No compression all cylinders

3

31deluxe

Member
Working with a friend to get his 30 coupe running. Got caught in a fire years ago but it was pulled out by the firemen .

It was running before the fire.


We wired it up. Good spark rotor turning



NO COMPRESSION ALL CYLINDERS. Timing gear good.



Any suggestions as too troubleshooting.
 
Are you POSITIVE the timing gear is good? My only sure check is to pull the gear cover from the front of the engine and spin the crankshaft. If the timing gear CONTINUOUSLY spins, it should be good.... Otherwise valves for all four cylinders could be stuck, but that's pretty unlikely. Good luck!
 
Even if the timing gear turns, the valves could be stuck open. It only takes one in each cylinder and if the motor has been hot, I think itis quite possible they are sticky enough that the cam is able to open them but the springs, maybe weakened by the fire, can't close them.
 
Took the side cover off of the timing gear cover. Could see the timing gear moving when cranking. Plugs out - see valves going up and down. Compression tester and "thumb" test -No compression all 4
 
If the 'valves are going up and down' then check the valve lash and look at the timing gears to make sure it hasn't jumped time for some reason.
 
If the motor got too hot, the rings might have lost their tension or the head warped (unlikely)
Give us some idea on how hot it got. What was the condition of the radiator afterwards, likewise paint, grease running out of the wheel bearings? Distributor body charred or gone?
 
I will try to get a little more info on the fire. He said he changed the head gasket and manifold gaskets. Loose manifold gaskets?
 
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This chassis was in a house fire,the coupe body was destroyed,warped and soft as cheese.The engine too a lot of heat from the fuel tank burning..upon disassembly and inspection the entire long block was completely salvageable..
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Fire was so hot it warped the right front wheel,consumed everything that would burn on the engine but the internals were fine.Whats important is the floor the car was sitting on,this one was on concrete.Heat rises and concrete doesn't burn,tire fire is hot and the interior of the restored coupe burns hot,but the chassis didnt see that kind of heat.
 
You could try diagnosing just cylinder 1.


Get the rotor pointing correctly to spark plug one, Use the timing pin to find TDC cylinder 1 (rotor should still point to spark plug 1/cylinder one). If not pointing correctly, mechanical timing has slipped.


If rotor and timing pin align correctly, with the valve access cover off, use compressed air into the cylinder 1 to locate where the leak is (leak down test). You may have to drop the oil pan. If you hear air in the exhaust, exhaust valve is not seated, if you hear air in the Intake manifold/carb, the intake valve is not closed. if you hear air in the bottom end then it is possible rings, block. If the radiator cooling system is full and bubbles in the radiator or you may hear air in the radiator if radiator is not full, bad head gasket, cracked block. Not sure if I have all the symptoms/causes here.
 
30 Closed Cab PU said:
You could try diagnosing just cylinder 1.


Get the rotor pointing correctly to spark plug one, Use the timing pin to find TDC cylinder 1 (rotor should still point to spark plug 1/cylinder one). If not pointing correctly, mechanical timing has slipped.


If rotor and timing pin align correctly, with the valve access cover off, use compressed air into the cylinder 1 to locate where the leak is (leak down test). You may have to drop the oil pan. If you hear air in the exhaust, exhaust valve is not seated, if you hear air in the Intake manifold/carb, the intake valve is not closed. if you hear air in the bottom end then it is possible rings, block. If the radiator cooling system is full and bubbles in the radiator or you may hear air in the radiator if radiator is not full, bad head gasket, cracked block. Not sure if I have all the symptoms/causes here.
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You shouldn't need to remove the oil pan, just remove the oil fill cap! I would only use 60 lbs of compressed air.
 
Big hammer said:
You shouldn't need to remove the oil pan, just remove the oil fill cap! I would only use 60 lbs of compressed air.
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True, but suggested dropping the pan in this case for an inspection, since it has been through a fire. My feeling is better to check out the bottom end before getting it running. Best to be thorough by dropping the pan, and putting in new pan gaskets may be a good thing due to the fire.
 
My logic I have seen this before and it takes munch heat to damage engine mostly
plastic stuff wires yes . Idea is an engine will not burn, the engine is not fire wood, its
just the burnable stuff. We had a mint 58 Continental covert' house fire, the car
toasted what a shame we salvaged that and a mint Hudson also toasted. The 430 Lincoln
we replaced the melted fuel pump carb and distributor. New oil started up like a champ
same thing with Hudson 6 runs perfectly. and I still have both engines storage...
 
How soft are the valve springs? That motor has been pretty darned hot. I suspect they have lost tension. Piston rings might have done the same.
 
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It doesn't take much of a cylinder to produce "thumb compression". Must be stuck valves. They may be moving but not closing. I'd pull the head, the valve cover and the pan and look the internals over. If you plan on salvaging the engine its good to know what it looks like inside.
 
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