dead cylinder

[baja32]

I have another engine that has 120 psi of compression on 4 cylinders, 130 psi on one cylinder, and ZERO compression on another cylinder (specifically cylinder #2, top port side). It starts and runs ( its another 150hp v6 blackmax) I think its a 1984 but not sure. What can I expect if I continue to run it without doing anything about the dead cylinder?

-notes on state of other systems: cleaned and rebuilt fuel pump and all carbs, cooling system works fine.

I have thought up a few scenarios:

a.)when dead cylinder has gotten to TDC the air/fuel charge has escaped back into crankcase
-any remaining fuel ignites and the exhaust gets blown back into crankcase (which can't be good)
b.) if above is true, can I assume its being lubricated?

Again I can be very wrong so please comment, I'm a 21 yr old college student that loves boating and tinkering with engines. Have learned plenty so far on this board.

 

[Faztbullet]

Re: dead cylinder

What can I expect if I continue to run it without doing anything about the dead cylinder?

It becoming a self ventilated crankcase....with rod hangin from side.

I have thought up a few scenarios:

a.)when dead cylinder has gotten to TDC the air/fuel charge has escaped back into crankcase
-any remaining fuel ignites and the exhaust gets blown back into crankcase (which can't be good)
b.) if above is true, can I assume its being lubricated?

Above is not true as if it has no compression it cannot make crankcase vacuum to allow outside atmospheric pressure to provide fuel/air charge,thus no lube. Aluminum piston dragging on cast iron cylinder will eventually sieze and lock-up...

 

[baja32]

Re: dead cylinder

can I adjust the timing on it or will its performance be erratic cause of the dead cylinder??

 

[Faztbullet]

Re: dead cylinder

Its performance will really be lacking, timing wont help nothing and its going to cost you more in long run if you dont repair it now....