451Mopar
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Great, the set we had would have been like 20 years old
Roller rockers time?
- Thread starter Mark1972
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More like fifteen... They got bushings when I was at my old house... Moved here in 08...
You really should not need roller rockers for that cam. A good set of originals should work fine and not blow through like that.
Do you think there could be an underlying issue such as lifters pumping up and causing coil bind? Or just bad stamped rockers?
451Mopar
Well-Known Member
The pushrod poke through seems to be a common failure point with >0.500"+ lift cams and old used rocker arms.
I never tried the replacement rocker arms, but Mopar Performance did offer (long ago) a "performance" replacement that was supposed to be stamped from thicker steel?
Other issue with stock rocker arms is they are usually less than 1.5:1 ratio, and I usually go to a 1.6:1 ratio when I get the roller rockers. Usually the 1.6:1 ratio costs the same as the 1.5:1 too. Just need to make sure the heads and valve springs can handle the extra lift. Piston to valve clearance changes are minor. They change more by duration and ICL, but best to check if the current clearance is tight.
I never tried the replacement rocker arms, but Mopar Performance did offer (long ago) a "performance" replacement that was supposed to be stamped from thicker steel?
Other issue with stock rocker arms is they are usually less than 1.5:1 ratio, and I usually go to a 1.6:1 ratio when I get the roller rockers. Usually the 1.6:1 ratio costs the same as the 1.5:1 too. Just need to make sure the heads and valve springs can handle the extra lift. Piston to valve clearance changes are minor. They change more by duration and ICL, but best to check if the current clearance is tight.
Mark1972
Well-Known Member
The stamped steel rockers that were put on the engine when it was built were the originals. I've also heard that new stamped steel rockers(Melling)have heat treatment issues. Either way, I've got the new roller rockers now, at 1.5 ratio, because I really wasn't looking for more power, just reliability. Really hoping the new pushrods(9.200")show up this week so I don't lose another weekend with the car sitting. Driving season doesn't usually last long around here. These heads will take up to .600" lift, so the 1.6 would work. I'm hoping there is no other issues. Now that I'll have swapped out the rockers and shafts, the only thing left from the original motor is the block and crank. If one of those fail, I'm done, lol.
SRT_Blubyu
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I'm not very familiar with vintage Big Block Chrysler engines.. but shouldnt the pushrods have a bore hole up the shaft to supply oil to the tip where it meets the rocker pocket for lubrication ? I would think friction could easily produce the results youre seeing...
Mopars didn't oil through the pushrod... They oil through the shaft..
SRT_Blubyu
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10-4.. just a thought. seems very odd to be punching through rockers like that
Mopar2u
Member
Say what you will about UTG, but I believe his experience can be helpful.
Skip to 1:13 to get right the the rocker arm part:
Seemed related to me. Even though this is a small block, you could be having a similar lifter problem where the lifter is not pumping up (or bleeding down) and letting the pushrod hammer away at the poor stamped steel rocker. Under normal pre-load, this will never happen. But if there is any clearance, perhaps it will eventually bang the pushrod through.
Skip to 1:13 to get right the the rocker arm part:
Seemed related to me. Even though this is a small block, you could be having a similar lifter problem where the lifter is not pumping up (or bleeding down) and letting the pushrod hammer away at the poor stamped steel rocker. Under normal pre-load, this will never happen. But if there is any clearance, perhaps it will eventually bang the pushrod through.
Mark1972
Well-Known Member
Thanks for the UTG link. I think I've actually seen that episode, but I didn't put 2 and 2 together until watching it again now. I'm curious now to look at my lifters. I'm wondering what kind of pressure it should take to depress a hydraulic lifter? I thought there was a spring inside the lifter as well?
I agree ductile iron rockers are good way to go but I warn the buyer to be sensitive to the ones from Crane. Though Crane was a reliable vendor for many, many years... They have gone through some dire straits during their bankruptcies and the quality went downhill.. Best bet is to sticky with the Iskys..
Just my $0.02...
The link was pretty comical.
Roller cam, 550 lift, and he says the wimpy stock rockers should be , Mooooore than up to the task...
He's alone on his hopes and dreams..
Which ironically turned out to be WRONG.
Roller cam, 550 lift, and he says the wimpy stock rockers should be , Mooooore than up to the task...
He's alone on his hopes and dreams..
Which ironically turned out to be WRONG.
Didn't watch it, stock rockers are fine... In a stock engine.... More than 480 lift or aggressive profiles (Think Comp Extreme Energy or anything from Ultradyne) loose the stamped steel rockers... I've always run the Isky's have no experience with the Cranes, my previous post I listed Isky first, OE second, Crane & Erson third & fourth because I believe when Erson was selling ductile rockers they were re-packaged Cranes... In the last years of selling Ductile Isky was re-boxing Cranes too... Why they would do that when they previously sold the best ductile rockers I have no idea... I know there Crane had an issue with adjuster screws that weren't hardened properly.. But I believe the rest of the rocker was fine so if you get Cranes replacing the screws should be SOP..
I know a pretty well respected SS racer that uses Iskys on his race engines with 750 lbs open spring pressure..... The rockers never give him trouble...
I know a pretty well respected SS racer that uses Iskys on his race engines with 750 lbs open spring pressure..... The rockers never give him trouble...
BSB67
Well-Known Member
The set of Cranes I bought in 2016 had soft tips that wore. I believe Glenwood had the same issue with the Crane iron rockers. I would trust the old Isky over them any day of the week.
The major issue I had with the Cranes ductile iron rockers was that they were not hardened properly and the pushrod ends wore through the rocker.. Even though I had great oil flow. This happened many years back, and I had a meeting @SEMA with the Crane engineer. I brought samples and he went viral and totally blew out... I moved on threw them all in the dumpster and installed roller bearing Harland/Sharp rockers, installed and adjusted up all has been fine... Note that as I posted previously this was during the time Crane was going through a bankruptcy, so other early or later production runs may be OK. But for me, no more Crane stuff..
Just my $0.02...
Just my $0.02...
451Mopar
Well-Known Member
I'm just shocked at how expensive rocker arms have become.
Back when I bought the harlan sharpe rockers for my Coronet, maybe 7-8 years ago, I think they were in the $600 dollar range?
Back when I bought the harlan sharpe rockers for my Coronet, maybe 7-8 years ago, I think they were in the $600 dollar range?
How much now? When I last looked H/S were in the $450 range but that was back around 2000... Instead I bought threes sets of Iskys still in the vacuum sealed packaging for $100 per set...
451Mopar
Well-Known Member
Post #18 link to summit racing. $804 for the S70015K, and $916 for the S70015KE version trick flow recommends.
Harland Sharp S70015KE Harland Sharp Heavy-Duty Roller Rockers | Summit Racing
The 1.6:1 ratio S70016KE that I used on the trick flow 240 heads are now $970! I bought them when the Trick Flow 240s were first released, I think they were under $700 back then.
CHRYSLER Harland Sharp S70016KE Harland Sharp Heavy-Duty Roller Rockers | Summit Racing
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