Ok,

I just got this 87 T/A with a LG4 305. I pulled off the passenger valve cover PITA, to find a very very loose rocker arm, (obviously the problem). Now, I also noticed a rubber orange gasket that was totally blown out near the bottom of the rocker arm. I was expecting to see vast amounts of buildup in the head due to 178k miles, but there is NONE>?....... I dont know what to think. I have some pushrods form another 305 I am going to visually compare them to the pushrod from the T/A becusae it was smoothing itself out on one side. BTW there is way to much elctrical **** under the hood But let me know what you guys think. And direct me to somewhere with all the details on rocker arm settings...thanks

Proud to be a third gen owner, even if it is a 305.

Z28Bama

 

Take a close look at the rocker studs to make sure one (or more) isn't pulling out. The '87 engine should have a roller cam and lifters, which aren't prone to wear and lobe failure that would cause the unexpected valve lash problem.

Your spare push rods might be longer if they are from an older flat-tappet cammed engine, so don't be totally surprised.

 

Well,

I still have to check out the rocker stud, but just FYI, the pushrod's aren't compatible, about a 1/4" difference! And by the recommendation of the local performance parts guy, I am gonna keep the pushrod, it's not that bad.

 

To reset that rocker do this:

Bump the motor over with the starter alittle at a time:

When the intake valve just closes( on seat) adjust the exhaust.
When the exhaust valve just starts to open, adjust the intake.

Works on any motor reguardless of the fireing order.

 

Going out to take pics today, will post them this evening. Thanks

 

Well,

I replaced the thermo with 180* and then took off the rocker arm to the cylinder next to the rocker arm in question, they were the same height, so that pretty much eliminates stud coming out. So I had the wife start the car while I adjusted the valves to the best I could, I just tightened the ones that were ticking, (found 2 others), just to the point that they stopped, I mean within 1/16 of a turn. Will this suffice or should I use the feeler guage and exact it? Also, I had the AIR system disconnected and the air cleaner assembly off during this. I noticed an intermittent very very soft backfire while listening from behind the car, could this be because AIR and cleaner were off? I just wanna make sure before I put that valve cover back on. And with the thermo.....there was almost NO water in the block!!! So I ran it until the thermo opened with the cap off to get rid off air pockets, does that work well? Thanks

Z28Bama

 

Anyone? Comments?

 

You need to be sure you adjusted your valves the correct way. You need to be sure you got zero valve lash, do it like F-bird said.. once you got the valves set in correct order tighten till the the push rod barely turns in your finger then go 1/4 turn I believe. There are a lot of post on valve adjustements.

 

The method you used to adjust the Rockers is fine, I personally like to go 1/4 Inch past the "no tick" Point.

F-bird is also right, but I find it easier to adjust while running to assure none Tap.