Murakami

About 6 weeks or 1000 miles ago my engine started to miss. Cylinder number 4 on my 22re wasn't firing. Pulled the plugs and #4 was black with a lot of build-up on it. Pulled the valve cover and #4 exhaust valve had zero clearance. Adjusted valves to spec and all was good. Now 1000 miles later, same issue, pulled valve cover, exhaust valve has zero clearance, adjusted valve again and it's back to running ok. Obviously there's a bigger problem here and I'm wondering if anyone here has some ideas as to what it may be. Seals? Guides? I'm not going to keep adjusting my valves every 1k. Do I need to start shopping for a new head? Any advice or suggestions would be much appreciated. Thanks.

Kiroshu

Ok first off did you adjust the valves hot? If so then it sounds to me like a sticky valve. You could try taping the valve spring a few good times with a hammer to loosen it up. Spray some carb cleaner around the valve and spring. It is Stock right?

Murakami

yes, i adjusted the valves hot. the first time i didn't because it was my first time on this truck and it took me a while. this time i knew exactly what needed to be done and adjusted them while the engine was hot to .007 and .011. i know they're supposed to be .008 and .012 hot but after reading a lot here many seem to think the engine runs better at the former specs.

by the way, engine has 156k.

as far as being stock, the previous owner said that a new head was put on the engine maybe about 20k ago. he said it was just to freshen up the engine. I know that sounds ridiculous but at the time it didn't concern me because the body and the chassis were super clean and had zero rust which was the most important to me. I figured if the engine needed work or to be rebuilt I would do that but at least I had a solid platform to work with. But that's a separate story.

Separately, timing chain and guides look good, so at least that was replaced properly.

When I pulled the oil pan when I was putting in my 4.88s I found some plastic pieces and some aluminum pieces. I'm thinking the timing chain was probably broken and that and the head were replaced. The plastic pieces are not from my current guides and i don't know where the aluminum pieces are from but I assume maybe the timing cover.

Kiroshu

Well you can take the valve cover and crank the engine over and watch that specific valve and see if its sticking or if somethings wrong with the rocker arm.... just disconnect the coil wire comming from the distributor and have someone turn it over and watch.....the fact that it has a new head kinda troubles me...... since the last 1k miles its been ok? How is it doing now? Try beating the valve spring with that hammer like i told you.... may help. They make a few aftermarket things that help sticky lifters and valves but 99% of them ar trash and don't work but you could try it as a low budget deal. Yea who ever did the chain and head before prolly didn't pull the pan thus it was not cleaned out thus leftovers from previous gudies are in there and prolly timing cover piceces when the previous failing chain was slapping...

Murakami

for the last 1k after i adjusted the valve the first time it was running fine. decent mpgs, smooth, good power. but then the same thing: i was on the highway and suddenly it loses some power, becomes less responsive and stutters a bit if under load, say going up a hill, then when I come to a stop it's misfiring and vibrating.

it didn't seem like anything was sticking when I was turning over the engine before adjusting the valves. but both times, the exhaust valve on #4 had zero clearance. i have to keep backing off the tappet. the rocker arm should be loose at that point, but you can't move it. i'm no mechanic but if the valve or spring was sticking, i think it would be stuck open and there would be clearance, or more clearance than usual. is that correct?

yoterr

yeah your right, are you tightening the valve down enough? seems like the adjuster keeps coming loose, maybe some blue loctite? DEF BLUE!!! never use red, itll never come undone

Kiroshu

Are you adjusting the valve with #4 piston TDC? Can you wiggle or move the rocker arm? Are you tightening the bolt on the the rocker when after adjust? You said you have 0 clearnace? Can you get any feeler under it?

Kiroshu

Well yes if its stuck open the valve will have more clearance but if its stuck closed and the rockers just hitting the stuck valve then yea..... no clearance....

bugs1961

Just a thought. The valve seat may not have been driven all the way into the head when it was rebuilt/assembled and the impact of the valve banging into it slowly drives it deeper into the head. This would cause the valve clearance to slowly decrease until it reaches 0. If it were my engine, I'd pull the head off and take a look at all the valve seats and valves. I would have a new valve seat and valve (and guide if it's worn) installed in that cylinder and the others verified by a good machine shop.

yoterr

hermm, didint think of that...try sea foam !! yes it works, get deep creep (in a spray can) n spray it down your intake while running, spray about half then let the engine die, then spray a little bit more (not a whole lot ur hydro lock ur engine) n let sit for 15 min then start it up and watch the smoke

Murakami

i am adjusting at TDC and i'm definitely tightening the lock nut. when i wiggle the rocker it doesn't move at all.

The sense I get is that the valve is moving up into the seat until it hits the rocker. is this normal for a new head to break in? after ~20k miles and this much movement?

i'd like to pull the head and take a look but i really need to try and pinpoint the issue. i live in the city and i don't have a place to take the engine apart and leave it like that until i can figure out what it needs and have it worked on. what i'll end up doing if necessary is buying a new engnbldr head and whatever else and just try and straight swap it out in 1 day if it turns out the head needs to be pulled.

seafoam? not sure what that does but i'll research it.

thanks for the help!

Kiroshu

Where did he say he got the head from....

Murakami

he didn't know much about the head replacement or why it needed to be replaced. the previous owner before him did it. my previous owner didn't have the truck for a long time. that's reason for suspicion but like i said, i mostly bought the truck because it was clean and that's hard to find in the northeast. i don't mind working on the engine but i just need to figure out exactly what the problem is.

Kiroshu

Head work...

yoterr

youtube sea foam, if its sticking shut, this will freeer up

eugenedbrooksiii

Exhaust valves can start stretching in their old age. If you have head work done I would suggest that you buy new exhaust valves.

Eugene

Murakami

truck started vibrating again today and i'm getting pfft, pfft out the exhaust. i'm sure it's my exhaust valve again.

if the valve is burnt is it typical that you would be able to keep adjusting it to get it to work properly like i've been doing?

i'll pull the valve cover again this weekend to check the valve clearance but i'm pretty sure i'm looking at having to pull the head soon. guess i should start looking for a garage to work in.

i also ran two cans of seafoam through recently but it doesn't look like that's going to solve my problem.

eugenedbrooksiii

Your symptoms are consistent with an exhaust valve stretching. As others have said in this thread, it is time for you to have head work done. You should plan, and insist, on new exhaust valves. I would not keep adjusting and running an exhaust valve that is stretching as outright failure of the valve is an option.

Eugene