Dropped A Valve Any Bright Ideas Lol?

[boostn0199]

I was doing the valve springs with the head on using compressed air to hold them up and as I was putting spring back on the cylinder moved down and dropped the valve and now the cylinder is at the bottom with the valve down there, Ive pretty much prepared to take the head off now but just going to ask before I do if anyone has any ideas. <div><br></div><div>And also if Im taking head off what head gasket should I go for, stick with the stock rb25det or aftermarket metal one and what thickness?</div>

[STATUS]

magnet on end off coat hanger down guide.

[boostn0199]

How strong does the magnet have to be? And should I take the seal off or leave it on, because I was trying pull it off and it doesnt come off

[jiffo]

As suggested, magnet down valve guide plus go to Supercheap and buy one of their $129 borescopes which will fit down the spark plug hole.

You'll need someone on the crank to slowly and accurately bring the piston up, remembering the valve will need to lean over a bit, not straight up and down.

It's worth putting some time and effort into it as the head off will really add expense, you'll decide to get the head done up while its off................

Once you get back into it, don't just rely on the compressed air to hold the valves up, get the piston up and have someone with a socket on the balancer hold the crank for you. (as the air tries to push that piston back down)

[boostn0199]

Where do you find a magnet that small and that strong. I put one down the spark plug hole and it doenst pick it up.

[Dobz]

Someone must make a telescopic magnet small enough to fit down the valve guide. A good trick I was taught was to feed a bunch of the thickest nylon pull starter cord you can get into the cylinder through the sparkplug hole, enough so when you push the piston up to tdc it puts pressure on the valves to hold them up. Just make sure you leave a good length of cord out so you can extract it when you're done.

[boostn0199]

Wtf the magnets dont stick to valves?

[STATUS]

should stick to the rb25 ones, wont on rb26 though.... maybe the later r33 used a different stainless which is not magnetic.

i quickly ran out back (before posting my reply above)to test the rb25 head i had here with my snap on telescoping magnet and it picked up the valve.

[Rolls]

Where do you find a magnet that small and that strong. I put one down the spark plug hole and it doenst pick it up.

pull apart a microwave lol, those ones are ridiculous, might need to cut it up though.

seriously though you should be able to buy a rare earth magnet that is small enough.

[turboedsloth]

kincrome do a small strong telescopic magnet

[boostn0199]

Just checked with 3 different magnets on the valve that is out and unfortunately mine is not magnetic. Looks like only choice is to rip head off.

Any headgasket recomendations?

[discopotato03]

Some will think differently but really the best situation when aiming for aftermarket springs and cams is to lift the head off and get it freshened up . The reasons being that head gasket sealing on a well loved engine can become marginal when looking for more revs higher boost etc . Things like valve guides and seats (valves and chamber seats) can be worn and not want to seal properly .

With my 33 25 I bought a second hand head , thanks woolaf , and had it all done and changed over complete .

That way I know the guides/seats/gasket will seal . I did want a bit of porting/bit off its deck/larger exhaust valves/wire rings fitted so was all done and changed in one go . Actually the belt/idler/tensioner/oil seals/water pump were done at the same time because it was around that mid 80 000 stage and was due anyway .

Yes air pressure pushes pistons down if there is nothing to stop the crank turning ie in 5th gear or a socket and bar on a crank pulley bolt if you can get at it .

I know its easy to be wise in hindsight but this was a bad time of year to take on a job like that because if something stuffs up the machine shops can be reluctant to take it on just before christmas .

So unless you fluke it quickly and thread that valve back up its guide I'd be begging your local machine shop to freshen up the head if you can get it to them quickly .

If you have alternative transport I'd pull the head off and do it properly - after inspecting everything and having it all close to factory tolerances . I'd still do my best to get 3 thou cut off the deck so that the head gaskets sealing rings have fresh material to crush against and seal properly .

Old adage , do it once do it properly and have no dramas .

A .

Edited December 21, 2010 by discopotato03

[blk94r33]

Where do you find a magnet that small and that strong. I put one down the spark plug hole and it doenst pick it up.

Next option, not sure if it'll work, but get something you can feed through the guide with super glue or a good adhesive on it, then pull the valve back through?

And for future reference, always have the the cylinder your working on on TDC with a bar holding the crank before you add compressed air... So if th valve falls in it can't go all the way into the cylinder...

[boostn0199]

Some will think differently but really the best situation when aiming for aftermarket springs and cams is to lift the head off and get it freshened up . The reasons being that head gasket sealing on a well loved engine can become marginal when looking for more revs higher boost etc . Things like valve guides and seats (valves and chamber seats) can be worn and not want to seal properly .

With my 33 25 I bought a second hand head , thanks woolaf , and had it all done and changed over complete .

That way I know the guides/seats/gasket will seal . I did want a bit of porting/bit off its deck/larger exhaust valves/wire rings fitted so was all done and changed in one go . Actually the belt/idler/tensioner/oil seals/water pump were done at the same time because it was around that mid 80 000 stage and was due anyway .

Yes air pressure pushes pistons down if there is nothing to stop the crank turning ie in 5th gear or a socket and bar on a crank pulley bolt if you can get at it .

I know its easy to be wise in hindsight but this was a bad time of year to take on a job like that because if something stuffs up the machine shops can be reluctant to take it on just before christmas .

So unless you fluke it quickly and thread that valve back up its guide I'd be begging your local machine shop to freshen up the head if you can get it to them quickly .

If you have alternative transport I'd pull the head off and do it properly - after inspecting everything and having it all close to factory tolerances . I'd still do my best to get 3 thou cut off the deck so that the head gaskets sealing rings have fresh material to crush against and seal properly .

Old adage , do it once do it properly and have no dramas .

A .

So are you saying I have to get the head decked? How much does it roughly cost? Still no idea what head gasket to go for.

[discopotato03]

The surface of the heads deck gets compressed slightly by the gaskets fire rings when the head is bolted down . To get a new working surface you need to take a light skim off it if you want good sealing because it won't compress twice . I'm only talking about 3 thou assuming the head is straight to start with .

My experience is that Genuine Nissan head gaskets are good things but its going to depend on what you're using your engine for .

A .

[Adriano]

Is it inlet or exhaust, i would pull the manifold off, and use whatever you can to try and get the valve back up. $165 for a boreoscope would be very handy, and you can easily sell it when done. 5 min araldite on a bit of wire to pull the valve up,

[Beer Baron]

adriano is on the right track. needs a bit of lateral thinking done here. its like the problem of getting the pen cap out of the bottle without disturbing the bottle etc (fill it full of water and float it out). pls don't try that example though! but I'm sure there is a way to get it out and back up into the valve guide.

[boostn0199]

I had the borescope and tried for hours since my valves are not magnetic it is even harder so oh well Im taking the head off. It took me couple of hours to get it all off and I spent about 5hrs mucking around trying to get the valve. Ill be going for max about 300kw 18psi on e85 and Im leaning towards using the nissan headgasket as one in it at the moment from day 1 has lasted at this power I dont see why a brand new one wont.

Ive read alot of problems with cosmetic ones and the jap ones are ridiculously expensive and considering on just jap they have a complete engine gasket kit for $380 looks like value for money and will probably get away without needing to deck the head with the standard head gasket.

[Thelen]

For magnets: http://www.thinkgeek.com/geektoys/science/770f/ is cheap and will do the trick. SAU should probably just buy a bunch of them and give them out to members at some cruise/meet.

Or some bright chap could work out also how to make a kit out of it (ie the coathanger with magnet glued on or something) >_>

[discopotato03]

Again your call but the head is/was off and thats the time to make sure everything about it is to at least factory spec or better . I'd always worry that the new gasket wouldn't seal reliably long term if the head wasn't skimmed and if it doesn't its got to be done again . Easy for me because I have other cars I can drive and as I said I bought another head so everything could be done at my leisure . I must chase up the original 33 one because its in good nick and sell it .

A .