Tuner@Swift

iTrader: (1)

Background: Just finished my 2.3l build which started right up and ran great for about 30 mins. While checking for leaks, I discovered that my water pump was leaking coolant from the shaft. I shut the car off and let it cool down to ambient temps, then retorqued the head studs. A few days later, I pulled the timing belt off and replaced the water pump. When I went to reinstall the timing belt, I noticed the intake cam gear was able to rotate about 30 degrees independent of the cam(MIVEC cam gear, capable of 30 degrees advance). It had never done so when installing the timing belt before so I assumed it had lost hydraulic pressure in the gear itself. I removed the cam gear and tore it down to see if any of the 4 oil seals had given out or if anything was broken internally. Everything seemed fine, so I reassembled and put it back on the cam and reinstalled the timing belt. I rotated the crank 8 times and made sure timing was correct. When I tried to start the engine, it acted like it was very low on compression. I checked compression on all 4 and got 20 psi from all of them. I then did a leak down test on cylinder 1 at TDC and it wasn't holding anything. I could hear air out the intake valves. Assuming the worst, I pulled the head to check the valves and make sure I didn't totally **** something up and bend a valve or worse. Valves were perfect, pistons had no play (rings seemed good) and there was nothing wrong with the gasket. I inspected the head closely and verified valve position compared to cam timing marks. With the intake cam marks aligned to TDC, the intake valves were open almost 1/4". If I retarded the cam 1-2 teeth, the valve would fully seat.

Now for my question: With the intake cam aligned TDC, shouldn't the intake valves be fully shut?

The only thing I can think of is that I may have reassembled the MIVEC gear wrong and now the intake cam is advanced when it should be at 0deg. Does this seem possible to anyone else? Or am I completely retarded?

TTP Engineering

iTrader: (465)

It seems the mivec gear has no oil pressure. Did you prime the oil pump?

Tuner@Swift

iTrader: (1)

MIVEC only needs oil pressure to advance the cam. With no pressure, the cam will be at 0 deg advance. I think that when I put it back together, I put the vane rotor in upside down/backwards which put the bump stop (circled in red) on the wrong side, which would force the intake cam to rest about 1-2 cam teeth advanced.

crcain

From memory, when the intake and exhaust cam gears are lined up with the valve cover marks, and the crank is at TDC for cyl 1... I'm pretty sure this means cyl 1 is between the compression and power stroke... however if this was the case, all valves would be closed well before TDC and well after TDC.

Only other possibility is cyl 1 is between exhaust and intake strokes, and in this case, at TDC between exhaust and intake, both valves should be slightly open (overlap), with the exhaust valve closing just after TDC and intake valve opening just before TDC.