Stripped plug!

[batmmannn]

Well I pulled #5 plug and as feared it is all to hell. Stripped? JB weld on it? Not sure. Looking down into my plug hole I see that it has some sort of lip 3/4 down either from some gunk that was put in there or from being stripped. I don't know how it could have what looks like a solid lip in the threads if it was stripped. New plug starts in there fine but apparently won't tighten down. The plug look strange like the threads are filled with goop rather than sheared off. Took forever to get out of the block, Do I get a die and try to run it through or am I screwed and have to pull the motor take the block to a machine shop? Or do I just say screw it and part it out? Disgusted now. Scott


I found this info, maybe I can run a tap through and be fine. Seems I have encountered a plug that has welded itself to the block....Lucky Me! I bet number 4 and 3 are the same way, might as well pull the heads and do the HD as well. This is what happens when you design a car that people can't get to the plugs on they don't get changed like they should. Looks like this turned into a summer project. DAMN!



A: There are a number of ways to repair stripped threads. In fact, it may be possible to simply chase the old threads with a tap and clean them up. Or, as illustrated, you can insert a Helicoil. There are several types of repair inserts, but we prefer Helicoils. I'd give your mechanic a shot at fixing the threads before I held his feet to the fire. When a spark plug has had a chance to marry a cylinder head for 100,000 miles, it's not uncommon for the aluminum threads to come out of the head with the plug. (I pull and inspect plugs every couple of years and reinstall them with a small dab of antiseize compound, but that's another column.)

A proper thread repair should last as long as the life of the car. This type of repair can be used for almost any threaded fastener, by the way. And that includes cast-iron, steel and aluminum parts. Warning: Installing a Helicoil or other threaded insert looks simple -- but it's not. Any readers out there who wish to attempt it might want to practice a couple of times on scrap parts.

Start by threading the special Helicoil tap into the remaining threads in the head. This is to ensure the new threads are concentric and parallel with the originals. Continue threading the tap in to cut the new, oversize threads. To avoid getting aluminum chips in the cylinder when retapping the threads, you should coat the tap with grease. The chips will stick to the grease and come back out with the tap. Back out the chip-laden tap, and clean up any remaining chips.

I've also filled the cylinder (before tapping the hole) with oil-soaked clothesline to catch any chips -- but that was in a racing engine with a squish band only a few thousandths of an inch deep. Street engines with a more normal compression ratio should be fine if you are careful, and blow the chips out with compressed air. Mostly, you don't want any chips to find their way out the exhaust port and wind up in the catalytic converter.

Now you can thread the appropriate-length coil over the installation mandrel. There's a raised flat on the mandrel that will catch on the tang in the coil, allowing you to thread the coil into your new threads. The coil is a little bit bigger than the threads, which will keep it in place when you're finished. The tang will pull the coil into place from the inner end. Once the coil is in place, remove the mandrel.

Now, use a pair of needle-nose pliers to break the tang off. It's prescored to break off cleanly and easily. Do NOT drop the tang into the cylinder! A few aluminum chips will not damage your engine, but a 1/2-in.-long piece of sharp stainless steel wire will tattoo the top of your piston and the combustion chamber before it finally gets out past the exhaust valve.

[cre]

As I think you've found now that you've dug a bit more, this isn't a "part it out" type of problem... quite repairable. Given that I can't look and see what you're dealing with my first suggestion would be to try a tap to see if there are threads still present and if they're just distorted... then, if need be, use an insert repair. My preference is a timesert, but yes, there are many different options.

[batmmannn]

You are right Cre, we humans sometimes throw our hands up in despair and cry why me oh lord, WHY ME??? But then I found that info and I called Auto Zone and for $10.00 and a trip to town I bought a thread chaser part number 25155 put some oil on it and chased the threads through. #5 plug is now in and tight! I will read your link though because though it is in lord know what I will find in 2, 3 and 4. Those must be some old plugs under the plenum. I will be taking the rest of the plugs out and doing the valve covers and taking a compression test I suppose. I just want to get it running again before I do all that. I ordered a fuel pump from Ebay and will do those diagnostics now. Looks like I have to buy a roll of vacume line and replace the vacuum lines just cause they look dry and possible might be leaking. Here is a pic of the tool I used.

Question: If they recommend blowing out the cylinder with compressed air don't you need an exit for the air to push out any fragments or bits or do they just hopefully come back out the spark plug hole? Wow sorry I found another thread on here about this but they didn't mention the chaser so I guess it's good that I did, also read about the vacuum and small hose technique. Thanks

[cre]

Be careful with eBay parts... a LOT of cheap Chinese knockoffs and poorly made refurbs floating around out there. There are some things I will never buy off eBay (unless it's the eBay site of a regular store which I trust): oil pumps, fuel pumps, injectors, tuning devices... critical components.

[batmmannn]

I got one for $30.00 shipped and the guy at autozone said i had the same part number as the one he was selling for $140.00 Here is the link. Is this junk? Thanks
http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWNX%3AIT

[cre]

Just because the post the same part number doesn't mean it's the same part... a LOT of companies post the part number used by competing manufacturers so you're more likely to see their product too and to show that it's compatible.

I can't comment on whether that pump is any good.. I have no idea who actually made it. It could be a great pump, just no way of knowing other than dissecting it when it comes in.

[907mge]

I'd recommend rockauto.com. I've ordered from them a few time before and never had a problem. You can get name brand parts at prices far less than advance and auto zone. And you can aways cross reference part #s.

[batmmannn]

Thanks 907 mge I will check them out, but I guess I will try the cheap one out and see how it does worst case senario I have to change it in a year or two but this car will get occasional use at best and at that price I figure it is worth a try. Just not too much money right now to throw at these cars. Luckily I bought a full head gasket set years ago when these problems developed. Now I need to find it and pull gaskets from it for what I need to do. I still don't think I have blown HG in either of them so I am hoping to just get them fixed up and running and perhaps rebuild them later or sell them both and get something like a 90 or 91 turbo somewhere. We'll see. If I can fix them both I might just hang onto them. I am not into all the speed like I used to be. I am a single Dad with a 7 year old and I have a full sized Batmobile being put together in CA that I will need to finish assembling. Thank Cre! I got the Plenum off the Black Supra and posted pics in that thread for the valve noise. Scott

[batmmannn]

#5 plug is still not right I am looking at a helicoil now has anyone done one is it difficult to do? Is it expensive? Can I do it by just pulling the plenum? Please chime in guys. Thanks