flickjo68

First off, i have a 1968 coupe with what i am fairly certain is a 302. the previous owner said it was a 302 but it was originally a 289. he said the engine was replaced but had no reciepts to prove it so i'm not sure. (i hate to sound stupid, but i don't know) now for the problem... when i got the car, it had an annoying ticking that sounded loose rockers so i talked the guy down a little planning on it being an easy fix. after i got home, i took the valve covers off and found that every rocker had a ton of play in it. when i tried to adjust them, however, i realized that the rocker nuts were all the way to the bottom of the threading on the studs. i found out that these were called positive stop rocker studs which meant that you were supposed to torque the nuts against the stops and the rockers were adjusted. (correct me if i'm wrong.) At their tightest position, there was still a ton of play in the rockers and the car was noisy as hell. in other words, you cannot possibly tighten the rocker nuts down enough to be correct. i also checked to make sure that all of the pushrods were straight, which they are. i am wondering if the problem is caused by a worn down cam, (lobes worn too much) or worn out lifters, or a combination of both. it seems to me that it would be more likely that excessive wear would be responsible for everything geing the same amount of play? also, i can remove a few of the spark plug wires from the coil with no difference in the idle. (runs crappy either way)( brand new plugs and wires with no difference) i also noticed that if i remove a vacuum line that goes to the vacuum advance, there is no change in the operation of the car. is there any way that a bad cam could be causing all of these problems? or, if not, does anyone out there know what could? i would greatly appreciate any help i can get. thanks and happy holidays.

67mustang302

Could be a bad cam/lifters, and/or pushrods are too short. Is it a solid or hydraulic cam? Solid should have some clearance, but it shouldn't be much. Have you checked the clearance with a feeler gauge?

fast65

I had a horrible ticking sound coming from my 302 awhile after I got it. I took off the valve covers and found that one of the rocker arm studs was almost ripped all the way out. It turns out that one of my lifters blew apart and the valve was opening. I'd check your lifters first and if they're fine than it's probably your cam.

I'm not an expert on engines (yet) so if I'm wrong then someone please correct me.

gooser

i'm not sure a camshaft can wear enough to cause problems exactly as you described. look elsewhere and start with incorrect parts.

Starfury

Sounds like you have a couple dead cylinders. What I'd do is pull the intake, pull a couple lifters, and inspect the cam. A dial indicator would be great, but with the kind of wear you're talking about, it should look like somebody took a grinder to the cam lobes and bottoms of the lifters.

mat11089

Most certainly can,If it wasnt broke in properly or valves not adjusted or just poor installation all around or mechanical malfunction.
Also, flickjo, you didnt just find them loose and tighten them right?There is a procedure of bringing it to tdc on 1 and then 6 and certain valves can be adjusted at each one....If you just tighten them at any point you will have serious problems.I would get a hand tach also and then pull wires and see what happens and just a lil fyi You dont pull plug wires of the coil,they pull from the cap.Only one wire is on the coil...

Starfury

Mat, his heads are the nonadjustable rocker type. You should still torque them down while the lifters are on the base of the lobe to keep from flattening a lifter, but there is no adjustment. You tighten the nuts all the way to the base of the threads and then torque them.

mat11089

youre right that was my point, to do it at te proper position

flickjo68

oops, that was my bad about the coil thing. i meant to say the dist. cap. (it had been a long day.) i do know about the sequence of adjusting the rockers, also. about the pushrods being the wrong length, i compared them with my other '68 302 that runs fine and they were the same length, if that means anything. i was just trying to figure out how likely it was that the cam could be the problem before i started taking things apart for no reason. thanks for the help so far.
[quote]ORIGINAL: mat11089


Also, flickjo, you didnt just find them loose and tighten them right?There is a procedure of bringing it to tdc on 1 and then 6 and certain valves can be adjusted at each one....If you just tighten them at any point you will have serious problems.I would get a hand tach also and then pull wires and see what happens and just a lil fyi You dont pull plug wires of the coil,they pull from the cap.Only one wire is on the coil...

Starfury

With the pushrods being the same length as your other motor, I'd be inclined to suspect the cam=/