Missing screw in throttle butterfly

[theultimatehero]

I bought a complete SR20 swap recently and I have been going through the installation into my s14. I drove the car that the engine was in previously and I didn't notice anything wrong with it (hence buying it), but I am very concerned about one thing. Here is a photo of my throttle:

http://i1369.photobucket.com/albums/ag204/collinseib/Janice%20S14%20Build/IMG_1857_zpsgl1esi0h.jpg (http://s1369.photobucket.com/user/collinseib/media/Janice%20S14%20Build/IMG_1857_zpsgl1esi0h.jpg.html)

As you can see, its missing a screw! I have read that this isn't entirely uncommon and that the axle itself may even be broken (have yet to remove TB to inspect). I'm wondering what I should do about this. Should I start looking around for the missing screw? Should I remove the intake mani and look around? should I be trying to stick a magnet in the spark plug holes looking for the screw? How will I know if the screw is in there somewhere causing havoc?

Mind you I have no idea if the screw came out during transport of the engine to my place, or it had been gone for years and it was run through long ago. Trying to figure out how concerned I should be.

[BoredEE]

What I would do, is pull the intake manifold. Look for it on the valves. If you don't see it pull the plugs, look for damage on the piston and for the screw. Next pull the exhaust manifold look for damage and the screw. Unlikely for it to pass but you never know.

Next slowly rotate the engine by hand and stop if you feel any binding. If the engine rotates fine, you are probably okay to reassembly and run.

Also that screw is brass a magnet won't help you.

[Kingtal0n]

What I would do, is pull the intake manifold. Look for it on the valves. If you don't see it pull the plugs, look for damage on the piston and for the screw. Next pull the exhaust manifold look for damage and the screw. Unlikely for it to pass but you never know.

Next slowly rotate the engine by hand and stop if you feel any binding. If the engine rotates fine, you are probably okay to reassembly and run.

Also that screw is brass a magnet won't help you.

perfect advice thank you on the first try

only thing I can think of besides this would be ask the supplier, maybe someone there removed it to use on another engine. I remember having 10 sr20 engines sitting around a shop, you are tempted to just grab items from them.

[theultimatehero]

I've not had a chance to take anything apart yet, but I've done some research. Let me know what you guys think.

The cams I have lift 11.5mm. So about .450". That is plenty of room in my estimation to allow that tiny screw into the cylinder. If it was running when it came out, I feel as if the screw must have gone into the combustion chamber. From there I can't imagine. If the screw held up to the combustion it could have made it's way out of the engine too. If all of that has happened the turbo would have been mangled. I'm starting to think this either happened long ago and it was dealt with, or the screw was hijacked like KingtalOn suggested.

[JC_SX]

That bolt isn't hanging around inside your sr20, it will have come loose, been sucked through the intake/head and exhaust without more than 3 seconds passing it would be through to the turbo/exhaust, I'd doubt you're turbo would be damaged or the engine as it would be a nice bit of metal of small size that probably found its way to the exhaust down pipe within seconds of being loose,
I've been behind turbo cars throwing chunks of flaming metal as they det and shave Pistons rings, valves and Pistons out the exhaust under load, I remember a mates Renault 5 doing exactly that whilst following him on a spirited drive, by the time we got home his engine had shot itself out the exhaust.
Surely worse case is its lodged in your inlet manifold as its to big to be atomised and injected!


JC SX

[jr_ss]

The screw is not brass. Its just the typical cadium plated steel bolts/screws/nuts/washers Nissan uses on all of their engines. Boroscope would be the easiest solution to look into the cylinders to inspect for damage. I'd be on the hunt for it, however, generally when the shaft cracks its the one closest to the pulley, not the one next to the TPS. Loctite the new screw back into place or tack weld the head to the shaft.

[anti tyler]

The screw is not brass. Its just the typical cadium plated steel bolts/screws/nuts/washers Nissan uses on all of their engines. Boroscope would be the easiest solution to look into the cylinders to inspect for damage. I'd be on the hunt for it, however, generally when the shaft cracks its the one closest to the pulley, not the one next to the TPS. Loctite the new screw back into place or tack weld the head to the shaft.

Exactly, don't just to dismantling things unless you seriously feel the need to.

That screw is either long gone or floating around nearby. Pick yourself up one of the 9mm inspection cameras advance auto parts sells and get yourself acquainted with it.