Sticking Intake Valves?? (1 Viewer)

[marlow]

Just curious if this has happened to anyone else. My 1985 (recently acquired) had sat for 13 years. I drained the fuel, changed fluids, new battery, new gas and it fired right up. I drove the truck for about 25 miles and broke a push rod because of a stuck intake valve. I pulled the head and sent it off to the machine shop where they checked for flatness, guides, valves and new seals. Put the head back on the truck and it ran great for another 50 miles. Started it up the other morning with a dead miss and then a load tap noise then it ran fine. This morning went out to start and it did the same thing but did not smooth out. I pulled the valve cover and two more push rods were broken. This time however the valves do not look like they are stuck. I should mention that the valves were extreme tight the first time I checked everything out. So..has anyone had this issue in the past...should I pull the head and have the machine shop replace the valve guides even though they are within specs...could the previous over tightening caused fatigue on the push rods and why only the intake valves. Any thoughts

are greatly appreciated.

 

[gregnash]

Ouch! Yeah needs to go back to the shop and have them replace guides I would say. I am assuming that valve seats were fine and within spec, same with springs, etc? You are getting oil up to the top of the valve train correct? Seems like a pretty catastrophic failure, maybe something else going on down low? Maybe replace the push rods since you have blown a couple now? And maybe pull the oil pan and see if there is anything weird down there....

 

[marlow]

Sorry Greg for taking so long to respond. I spoke with the machine shop and they are as perplexed as I am. I think I will replace the push rods and see how it goes. If it continues to have issues I will pull the head I guess. Everything in the valve train seems to work fine. Cross my fingers. Thanks for your thoughts.