Stuck valve!

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NWMO
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Stuck valve!

Post by NWMO » Sun Feb 02, 2020 2:50 pm

Hey all,

I was driving my car home a couple of weeks ago and I lost power with difficulty idling. I found the fuel evap air hose melted and thought it was maybe the issue. After confirming good function on VSV and the air valve, I serviced the evap canister per the FSM. With nice weather and time I put it back together after lunch today to find it did not help with the issue. Confirmed timing visually by pulling the front cover, still good (thought maybe it jumped a tooth or something). It idled just well enough I could get out and rev it by hand under the hood. Clearly bad noises under the valve cover. Here is what I found:
5AF5C5F7-BAF0-439F-84EA-06E1B7FB2DD3.jpeg
B2377326-1F30-411F-9050-30F080753256.jpeg
Valve is quite stuck. So, I’m considering just pulling the head off my parts car (3A vs 4A) and give it a try. I really hope to take the Rusty Frog south to Springfield in a couple weeks.

The head had been gone through by a reputable shop. I assume if the spring broke, it would get to this point pretty quickly. I know he checked springs, but don’t know if he replaced all or some.

All comments/suggestions welcome.

TIA,

Chris
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Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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NWMO
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Re: Stuck valve!

Post by NWMO » Sun Feb 02, 2020 3:57 pm

Here is a pic of the parts car engine.
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Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

teranfirbt
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My tercel:: '86 SR5 4WD, 5AFE, lifted rear, 195/70/14 tires
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Re: Stuck valve!

Post by teranfirbt » Sun Feb 02, 2020 4:17 pm

Only comment is Damn!

xirdneh
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Re: Stuck valve!

Post by xirdneh » Mon Feb 03, 2020 12:54 am

I wonder if the valve dropped and hit piston them maybe got bent. If so piston could be banged up and cracked. Worse yet a bent rod
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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Petros
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Re: Stuck valve!

Post by Petros » Mon Feb 03, 2020 4:23 pm

likely that exahsut valve seized, you will be lucky if there is no/minmal damage to the piston. it appears your valve spring is broken, that would allow the valve to hang down into the combustion chamber, where it would overheat.

if it has not trashed itself you can rebuild it, new exhaust valves and guides, as well as stem seals. If you use your parts car head you should replace all of the exhaust valves and valve stem seals while the head is off. they do not cost much, and you will avoid having the same problem.

this occurs when you use the factory 5 deg BTDC spark timing (done for emissions), it allows the exhaust valve to open while fuel is still burning and has a very hot exhaust. you should run 10 to 12 deg BTDC timing advance to avoid overheating the exhaust valves in the future. the 12 deg BTDC timing will also slightly improve power and econmy.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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NWMO
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Re: Stuck valve!

Post by NWMO » Mon Feb 03, 2020 8:11 pm

Alrighty then,

Peter, I run my engine somewhere around 12-15 deg BTDC.

After getting pulled, I carried the head in and flipped it upside down on the bench and then went back to check the piston top. Definitely some contact on the piston top, but cylinder walls look good and #1 and #4 Still seem to be twins with respect to height.

When I went back to the bench to get pics of the “stuck” valve, it had slid back (gravity) into the head. It moves freely in it’s normal range of motion, but is bent enough it won’t slide out. Honestly, I don’t see any damage on the valve. Soo,

The hillbilly in me wants to clean things up (smooth up the piston top), get the head checked out/worked over and put it back together. I’m not nearly as experienced as some, but it almost seems the spring broke and created this failure.

Now, I am not saying this contributed to the failure, however, I am using the 272 regrind cam from Delta.

All comments and suggestions welcome.

Chris
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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NWMO
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Re: Stuck valve!

Post by NWMO » Mon Feb 03, 2020 8:16 pm

pics

the undamaged piston is #4 piston position when #1 is as shown.
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Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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Yaut
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My tercel:: 1985 Toyota Tercel 4WD automatic, lifted 1.5", 15 inch wheels

Re: Stuck valve!

Post by Yaut » Tue Feb 04, 2020 2:52 pm

Chris,

My guess is the spring broke and caused all of this. If the spring broke, the valve likely would have dropped and then got bent by the piston hitting it. Those pistons will probably be fine to run as is as the damage doesn't seem to reach the cylinder wall and don't seem too deep from the pictures. You may be able to get away with pulling some springs and valves out of the parts head and lap them in as long as the valve seat looks undamaged. This is on your 4A-C engine, correct? I sure hope you can get it back together in time for Springfield. If you need help finding parts, as always, let me know.
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

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NWMO
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Re: Stuck valve!

Post by NWMO » Tue Feb 04, 2020 5:18 pm

Thanks Diarmait,

I’m dropping the head off at the machine shop as I go by this evening (on the way to my son’s basketball game fortunately). Dave will hopefully get a look at it tomorrow and get the needed parts coming. If he doesn’t have time to swap springs, etc., hopefully he can just check/repair the valve guide and lap the valve, I can take it from there.
Many will likely say lapping the valve is easy, I just haven’t ever done it. A mild abrasive and some light spinning (by hand or with a drill??)?? I’m always ready to learn.

Then it is obviously the matter of getting it back together which is certainly my plan (hopefully the weather cooperates).

Chris
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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Yaut
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Joined: Thu Jan 10, 2019 5:34 pm
My tercel:: 1985 Toyota Tercel 4WD automatic, lifted 1.5", 15 inch wheels

Re: Stuck valve!

Post by Yaut » Tue Feb 04, 2020 5:50 pm

Chris,

Good luck. Sounds like you have everything figured out. And yes, lapping is easy. There are plenty of videos on YouTube but basically you use lapping compound and either a handle with a suction cup on the end to spin the valve against the seat or a drill and a rubber hose attached to the valve stem to spin it in the seat with the lapping compound applied.

Diarmait
'85 Toyota Tercel DLX 4WD (tan)
'85 Toyota Tercel DLX 4WD (white)
'84 Toyota Tercel SR5 4WD (red)

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SirFoxx
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Re: Stuck valve!

Post by SirFoxx » Tue Feb 04, 2020 5:53 pm

NWMO wrote:
Tue Feb 04, 2020 5:18 pm
Many will likely say lapping the valve is easy, I just haven’t ever done it. A mild abrasive and some light spinning (by hand or with a drill??)?? I’m always ready to learn.

Then it is obviously the matter of getting it back together which is certainly my plan (hopefully the weather cooperates).

Chris
I've done it both ways. Put some lapping compound on the valve seat and valve, carefully put the tip of the valve in the drill (cordless is preferred for lower speeds) and start spinning and bumping the valve against the seat until you see a good pattern on the faces. If you pull the valve against the seat and dont let off, you'll start getting things real hot. Also make sure to wrap the tip of the valve in tape or sheet copper to avoid galling from the chuck.
1988 DLX Tercel Wagon w/ weber (RIP)
1985 4wd Tercel SR5 (RIP)
1981 Toyota Tercel

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Petros
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Re: Stuck valve!

Post by Petros » Tue Feb 04, 2020 9:57 pm

you have the head off, replace the exhaust valves, all of them. it is not worth the risk! they do not cost much, well worth it. They get heat damaged and you risk haveing them break off and trash the engine. I have seen it happen a number of times, even happened to me once. I even had the valves tested and reground, all looked good, but a peice of the exhasut valve broke off after only about 50k miles after a full overhaul. you only have to buy three more exhasut valves, just do it.

Intake valves are usually safe to reuse fine, they do not get as hot as the exhaust.

odd the valve spring broke, factory toyota valve springs are very durable. I have been running that cam for many hundreds of thousands of miles without spring problems.

I had three engines worth of valve springs and I set up a valve spring tester (easy with a press and bath room scale, I use my drill press to push them down the same amount and measure their pressure on the scale). I was surprised to discover a fairly large range of difference between all of the springs (though not as large as the junk aftermarket springs I have tested in the past). I took the best 8 springs out of the 24 I had available. Been running that for almost 400k miles.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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NWMO
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Re: Stuck valve!

Post by NWMO » Sun Feb 16, 2020 9:18 pm

Hey all,

Pushed hard to get everything back together late last week, got up early Saturday and drove 250 miles to Springfield, MO for an overlanding show. Met Diarmait for the show and after a couple of hours, decided to go do some National forest road driving. Car did fine, pushed it a little harder this time as I had my boys along vs my lovely wife. Car trucked home well this morning, I will retorque the head NLT this weekend. Fun videos on FB, going to work on a mini snorkel, water doesn’t burn well.

Chris
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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NWMO
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Re: Stuck valve!

Post by NWMO » Sun Feb 16, 2020 9:20 pm

pics
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Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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NWMO
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Posts: 963
Joined: Wed May 20, 2015 1:08 pm

Re: Stuck valve!

Post by NWMO » Sun Feb 16, 2020 9:22 pm

more pics
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Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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