been using them a lot too.
You were in good company with those folks. I bet that was a lot of fun and a big learning experience as well.
I've been to Branch's shop a few times. I never had the pleasure of meeting him,but it's different now since the company has been sold twice. It is still a cool place. Lots of history there. Its pretty much a 1 man operation now. He worked with Jerry for a long time and he's keeping the shop going.
Just one thing about oil. We just released a private label brand of oil that (so they say) has the highest levels of zinc of any oil currently on the market. So my question is, if zinc is not important to a roller tappet engine why would we offer it?
 
DusTed74 said:
So my question is, if zinc is not important to a roller tappet engine why would we offer it?
Click to expand...
I never said that but from my years in the dealership I can think of one other good reason when used in a
Harley Davidson Motor.

The air-cooled Harley Davidson street motor is one of the hottest running, most oil destroying powerplants
ever offered to the general public. anything that adds to the durability factor is a plus there.

Not to stray so far off-topic but you have to admit, that's a pretty valid point. I used to see HD owners filling
up with straight 70 weight Shell Rotella or John Deere oil made for diesel engines.
 
The question as far as spings go is what camshaft lobes are you using? The heads can come with folded cardboard, or NASA unobtanium ovate that handle .800 lift. What matters is what the cam needs. The roller lifters are heavier - especially the ones that are full bodied. So figure out the cam, then worry about the springs.
 
Points all well-taken. Here's what MRL says about the lifter design (Yeah, I know, It's an ad):

"Pro Plus Series Lifters feature a 4-column design for ultimate strength and rigidity while minimizing mass."
______________________________________________________________________________________

I only saw one beehive spring set listed by Comp Cams and one by Lunati. Are there others?
 
Camshaft? Probably something along the lines of this Lunati; even milder than I first
considered but big enough and probably better for a cruiser/driver:

Specs for Cam

•Series- Voodoo (3-Bolt)
•Other Part # 60331
•RPM Range - 2500-6600
•Advertised Duration - 267/273
•Duration at .050 - 237/243
•Lift -.566/.578
•LSA/ICL - 110/106
•Valve Lash - 0.016

-or-

•Series- Voodoo (3-Bolt)
•Other Part # 60332
•RPM Range - 2800-6800
•Advertised Duration - 273/279
•Duration at .050 - 243/249
•Lift -.578/.585
•LSA/ICL - 110/106
•Valve Lash - 0.016
 
Old Man Mopar said:
I am looking for honest realistic opinions on how many miles I can expect to be able
to street drive (goin' cruzin') a 400/470 with the best MRL roller lifters (with the larger
roller wheel) and a mild (approx. .580 - .600 lift) solid roller camshaft before having to
have the lifters rebuilt or replaced. What about valve spring life?

Below are the valve spring specs:

1.550" o.d. dual spring
138 lbs. @ 1.950" installed height
430 lbs. @ 1.250" open
420 lbs. per inch rate
.680" max. valve lift
Click to expand...

I have many engines out there that I have built, and many more around the world running our solid rollers. Most are street/strip. I have a few that are street only and have many thousands of miles on them, and we have yet to have any fail. I don't recommend rebuilding lifters, and they don't need it unless they are pushed to the ragged edge in a racing application where valve float may occur every now and again. Every time you press the axle out of the body to "rebuild" the lifter, you weaken the body.
In a street application, where the engine runs at or below 3000rpm 90% of its life, they will last just about forever, as long as the valve train is set up correctly. If you float the valves or cut off all the oil to the lifter, it wont survive no matter who's lifter you use.
 
Thank you Mike. I was hoping that you would chime in and that is about what I wanted to hear.

After checking on roller lifters, including the ones with the bushings instead of the needle bearings,
yours are the ones that I am going to buy.
 
The 60331 is what I had Mike put in mine when he built it. If your interested here's the thread
http://www.forabodiesonly.com/mopar/showthread.php?t=286851

Haven't heard it run yet, but I'm getting close to being able to start and move the car for the first time since I bought it 4 years ago. Bought it as a roller.
 
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