Old valve adjustment help! 1976 C10 Custom Deluxe 250 4.1 straight six

[DIG]

I am 23 and NOT mechanically inclined. I do my research through forums, YouTube and articles. Sometimes a manual if I'm lucky enough to find a source for one. That being said I've done ok for myself until now. I have a long way to go and I do not want to be a mechanic. Just a means to an end to try and restore my deceased brothers truck in his memory. He was the mechanic but he passed away when he was 17 and I was just 6 years old. He would have taught me everything he knew and learned with me but sadly that didn't happen. All that being said I need some serious clarification on exactly how much play/looseness/resistance the pushrod of the hydraulic valves should have. When I first went to adjust them there was a slight tapping sound after I did an oil change from oil that had gas in it. I had just rebuilt the Rochester monojet carb and replaced the fuel pump hoping to solve my gas into my oil issue. A few days of adjusting later, trying every method I could find and it's Hella loud tapping and makes me very nervous! I really hope I didnt break something. Can anyone tell me how much resistance there should be on the pushrods when rotating them? Should I be able to wiggle the valve arm with moderate force?  I've watched and read so much on this my head is spinning. They all seem to contradict each other or not offer enough clarification on exactly how much resistance is required for proper zero lash. So now I am stuck with a truck that can't be ran as I'm afraid to break anything. Any help would be greatly appreciated!

[zieg85]

Do you know which one is the culprit?  The lifter may be collapsed.  You can remove the side cover and take a look, it would be very apparent if it was.

[DIG]

To be fair no I don't know. I was just assuming from past experiences and research that It sounded like a valve tap. The truck has not been driven often (only a few times for less than a mile every year) since sitting for about 6 years. I started working on it last summer but it had sat for around 9 months with gas in the oil. Once I noticed the issue I stopped running it. I have now fixed that problem I believe and have run into the current debacle. I had no idea what those side covers even were. What part is the lifter? The plunger looking thing? The truck was not professionally rebuilt but rebuilt about 20 years ago. It has about 60k on the odometer but I don't know if it was reset or if the engine was rebuilt or just maintenanced. I wouldn't think that any serious damage would have occurred to the engine but I guess I can check. I am not going to put any more money and time into the engine if it's going to cost me more than swapping a v8 in. At factory a 1976 250 only makes 105hp and similar torque which is just disgraceful considering mine gets the same mpg as a big block! I am pretty sure I'm just adjusting them wrong though. Like I said in my original post I have no idea what I am doing and just following what I have read to get something done. But seeing as the valves are pretty integral in getting the engine to run properly I am trying to get them right before I throw in the towel on this engine all together. I am not trying to spend a bunch of money on it knowing full well that I want a better engine.

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[JohnnyPopper]

Can't say I've ever done a 6 cylinder, but hydraulics are pretty much the same.

With the valve cover removed, you need clips to keep the oil from spraying out of the rockers.

While the engine is running, you back off the nut of each rocker until it makes noise, then tighten the nut 3/4 to 1 full turn.

Replace the cover and clean up the mess it will make.

Should be good to go.

[DIG]

OK. I have read quite a bit of controversy around running or cold valve adjustment. Is it safe to do it while running? Dont the valves move up and down while it's running and won't that make it hard to adjust? Would cardboard or something else be a good shield to prevent oil spraying all over my engine bay? What clips are you talking about?

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[zieg85]

These are the lifter cover.  Yes you can adjust them while running.  Grab each one and see which one is loose.  May be just stuck from setting but each cover will expose the lifter for inspection

[DIG]

Ok. Do I need to replace any gaskets or can I just use the old ones? Or otv even tho I hate to use that. I'm not really trying to spend any money.

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[zieg85]

Sometimes the gaskets are fine, sometimes they come out in pieces.  If it were me.  #1.  remove valve cover to find out which one is loose.  Oil should be squirting out every rocker arm hole.  Tighten is when running till it quiets up.  If the threads exposed on the rocker studs are fairly close to being the same, you are done.  If the loose one shows a bunch more threads to tighten it down to quiet it you either have a bad camshaft or the lifter is collapsed.  I have removed lifters and soaked them to free them up.

[DIG]

Alright thanks. I guess I have some work to do. Right now I am just taking a few days break to clear my mind of frustration haha. Thanks for the help guys/girls!

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[zieg85]

You'll get it.  Just have to do it.  I have had engines that actually sounded like a rod knock after they had sat for a while.  Adjusting the lifter to quiet it broke it loose then I backed it out until it is started tapping again and then tightened it to quiet.  Then 3/4 more of a turn.  Right or wrong that is what it worked out for me.

[DIG]

Yeah I am to that point right now. Ride it til it dies sort of thing. Or take it out and sell it.

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[JohnnyPopper]

https://www.summitracing.com/parts/MRG-1015

These get clipped to the end of your rocker to keep the oil from spraying all over.

The nut in the middle of the rocker doesn't move while the engine is running.

Loosen till it taps, then tighten 3/4 clockwise. righty tighty lefty loosey 

[DIG]

Thanks. I'm just gonna mock something up out of good ol cardboard and go at it. Some are already tapping quite loudly. Should I start with those then loosen the others?

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[JohnnyPopper]

Some of those act like geysers so if I were you, I would get some plastic bottle caps and drill a small hole though them and zip tie them to the end of the rocker, securing them behind the push rod.

Won't matter if you don't go for the clackers first, I would just start at one end and move to the others.

Keep us posted as to what happens...

[DIG]

Bottle caps sounds like a great little trick. Unfortunately I don't have any. I've heard about ppl using valve covers with a slot cut out in them so I replicated mine with cardboard and duct tape with a slot cut out. Best I can do for now. Might add more cardboard to the rest of the engine bay to protect it from splatter. Not that my engine is clean but having oily surfaces just sucks haha

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