e-z lok for spark plug thread repair

arborlicious

arborlicious

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Blue Mountains Australia
I'm repairing MS661 cylinder that has stripped spark plug thread. Time-serts look to be a great option but they're very expensive - tooling wise anyway.

I see some have successfully used the thick walled e-z lok solid inserts (pioneerguy600) and I'm wondering about technique and tools for drilling and tapping. I'm assuming you have some sort of jig for drilling? Or is there some way to do it with a special set of STI taps - I doubt it. Drill size is 11/16".

I'm looking at the e-z lok 329-1406 inserts which are 3/8" long and have the M14-1.25 internal thread and 3/4"-16 UNF external thread. Also, the e-z lok spark plug inserts don't use the regular driving slot so how do you install them?

Steve
 
pioneerguy600

pioneerguy600

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Yes I have an adjustable angle vice clamped to either a heavy drill press or the mill. I have a rod that fits in the chuck to indicate the angle the current plug hole sits at, once set then I replace the rod with the drill bit and drill it out. The special Time cert setting tool will work with all the inserts I have used so far but the threaders are all different from one insert to the others.
 
arborlicious

arborlicious

ArboristSite Member
Joined
Jan 19, 2014
Messages
86
Location
Blue Mountains Australia
Yes I have an adjustable angle vice clamped to either a heavy drill press or the mill. I have a rod that fits in the chuck to indicate the angle the current plug hole sits at, once set then I replace the rod with the drill bit and drill it out. The special Time cert setting tool will work with all the inserts I have used so far but the threaders are all different from one insert to the others.

Thanks for the info pioneerguy600. I've decided to go for the cheaper option and use a heli-coil. I know they're troublesome for spark plug thread repair but I don't have a drill press or milling machine handy.

The product I'm using is the powercoil brand and comes with a kit including the pilot nose STI tap which I'm managed to thread in successfully - there was enough of the old threads to get the tap lined up nicely.

I'm thinking to use some high temp RTV on the insert to make sure it seals properly–don't want to lose compression.
 
pioneerguy600

pioneerguy600

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Thanks for the info pioneerguy600. I've decided to go for the cheaper option and use a heli-coil. I know they're troublesome for spark plug thread repair but I don't have a drill press or milling machine handy.

The product I'm using is the powercoil brand and comes with a kit including the pilot nose STI tap which I'm managed to thread in successfully - there was enough of the old threads to get the tap lined up nicely.

I'm thinking to use some high temp RTV on the insert to make sure it seals properly–don't want to lose compression.
That will likely work fine for you, I usually seal the inserts in with JB weld just to make sure they don`t leak around the threads and not likely to back out.
 

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