Zero compression Cylinders 2-4???

[moberg12]

I recently purchased a non-running 1995 ranger. The previous owner stated it was not running due to a timing/compression issue. First thing I did was put a new timing belt on, I was careful to make sure all timing marks were lined up, so timing is good. Last night I ran a compression test Cylinder 1-115, 2-0, 3-0, 4-0. This is a bit puzzling! I ran the test through twice just to make sure.

I know it is highly unlikely that there would be broken rings, or stuck valves on 3 cylinders. This morning I pulled the valve cover just to make sure the cam was in one piece. Cam and valve train seem to be rotating normally. So I'm thinking this has to be a head/head gasket issue. Am I missing something??

 

[adsm08]

Yes, you are missing something. Compression on three cylinders.

Does the cooling system hold water? If it is low I would try filling it, with at least one plug out from every cylinder, and see if any of them start filling with water. If they do just go get a new engine.

 

[moberg12]

Yes, you are missing something. Compression on three cylinders.

Does the cooling system hold water? If it is low I would try filling it, with at least one plug out from every cylinder, and see if any of them start filling with water. If they do just go get a new engine.

I have never seen this engine run but it was full of coolant before I took it apart for the timing belt. The coolant that came out looked decent, maybe a bit rusty but no signs of oil contamination. If it is the gasket I would think it was likely a failure between cylinders vs. at a water jacket. Oil is clean too.

 

[RonD]

1 and 4 are a matched set, as are 2 and 3, so 1 and 4 are both at top dead center(TDC) at the same time, then 180deg later 2 and 3 are at TDC, this balances the engines rotating mass.

The Cam is what determines if #1 is at TDC Compression stroke or TDC Exhaust stroke, and #4 would be on opposite stroke

So unless cam is broken midway, 1 and 4 should both have compression if either one does, even if valve timing is off a bit

Timing marks on the 2.3l/2.5l can be a bit confusing since Cam Gear and AUX gear often have BOTH marks, a triangle and a diamond
AUX gear uses diamond and it lines up at 12:00
Cam Gear uses triangle and it lines up at 4:00

Crank gear's woodruff key slot lines up at 12:00

 

[moberg12]

1 and 4 are a matched set, as are 2 and 3, so 1 and 4 are both at top dead center(TDC) at the same time, then 180deg later 2 and 3 are at TDC, this balances the engines rotating mass.

The Cam is what determines if #1 is at TDC Compression stroke or TDC Exhaust stroke, and #4 would be on opposite stroke

So unless cam is broken midway, 1 and 4 should both have compression if either one does, even if valve timing is off a bit

Timing marks on the 2.3l/2.5l can be a bit confusing since Cam Gear and AUX gear often have BOTH marks, a triangle and a diamond
AUX gear uses diamond and it lines up at 12:00
Cam Gear uses triangle and it lines up at 4:00

Crank gear's woodruff key slot lines up at 12:00

Thanks for the response. This was my first time doing a TB on this 2.3l engine, but I have done them on other engines. I did research the process beforehand and I was aware of the different timing marks. I lined triangle to triangle, diamond to diamond, and the little dot just right of the key to the notch, key was at 12 o'clock. I then ran the engine around a few times by hand and everything was still lined up.

Interesting note, when I got in there to replace the belt, the old belt was not broken, and there were not any missing teeth. Cam and crank timing were aligned but the aux gear was out about a quarter turn??

I will definitely recheck the timing.

 

[RonD]

If you put spark plugs back in, don't have to be torqued tight
Then put your hand over intake inlet(remove air plenum/tube) and crank engine, it should be all suction, 2"+ on vacuum gauge, if you feel air pushing back out then intake valves are not sealing.

Make sure dip stick is in all the way, then pull off oil filler cap and put a piece of paper over opening, crank engine, if it is getting pushed up then ring and/or piston issue.

 

[moberg12]

If you put spark plugs back in, don't have to be torqued tight
Then put your hand over intake inlet(remove air plenum/tube) and crank engine, it should be all suction, 2"+ on vacuum gauge, if you feel air pushing back out then intake valves are not sealing.

Make sure dip stick is in all the way, then pull off oil filler cap and put a piece of paper over opening, crank engine, if it is getting pushed up then ring and/or piston issue.

I was planning on doing a leak down test of sorts on it tonight. The hose for the compression tester has a schrader valve in it that I can remove, Then just pump shop air into the engine. The valve cover is off right now so getting the cylinders to top dead center shouldn't be difficult.

What exactly does the aux gear run that it needs to be timed with the cam and crank. On older BMW straight 6 engines that I am familiar with it is just the oil pump, and it doesn't need to be aligned at all.

 

[adsm08]

On the original run of the 2.3 the aux ran the distributor, so if it wasn't timed right you would have had to re-stake the distributor. You don't have a distributor. If you don't have a cam synchro type sensor in that spot (like my Mustang doesn't) I don't know why having the aux shaft out of time would make any difference. Unless it has a balance weight attached somewhere.

 

[RonD]

Yes, AUX gear is now used for sequential fuel injection for the most part, since it is the same size as Cam Gear, timing it with Cam Gear allows use of a Cam Sensor on the AUX gear which is easier than trying to locate a sensor on the Cam.

Crank sensor tells computer position of pistons, like #1 at TDC but not what stroke
Cam sensor tells computer what position Valves are in so it can time sequential injection better, also better for spark advance/retard, so better "fine tuning"
But AUX gear position can't effect compression

AUX Gear also drives oil pump shaft and as adsm08 said that shaft was also used to drive a distributor.

 

[adsm08]

Yes, AUX gear is now used for sequential fuel injection for the most part, since it is the same size as Cam Gear, timing it with Cam Gear allows use of a Cam Sensor on the AUX gear which is easier than trying to locate a sensor on the Cam.

Crank sensor tells computer position of pistons, like #1 at TDC but not what stroke
Cam sensor tells computer what position Valves are in so it can time sequential injection better, also better for spark advance/retard, so better "fine tuning"
But AUX gear position can't effect compression

That's what I thought, but I am not very familiar with these Lima engines. I've only worked on a handful, and it was mostly small repairs. I've only owned one, and all I've done to it so far was a thermostat and oil change. And it doesn't even have a cam sensor.

 

[RonD]

The old EEC-IV computer could do sequential injection if it had TFI distributor telling it when #1 was on intake and then compression stroke, and if it had separate wires for each injector.

But when "they" went distributorless most went back to Batch Fire, just 2 wires for 4, 6, or 8 injectors.
When Cam sensors were added computer then knew when #1 was on intake stroke.

Although I did read there were some EEC-IV's that could ID #1 intake stoke on startup by selectively opening #1 injector and watching for #1 misfire, the slowing of the crank, no power added, so it could ID #1 intake and compression stroke and then it had firing order for sequential injection.

 

[moberg12]

I think I found the culprit, head is also cracked between the valves on cylinder 4.....

 

[RonD]

Oh I don't know, a little RTV and JB weld and she'd be as good as new

Or not

 

[moberg12]

Time to find a replacement head.

 

[moberg12]

Will a head from a 93 mustang work? Will the manifolds all bolt up?