zeeke

After running 4 hours between 70-75 MPH one of the rockers let go. Looking to replace them all as well as the push rods. Motor has about 3K on it, 455 .30 need to make a trip to the engine shop to get the full specs. Thank God this happened on the way back. Going to change the distributor to possibly and MSD. Something with a rev limiter.

Also can I use 3/8" vs. 5/16'' push rods?

#5 exhaust valve

I know I should put this post in the engine build section but I think more people would see it here.

TripDeuces

How much lift was on that Crane cam?

zeeke

They said it was a Sealed Power Cam CS-1023R but I can't find anything on the web for that #. I'll try to call again tomorrow.

oldcutlass

I moved this to the engine section. Here is a link to specs. The lift should not have caused your rocker to break. Was the pushrod bent?
https://www.opticatonline.com/part/s...ngine-camshaft

zeeke

i didn't roll it on a flat surface but it looked ok. I didn't bother because it was worn from banging around.
And ideas as to why it broke? I did hit it once hard about 300 miles earlier. Punched it & it didn't shift until about 80. I didn't have a tach but it was up there in RPMs for about 20 seconds. My average speed was 75 for 300 miles.

I didn't notice any issues until I was 30 miles from home in traffic.

RetroRanger

on my buddys 460 powered torino a rocker broke for no apparent reason, after checking everything we just got a new rocker and put it back together w no issues to report after the next couple years of ownership

zeeke

I was looking at Comp Cams. They sell a whole kit for $307. My intention is to take this car on long trips and cruises. Can't deal with breakdowns. I also think I'm done with points. Never had issues with them with the 350 but this 455 seams to eat them.

Are the rockers and hold downs the same for 350 & 455?

Run to Rund

There are three likely sources for rocker failures:
1. insufficient oil supply. This appears likely by the scuffing.
2. end of slot hits the stand due to high lift (generally over .52" or so). Fix this by using a carbide bur in a die grinder on the end of the slot.
3. pushrod cup failure, with pushrod punching through. Caused by high spring pressure, generally over 500 pounds open.

zeeke

Checked the oil volume, pressure and engine temp constantly. Oil was in range and averaging about 40 PSI the temp on the other hand ranged from 165 to 180 occasionally hitting 190 in the 50 - 60 MPH range. I'm guessing the low oil temp could be a concern. When I had a 195 thermostat in the car it ran over 200. It runs great at 180. I'll look into a 190 stat but I'm not sure it will run that hot. Radiator is a 2 core aluminum (4 Core replacement). Just about to give Comp Cams a call to see if I can use their kit. It has new rockers, push rods and new hold downs.

Are the rockers from the 350 the same for the 455. If so I can install them temporarily to see if there is any other damage?

Fun71

Didn't someone here post recently that one of his new lifters didn't have a hole in the plate, so no oil flow up to the rocker? Perhaps a similar thing, some sort of blockage in the lifter/pushrod that restricted oil flow.

oldcutlass

Your engine temp is not a problem, running at 180 is fine. When you get it back together ensure you have oil flow to all the rockers.

zeeke

Going to have to look for a valve cover to cut the top off of. I'll put something in the parts wanted section.

Still looking for an answer on the 350 to 455 rockers, compatible or not.

oldcutlass

Yes they are the same.

BillK

Were the rockers new when the engine was built ? They look like they have a million miles on them

zeeke

Bill they are the originals. The motor they came out of had about 35,000 on it. If I find the odometer I'll give you an exact milage #. I've put about 3K on it since the rebuild. Tomorrow I will pull 2 rockers off my 350 and look for a valve cover in a salvage yard I can hack. Not going to be easy since everything that old in this area has been sent to the shredder. I'm starting to lean toward not enough oil getting up to the top of the motor. Thanks Eric.

I ordered a new set of roller type rockers from Comp Cams for a 455. They are not true rollers, but do have a type of roller on the end. It comes in a kit, but I have to measure the rods after I put the new rockers on. When I build the 350 I'm going to specifically build it for highway cruising. I already have a 200R and a 278 posi rear in storage.

I will tell you this much, running at 75 MPH for 4 hrs with the top down, the wife next to me and the kids home was a highlight in this year summer. I wouldn't have ran that speed with them in the car & I would have been subjected to their, almost never ending, bickering.

joe_padavano

Yes, the rockers and bridges are all the same.

Fun71

Yuck. That is a lot of wind noise and buffeting for an extended period of time, and it's magnified for the back seat passengers due to the aerodynamics forcing the airflow over the windshield to drop right into the rear seat.

Last time I did that my scalp still felt like the wind was whipping my hair for hours afterwards, and my ears were ringing like after being at a rock concert.

zeeke

That's the catch, no one in the back seat. Wife rolled her window up and I can't hear for s!#t anymore anyway. Hair felt good though. I still have that for now.

Getting back to the engine, I ordered a kit from Comp Cams, then after it's installed I need to measure for push rods and order those. That should be fun. Spoke to the engine shop, they will give me a crash course on how to do that. In the meantime I will pull the rockers and bridge off the 350 to see if there is any further issues. Hope fully those push rods are the same size.

Run to Rund

Start the engine with no valve cover. Properly metered Olds engines don't spray oil like Chevy engines, it sort of dribbles/runs onto the rockers. With proper oiling and valve to rocker clearance (solid lifter cam) or none (hydraulic), you won't get hammering of the rocker tips, and they last a long time. I am using the same used OEM rockers I got from a junkyard in the 1970s and have used since then.

Fun71

zeeke

Maybe I'll have better luck with these. Still haven't put the 350 ones in yet. I ordered a Tach and a points conversion kit. The cam that's in the engine states it's a 2200 RPM cruise speed, no way to tell without a tach but I bet at 75 MPH it's closer to 3500.

I'll need to measure and order push rods now, too.

zeeke

Put 2 rockers and a bridge in the 455 today from the 350. They didn't look pretty but I got to test drive it before I start to install the Comp Cam gear. Car responded great but knocked when punched above 60. Need more Octane. I usually put a can of 108 in the fuel but I guess that doesn't hold in the fuel long.

I have to finish the install on the tach and after that install the rev limiting modulator to replace the points.