I few weeks ago i posted that my 914 sounded like a harley...with little power. i have now discovered why. I found the spark plug still coonected to the plug wire floating around beneth the fuel injection system?...I tried to reinstall it but nope!...no bite in the threads. Is there a cheap easy fix...or dare I say it...a larger diameter plug I could make work until i can re-do it?

Helicoil


It is temporary though. You will need to take your head to a machinist or replace it eventually.

I had to fix one at the racetrack once. My dad had cross threaded it the day before but didn't really say anything. At the track the plug blew out as I was full throttle on the front straight.
It was loud.
I hauled butt to the nearest auto parts store and bought a time-sert kit. A time-sert is like a heli-coil but it's solid, not a spring. I spread a thin layer of grease on the tap and tapped the hole, installed the insert, and ran the engine for a couple minutes with the spark plug out to blow any chips out the hole.
It was still loud.
I put the plug back in and it ran fine. I rebuilt the engine a couple of years later and there was no sign of any scoring or damage in that cylinder. The time-sert was good enough that the machinist that built those heads told me to just go ahead and time-sert the other 3 holes myself. It's been 8 years and they are still good.

Go with the Time-Sert. It's a much better piece than a Heli-Coil. I had a Heli-Coil let loose on my John Deere head and it tore up the threads.

.....and the reason the plug blew out was more than likely because of the crack that you'll find in the chamber leading up to the spark plug hole.

I blew 2 plugs once on my VW when a heater hose blew off. I overheated the head and both plugs shot out. I did the Time-Sert. Worked great. I would look at why it blew. Cracked head or cooling issue?

I was thinking about the reason......anything I do will just be a bandaid. Might need to look for another motor as I have no idea what this one has been through.

If it has 1.7 heads it may be cracked. If it has 1.8 or 2.0 914 heads I'd bet a Varsity dog it's cracked!

That's why I suggested the Helicoil as a temporary fix. They are usually half the price of a time-sert kit and there's no reason to spend extra $$$ on something that you are going to replace anyway. I had this trouble on my 71 Super Beetle and used a time-sert to fix it. But that also blew out. When I took my head off... yep... cracked.

Only time I've seen an insert work is when somebody cross threads a spark plug into a head and when the plug is removed, the threads come with it...

Worked for me on my bug. The dealer had a small round plate with a threaded insert on it, They tapped the hole, threaded the insert into the hole until the plate was against the head, and punched a dimple or two into the plate and the head.

Car ran fine for 250K.