Exhaust valve bucket fell out!!

That sucks! Do you do a total rebuild or pick up another motor?

 

Yeah you're telling me lol. Nope, I bought a reman head from Allied Motor Parts and replaced it myself. Thing that really stinks is she still eats a tiny bit of coolant. It'll go down maybe 1" in the overflow every 1000 miles. Been running strong for 8000 miles so far but I wonder if I got a bad head? Maybe a crack they missed? No oil in coolant or vice versa. Only possible sign is plug #3 looks different, almost like its its gotten some moisture. But there's no misfire or smell or anything weird yet. It's such a small amount I guess I'll run er till she blows, then get a junkyard motor and rebuild the original...maybe turbo if I have the funds.

Anyway I recommended them to another forum member before I discovered it was using coolant and he has had no issues with his.

 

That would be easy to fix in place. Pull both cams (make sure you insert the set bolt into the exh. cam gear) and use a magnet to pull the bucket. While you're at it check your other valve clearances and insert new shims with the cams off.

 

Is it okay to replace one cam, and not the other? I'm thinking about doing this the easy way, just because I'm crammed for time.

What I'm thinking,

Pull the cam, replace the bucket and new shim. Replace the cam with a new one, then check clearances. If off, take to a machine shop to get ground down.

Sound okay?

 

Whoa whoa whoa .....what are you grinding? Valve clearance is not adjusted by grinding the cam lol. That's what the shims are for. They come in different sizes. You need to measure clearance with feeler gauges, the pull shims, measure with micrometer and do the math to figure out what size new shim is needed.

Yeah, no problem just replacing one cam. If yours is not usable you can check out NW Team Yota (Yota Shop) I think they sell cams for @ $200.

 

Why are you crammed for time if you have another truck.

If that's the only vehicle and it had to fixed over a weekend I'd have tried it but now I think I'd be wanting to see what exactly happened so as not to do it again. I think you get a core on the head as long as it's not broken.

I'm kind of wondering if the clearance on that last valve got wayyy too tight and set the ball rolling to need a valve job.

 

From what I understand, a machine shop can machine down the shims if the clearances are too tight. That's what a shop I worked for long ago did.

 

I have a lot going on right now. A full head replacement would have to wait till early 2020 before I could get to it. I could probably squeeze in a new cam and shim in a coming weekend.

I assume the valves are all fine. The truck passed a compression test with flying colors which tells me the valve is seating properly.

 

Ok, yeah they probably can but I don't understand why you'd want them too. You can buy new shims for like $7 a pop. I wouldn't mess with machining them because I don't think they are designed for that. But someone with more experience may know.

 

I wouldnt trust the shim that has been modified. The surface hardening only goes down a few thousanths and they will be milling that off.

 

That's what I'm thinking too

 

Thanks for the info guys! Lots of good stuff here.

 

I would personally toss the shim back on, and see what happens. If the cam looks okay and not all gaffed up then I don't see a reason in doing unnecessary work.

 

The cam has some damage on the edge. Also the bucket was destroyed by the cam hitting it without the shim.

Only thing I'm worried about is if I replace the cam, bucket, and shim (~$200-250 in parts) then find there's something more deeply wrong that then requires me to replace the whole head (~$600-700) I'll be out almost a grand.

My plan is: pull the cam, replace the bucket, throw the old shim in there and put the old cam back in. Turn the motor by hand a few times to make sure the bucket doesn't want to come way high and throw the shim again for some weird reason. If it seems okay, then order the new cam and shim. It's more work but could save me a lot in the long run.

 

If the clearances are too big then grinding the shims wouldn't work.

Your plan sounds ok. Check the clearance with the new bucket, and check that it turns ok. Probably worst case is it spits the shim out again for some reason, then you'd have to figure out why and maybe pull the head.

 

Tru dis

 

Since your doing it yourself and you know what your doing and this isn't going to disable your only vehicle.

Heck yeah, play with it and see, heck don't change the cam, just sand down the sharp edge and keep the revs down.

 

So I've hit something super strange.

All the valve clearances we're fine when I started.

I lined everything up TDC and proceeded to remove the intake cam (it was the intake lifter, not the exhaust as the title says).

I removed the cam, replaced the lifter and shim, and replaced the cam. Bolted everything down per FSM. Evenly, and slowly. Then I replaced the timing chain gear.

Everything was back and I was going to text the clearances when I noticed every single valve except the original faulty one was stuck open. Even when the back of the cam was over the shim, I'd have 1/4' clearance.

I've never seen such a thing. You can see I the photo they're all stuck open at various depths. I tried to remove the spring on one to try and pull the valve shut, but it wouldn't budge and now I can't get the spring back on because the valve stem is so low since it's stuck open.

Wtf is going on here?!

 

I guess the old gas (3 years old) could have cause the valve stems to get sticky. I'm not sure how to clean them up so they move without removing the head. This may be why the initial shim fell out. The valve could have stuck open leaving a large gap between cam which then let it fall out.

 

So I buttoned it back up. Old cam, new lifter, old shim. The clearance was .007 on the problematic valve after putting it back together. I rotated the engine a handful of times using the timing chain gear bolt. Some of the valves would stay open for a second the POP! back closed. I kept doing that until only 2 needed a tap with a rod before they would pop back.

I said screw it and buttoned everything back up and cranked her. She hesitated and sputtered, like being out of time, for about 5 seconds. After that, she's running beautifully. I took her for a spin and even pushed close to redline. Everything sounds great, for now!