My 85 258 has some ticking noise I can't nail down. Here is the story. Changed a carb and somehow a spare set of carb bolt down nuts were left on the upper butterfly plate of the carb. They got into three cylinders and did some damage. Found 3 pushrods badly bent too. The machine shop I took the head to said the valve guides were too tight, the valve springs were shot so replaced all that along with the normal work to a head. Put it back together and had another round of bent pushrods. Only a couple and in a different spots than the first time they bent. Also have had a ticking noise that is louder under load. Took it to another shot and they thought maybe the lifters so took the head off again and replace lifters. the ticking noise was quieter at idle than before, but still noticable under load so I would say the lifters made it better. Not it is ticking loudly again and fear bent pushrods again.
I haven't gone in again yet. One thing that bothers me now that I think of it. When I took the head to the machine shop I left all the rocker arms, bridges and piviots/bolts as is. When I got the head back all those parts were in a bag. I had a tough time getting rocker arms to line up over the valves and tried every combination in the book to make them line up. After several hours and work to accomplish this I finally took a wrench and basically bent the bridges to make the rocker arms line up over the valves.
Does anyone know if that was a major mistake? In my book it says to be very careful with those parts/bridges and that they should be removed and replaced from exactly where they were etc. The only thing I can think of at this point is maybe this is what is causing this ticking noise and bent pushrods. Can new bridges be had?
It sounds like when they removed the bridges, they bent them which isn't too hard to do. I also bent some pushrods after changing the valve springs. Some of the lifters had pumped up causing them to bend as soon as I turned the engine over. There is a way to check to make sure you have proper pushrod length. You'll have to search here or the net. I've had 2 eagles with the 258 and they both had valve train noise. One even after a rebuilt top end was put on.
If the shop that rebuilt/repaired the head "decked" it o.010 to o.020 of an inch, the pushrods might be too long. They also raised your compression ratio, and the engine might ping more easily than before and want higher octane fuel and less ignition advance.
The bridges bend easily while removing them, but they can be bent back into shape like you did. The rockers are supposed to remain paired with their pivots, but they don't have to stay with their bridge or valve location, necessarily. If they show a lot of pivot wear, they should be replaced. An overly worn rocker/pivot will occasionally seem loose when the lifter is on the base circle of the cam(no lift), and can be a source of a rattle in the top of the engine. If the noise comes from down in the block, its a stuck lifter or one that doesn't get enough oil pressure to remain pumped up at idle(this noise is a ticking at idle that goes away when off idle, with increased oil pressure).