Here is the deal. I bought a d16z6 sohc vtec engine off a guy on here. I wont say his name until I am sure that I have a problem. The motor was sitting in a garage for a certain amount of time (unsure exactly how long). However, when we put the motor in my car it wouldnt start. It went into an 89 si hatch that I have rewired obd-1. I know the wiring is good and it is getting fuel and spark. When we put a compression tester in each cylinder this is what we got....... reading right to left 1......2......3.....4.......... 40 psi - 30 psi - 90 psi - 50 psi . The motor spins like it has no compression. We decide to add a little oil to the cylinders. compression jumps up to 200 exactly in every cylinder. The test was done on a cold motor with all plugs removed and the throttle plate wide open. Once we start the motor up, it starts smoking for like 10 minutes and wouldnt stop. So, we decide to pull it out and put in another one. With the new engine, everything worked fine.

I email the guy back and he says that the engine ran fine and was shocked when I said it was smoking. He told me that the rings could have gotten stuck in the pistons. I have never heard this happen before but, I have no idea.

Another key factor is, the engine was run on synthetic oil only. We decided to put in some 5w-30 mobil one synthetic. I have heard about people using synthetics and having to use a thicker weight to keep it from seeping.

I know I didnt hear or see the motor run before I bought it. I can honestly say I wont do that again. I was just curious if anyone else has bought a used motor that was sitting for a while and possibly had the same symptoms.

Any help would be great.

Thanks

 

rings stuck in the piston? wtf?

 

beats the hell outta me. I havent bought a motor that was sitting for a while. I didnt think when you added oil, it would raise the compression that much either. So who knows.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KB Tuning &raquo;</TD></TR><TR><TD CLASS="quote">reading right to left 1......2......3.....4.......... 40 psi - 30 psi - 90 psi - 50 psi . The motor spins like it has no compression. </TD></TR></TABLE>

That's way too low, even if it has been sitting. Rusty valve seats can cause low numbers, but the oil you added to the chambers removes that as the problem. Pull the head and check the cylinder walls. I bet there is either excessive rust, or excessive wear.

 

motors dont just go bad by just sitting there. Unless the guy left the motor sitting outside and rust took over as jim sayd.

 

I give you props for adding oil and then doing the compression test. Remember that little thing called gravity, well it has an effect on everything. Oil ran off the cyl. walls, causing the rings not to seal. When you added the oil, the rings sealed and then began to smoke. Well, thats normal. I would not condemn the engine at all. I would have let it run for at least 20 minutes and then yanked the plugs to either clean or replace them. I doubt the walls are scored or rusted beyond repair. Also, I had the same problem with a 2001 Civic at the shop. Added tranny fluid and it ran. Smoked of course, but it ran.

 

The only problem I have with this is, the compression rose a whole lot. After adding oil, you could tell the engine sounded like it had compression. The first time it was spinning like crazy. Then, it started making a pumping sound. This was when compression bumped up to 200 psi. I know the motor isnt completely bad. However, I didnt want a motor that smoked. As it is, I have like 4 motors already that smoke. I was told that it was a good motor. For now, it is out of the car and I have no idea what to do with it.

I think I am just going to buy some engine building tools and start rebuilding.

Thanks