engine and drivetrain Replaced spark plug wires, 20 miles later engine runs rough wont start

[OriginalOwner]

you said,  "If I remove ignition wires to cylinders 3 or 4 while the car is running nothing happens. Engine continues to sound equally rough. If I remove the ignition wires to cylinder 1 or 2 the engine sputters and stops."

 

Exact same symptoms I had last August when my head gasket let go.

 

"definitely" +1 LimeySteve:  blown head gasket between #3 and #4.  Compression testing will verify.

 

Cheers,

 

Carl

Edited July 11, 2015 by OriginalOwner

[TobyB]

...and I was gonna say swap the wires on 3 + 4 and see if it runs better.

 

But yes, do a compression test...

 

t

[pmg]

Today a learned about compression tests. Neat. That makes a lot of sense to test for.

 

 

Clearly cylinder 3 & 4 aren't too happy. So replacing the gasket seems to be the way to go. Fun.

 

Also, cylinder 2 appears to be running a bit weaker than 1 and both appear to be a bit weaker than the 180psi I've seen as "standard" elsewhere on this forum for a stock later model M10 engine at sea level.

 

What else should I check for/do while I'm down there? I've got all the books and motivation but none of the experience. 

 

Thank you everyone for helping a noobie out.

[Guest_anonymous]

Today a learned about compression tests. Neat. That makes a lot of sense to test for.

 

 

 

[Simeon]

I wouldn't worry too much about the absolute figures. Who is to say how well your gauge is calibrated compared to the 180psi gauge. You are looking for differences between cylinders and obviously low figures.

3 and 4 almost certainly a head gasket failure. 1 and 2 are fine for a run in engine.

[TobyB]

As to other things, it really depends on what you're up for.  If you just want to get running again,

you can check the head for straightness and damage, clean everything, and bolt it all up.

If the surface is very good, you can just clean it well and bolt it right back on.  If it's a bit

scuffy, a .005" "clean up" cut helps guarantee a good seal.

 

However, when the head's off, you can also 'freshen' it at a machine shop- new guides,

guide seals, and a valve grind.  That generically runs 3-500 smackers, and may help

with oil burning and improve power just a bit.

Also an easy time to do heater hoses and such, since they're way easy to get at.

 

Sorry about your head gasket...

hth

 

t

[72pdx02]

I would replace the plug wires.  I have had new pretty blue ones fail.  Went back to OEM and no problem.

[Arizona02]

The 1st video after 9 seconds elapse the throttle is wide open and then I hear the compression coming threw the carb. Bad head gasket .

Edited July 13, 2015 by Arizona02