questions regarding spark plug thread length (Time-Sert stuff)

[Ken Keith]

Hi q-heads,

I've been trying to determine what size insert I need for my '88 
5kcstq spark plug thread repair job I have to do.  I am making 
progress, as far as data collection.

I got a hold of a Bosch Spark Plug Numbering System sheet from 
a lister (thanks, Tom!).  It describes what all the numbers and 
letters in the part number mean.  

According to it, my W7DTC plugs are:
W = 14mm thread diameter
7 = heat range (scale?)
D = thread reach 3/4" (.708" with tapered seat)
T = 3 ground electrode
C = Copper core center electrode

Okay, this is interesting stuff.  So, it sounds like I need the 14 x 
1.25 kit for these plugs, since there is only one 14mm kit offered. 

However, the only size inserts available for the Time-sert kit are of 
the following lengths.
.270
.320
.370
.430
.530
.600
.660

All of these are shorter than .750", so I'm not sure what that 
means.  I _still_ haven't gotten to measure my plug to see what it 
physically is.  I don't have much of a reason to doubt the Bosch 
info tho'.

Perhaps the inserts are available in longer sizes.  I had one 
response from a lister saying that the 15mm (.600") one was the 
way to go.  I only want to do this the one right way, if I can 
determine what it is.

Thanks again for any insight,

Ken
'88 5kcstq
'85 4ksq
'87 5kt
'94 SL2