Hi all,
For the past few months my friend and I have been rebuilding a slightly modified 3L with a CT20 turbo and 2LT exhaust manifold +intercooler in a 1990 LN106 Hilux crew cab. Some time in March the truck broke down while on the highway. After a compression test, the compression numbers for cylinders 1 to 4 respectively were 495 PSI, 455 PSI, 305 PSI (345 PSI with oil), 450PSI. We decided to rebore and rebuild the whole engine after discovering this and got a Terrain Tamer 3L 0.5mm O/S Rebuild kit.
After 4 months we got engine back from the machine shop, and some miscellaneous parts we needed (valve seals, valve exhaust tubes etc. were not part of the rebuild kit and took a month to come in). Put the whole thing together, fired it up, and we got a RPM dependent somewhat metallically sharp "tick tick tick" sound when any gas was applied and the truck could not hold an idle, and just didn't run. The following day we did a compression test out of the recommendation of a friend, and our compression numbers for cylinders 1 to 4 respectively were: 365PSI, 370PSI, 355PSI, 355PSI. After adding 5 eye drop sized droplets of oil into each cylinder, the compression numbers were unchanged.
I called my uncle who's rock solid with Toyota engines (as a disclaimer he did mention he strictly is a petrol straight-6 engine guy) and he suggested that I might need to keep trying to start it to get the temperature of the engine up, and hope the diesel combusts and start breaking in the rings.
Other Background information:
-Valve clearances have been checked and are still good
-Small block stuff is all good (piston diameters, ring gap, groove gaps etc)
-Timing belt is new and timing is all good.
-Main Bearing Journal is 0.025mm U/S instead of 0.05mm, and the clearances are all good.
-Head was properly torqued with new hardware
-Injector is not advanced or retarded, and right at the Toyota match mark for the time being.
-Head Gasket is the thickest head gasket available at (I think it's the F thickness) - came with the rebuild kit, engine could use thinner one if it had to based off of protrusion
-I personally did not assemble the cylinder head. The machine shop did, but based off of their competency and the valve tappet gap being within limits, I assumed that the head was good to go.
-Engine turns over smoothly with no "clanks or dinks" that could indicate valve to piston strikes.
Which all of this leads me to believe: that I need to break this engine in by just forcing combustion (if that's a thing at all), I need a new head gasket, or the machine shop I used goofed up a valve job. That's what I can think of to cause all 4 cylinders to be 100 PSI low, and I'm all ears for any experience or suggestions on the matter. Other things that could be addressed are maybe reconditioning the injectors, but i'm ignoring that for now because that would not contribute to the lack of pressure in each cylinder. Unfortunately, both my friend and I are going back into the military here shortly, and we're desperately trying to get this sucker fired up so my wife or family don't have to deal with a brick of a truck while we are gone.
Located in Utah.
For the past few months my friend and I have been rebuilding a slightly modified 3L with a CT20 turbo and 2LT exhaust manifold +intercooler in a 1990 LN106 Hilux crew cab. Some time in March the truck broke down while on the highway. After a compression test, the compression numbers for cylinders 1 to 4 respectively were 495 PSI, 455 PSI, 305 PSI (345 PSI with oil), 450PSI. We decided to rebore and rebuild the whole engine after discovering this and got a Terrain Tamer 3L 0.5mm O/S Rebuild kit.
After 4 months we got engine back from the machine shop, and some miscellaneous parts we needed (valve seals, valve exhaust tubes etc. were not part of the rebuild kit and took a month to come in). Put the whole thing together, fired it up, and we got a RPM dependent somewhat metallically sharp "tick tick tick" sound when any gas was applied and the truck could not hold an idle, and just didn't run. The following day we did a compression test out of the recommendation of a friend, and our compression numbers for cylinders 1 to 4 respectively were: 365PSI, 370PSI, 355PSI, 355PSI. After adding 5 eye drop sized droplets of oil into each cylinder, the compression numbers were unchanged.
I called my uncle who's rock solid with Toyota engines (as a disclaimer he did mention he strictly is a petrol straight-6 engine guy) and he suggested that I might need to keep trying to start it to get the temperature of the engine up, and hope the diesel combusts and start breaking in the rings.
Other Background information:
-Valve clearances have been checked and are still good
-Small block stuff is all good (piston diameters, ring gap, groove gaps etc)
-Timing belt is new and timing is all good.
-Main Bearing Journal is 0.025mm U/S instead of 0.05mm, and the clearances are all good.
-Head was properly torqued with new hardware
-Injector is not advanced or retarded, and right at the Toyota match mark for the time being.
-Head Gasket is the thickest head gasket available at (I think it's the F thickness) - came with the rebuild kit, engine could use thinner one if it had to based off of protrusion
-I personally did not assemble the cylinder head. The machine shop did, but based off of their competency and the valve tappet gap being within limits, I assumed that the head was good to go.
-Engine turns over smoothly with no "clanks or dinks" that could indicate valve to piston strikes.
Which all of this leads me to believe: that I need to break this engine in by just forcing combustion (if that's a thing at all), I need a new head gasket, or the machine shop I used goofed up a valve job. That's what I can think of to cause all 4 cylinders to be 100 PSI low, and I'm all ears for any experience or suggestions on the matter. Other things that could be addressed are maybe reconditioning the injectors, but i'm ignoring that for now because that would not contribute to the lack of pressure in each cylinder. Unfortunately, both my friend and I are going back into the military here shortly, and we're desperately trying to get this sucker fired up so my wife or family don't have to deal with a brick of a truck while we are gone.
Located in Utah.