Good morning.

I'm changing out the plugs on my 93 Vette. Everything has been going smoothly (blood, sweat and tears.. but mostly blood..lol). except for one stubborn plug. It is for cylinder 7 on drivers side (closest to fire wall). The old plug was removed easily (didn't force it, broke free nice and came out easily). I can't for the life of me get the new plug in. Trying different angles, etc. but it just isn't catching. Any suggestions, help. Really want to get her back on the road for some fun summer driving.

Thanks.

 

Have you tried using a piece of vacuum hose?

 

What do mean a vaccuum hose?

 

You attach it to the wire end of the spark plug and use it to twist the plug in. This allows for almost impossible angles and really presents no force to push the plug in a direction it doesn't want to go. It will also not transmit enough torque to strip anything.

Also, have you tried starting the old plug back in? It is a very low probability, but the new plug may have a damaged thread lead.

 

Why not try several different plugs. Sometimes part tolerances work against you. If the old came out easily try putting it back in to get the feel of how it should be

Using a piece of vacuum hose per bigc55 is a great suggestion, especially around the AC compressor.

 

My C4 is by no means stock, but I access #7 from below.

 

I pulled the ASR out of the way and all the drivers' side plugs were easily accessible. Did have to use a swivel on #7 but no big deal to hand thread the new one in.

 

This. Also, depending how agile you are, I have found that the back two plugs on the PS are much easier if you lay across the engine, from the DS, and reach down. It sounds strange, but works like a charm.

 

I would try:

1) Screwing the old plug back in - if it goes in pretty easily - assume you have a buggered new plug and go get another new spark plug.

2) If the old plug doesn't go in easily either - I would assume that you may have a bit of damage to the cylinder head threads... Don't panic - there are two or three ways to deal with this...

a) Get a spark plug thread chaser from the parts store - they are meant to fix exactly this situation - screw it in gently by hand to get it started - then once it's started - you'll need a wrench or a ratchet / socket to screw it the rest of the way in.... (Ideally you can start it by - holding it in place perpendicular to the angle of the plug - look at another cylinder for reference, and turn the chaser slowly counterclockwise till you feel it "drop or engage the thread - then turn it in - clockwise gently)...That thread chaser should gently "fix" the problem area.

b) I don't know the company name off hand - but there is a company that makes a very specialized tool that slides in the spark plug hole - then an expanding mandrel pushes a thread chaser radially outward - so it catches the spark plug threads on the combustion chamber side of the head - and chases the thread from the inside out.

c) An old mechanic I knew would sometimes use a 1 X 42 belt sander to put a more exaggerated lead in chamfer on the front of a bolt in those occasions where the bolt would just not want to engage the female threads (or where a bolt had to be "shortened" a bit). You could do the same with the recalcitrant spark plug - using a small triangle file ... What do you have to lose.... Again - install the plug by hand to avoid cross threading...

My bet is that a new plug will fix the problem....

 

Try the vacuum line trick first. Use 3/8" i.d. by about 5" or 6" long. I use it for removing plugs, too. That keeps you from dropping a plug! Works wonders!

 

….. … Same here , My Gen 1 Dart block utilizes a drivers side dipstick and tube that goes right between the #5 & #7 header tubes … its just easiest to get 5 & 7 from under the car …..