LT1driver

without taking intake off on motor how can I tell if cam has wiped lobe, this is on big block solid lifter cam. thanks.

midyearvette

pull the valve covers and look for a valve that does not move or moves less than the other rockers as you spin the mill....good luck...why do you ask? what are your symptoms??......

LT1driver

some of the rockers loosen up after driving/running car for short time (less than 1hr total time) and need adjusted again ...solid L-71 cam...new rocker studs, new rocker arm nuts,
new motor with less than 3 hours on motor, broke in 2500 rpm for 30 minutes without issue, changed oil and readjusted valves, set timing etc. after brake-in.

midyearvette

drive the car and see how well your latest valve adjustment holds....if the cam were wiped all the way you would have seen it when you set the valves the second time....if it's starting to wipe you will hear the valve train getting louder in a short time running.....or backfiring through the carb or the exhaust or starting to run poorly....i would re check the lash after another 500 miles or sooner...are you running poly locks?....

narlee

Are they press in studs. If they are maybe they didn't do a good job and they are pulling up.

mechron

use a dial indicator!! of course you can use the eyeball method (are all the rockers/ valves moving equally??) or the noise method (if you have clacking and the rockers are moving in different amounts, your cam is going flat) i have seen cams go flat to where the bottoms of the hydraulic lifters had a hole in them (yes. they were very dished shaped as were the cam lobes)..

mechron

narlee, no offence, but to my knoledge, ALL BIG BLOCKS HAD SCREW IN STUDS) my 66 396 360 HP big block had screw in studs, and it was one of the firsts, and all of the big blocks i have ever worked on have had the 7/16s screw in studs.

the press in rocker studs were from the 60s (and 70s smogger heads) on small blocks, or the 60s fuelly/camel hump heads, the ultimate heads(the fuelies) at the time would pull the pressed in studs out with increased valve spring pressure. in the old days we would just pin them. that is drill through the stud boss and install a roll pin through the stud and the boss to keep the rocker stud from pulling out. i have seen many pressed in studs pull out with stronger springs, but never with roll pinned/pressed in studs. but who cares? now all heads have screw in rocker studs.

landshark 454

One thing to check is the heads of the valve stems. Since engine is fresh, it is probably cam wear, but those symptoms are exactly what you get if a valve is loosing a keeper. Big blocks were notorious for this, back in the day, and I saw it happen too many times. Happened to me once.

I had a friend that had the exact problem with an L88, and he decided to drive the car home, and call me in the morning. On the way home, the engine dropped a valve, and ventilated the block. Another friend with an L78 caught one just in time, by chance.

I would check the valves before I ran the engine again. Just look carefully at the side of the rocker, where it meets the valve. The valves should all look the same, and have the same amount above the keeper. Rich

66BlkBB

When I bought my car it had a miss in it that I could not get rid of. That caused me to pull it apart and I found that there was two lobes down on the cam. If the valve train is OK and the adjustment on the valves hold and you still get some type of miss in the engine, then I would suspect a flattening cam lobe.

buns

Exactly. They are so cheap now you can't afford not to have one. Grizzly Industrial has one with a magnetic base for $21.95.


http://grizzly.com/products/Magnetic...-Special/G9849

GCD1962

You can buy a cam checking tool from Summit or Jegs. Not real expensive

Proform #PRO-68902 - $76.95
Summit #SUM-900132 - $55.95
Proform #PRO-66830 - $61.95
Search the sites for Cam Checking Tools

LT1driver

screw in studs.....mechron had a wiped cam with holes in lifter bottoms on 396/350 camaro back in the day, funny thin ran fine with power and no noise, discovered on taking it out to put in mechanical cam, original owner I got it from always used conoco oil ... maybe that was why

I will check valves in all ways suggested and will do final check with dial indicator and last choice is pull cam and check thanks for help guys. will get back when I get results, have to put differential back in first so I can move car.