L3mur

Hey guys,

This winter I put a vvt head on my 96 miata and changed the clutch/flywheel. I followed the megasticky for vvt engine swaps and found it very helpful, but now I'm having an issue on startup. Initially when I tried to start it the timing was off and the car would not start. I triple checked it on the engine stand, but did not rotate the motor over twice before adding tension. I think that is where I made my mistake. Now it is retimed and the car started on the first try. The problem is that there is a very loud metallic noise.

My thermostat housing cover cracked and I am waiting for a new one, so I figured I would do some more research until I can work on the car again. The noise appeared to be coming from one of the cam gears. It didn't get louder when I opened the oil fill on the valve cover. I didn't get under the car with it running yet to listen there(possibly clutch flywheel install related). I'm guessing I damaged a valve trying to start it with the timing off(non interference motor though?) or the vvt actuator is messed up. The VVT actuator has oil going to it. I ran a 4an line from an oil filter sandwich to the threaded port right below the factory inlet. I took the line off to confirm oil is in the line. Also I thought no control of the vvt may cause this, but found some examples of people running it that way with no issues.

Not sure if specs will help, but here they are
96 block
used vvt head purchased on here
stock 96 cam and crank sensors until i get it running right then install my MS3 and nb sensors
vics manifold
96 coil pack mounted on modified valve cover
oil line from oil filter sandwich for vvt supply

Anyways, heres a video. Any feedback would be greatly appreciated.

https://flic.kr/p/G7xUGL


miata vvt head by matt taylor, on Flickr

curly

iTrader: (25)

You're machining something in there. Check the front main pulley. Sounds tinny like the trigger wheel.

patsmx5

iTrader: (16)

My guess is a bent valve, or you spit a shim on one of the valves. A compression test would shine some light into this.

Twibs415

iTrader: (8)

the sound is too fast imo to be cam related. i would yank all the plugs and spin the motor by hand and see if you feel it in the crank. did you happen to use arp flywheel bolts or an aluminum flywheel?

L3mur

I installed the flyin miata happy meal and reused the oem clutch and flywheel hardware torqued to spec.

After hearing Curly's tip I took a look at the crank pulley/trigger wheel. The crank sensor was set too close and was making contact with the trigger wheel! That may have been the noise. I adjusted it to credit card distance. Pulley looks fine.

I did a compression test and came up with a different issue. Compression numbers seem ok #1 158, #2 170, #3 170, #4 165.

When testing cylinder 4 last, air was coming out of cylinder 3. I tested number 3 again and it was still 170. Then I moved to 1 and the air was coming out of #3 again. I wanted to try testing cylinder 2 again, but ran out of battery. If a valve was sticking open or the headgasket was shot wouldn't that cylinder read low? I'm doing some googlefu right meow. Any idears?

patsmx5

iTrader: (16)

Good comp, engine is fine. The air moving around is probably because the two cylinders in question both have their intake or exhaust valves open at the same time and it's leaking across. Nothing to worry about.

L3mur

Thank you for the help everyone. This is all uncharted territory for me. Learning a bunch