engine and drivetrain Stuck Exhaust Valve

[Boultman]

My '75 2002 started a mean tapping sound out of nowhere.  I've had the car for two years, drive it very regularly (almost daily when it isn't 104 degrees here in Coastal Texas).  I have never had an issue. 

Religiously maintained, driven hard on occasion, but never abused, blah blah...

 

I took a 30 minute drive last weekend, non-spirited i might add, then stopped at a seafood market for sunday football shrimp to boil.  I was in the market for 10 minutes.  I started the car back up and it hesitated slightly, then the knocking/tapping noise.  I limped home 2 miles or less and parked it for a week.  I knew it sounded like an upper engine issue.  I waited for my valve cover gasket to come in, and pulled the cover off this morning.  

 

The exhaust valve is stuck down on cylinder 3.  

 

Questions:

• does this normally happen when parked?  It seems like valve issues would occur at high rpm, driving the car hard.
• Since the valve stuck, does this mean the piston was crashing into it, and it is toast?  (interference engine). 
• Is there a chance i can pour some magic lube over the valve and free it up and be on my merry way to another 10k of care-free miles?

 

Aside from the stuck valve, everything is spotless with little or no wear.  Timing chains are perfect.  

It is hard to say what all was done in the past, rebuilds or otherwise.  The previous owner only had it for a couple of years, but also took excellent care of the car.  

 

Any quick and easy things i need to try before yanking-out the top-end?  Anyone in the Greater Houston Area i should call and have the entire car towed-to?  

 

cheers.

[Son of Marty]

40 minutes ago, Boultman said:

.  

 

The exhaust valve is stuck down on cylinder 3.  

 

Questions:

• does this normally happen when parked?  It seems like valve issues would occur at high rpm, driving the car hard. 
• No this doesn't usually happen at all, it could be a collapsed valve spring or the valve guide is worn enough to allow the valve to cock to one side and jam.
•  
• Since the valve stuck, does this mean the piston was crashing into it, and it is toast?  (interference engine)
• Yes,more than likely you toast on this one, sorry
• . 
• Is there a chance i can pour some magic lube over the valve and free it up and be on my merry way to another 10k of care-free miles?

          Probably not going to happen, if you were that lucky you'd have won the lotto by now

 

 

 

 

[TobyB]

Wow- yeah, that's really unusual.  I wonder if maybe there are some aftermarket valve guides in there...

 

As SoM says, tear it down.  And post pics.

 

The only 'stuck' valve I ever had was when a blue shop towel went down the intake and got wrapped around it.

 

t

 

[Boultman]

It seems like if i was having valve guide issues, that it would have been a little more progressive.  Smoking, or using oil.

 

This car runs like a top, zero smoke, burns zero oil, and has no oil leaks.  Which makes this even more of a surprise. I've had all sorts of odd euro toys and have never had anything like this happen. 

 

I had an '87 911, and it slowly showed signs of the dreaded 3.2 carrera valve guy issues... slowly burning more and more oil, smoking a little more each start-up over the years...

[Son of Marty]

9 minutes ago, Boultman said:

It seems like if i was having valve guide issues, that it would have been a little more progressive.  Smoking, or using oil.

 

This car runs like a top, zero smoke, burns zero oil, and has no oil leaks.  Which makes this even more of a surprise. I've had all sorts of odd euro toys and have never had anything like this happen. 

 

I had an '87 911, and it slowly showed signs of the dreaded 3.2 carrera valve guy issues... slowly burning more and more oil, smoking a little more each start-up over the years...

Yes you would think it would smoke and use oil, but maybe with fresh seals it might not for a while, I only put it out there as a possibility but the M-10 aren't  really know to wear valve guides to the point of cocking. 

[Mike Self]

I've not heard of this happening on later 02s, but on my '69 the original exhaust valve seating surfaces (on the valve) wore to the point where one actually pulled through the seat, popped up and broke the rocker arm.  When I pulled the head, I discovered the other three exhaust valves were about to do the same thing.  Must have been a bad batch of valves.  Didn't damage the seats; I fitted new valves, ground 'em and went on my merry way--with all new bushed rockers.  That was 124k miles ago.

 

I suspect that the piston in that cylinder has been kissed--hard to tell if the rapping sound was the rocker hitting the depressed valve stem (excessive clearance!) or the valve hitting the piston.  Hopefully the former, not the latter.  But you're gonna have to pull the head to see what damage there is...

 

Unusual occurrence, though.  You don't hear of many non-racing M10s doing that.

 

Let us know whatcha find.

 

mike

[JerryC]

The OP's description sounds a lot like what occurred with my daughter's Ford Escort. It turned out to be a dropped valve seat. It clattered quite a bit. You really do want to tear into this and figure it out. But, like Mike says, these types of things can usually be successfully repaired.

 

Car story - the kids didn't bother to figure out what was causing the noise, and ended up with a cracked piston to go along with the trashed head. Amazingly, with some shopping around, we repaired that old Ford for about $600 in parts and gaskets, and it has run well for the last 50k miles. Refurbished head online cost was $300 plus $50 shipping from Florida, and Rock Auto had all the rest for cheap. During my online research, I found this to be a fairly common occurrence on those cars at 120k - 180k miles. Ford cheaped-out on the intake valve seats by using powdered metal instead of billets. After some wear and tear, and then some low coolant, number 4 typically falls out and shatters inside the cylinder. Wish I'd taken pictures, but there are many of them online.

[gracer]

I had a intake valve spring break on my 67 1602 with 8K miles on the speedo.  The valve was bent by the piston and luckly stuck in the valve guide.  I was on a mountain pass about 40 miles from the closest town.  I drove it to the town and then a friend towed it 100 miles to Klamath Falls.  There was no dealer there then.  It took me about 4 months to get it repaired.  Car ran for another 150K before I overheated the engine. 

Take the head off and survey the damage.  Good luck.  G

[s4sprint72]

My Dad's 1962 Riley One-Point-Five used to suffer from sticking exhaust valves. However, that was when starting from cold on choke. There'd be a very loud bang - like a gunshot as the piston hit it. The BMC 'B' series engine must have had an oil starvation issue in the rocker chamber (pushrod operated) when cold. Are your M10's oilways clear? As others have stated, you must lift the head and check for damage and be sure to clean any debris away thoroughly. You are fortunate yours isn't a modern design or Lotus twincam with inclined valves as the damage would likely be considerable (I write from bitter experience.). Good luck. I hope there's minimal or zero damage and look forward to you posting your photos.

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[Boultman]

The sound was definitely from the head/top.  Where the rocker was tapping on the top of the valve stem that is stuck down.  The oil is always spotless. When i lifted the valve cover off, everything looked excellent.  Photos below. 

It sounds like i won't know much else without pulling the head. But these in lies my dilemma.  Do i even attempt to get into this thing, or do i tow it off to a reputable indie here in Houston.  This would be one of the more involved projects that i've done, but i'm confident that i could get it all done myself. (Head re-done by someone else, and any.. uhhh... bottom end machine that MAY need to be done. 

However, it's a time issue with me.  Two small kids and a demanding and stressful business.   

 

Any clue what kind of money we are talking about to have someone else do everything?  assuming it needs a top-end rebuild and not much more?

What about purchasing a rebuilt head and sending mine in as a core?  What kind of money there?  Does this take away any value/originality on these cars?  

 

Like most things, it is a balance between time and money.  I don't mind spending a little extra to have it done really well, correctly, and quickly.  We are JUST getting into driving weather down here... 

[Son of Marty]

Well I think if it was me I'd pull the head myself and see what's going on and if the piston is still usable then shop for a rebuilder. the head is not to tough to get on or off at home.

[rstclark]

If you have access  to an engine hoist  just disconnect all lines and electrical  and pull the head off with the manifolds attached.

  Saves a lot of work and you will be able to see the condition of the head and piston  If you have to take it apart for headwork

you can do it all in the air

You have nothing to loose by trying to figure this out yourself. Especially since you won't be driving this to a repair shop

[TobyB]

 Pull it!  You may have to pull your strut brace first.  Is that a shot of the stuck valve?  Because the retainer doesn't look very low-

can you see/ measure that it's below the level of the other 3?

 

Are you SURE the adjuster didn't slip?

 

Do I have MORE questions?  Yes!  Yes, I do- with #1 at tdc (so #3 is at BDC) can you move #3's valve?  (you can compare to #2 for spring pressure)

 

I thought I had a stuck valve once.  See above- blue towel.  I could FEEL it wasn't letting the valve snap closed...

 

If your LCAPS  (local chain auto parts store) has one, borrow a borescope- that will show you what's up in a hurry.

 

hth,

 

t

[s4sprint72]

What a great looking car! I agree with the other guys. You can lift the head yourself. It needn't take long to do and you will then know exactly what's the score. If you give the job someone else then how much trust do you have in those people?

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[Boultman]

I got a cheap USB borescope off Amazon to take look through the plug hole.  The cheap kind works really well, but doesn't allow you to really turn the camera up back toward itself to see the valves.  however, the cylinder with the stuck valve looks darker and more oily compared to the others.  not sure if this was a longer term thing, or just from the two miles i drove it with the stuck valve.  I don't see piston damage, but it is pretty black and coated.  but i didn't see any scoring, etc.

 

My options are to pull the head, or just trailer it to a reputable mechanic here in Houston.  Does anyone know of a good shop?  i'd like to give them a call and see my options before i spend precious weekend hours in my extremely hot garage.  

 

I may have asked before, but what do you guys think about purchasing rebuilt heads, and shipping this in for a core?  Affect value much, as the engine would be less "original"?