Okay...Bought a 92 ranger 4x4 5 speed with a 3.0...blown head gasket, oil full of water, was leaking into cylinder 1, 2, and 3...The WHOLE passenger side bank....Took the heads off, did visual inspection, all looked good...They were cracked in between a water port and head bolt hole, in the middle two lower/exhaust manifold side of the head...I don't believe this was the cause of the leaking head gasket as the gasket was visually bad upon removal...

Inspected cylinder walls/piston tops, All looked good no unusual grooving or pitting...hardly a lip at the top of the cylinder

Valves moved properly and seemed to seat well...(poured water into head while upside down and none leaked off)

Pulled the pan and looked at rods, made sure bearings were all tight.
All looked normal upon inspection.

Installed new head gaskets and put everything back together and got the motor back in...No compression. No parts changed except for the head gaskets, intake gasket, plenum gasket, the starter ring gear on the flywheel, and a new starter.

Verified camshaft timing was in proper placement, cam is not worn out, all valves move while motor is turning over...BUT I HAVE ZERO COMPRESSION ACROSS THE BOARD!!!

I have been a "shade tree" mechanic for a very long time, i'm pretty familiar with the ford 3.0 duratec motors...but this has me stumped, never seen anything like it. HELP!!!!!!

:conf used::cra zy:

 

Welcome to the forum

3.0l Vulcan engine is a non-interference engine, so valve timing can be off and valves will not hit the pistons, but timing chain has never been an issue with 3.0l vulcan

0psi compression reads like a gauge problem

pull all spark plugs and turn engine manually while you have a finger in #1 spark plug hole.
If it doesn't get pushed out then you will need to pull front cover to get at timing chain.
Crank woodruff key could have been sheared off if engine hydrolocked, so crank and cam gears are out of time, cam would still turn, just no longer in time with crank.

When crank pulley is at TDC mark #1 exhaust valve should have just closed and intake valve just opening, OR both valves have been closed since BDC and pistion was on compression stroke, if a valve is open then crank/cam timing is off

 

I never thought about the key being sheared off, I saw it happen in a 4.0 but it wasn't turning the cam at all, and it happened on the camshaft side of the chain.
but it isn't a gauge problem, as i checked with the finger method first. But the key being sheared off makes sense now that you say that...Because it made some compression whenever i took both rocker arms off of cylinder #1.

 

Am I reading right? I thought you said you found cracks in the head and you reinstalled them. I don't think it is a good idea to use cracked heads if that is what you did.

 

Yes you read it right. The crack in that spot didn't concern me. and i don't think it has anything to do with this problem...and i'm poor and need the truck, worth it in my opinion to take the risk, rather than spending the $$ on a 25 year old truck.

 

Keep an eye on your coolant level and check the oil on a daily bases for coolant contamination.
You may also have steam coming out of your exhaust, from other cracks you can't see.

Head gaskets just don't fail all on the own, the most common problem of head gasket failure is overheating.
When the engine over heats, the cast iron in the heads expands more then usual, and this compresses the head gasket beyond its normal range.

So when the engine cools, it's no longer doing it's job of sealing the combustion chamber and you get a failure.

Overheating also causes cracks in the head.

The question is, why did it over heat in the first place ???

 

I'm not entirely sure why it overheated, this is the way the truck was purchased. I only found the two small cracks using metal shavings from the head. (part that doesn't mate to anything) a magnet and pinging it with a hammer.

 

Of all the engines for these trucks to over heat, the 3 Litre Vulcan is probably the most durable and forgiving.
Make sure the head gaskets are put on right, there is a right and a left with these.
There is a coolant hole at the back of each gasket that has to be at the back.

 

Yes, that is all I can think of from your description.

Image of timing chain gear set for 3.0l here: http://i.ebayimg.com/images/g/m9cAAO...UE2/s-l640.jpg

Looks like cam gear has built in key
Crank still uses woodruff style

Woodruff key could shear off and cam wouldn't turn any more but it can also wedge itself so cam still turns but out of time with crank/pistons

Check TDC and see if valves look right

 

I had the same problem with my 3.0L 2005 Ranger. Long story short, it turned out to be a stopped up exhaust. Catalytic converters were internally trashed and the trash accumulated in the resonator just before the muffler. Disconnected the exhaust and the compression came back and the engine purrs like a cat again. I replaced the exhaust. Hope this helps.