will your roller rockers last??

[grumpyvette]

if were talking about a corvette running major street driven miles
ID tend to get the STEEL roller rockers NOT the aluminum for TWO reasons
LONGER FATIGUE LIFE
MORE CLEARANCE,(retainer,spring,ETC.)
roller rockers like these work fine, but should be considered for replacement after about 60,000 street miles
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=163195&prmenbr=361

BUT THESE (below) will LAST LONGER IN MOST CASES ON THE STREET, and are REBUILDABLE, with replaceable bearings
IVE NEVER SEEN THESE HAVE PROBLEMS WHEN INSTALLED CORRECTLY

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=191752&prmenbr=361]http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=191752&prmenbr=361

the STAMPED ROLLER TIP rockers

are a waste of money in most cases as they dont do much more than the stock rockers other than potentially getting you a better rocker ratio IF you get the 1.6:1 ratio rockers as they have about the same friction as stock rockers provide, the roller tips provide almost no benefit at all in reduceing friction


if your running a street style spring pressure range your unlikely to have problems BUT
it will depend to a great extent on BOTH the RPM range and THE spring PRESSURES your running,( good HIGH oil flow volume to cool the springs and rockers,helps here gentelmem ) CAST ALUMINUM ROLLER ROCKERS (or for that matter all aluminum roller rockers) should be looked at as an expendable wear item that should be checked and replaced occasionally
the STEEL roller rockers are normally more durable and rebuildable, comp cams and CROWER CAMS make them
but even those need to be frequently checked if your running high spring pressures and lifts over about .600
it should go without my pointing it out that your valve train geometry must be correct as are all clearances also if you expect the rockers to live very long

 

[Ken]

 

[Ken]

As fate would have it, in a similar vein...

The September issue of Chevy High Performance magazine has a related article to this: Kevin McClelland has the following as the lead-off to his Performance Q&A column:

LOVE/HATE RELATIONSHIP

Love part: What camshaft manufacturers can do with a roller tappet and a lobe is magic. And when you think of the rpm ranges that are possible with pushrod engines today compared to twenty years ago, it's nigh unbelievable.

Hate part: When a needle or roller bearing comes apart inside a precision racing engine, it's not a pretty thing. I've seen the aftermath of disintegrated roller tappets, roller rockers, and the Torrington bearing that nestles behind the camshaft. Pieces of the bearing bounce around the pistons and go down to the oil pan where they end up in the oil pump and jam it. Your oil pressure gauge dropping to zero as you near the finish line is the last thing you want to see.

Monitoring your engine's valve lash and recording the adjustments from the beginning of a freshly built engine is the only way to identify a roller tappet or rocker arm that's dying, and sometimes you get lucky and find a tappet that's on it's way out. If one valve is looser than the rest by a good deal (0.006 to 0.008 inch), it's probably ready to take a hike. Though Comp Cams and Crane recommend inspecting your roller lifters every 100 runs; I've had them go out before then.

Recently, I was giving my roadster a complete going over before commencing three straight weeks of racing. I'll be running five different races, so I won't have the time to service the car, and I could log as many as 50 runs during those three weeks. Over the past couple of valve adjustments, I've noticed that the clearance is picking up lash. The #8 exhaust was really starting to bother me. After setting the lash this time, then rotating the engine and checking it again, the lash changed. Thinking the worst, I took it apart, but found that the tappet and rocker were fine, but the posi-locks on the stud girdle had worn enough that they had built up a ridge. On one rotation they would seat and the next rotation would register on the ridge and take up all the lash.

The moral? Know your valvetrain and keep your eyes peeled for wear of any type.

 

[Jack]

For those running solid FLAT tappets ... There are versions that supply oil directly to cam lobes. Some have a small groove running lengthwise ... others have a tiny hole EDM'd through the lifter face. Check with Crower or Howards Cams. I've got a set of Howard's EDM'd "direct lube" in the circle track car (about $90) ... they're an Eaton lifter w/good snap ring. Oil pressure dropped less than 3 psi vs non-EDM. Also running Comp HiTech Stainless roller rockers ... nice pieces. BTW ... Comp's Chromemoly RR squirts oil from pushrod cup straight up ... their Stainless RR squirts it toward the polylock.
JACK:gap
-addendum- seems jegs gets $401 for the comp hitech stainless ... I recently bought em from ERW in Ft. Lauderdale for $325 ... were dropshipped direct from comp for another $10.

 

[Tom Bryant]

Looks like a good arguemant for running screens over the oil drain backs.

Tom

 

[jenavet]

Looks like a good arguemant for running screens over the oil drain backs.

Tom

yep...i did that before...didnt recheck the lash...rocker lossened up...lash cap fell out...pushrod bounced around and punched a hole in the side of the lifter...slightly bent the valve...i found all the pieces of the lifter but one medium sized piece....30 runs later....kaboom!!! sure enough i found the other piece...i have had everything screened on all my motors since......but some oil pump manufacturers[like titan] do not recommend screening the valleys....i did it anyways.