Hello all, I recently had a spark plug pop to discover the hole had been helicoiled. My mechanics tried to do a second but it just keeps popping. Opinions needed here: should I a) send head to machine shop for repair/new spark plug hole or b) get a replacement head? Many thanks for your opinions. Cheers, Marko
1975 Shadow: spark plug pops out and helicoil issue
1 - 20 of 22 Posts
Joined
·
1,079 Posts
Google time sert and you will.
Joined
·
740 Posts
Here are some videos, watch the 6 one from the top.
You may want to contact them and make sure that the hole is not already to big for the insert, but unlikely since the insert will require a bit more removal then it took for the Heli-coil.
Is the Heli-coil still in there ?
++ TIME-SERT Screw thread inserts. Threaded bushings for stripped threads repair threaded bushings inserts for stripped threads insert thread repair (timesert.com)
You may want to contact them and make sure that the hole is not already to big for the insert, but unlikely since the insert will require a bit more removal then it took for the Heli-coil.
Is the Heli-coil still in there ?
++ TIME-SERT Screw thread inserts. Threaded bushings for stripped threads repair threaded bushings inserts for stripped threads insert thread repair (timesert.com)
Joined
·
1,079 Posts
Go to the Time Sert website, they have data on drill sizes needed for stripped out holes. You will likely need what they call a Big Sert thick wall insert, all info is on their site.
Joined
·
740 Posts
Still very difficult to get it square into the head, plus any bit that has to drill such a large hole will grab that soft aluminum and want to go sideways.
It's almost a job where one would have to clamp the head in a proper drill press or milling machine to do it right.
It's almost a job where one would have to clamp the head in a proper drill press or milling machine to do it right.
Joined
·
252 Posts
I vote for "b" (worse experience than yours with a helicoil : a piece of the helicoil broke and found it’s way blocking the exhaust valve with subsequent damage to the engine).
Joined
·
1,079 Posts
A short pilot drill and/or pilot reamer will do the job. I've custom ground drills to make them pilot drills when a similar job as discussed needs doing. There are specific angles to grind the cutting edges of a drill bit so it won't grab soft aluminum or brass. I have a full set of number drills all ground specifically for use on soft materials. A skilled person can successfully drill a Shadow head, tap it, and fit a Time Sert without removing the head from the engine. It is tricky, but not really difficult if you have the correct tools and skill.
so I have what is probably a silly question: I see an M16 x 1.5 time-sert thread repair kit. It does not mention spark plug repair. Is this the right kit? Perhaps it goes without saying Jim, I’d prefer something that doesn’t involve the removal of the head, done by a person with the skills to do it.
Joined
·
1,079 Posts
You want a 14 x 1.25 spark plug Big Sert. Check the OD of the Big Sert on their website and have your mechanic determine if there is enough material to fit one.
Joined
·
1,079 Posts
This may also work if the hole is not too large. If you can get the tap to thread at least half threads, you could Loctite it in with 620 retaining compound.
OEMTOOLS 25647 Spark Plug Thread Repair Kit, 14 Mm : Amazon.ca: Automotive
OEMTOOLS 25647 Spark Plug Thread Repair Kit, 14 Mm : Amazon.ca: Automotive
www.amazon.ca
Joined
·
1,079 Posts
Here is what you need for previously Helicoiled spark plug holes: ++ BIG-SERT Oversized Spark plug thread repair kits ++ spark plug thread repair for oversized holes previously repaired spark plug holes threads stripped
Drilling is not required, the included piloted taps prepare the hole without drilling.
Drilling is not required, the included piloted taps prepare the hole without drilling.
1 - 20 of 22 Posts
Join the discussion
