itchybon

Hi all - I have a 97 tacoma w/3.4l v-6 engine. I'll make this short. I blew a spark plug out of the hole busting 1 of my ignition coils. Short of dismantling the head to rebore the hole the valve cover has metal tubes around the spark plug hole. The tap will fit but I can't get a socket on it into the hole because of these sleeves. a mechanic thinks they are pressed in not screwed in. If I remove the valve cover might that give me access to the sleeve. As you know on these engines the spark plug is recessed several inches so even to remove the plug you need a long extension on your rachet. If I thought I could get the sleeve out without removing the cover would be a big help. I know the problem with getting shavings into the cylinder but I'm limited financially so I'm trying to do it myself. any help would be greatly appreciated. I have owned 2 or 3 tacomas and have never seen the plug holes strip out.

itchy

Shredhead

Have You looked at a hela coil not sure if I spelled that right, but Napa has them, it took me about an hour worked great on my 93 4cyl #4 plug hole.

oakfloor

how did you blow out your sparkplug??

Shredhead

My truck was used someone cross threaded the spark plug

Toysport9601

I believe if you take the valve cover, you can actually pull those cyliders out. They will have a rubber "O" ring at the bottom of it. I dont believe they are pressed in. Some parts stores sell "thin wall" sockets. (if regular sockets wont fit) Use a 12 point socket for the tap. I am positive it will fit on the head of the tap. I have been in that position before in my Corolla. #1 plug was cross-threaded and also the EGR pipe to the exhaust manifold was crossed-threaded. Also make sure you are using the right tap. Goodluck!!

mdilligan

A Heli-Coil or some other version of the same thing will fix this almost better than new. The trick will be doing it without getting shavings in your engine if you do it without pulling the head. You won't be the 1st person to do this though, and there are a ton of backyard tricks to doing it, in fact you might even find a garage than has experience doing it this way.

One trick I've heard of is to turn the engine until the cyl you are working on is just coming up on the compression stroke (piston at bottom pf stroke, all valves closed), then pack the cyl with grease. Tap the hole and then carefully turn the engine over, if you are lucky the grease coming out of the hole should flush out all the metal chips. You'll have to do a little additional clean up to get most of the grease out of the cyl so you don't hydrolock the engine when you start it up. You might also start it without the plug in and be ready for a bunch of crap to come flying out to really get the last of it out. It'll be messy but having grease in the cyl is a lot better than chips.

Matt

itchybon

[quote=mdilligan]A Heli-Coil or some other version of the same thing will fix this almost better than new. The trick will be doing it without getting shavings in your engine if you do it without pulling the head. You won't be the 1st person to do this though, and there are a ton of backyard tricks to doing it, in fact you might even find a garage than has experience doing it this way.

guys, thanks for the tips. I pulled the valve cover but the metal sleeve surrounding the spark plug is pressed in and without a speciality tool, it cannot be removed. I have tried a thin wall socket but it won't fit. the heli-coil tap has a 19mm head which when used with a 19mm socket is same diameter as the sleeve. I have considered grinding down the tap head to fit a 18mm socket as that will go inside the sleeve. other than that, I'm tapped out on ideas.

Brian R.

This may be obvious, but if you are going to grind down the tap for the helicoil insert, it has to be done very precisely on center so that the socket will turn it on axis, and not wobbling as it cuts the threads in the head since there is very little room for side-to-side movement for the socket in the tube.

An alternative to grinding down the tap is to jig the tap and an extension and weld them together to make a long tap. At least this would give you a skinny tool that would give you some room to work in the tube.

IMO, the best way is to remove the head and pay a shop to remove and press in the tube. Then cut the threads with the head off. I don't like the idea of putting anything in the cylinder, either grease or cuttings from the threads. Anything in the cylinder (grease) is going to wind up with some of it in the exhaust manifold and cat. converter.

Shredhead

Heli coil glad someone new how to spell it, when I did mine I didn't do any thing special just used oil, once I got the initial threads I did about 1/2 to one turn of cut backed off cleaned the oil and the shavings and kept repeating the prosses.

Brian R.

How did you cut the threads with the tube in place? It sounds like you removed the tube first.

Flash75

Here are some tips on general maintenance, most apply to this discussion. If you are going to tap damaged plug threads for a Heli-coil without removing the head use grease on the tap rather than oil. Grease will catch the chips better than oil. There is no way to be sure some chips do not drop into the cylinder. After you have tapped the hole tape a length of water hose or clear plastic tubing to a shop vac and suck out the combustion chamber. If you don't use a shop vac you can tap the hole with the exhaust valves open. When finished blow out the cylinder with an air compressor, hopefully any loose chips will blow out the exhaust. It's better to have a stray chip in the exhaust then in the cylinder.

Do not remove spark plugs from an aluminun head with a hot engine. Wait until the engine cools before removing plugs. It's best to wait over-night.

Always start the plugs by hand using an extension on a good plug socket, leave the ratchet on the bench until the plugs are screwed in. You can also screw them in with a length of hose around the plug. If a plug will not screw in easily find out why and correct the problem rather than grab a bigger wrench.

20 years ago I bought a used Fiat 124 with a twin cam aluminum head. The previous owner gave me a container of anti-seize and said use it anytime I replace plugs. There are some pros and cons on the anti-sieze. The liquid lubricates the threads so you may need to consider reducing the plug torque values to keep from over tightening the plugs. Most manuals will specify plug torque but they do not say if the values are for dry or lubricated threads.

If you don't have a good plug socket with an insert to hold the plug buy one before the next plug change. Good tools are cheaper than repairing a damaged engine.

Good luck itchy.

Clifton Gordon

Brian R.

It is standard practice to specify torque on lubricated threads. Always lubricate bolt or plug threads. For plugs (or any steel bolt in an aluminum hole), use the antisieze and the recommended torque. For bolts in steel or iron, use engine oil.