Run time on Roller rockers before failure?
Thread Starter
Race Director
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From: Indianapolis IN
Run time on Roller rockers before failure?
I was reading a thread in ENGINE MODS http://forums.corvetteforum.com/zerothread?id=467119
and was surpised to see the minimal length of time that SOME of the RR's lasted.
Any experinces here I could learn from? Should I be concerned? I am looking at the Pro Magnums for my new engine.
[Modified by ld85, 1:42 PM 1/15/2003]
and was surpised to see the minimal length of time that SOME of the RR's lasted.
Any experinces here I could learn from? Should I be concerned? I am looking at the Pro Magnums for my new engine.
[Modified by ld85, 1:42 PM 1/15/2003]
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Re: Run time on Roller rockers before failure? (ld85)
No personal experience with aluminum RR's, but I do know that Smokey Yunick, in his book POWER SECRETS, advises against rr's for the street. Another book, S-A Design's HOW TO BUILD THE SMALLBLOCK CHEVROLET, warns of needle bearing problems in the long-term. A third publication, the old HOW TO HOTROD SMALL-BLOCK CHEVYS, quotes engine builders as saying that the aluminum rr's have "a maximum safe life of six hours (!) " and "a maximum of 2000 racing miles could be run before replacing them." The short fatique life of aluminum is also called into question. Since these are older publications, no mention is made of the newer, steel or stainless steel roller rockers.
They all seem to agree on this however; for non-racing engines (that's non-PURE-racing engines, not 'weekend warriors'), the stock stamped-steel units are more than adequate.
I did run a set of roller-tipped stamped steel rocker arms on my 406ci low-rpm torque motor. AT 75K miles, several of them had damaged/worn rollers . I replaced them with the (aftermarket) stock type.
Proceed at your own risk.....:)
Hope this helps.
Larry
'96LT4coupe
:seeya
[Modified by rocco16, 4:56 PM 1/15/2003]
[Modified by rocco16, 4:57 PM 1/15/2003]
They all seem to agree on this however; for non-racing engines (that's non-PURE-racing engines, not 'weekend warriors'), the stock stamped-steel units are more than adequate.
I did run a set of roller-tipped stamped steel rocker arms on my 406ci low-rpm torque motor. AT 75K miles, several of them had damaged/worn rollers . I replaced them with the (aftermarket) stock type.
Proceed at your own risk.....:)
Hope this helps.
Larry
'96LT4coupe
:seeya
[Modified by rocco16, 4:56 PM 1/15/2003]
[Modified by rocco16, 4:57 PM 1/15/2003]
Drifting
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From: Charleston, WV
Re: Run time on Roller rockers before failure? (ld85)
I'd be interested in that myself. I hadn't heard of failures myself but haven't been over to that column for a while. It may have to do with the fact that a lot of guys use oil restrictors when using roller rockers. I would think they'd be pretty good though because they are OEM on some engines.
Burning Brakes
Joined: Oct 2001
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From: Tracy California
St. Jude Donor '05
Re: Run time on Roller rockers before failure? (ld85)
Huh? I've running CompProMagnums for years on the street. I've never had one fail, become noisy or wear out in any fashion. I also know for fact that there are many people that run aluminum RR's on the stret also.
I think it depends on your spring pressures. Solid roller cams can be very demanding on other parts.
KM
I think it depends on your spring pressures. Solid roller cams can be very demanding on other parts.
KM
Former Vendor
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From: St Marys PA
Re: Run time on Roller rockers before failure? (88-406)
I find that hard to believe that they won't last :confused:
There is less friction, therefore less wear than a regular stamped rocker, so why wouldn't it last longer? Granted sometimes the ratio is bigger putting a little more stress on them. But when I look at my pro mags compared to a stamped rr, there is no comparing which would take more abuse.
And a statement like 2000 race hours is a little silly to begin with. That would take the average person, ~100 yrs to accumulate.
Not saying the statements were not made in the books/articles, but I call BS on them.
There is less friction, therefore less wear than a regular stamped rocker, so why wouldn't it last longer? Granted sometimes the ratio is bigger putting a little more stress on them. But when I look at my pro mags compared to a stamped rr, there is no comparing which would take more abuse.
And a statement like 2000 race hours is a little silly to begin with. That would take the average person, ~100 yrs to accumulate.
Not saying the statements were not made in the books/articles, but I call BS on them.
Safety Car
Joined: Feb 1999
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From: Mexico Beach FL
Re: Run time on Roller rockers before failure? (ld85)
My new Crane Gold roller rockers lasted about nine months until one had the needle bearing come out of place and put little needle bearings throughout my engine.
My new Crower Stainless steel roller rockers have been in for about 30000 miles with no problems.
Tom Piper
My new Crower Stainless steel roller rockers have been in for about 30000 miles with no problems.
Tom Piper
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From: O'Fallon Missouri
Re: Run time on Roller rockers before failure? (rocco16)
No personal experience with aluminum RR's
Larry
'96LT4coupe]
Larry
'96LT4coupe]
Le Mans Master
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From: delmont pa
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Re: Run time on Roller rockers before failure? (ld85)
with hydraulic lifter cams they will last forever,but on solid lifter engines letting the lash get loose will kill them because of the pounding they will take. this the same reason hydraulic roller lifters last a long time but solid roller lifters need rebuilt or replaced evey 150 hours. :chevy
Thread Starter
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From: Indianapolis IN
Re: Run time on Roller rockers before failure? (clem zahrobsky)
Its good to hear that there are some people getting hi mileage on the roller lifters.
I agree on a street engine they should last a long time.
I will liekly call the manufacturer and get their input and info on failure history too.
I agree on a street engine they should last a long time.
I will liekly call the manufacturer and get their input and info on failure history too.
Pro
Joined: Oct 1999
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From: Markham
Re: Run time on Roller rockers before failure? (ld85)
My motor has about 35,000 miles on my set of aluminum RR and still going strong. They are T&D's for a SBC. I wouldn't worry about them.
Now my Comp Cam SBC solid roller lifters are only good for 15,000 miles before a re-build.
Now my Comp Cam SBC solid roller lifters are only good for 15,000 miles before a re-build.
Melting Slicks
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From: PITTSBURGH PA
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Re: Run time on Roller rockers before failure? (TurboVette)
i would think the failure rate would be from a too much spring pressure not from direct useage :cheers:
Melting Slicks
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From: NW Chicago Suburbs
Re: Run time on Roller rockers before failure? (ld85)
35K miles on my daily driver with GMPP 1.6 roller rockers. I drive this car all winter and park it for most of the summer (it's my Impala SS with an iron headed LT1).
Eric
Eric
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From: Sachse Texas
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Re: Run time on Roller rockers before failure? (ld85)
ld85,
You are talking about Roller Rockers, where as the topic you refered to is discussing roller lifters. Two entirely different things. A set of roller rockers will last you many miles without thinking twice about them. (By "many" I mean 100K plus)
You are talking about Roller Rockers, where as the topic you refered to is discussing roller lifters. Two entirely different things. A set of roller rockers will last you many miles without thinking twice about them. (By "many" I mean 100K plus)
Thread Starter
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From: Indianapolis IN
Re: Run time on Roller rockers before failure? (Vette92)
ld85,
You are talking about Roller Rockers, where as the topic you refered to is discussing roller lifters. Two entirely different things. A set of roller rockers will last you many miles without thinking twice about them. (By "many" I mean 100K plus)
You are talking about Roller Rockers, where as the topic you refered to is discussing roller lifters. Two entirely different things. A set of roller rockers will last you many miles without thinking twice about them. (By "many" I mean 100K plus)
I can see where the roller rockers are pretty robust from an engineering standpoint, I guess my main question was indeed about the lifters since the needle bearings inside them are a much smaller overall package.
From what I have read on the web since my post the general concensus is that the overall life of the lifters depends on the amount of lift / spring pressure (as someone stated above) and how agressive the cam is. I will not have a lot of lift or an agressive cam but will run this by the lifter manufacturers any way.
[Modified by ld85, 8:11 PM 1/15/2003]
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Re: Run time on Roller rockers before failure? (ski_dwn_it)
ski-
2000 racing miles, not 2000 racing hours
(I should have said "no experience with aftermarket aluminum rr's")
Larry
'96LT4coupe
2000 racing miles, not 2000 racing hours
(I should have said "no experience with aftermarket aluminum rr's")
Larry
'96LT4coupe
Safety Car
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From: Jacksonville Fl
Re: Run time on Roller rockers before failure? (ld85)
My Harland Sharps have about 5 years on them...look like new.
One thing...roller rockers will wear the valve stem tips off unless you use lash caps.
One thing...roller rockers will wear the valve stem tips off unless you use lash caps.
Safety Car
Joined: Dec 2000
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From: Jacksonville Fl
Re: Run time on Roller rockers before failure? (ld85)
Hmmm...now that you are talking about roller lifters...well, another story, lol\
This is what kills roller lifters: Using roller lifters in a non-roller block!
Yes, there are many roller lifters designed for non-roller motors. I have used them myself and had failure after about 3 years.
The reason for failure was side thrust related on the wheel. The wheel had eaten into the lifter body until the lifter body failed. Bleive it or not, it was due to the design of a flat tappet block. On a flat tappet cam designed block, the lifter bore is not perpendicular to the cam lobe, it is angle slightly to promote lifter spinning which makes the flat tappet cam/lifter last longer. This causes a roller lifter to have it's roller wheel thrust to one side or the other...and there is no bearing surface built in for side thrust, so the wheel eats into the lifter body sideways.
The fix for this is to have the blocks lifter bored machined and sleeved so the lifters are perfectly perpendicular to the cam lobe. Anything less will end up in limited lifetime for the roller lifter in a non-roller machined block.
As for stock roller lifter blocks...the lifter bores are perfectly perpendicular, so this problem is non-existant and the lifter last for hundreds of thousands of miles.
This is what kills roller lifters: Using roller lifters in a non-roller block!
Yes, there are many roller lifters designed for non-roller motors. I have used them myself and had failure after about 3 years.
The reason for failure was side thrust related on the wheel. The wheel had eaten into the lifter body until the lifter body failed. Bleive it or not, it was due to the design of a flat tappet block. On a flat tappet cam designed block, the lifter bore is not perpendicular to the cam lobe, it is angle slightly to promote lifter spinning which makes the flat tappet cam/lifter last longer. This causes a roller lifter to have it's roller wheel thrust to one side or the other...and there is no bearing surface built in for side thrust, so the wheel eats into the lifter body sideways.
The fix for this is to have the blocks lifter bored machined and sleeved so the lifters are perfectly perpendicular to the cam lobe. Anything less will end up in limited lifetime for the roller lifter in a non-roller machined block.
As for stock roller lifter blocks...the lifter bores are perfectly perpendicular, so this problem is non-existant and the lifter last for hundreds of thousands of miles.