miataracer

So, I am trying to get a freshly rebuilt f20c running for the first time and all was going well, spun the motor over without plugs until good oil pressure was achieved. After this, checked oil again and usual the oil level had dropped, but still on the last X. I then added oil until full, put plugs in and started it. Car fired up really nicely, but had this God awful noise coming from the top end and shut the car of immediately. Sounds almost as if the valve train isn't getting oil. Just a super loud clacking coming from the top end. Hopefully someone has some idea, because I don't...

windhund116

You adjust the valves, to spec?

Soviet

Ensure all the valve adjustment retainer nuts are there. If they are all there verify the clearances.

miataracer

That was the next thing I was going to check, but couldn't find my feeler gauges. I'm not sure that the amount of noise that I was getting could be from excessive valve lash, but I haven't heard an engine that has been way off. Hopefully it is only valves

Slowcrash_101

Oh it'll clack horribly if the clearance is too loose, it should sound like a sewing machine.

Billman250

Make sure the lost-motion springs are in place.

miataracer

Ok, so I checked valve lash and everything seems to be ok, the lost motion springs are there (assuming those are the springs underneath the middle "rocker arm"). The car turns over without plugs very nicely, smooth and quiet, but when you put plugs in and start it up, this clacking noise from what sound like somewhere in the first 2 cylinders. Really at a loss hear on where to go next

Soviet

Record a video of the sound and post it up.

Chuck S

Grasping for straws here:

Proper spark plugs? That would be NGK PFR7G-11S Stock No. 7772.

-- Chuck

miataracer

The plugs into have are the ngk ifr7g-11ks stock number 7746. I've looked at plugs to makeep sure they weren't actually touching the pistons...