I recently bought a 2001 B3000 with the 3.0. When I bought the truck I knew it had a misfire and was idling rough. Once you get it up to about 2000 RPM it smooths out. The previous owner just replaced the ignition coil, spark plugs, wires, cam positioning sensor. The injectors were swamped and the issue did not jump cylinders. They had a mechanic look at it and said compression was good, lowest number he said he got was 90psi. I was able to drive the truck home the 110 miles, but it is so sluggish and you can tell it is down on power.

This morning I decided to throw out everything that I was told about the truck and start trouble shooting. All cylinders are getting spark so I decided to do a compression test. To find out if I had a possible head issue. Also all cylinders had fuel so I could tell the injector were spraying. Here are the results from the compression test.

Cylinder 1 – 60 dry and 110 wet

Cylinder 2 – 110 dry

Cylinder 3 – 30 dry and 30 wet

Cylinder 4 – 0 dry and 0 wet

Cylinder 5 – 60 dry and 60 wet

Cylinder 6 – 110 dry

Here are my thoughts based on the results.

- Both heads need work because of cylinders 3 and 5.

- Piston rings are shot on cylinder 1 since wet test high a higher number.

- Cylinder 4 could be either valve or hole in piston since it has ZERO compression.



Since I need both head and piston work, I am planning on getting a used engine. Cost wise I can get a used engine for about the same cost as refurbed heads, so that I why I am leaning to just getting a used engine. Probably about the same about of work also.


Before I go and spend the money on that, has anyone had a similar issue? Could this happen from jumped timing? Does anyone have any other ideas?



Thanks in advance
Shane

 

Welcome to the forum

WET test will ALWAYS be a higher number, all pistons and rings leak air even when brand new

3.0l Vulcan engine should be 160psi, it runs 9.3:1 compression ratio(CR), general rule of thumb to estimate PSI is CR X 18 = PSI, 9.3 x 18 = 167psi
Can't believe a mechanic would pass a 90psi cylinder as OK, even on a lawn mower, lol

I think your numbers are falsely low because engine did run, and it shouldn't start and run with 110psi, but high numbers aren't the point of compression test, differences between cylinders using same pressure gauge and method is the point

After you pull the heads you can then inspect the cylinder walls to see if there are any ring issues

The 3.0l was never known for any timing chain issues, doesn't even use a tensioner, but it could happen

The 3.0l was a very good and reliable engine, so a low mile used one wouldn't be a big gamble, but they did burn valves, like any engine can, which was the usual loss of compression
You could pull the heads before pulling the engine, just to have a look and to check if the valves are the issue

The 3.0l OHV needs to be from a Ranger or Mazda B3000, if its from a Tarsus or Sable then the head gaskets need to be changed because coolant flow thru the heads is different on transverse mounted engines

 

Do what I did go to rockauto and just rebuild it. I spent 350 and got new gaskets, oil pump, bearings water pump valve job and the list goes on oh I would also replace the cluch If you rebuild it!!! Rockauto has a HD cluch if yours is a manual transmission my 3.0l runs unbelievably better maybe even better then factory!

 

I lost compression due to bad valve seats