70442rag

Hi Folks,
I thought I would let you know that I recently had a failure with a pushrod that snapped about 1.5 inches from the top (under the rocker arm) as a result of rubbing up against the pushrod guides. The motor is a 1970 Olds 455 with steel heads that have been ported and polished. The heads also have 7/16 screw in studs with Crane 1.6 roller rockers. The valves are oversize stainless w heavy duty springs. The cam is a Dick Miller unit with around .550 lift intake and exhaust. The guides are a two piece ISKY unit. I was told when I bought the pushrods a couple years back that they were chrome molly hardened but when we took a file to them they were able to score very easily. Upon further inspection, most of the pushrods are all scored in and around the guide plate area. It looks like many of the others are on their way to being "skinned". Last week we replaced the Comp Cams pushrods with a nicer set that is laser etched on the side. I believe they are called "Race Pro" and have an RP number on each.
After getting things going again and parting with nearly $500.00, I was advised by the mechanic that it does not appear that my valves are rotating as he had it running without the valve covers on and noticed that the keepers were not turning. He claims that this will likely cause premature wear or failure eventually and that something should be done so that the valves turn/rotate inside of the bronze guides. Is there any truth to this? Please help.....

Run to Rund

If you want the valves to rotate, you need rotators not retainers on the valve springs. OTOH, the pushrods and lifters should be rotating if a flat tappet (hydraulic or mechanical) cam is used.

cutlassefi

Correct, and I'd probalby consider finding another mechanic.

Hmmmm, this is the second recent post regarding Comp pushrods, anyone see a pattern here? I can't believe it, something from Comp failed, again!

Comp is a good cam company, but they're a better marketing company.
And your "Crane" rockers look like Comp ones.

70442rag

Thanks for the responses thus far.....where can I buy these "valve rotators" from? I assume we can install them without removing the heads? Is this one of those occasions where they fit a pressure hose into the spark plug hole and keep the valve seated nicely in the head by doing so? The cam is a hydraulic flat tappet not a roller. Is it essential that the valve stems turn otherwise premature failure will result?
Sorry- you are right the rockers are also Comp Cams not Crane. I've invested a fair amount of money into this motor and it would be great if this thing could live rather than me pouring more into it after only 1,300 miles of service.
Thanks in advance for the advice!

ah64pilot

Hey rag, I just had a problem with my "High Energy" pushrods on my mild convertible engine. The tips kept crushing...are you sure you didn't have those? I replaced them with the "Magnum" pushrods and they are most definitely hardened. They also have the etching on them with the length etched in them.

Either way, we both had failures of Comp pushrods in relatively mild engines...something isn't right there

70442rag

Hello Pilot,
I still have the ones we took out over the weekend- I'll try to take some pictures tomorrow after work and get them up for you to see. They do not have the laser etching on them. The guy that swapped them out for me says that they are likely made in China and are so bad that the ends have not been pushed into the barrels 100% straight. He has also told me that the thickness of the walls is not what Comp Cams specifies. I think they post something like .008 thickness and these are less than that- closer to .007 thickness. I will never use Comp Cams pushrods again. How's a guy supposed to know all of these things? It seems we trust the wrong folks and make assumptions that we should never make. Man I find this frustrating!

ah64pilot

A quick way to tell is look at their color. If they are grayish brown (raw metal) looking then they are the "High Energy" line from Comp. But I can tell you right now they are NOT the "Magnum" line if they have pressed in tips. The "Magnum" pushrods do not have pressed in tips. You probably did the same thing I did...I got what I thought were hardened pushrods and they were not. Either way, you're in good shape now with the better ones you got.

compedgemarine

you dont have to have the rotators, they were put on from the factory to try and help the valve surface for long term durability. most engines only used them on the exhaust valve. the theory is that the high heat on the exhaust side will cause the surface of the valve to weld particles to the seat so by rotating them it would help keep them from creating a void spot on the surface. most motors making big power have no rotators and they manage to go for tens of thousands of miles with no issues. the rotator by the way has nothing to do with the guide and the guide does not care if the valve rotates.

70Post

Correct me if I'm wrong here but I don't think you should be concerned about the lack of any "valve rotation/rotators". For YEARS on any HP Olds build this was/is usually one of the first things to be eliminated from the valve train (the valve rotators).

Edit: Compedgemarine was on the same "wavelength" as he posted similar info a few minutes before mine.

The_Jeremiah

I might be bringing up something dumb, but this was the first thing that popped into my mind, did you make sure you had enough clearance on the valve guide to run that kind of lift?

most oldsmobile heads from what i have seen with stock valve seals can run around .500 lift, maybe a little over, ad a positive valve seal to that equation, and im sure your hitting at .500 lift.

that being said, do you have at least .010 to .015 thousands clearance on the guide when the valve is fully open? if not, could be hitting, just my .02 cents

also, those look like regular cast iron heads to me, not steel, am i missing something?

ah64pilot

Steel heads? Do you mean aluminum?

507OLDS

The Comp Cams kit does not come with the correct pushrods,period. They are rarely ever the correct length for the application,and they don't seem to have the correct treatment for strength.
the rockers,studs,and guide plates are good pieces.Just get the correct pushrods.

70442rag

Thanks guys. Excellent input indeed. The heads are steel "J" heads that I bought off of a fellow in Michigan a few years back. There were extensively ported and polished and already had many of the things that I wanted to do such as stainless valves, 7/16 screw in studs, port / polish work etc They were rechecked in 2010 by my engine rebuilder (when he put the motor together) and he took them all apart and checked the valve components etc the only thing he had to do was to slightly plane the underside of the heads for straightness which is why the attached picture was taken.
As for the valves not turning....I guess my mechanic buddy was fearful that if the valves no longer turn, then they will wear in the same spot on the top of the valve stem and also wear in the same area on the sides of the stems. Also, because there are collisions that take place on the sides of the pushrods banging against the pushrod guides, he was also fearful that the pushrods may continue to wear in the same spot thereby trying to wear down the pushrods again and again (on the sides). I am hoping that these new laser etched, chrome molly hardened pushrods will take the abuse and not wear themselves thin the way the last ones did.

70442rag

sorrry, forgot to attach the pics....

70442rag

Understood. Thanks Brian!

ah64pilot

What's the difference with the "steel" heads? Can someone educate me?

70442rag

Sorry- I meant to say cast iron heads not steel....

atkinsom

I'm wondering the same thing here. So are we saying that with these high performance hardened pushrods the whole theory behind rotating goes out the window? Hence why HP Olds engines get rid of this function straight off? Curious for my knowledge down the road. Thanks guys.

jfb

hey buddie i have had a set from mondello performance for years and 2 engines and never had a problem but you do have to tell them the right numbers. I know a few people disagree with there products but i have had no problems with them at all. by the way do not pick used parts unless you know positively first they are real good it is a buyers beware market out there!

ah64pilot

Mondello pushrods are Comp Magnum pushrods with their own etching...and they charge you double the price

507OLDS

I do NOT and will NOT have anything connected to my car that came from Mondello.

As with everything else,you need to combine different pieces to get it all correct.The kits are just not it.