helicoil tap without removing the head?

[motitties]

So I just tapped the head and installed a helicoil on my tired old EJ22 and I did it without removing the head.... Am I an idiot for doing this? I used gear oil to thread it, hoping the higher viscosity would retain more of the shavings but I'm sure there's still a helluvalot of shavings in there... should I just crank 'er over and pray it blows out the exhaust valves or try to find a way to vacuum that crap out of there?

[PhyrraM]

I'm assuming your tlking about the spark plug.

Set the motor to a postion where all valves are closed, then use a compressed air blowgun to blow everything out of the plug opening.

If you think that some of the debris might be sticking because ot the gear oil, then blow some brake fluid down the hole and evacuate with the compressed air. Wear goggles, of course.

Do this until your sick of it, then do it again with the motor in a different position.

Sooner or later, you will feel pretty confident that you've got it all. Then blow it again with the valves open and the rings/pisting in a different position.

Should be good after that.

[motitties]

I didn't take any consideration to valve position before I started this job... oops... seeing as it's a horizontal cylinder, I might have just dropped a bunch of shavings on to open exhaust valves...

[Legacy777]

I had a similar issue on my Impreza

http://bbs.legacycentral.org/viewtopic.php?f=5&t=48064

Just for future reference grease does a better job at catching the shavings.

As for getting the shavings out, drop the exhaust manifold, get it so the valves are closed and spray brake cleaner in through the spark plug hole. Once you've almost filled the cylinder, rotate the engine quickly so the exhaust valves open up. This will allow the shavings and any other nastiness in the cylinder to be washed out. Put a drain pan under the engine to catch the backwash. Do this one or two more times until you feel all the shavings are out.

This is what I did with the Impreza. I tapped too far in and the grease blob with shavings fell into the cylinder. So I pulled the exhaust manifold and flushed with brake cleaner. All was good.

[motitties]

First of all, thanks to both of you for the good advice.

I opted to drop the exhaust manifolds seeing as it's stuck at the end of my driveway. Good thing i did because the exhaust manifold nuts were not much more than hand tight! So I replaced the gaskets and fixed 'em.

So I followed the procedure of closing the valves /filling with brake cleaner/ purging the cylinder via exhaust valves... i hope i didn't get that backwards though....

So I start'er up and there's a bit of pop/sputter for a second (assuming that's the brake cleaner burning out), I rev it up a bit and it runs fine for a couple seconds... I let it back down to idle and its missing on one cylinder. Rough idle and dies.

Now I'm inclined to think its an ignition problem. So I remove the plugs from the plugs from the problem cylinder and the one adjacent. Resistance readings are similar for both plugs and are properly gaped. However the plug from the problem cylinder already has a lot of oil/gas/gunk buildup around it. This leads me to think that it might be a compression issue? Perhaps the helicoil did not fully seat? The crush washer seemed to flatten as it should but I dunno... swapped both plugs and same issue...

[motitties]

Thinking back on it.. that plug went in way too smoothly by hand.... any chance I got an insert that just didn't match up with the plug? There a pretty tight tolerances there.

[Legacy777]

Does it tighten down ok?

[motitties]

it hits the bottom very abruptly... (not feeling the threads) doesn't feel like the crush washer is crushing although it appeared to have when i pulled out the plug..

Not sure what to do if i didn't get the coil seated far enough... I might have been a bit too careful threading it in. Its hard to see, but the coil does look a bit higher than where the plug should seat. The more I think about it.. maybe I didn't get the thing in there far enough... its threadlocked now though...

the threads in the head (helicoil) need to pull against the threads of the spark plug and thus the crush washer to create a seal all the way up right?

any ideas are appreciated!

[Legacy777]

What I would suggest doing first is do a compression check on all the cylinders and compare the one you repaired to the others. Or you could try and do a leak down test on that repaired cylinder to see if the repair appears good. The crush washer should "crush" against the helicoil and seal...unless the helicoil doesn't have a stepped edge and it's just a "thread" repair and the seating surface where the plug seals is supposed to be on the head....

If that's the case, then I'm not sure.

I will say that when I repaired my Impreza, the car surprisingly ran fairly well. It was only on occasion I would notice a little more of a rough idle. So if the car is running very badly or won't run....maybe you've got another problem. Did you try checking the resistance of the plug wires?

Do you smell exhaust fumes in the engine bay as if the fumes are leaking by the plug?

[motitties]

ok, so i replaced all four plugs and gaped them on the conservative side... and now it holds an ok fast idle but a rough low idle... it did have a sorta rough idle before but it's worse now. I made a temporary fix by manually adjusting the throttle position set screw. But I know that's only masking the real problem(s). I'm thinking that a compression test is probably the best way to sort this problem out. Hopefully those shavings didn't do a number on a valve seal or something...