[vicgto]

I started noticing a valvetrain ticking sound recently, pulled the valve cover and saw a rocker tip roller pin almost out. . I also saw 2 other rockers with loose pins. Needles to say I've lost all confidence in these rockers, they have less than 2000 miles on them. Something weird that I noticed when checking lash which I usually do before resetting is that most of the intake clearances were bigger anywhere from .005" to .015" form the initial .006". Not sure why this is but I think it might be to do with wear on the nut where it contacts the rocker shaft, there is a small contact area there and there seems to be some wear showing. There is sufficent retainer to guide clearance (.070") and not going into coil bind, Springs are Crane 99893 set up at 1.810" installed height.
Cam is OF with about .630 lift with Comp Solid Roller lifters. Looking for suggestion on new rockers, H & S or Scorpian, which one would give better valvetrain geometry, current have 9.4 inch pushrods which I did check for straightness.. KRE D port heads.

[Cliff R]

I've posted our experiences with those rockers many times. From the moment we put them in service (used several sets early on) they start to grind up the rollers where the pins go thru them.

On my own engine I had a few with as much as .018-.019" clearance by the time I figured out where all the metal on the magnetic drain plug was coming from.

Removed them from several other engines we had them in and same thing, found heavy wear at the pins.

I replaced mine with Crower Enduro rockers and no more issues.........

[vicgto]

Originally Posted by Cliff R

I've posted our experiences with those rockers many times. From the moment we put them in service (used several sets early on) they start to grind up the rollers where the pins go thru them.

On my own engine I had a few with as much as .018-.019" clearance by the time I figured out where all the metal on the magnetic drain plug was coming from.

Removed them from several other engines we had them in and same thing, found heavy wear at the pins.

I replaced mine with Crower Enduro rockers and no more issues.........

Cliff, I believe you had a similar set up to mine with the OF Hydraulic roller cam and Crower Solid roller lifters with lash at .006". I'm wondering if this combination is putting more load on the valvetrain due to insufficient clearance ramp, what are your thoughts?

I ended up going with 1.6 Crower Enduro rockers. I was planning on going with Harland Sharp but I did not want the additional lift from the HS 1.65 (which are closer to 1.7) as I currently only have about .060" retainer to guide clearance with the 1.65 PRW rocker. Also I I don't want to work the valve train any harder and I'm not sure that exta .020" -.025 valve lift would help my SD ported 295 KRE heads (Daves data sheet stops at .550" with 299 cfm and I'm not sure how much better they are above that).

I had an interesting conversation with Scott form Butler Performance who I ended up purchasing from. I don't know the accuracy of his statements but he said Crower, Harland Sharp, Scorpian and most other US made rockers are bigger than the advertised ratio (e.g. 1.65 is actually closer to 1.7). He said he was told by one of the manufactures this is done to overcome losses due to flexing of components during operation so you end up with advertised ratio, not sure how true it is but that's what he said. He also said the off shore stuff (e.g. PRW) are much closer to advertised ratio.

Anyway I hope I don't get anymore surprises with these rockers.

[djustice]

Originally Posted by vicgto

I had an interesting conversation with Scott form Butler Performance who I ended up purchasing from. I don't know the accuracy of his statements but he said Crower, Harland Sharp, Scorpian and most other US made rockers are bigger than the advertised ratio (e.g. 1.65 is actually closer to 1.7). He said he was told by one of the manufactures this is done to overcome losses due to flexing of components during operation so you end up with advertised ratio, not sure how true it is but that's what he said. He also said the off shore stuff (e.g. PRW) are much closer to advertised ratio.

Anyway I hope I don't get anymore surprises with these rockers.

Yes that is what i have heard too, David vizard and also Eric Weingartner has video's on this subject. Eric also demonstartes the overshoot on Ratio on one of his motors without spring pressure and with full spring pressure. and you can see what the actual ratio is. As for me i have been running Scorpion 1.5 ratio rockers for about 10 years now, first on a ramair 4 cam (edelbrock flat tappet) and now on a comp roller and no issues this far.

[PAUL K]

I disagree that rocker arms are intentionally made with a higher than advertised ratio to account for deflection or any other reason. It would screw a lot of conscientious builders if that were the case. As mentioned in an earlier post a set of 1.6 rockers were chosen because of minimal retainer to seal clearance. With the trend today of hi-lift cams being used in street cars you would have a lot of excessive guide wear, coil bind and smashed valve seals if rocker arms weren't correct ratio or usually a little less.

It's not as simple for the average fellow to check ratio as most would think. First the pushrod length needs to be optimized for each rocker arm because that will affect the net lift. Then one must decide whether to check with the valve spring in place or a test spring. A high RPM race engine will give up .030 or more lift checking this during the assembly if it's checked with a valve spring in place.

My guess is most of the "extra" ratio comes from second hand information that stems from the ratio not being checked properly by the originator of the rumor. I have checked many rocker arms for ratio and how far the rocker moves the pushrod towards or away from the rocker studs.... I do the later due to my dislike for grinding the head for pushrod clearance. I have found very few that have more ratio than advertised. I have found that some can be "tricked" to give more valve action by adjusting the pushrod length. But then one must decide between added valve open time or optimized geometry.

I have never seen a high end rocker shaft have anything but the advertised ratio. For many reason the shafts are dead nutz on, but if any rocker arm builder was going to add extra lift "for a reason" , the most logical being valvetrain deflection, one would think it would be the guys building rocker arms for a 9,000 rpm application using 1500 lbs. of spring pressure.

The only rocker arms I have found that consistantly check out higher than advertised is the Harland Sharp 1.65 and the Comp Cams 1.5 (which used to be advertised at 1.52) Pontiac rocker arms. I believe HS now makes four versions of the 1.65 and only one consistently measures close to 1.7. I asked Randy Sharpe directly about this and he had no idea as to why this is and wasn't aware of it. He said it definetly wasn't done for a specific reason, such as deflection. That might be why their newer 1.65 rockers measure closer to the advertised number.

FWIW


PS..... It'd be nice if a manufacturer would perfect an adjustable ratio rocker arm like Crane offered many years ago.

[steve25]

PRW quality rockers along with the open spring pressure needed to keep.630” lift in check is like trying to blend water and cooking oil.

Consider yourself lucky that you had no other engine damage.
Forget about Scorpions, there have been too many reported quality and failure issues with them also.

HR rockers have always been good, but there on the bulky side.
If you use them I would add a .010” shim under each spring unless your sure your over pressure as it is for the rpm your taking the motor to now.

[Formulajones]

That kind of stuff has been going on for years, and I don't view scorpion as any better either.

If you're budget oriented Harland Sharp is good quality if you don't mind aluminum bodies. They've been around since the 60's (I think it's been that long) They do tend to check a little bigger on the ratios, keep that in mind.

Generally I prefer steel body rockers and always go for Crower Enduro and just swallow the price tag, but lately they've been really hard to get. So last couple engines I've done the Comp Ultra Pro Magnum that are chrome molly and they have been excellent and reasonably priced.

[Dragncar]

Originally Posted by Formulajones

That kind of stuff has been going on for years, and I don't view scorpion as any better either.

If you're budget oriented Harland Sharp is good quality if you don't mind aluminum bodies. They've been around since the 60's (I think it's been that long) They do tend to check a little bigger on the ratios, keep that in mind.

Generally I prefer steel body rockers and always go for Crower Enduro and just swallow the price tag, but lately they've been really hard to get. So last couple engines I've done the Comp Ultra Pro Magnum that are chrome molly and they have been excellent and reasonably priced.

Can we get those Comp Pro steel rockers arms for Pontiac ? Can't find them.

[grivera]

Here are the Crowers and a 10% off discount code “10off”

https://crower.com/rocker-arms/stain...er-arms-5.html

[Stan Weiss]

Originally Posted by vicgto

I started noticing a valvetrain ticking sound recently, pulled the valve cover and saw a rocker tip roller pin almost out.Attachment 620119 . I also saw 2 other rockers with loose pins. Needles to say I've lost all confidence in these rockers, they have less than 2000 miles on them. Something weird that I noticed when checking lash which I usually do before resetting is that most of the intake clearances were bigger anywhere from .005" to .015" form the initial .006". Not sure why this is but I think it might be to do with wear on the nut where it contacts the rocker shaft, there is a small contact area there and there seems to be some wear showing. There is sufficent retainer to guide clearance (.070") and not going into coil bind, Springs are Crane 99893 set up at 1.810" installed height.
Cam is OF with about .630 lift with Comp Solid Roller lifters. Looking for suggestion on new rockers, H & S or Scorpian, which one would give better valvetrain geometry, current have 9.4 inch pushrods which I did check for straightness.. KRE D port heads.

Looking at the roller on that rocker I would pull the rocker check the valve tip. If it show wear I would pull the spring and check valve to guide clearance.

Stan

[tempest1964]

FormulaJones, can you tell us which rocker you used? I just went thru their listings and didn’t see anything for Pontiac. Did you use Ford? I have read that Ford can be used on Pontiac. Although I don’t recall seeing any at 1.5 ratio.
Thanks

[1968GTO421]

Originally Posted by tempest1964

FormulaJones, can you tell us which rocker you used? I just went thru their listings and didn’t see anything for Pontiac. Did you use Ford? I have read that Ford can be used on Pontiac. Although I don’t recall seeing any at 1.5 ratio.
Thanks

Yup, sounds like what I've been finding on-line

/www.compcams.com/products/rocker-arms/steel-rocker-arms/pontiac-2_magnum-3.html

(May stay with Harland Sharp rockers, over the decades they have been a reliable company.)

[turbo69bird]

Man I was just looking for rockers for my new build I agonized over some of the lower priced rockers Vs the Harland sharps . I have always run Harland sharp rockers on my cars and in the end I decided to use them again. I am so glad right now I made that choice instead of trying to save a few bucks .

[b-man]

They’re cheap for a reason.

As usual you get what you pay for.

[turbo69bird]

Originally Posted by b-man

They’re cheap for a reason.

As usual you get what you pay for.

Yeah but some items that were cheaper paid off like eagle rods. . I remember when rods were crazy expensive and then Eagle stuff came along and ended up being quite good. There have been items that were less money and worked out well . Unfortunately that doesn’t seem to be the case w cams lifters rockers ETC lately.

[Tom Vaught]

Originally Posted by b-man

They’re cheap for a reason.

As usual you get what you pay for.

x2 AGAIN.

CROWER HAS BEEN IN THE GAME FOREVER, REST IN PEACE BRUCE.

At one point it was like everyone was selling Junk from offshore.

Tom V.

[b-man]

I remember when PRW stainless rockers could be had for under $200 new, at the same time Crower Enduro were about $450.

In the long run you didn’t save anything because you had to buy something good later on.

Nowadays it’s easy to do research and see if cheap is actually good and sometimes it will be.

Do your research before pulling the trigger on parts that cost half or less than the more expensive ones. Right here on the forums there are plenty of failures reported on those PRW rockers so the information is there if you look.

[mgarblik]

In the stud mounted stuff, I have had good luck with the Crower SS rockers. Second in line would be the Comp. steel stuff although they have Chinese needle bearings. In aluminum body, Harlan Sharp is the only stud mounted rocker I would use. Although they do have failures, they have great customer service and promptly replace defects quickly with no questions or drama. I won a set of Scorpions in a drawing at PRI several years ago. I didn't install them. Traded them for some other stuff. Too many failures in multiple engine platforms. We have had at least half a dozen rocker arm failures on the dyno over the last 10 years. This is on many different engine platforms on student engines. In EVERY case it was pretty brightly colored aluminum body rollers from off shore suppliers. Pretty risky IMO.

[PunchT37]

Even on shaft systems, these cheap rockers are a danger. I did 2 mopar engines with Proform rockers. One LA motor, and one RB motor. BOTH had failures. Even with HFT cams and modest springs.

[b-man]

Crower 1.5 Enduro rockers with a .407” lift 068 cam.

The 1964 9770716 heads use pretty much impossible to find new 1964-1966 rockers so I figured even though the geometry wasn’t 100% perfect (but actually fine) they’d be a safe bet for the long haul.

Buy something good and you won’t regret it later like when you buy something that’s cheaply priced and you find out it’s junk.