P19 with dead cylinder

[Fastback50]

Hey guys, 

 

So I learned today that my fastback won't start because I have one piston that's doing nothing.  I've been unable to get the thing started in my free time the past few months, but today pulled all the plugs and had a buddy crank it while holding my thumb over each plug hole.  Number four didn't do a thing, so I then had him do it while I looked down onto the piston and sure enough, not even a wiggle.  Big bummer.  So, I guess I'm looking for ideas on what the most probable cause of this is, easiest repair solutions, and maybe even throw some estimates on cost at me.  Does this require a complete pull/rebuild?  Thanks.

 

 

[Reg Evans]

You can't see the piston through the plug hole.  You are looking at the top of a valve that is apparently stuck in the open position.  Get that valve  loosened up and you'll probably have compression in that hole too.

[Plymouthy Adams]

You can't see the piston through the plug hole.  You are looking at the top of a valve that is apparently stuck in the open position.  Get that valve  loosened up and you'll probably have compression in that hole too.

B I N G O.......and do follow the manual...no hammy-slammy on the valve

[Fastback50]

Okay, I'm on it!  Thanks guys--I've just gone from very bummed to cautiously optimistic!

[Fastback50]

I'm referencing my manual but don't see anything about what exactly to do with a stuck valve.   I'm guessing I'll have to remove the cylinder head?  I poured some tranny fluid down there to soak it, but know that may not be the answer.  Go easy, I'm a newbie 

[greg g]

Some times you can coax them free by going through the side covers and prying a bit on the spring or tapping on the lifter.

[dpollo]

A stuck intake valve will do more to foul up an engine's ability to run than most other ailments.  Put a slender punch or drift through the hole and GENTLY encourage the valve to close.  Take care that it is not actually in the open position when you tap on it.

Turn the engine and try again if it is.  Just don't force anything.   It may not hurt to do a compression test.  If it is not pumping up 80 pounds or more on most cylinders it will be hard to start.   Good compression would be 100 pounds plus. 

[Fastback50]

Thank you DPollo, I will try that tomorrow as I've run out of daylight and energy haha.  I got the passenger side wheel well out and tomorrow will access the valves and try it from that angle as well.  If I'm real lucky maybe the tranny fluid will loosen it up a bit overnight.  Someone tell me if they think the tranny fluid was a bad idea....a pretty knowledgeable guy I know that races cars recommended it, but who knows.

[_shel_ny]

One (1) no compression cylinder should not stop the engine from starting.

 

Do a compression check of all cylinders.

[Don Coatney]

FYI.

 

[_shel_ny]

And of course as is often mentioned here....................................  along with that compression, you need fuel, and a spark........ at the correct time. (static timing)

[dale]

There are lots of stuff better than tranny oil... Reslone, Seafoam, etc.

[Don Coatney]

There are lots of stuff better than tranny oil... Reslone, Seafoam, etc.

How is seafoam and Reslone better?

[Fastback50]

FYI.

 

 

Thanks Don!  Pricing a compression test gauge now...

[Fastback50]

How is seafoam and Reslone better?

 

I would like to know this also.  I got the rear valve cover off today and found the stuck valve.  I read my manual but can find anything specific on how to unstick the thing.  So, I dumped a generous amount of trans fluid (maybe 3/4 or 1/2 cup) in the topside and sprayed the underside with a bit of WD40 (as the spring had corrosion on it).  We turned the motor over a few times to verify that the tappet was moving, and it was.  I also gave the surface of the valve some LIGHT (no "hammy slammy" lol) tapping with a flat nosed punch, but things weren't moving so I let it be.  Any suggestions on my next move?  

 

 

[Dave72dt]

ATF will not hurt it.  ATF has been used for a long time to help free up sticky lifters. 

[Dave72dt]

You might try to get the valve to open a bit more, then tap the valve back down and repeat the process.  Even if you don't see the valve move at first, it should eventually loosen up and move. 

[Fastback50]

You might try to get the valve to open a bit more, then tap the valve back down and repeat the process.  Even if you don't see the valve move at first, it should eventually loosen up and move. 

 

Okay--same procedure with a punch from the bottom side you think?  I don't know how I could get too much lever there without being too rough...

[greg g]

The valve is stock within the bronze valve guide. Unless you can some penetrating lube between the stem and guide, it is unlikely to free up without some mechanical influence. Try turning the engine so there is space between the lifter and valve the tap up on the valve try wedging a chisel or small pry bar between the spring coils. Some heat like from a heat gun might help also.

[Dodgeb4ya]

No bronze guides in this engine. Valve might not be stuck so bad if a bronze guide was used.

[Fastback50]

The valve is stock within the bronze valve guide. Unless you can some penetrating lube between the stem and guide, it is unlikely to free up without some mechanical influence. Try turning the engine so there is space between the lifter and valve the tap up on the valve try wedging a chisel or small pry bar between the spring coils. Some heat like from a heat gun might help also.

 

Okay I'll try a little more mechanical persuasion today and see how things go.  I just don't want to bend or damage the valve.  I don't own a heat gun but this may be an excuse to buy one 

[Don Coatney]

When you buy a compression gauge make sure you get ether one with a rubber tapered tip (as pictured below) or if a screw in type get one with the "short" reach that goes in the hole the same depth as the spark plugs. A "long" reach screw in type will make contact with the intake valves and cause damage.

 

[Fastback50]

When you buy a compression gauge make sure you get ether one with a rubber tapered tip (as pictured below) or if a screw in type get one with the "short" reach that goes in the hole the same depth as the spark plugs. A "long" reach screw in type will make contact with the intake valves and cause damage.

 

 

10-4, will do Don.  Thanks.

[Reg Evans]

I would heat the area with a propane torch.

[Fastback50]

Well I figured out that the valve I was actually tapping on was the wrong one.  The valve that is stuck is inaccessible from the top side of the motor (without taking the cylinder head off).  I got a pry bar in the spring from the underside and attempted to gently move it that way, but no dice.  I'm now wondering if any of the ATF I put in plug hole #4 got to that valve at all (I'm not sure if they are in separate "compartments" under the cylinder head or not).  I'm wondering if torch heat or taking the entire head off are my only two options?