Messed up Plug threads
 

I went to change the plugs and wires in my 74 914 the other day. Unfortunately the #1 plug wouldn't tighten properly. Upon examination, it looks like there was previous damage to the threads. I am under the assumption that I now need to drop the motor, pull the head, and re-tap. Is ther another fix that will allow me to do it in the car?

Use a Time Cert to repair the threads, it can be done with motor together in car, but it is a bit of a pain, and care must be taken to keep the chips out of the motor.

The TimeCert is superior to Helicoils for this repair, I never had a timecert fail, had many a helicoil back out with the plug!!!

easy fix SmileWavy

go to your nearest VW parts store & buy a set of EMPI 00-4013-0 inserts

and the plug insert tap to go with 'em - or buy a KD 2123 tool on eBay

use soap on the threads as your re-cut so the chips don't fall into the cylinder

been done thousands of times with excellent results by thousands of VW guys :D

I would suggest using a very strong light and maybe even a Harbor Freight Bore Scope to look at the head area around the plug hole. There could be small cracks forming and if they spread then they could get to the valve seat area........

To expand on the cracks issue, several years ago my buddy Ted and I were doing a vintage race at Palm Springs and in the first practice session he blew a plug out of the engine in his 356. He used his handy tap and insert to repair the thread holes. In the second session he blew another plug and repaired it also. In the Sunday morning session he blew out another and did the fix on it also. All of these were done with the engine in the car! During the trophy race Sunday we fully expected him to loose the last one but.......he got the right side wheels off the pavement into the sand and rolled his car! Later in the week after pulling the engine and both heads, he found numerous cracks in all four combustion chambers so off to Tuttle's for weld repair.

I would be pulling the motor and doing that plug thread with the cylinder cooling tin off ,a type I is better cause it is closer to the tinware and easier to get the tap fully square to the hole.
Get this wrong and its a top end strip down on that side anyway,then you may as well go further.......
If you do it in situ take your time as do as John suggests,good luck.

We will be pulling the motor tomorrow I hope. I think it will be much easier. And I have a lift so the engine drop should be easy enough.

Why put 1/2" plug insert in a 3/4 in plug hole? Why not do the repair correctly the first time?

I have the Empi inserts, I used them back in the early 90's on T1 heads, the size you have to drill them to is way too big and had them back out the hole. Personally I'll never use them again as it's a poor repair.

Timeserts do a far superior job and they lock into place.

curious - my EMPI inserts are 14mm - same as oem plug size


3/4" is almost 18mm - ?? not oem size on any Porsche or VW I have ever owned

but on some Fords, old bikes and outboards - yes

it depends entirely on one's budget & desire to get back on the road

- and the perceived value of the car :D

.

Uhhhhh, he was speaking of the length of the insert. T4 heads take a 3/4 inch long insert, T1s use 1/2 inch long inserts. They don't interchange. BTW, 3/4" is 19mm, not 18.

The Cap'n