Ok, so I'm on my way back from a cruise in when I hear this loud pop and the engine dies. Managed to get it re-started and didn't see anything leaking so I limped home. Pulled the passenger side valve cover and lo and behold #2 intake rocker arm is cocked sideways and the push rod tip is busted off, guess I'm lucky I didn't blow th engine.

I recalled setting the lash a couple of weeks ago but didn't take it for a spin so figured I screwed something up in the settings. Since I didn't know if there was any other damage in the valve galley I decided to pull the manifold (what a hell of a job that was!) to my surprise I found that my engine which is NOM 283 out of a 64 Impala has SOLID lifters and all this time I was adjusting them as hydraulics it's a wonder the engine even ran at all. Now I have no idea what cam is in there so I'm wondering if I can go with hydraulics which are easier to adjust or leave well enough alone and figure out the best cold/hot settings. Anyone have any advice on the best course of action? ...thanks Mike

 

you really need to determine which cam you have..solid or hydraulic.....there are some who install solids on a hydraulic cam and set the lash at .005....you are lucky if you do not have any bent valves...do an air check on all cylinders....the pushrod broke because of interference probably at the piston to valve.....good luck

 

The first thing that comes to mind is that you have hydraulic lifters.

If you run solids on a hydraulic cam and you don't run almost zero clearance, you'll hear a click, turn the adjustment down a little more and you'll get a miss. There would be a very, very narrow window in adjustment between a click and a miss. Certainly not in the range of the normally accepted 3/4 turn down from zero lash. So, if you've adjusted hydraulic lifters before, you should realize very quickly, something isn't right. Enough so that you wouldn't put the valve covers back on until you figured out what's/what.

Check the rocker stud on the cylinder that broke the pushrod, it may be cut and let the rocker run on an angle. This very likely a possiblity if the valves have been run loose and noisy. You may even find the valves stem tips are rounded and need squaring up. Also check the rocker for even wear. If you find this condition, pull the heads and get it fixed.

I doubt you have any bent valves unless you seriously overwound it. Sometimes, old pushrods break.

If that engine still has the 1964 issue lifters in it, hydraulic lifters can be identified by a spring clip that holds the pushrod seat in. Solid lifters didn't have the spring clip. Some later issue hydraulic lifters may not have the spring clip.

If you're not sure what's in the engine, I'd pull the cam out of it and put in a matched set cam/lifters of your choice. That way, you know what you have.

 

Can you get the engine serial number? If so, you should be able to get a handle of what came in the engine orginially. Of course someone could have modified that engine when it was out of the 64 Impala and ended up in your Corvette as a "correct" engine (283). If you find more damage in your engine you might want to get a new performance cam and performance lifters to give it a little boost in power. Good luck.

 

If you DO find you have solids (and a matching cam) then I wouldn't go to the trouble of swapping them out just because hydraulics are supposed to be easier to adjust. I've gotten where I can adjust my solid lifters in 40 minutes or so and that includes me double checking the lash out of paranoia...

I've also gotten where I like the sound....just like a sewing machine when they are dialed in...
Likewise make darn sure you are running good oil with enough ZDDP in it...

If you adjusted the solids like hydraulics then you must have really cranked the lash down to zero, I agree with you, I don't know how the car would run at all like that !?

FINALLY, if you have the intake off anyway you may want to buy some fuel injection gaskets and block of the heat riser passages in the intake since you live in GA and cool things down!

 

I removed and inspected all of the lifters, they are all solids. None of them have the c-clip retainer. I will post the engine block number when I get off work but if I remember correctly it is a 283ci with 220hp (not 230hp).

 

the block number will not tell you which cam you have, you need to determine this.....if it ran ok before, why not re use the lifters and set them at .oo5??....we did that a lot back in the day...i still think you should do an air check.....jmho....

 

If you adjust mechanical lifters like hydraulics, the engine won't have compression. The valves will never close.

 

Since the hydraulic lifter cams have no clearance ramps to take up clearance gently like the solid grind cams do you can expect:


Noisy valvetrain

Cut rocker studs

Worn valve stem tips

Worn/cracked rocker arms

Broken pushrods

Less performance due to decreased duration/lift