wow how do i repair a spark plug hole in my cylinder head : V-Twin Forum: Harley Davidson Forums

spark plug · 07-19-2012, 07:46 PM

wow how do i repair a spark plug hole in my cylinder head priced a new and you have to purchase a pair which is roughly $1,300 is there an efficient way to repair them?

Uncle Salty · 07-19-2012, 08:14 PM

I imagine a TIME-SERT would be a decent repair. Also a machine shop could repair it.

1bdBagr · 07-19-2012, 08:55 PM

Used take-off heads are plentiful too.
Tim

NJ Rider · 07-20-2012, 06:34 AM

There are repair kits for that. If I'm not mistaken, it has a tap and an insert.
I don't remember if the spark plug hole has to be drilled oversized for the insert, but
grease the tap well (to keep metal flakes from falling into the cylinder), tap the hole and install the insert.

kustom_flames · 07-20-2012, 06:49 AM

I just did this in my 65 Chevy with aluminum heads. I first bought a cheapo rethread kit at FLAPS for $30. Didn't take. Use the Time-Sert! Because my first one did not take, the time-sert didn't work for me, so I used the next one up - Big-Sert. This if for the second tapping. I also used a product called Rapid-Fix to adhere it to the head. It is a 2 part system with a bonding agent and a 'welding powder'. So far has held up quite well...

Of course a used takeoff head might be the way to go...time-sert kits are about $150 or so...

jammer45u · 07-20-2012, 08:48 AM

Heli-coil will do the job. Get them at any good automotive store, reasonable cost.

HDWRENCH · 07-20-2012, 08:51 AM

I feel a time sert is the best option.. The heli coils are not a long lasting item when compare to the time sert. There are complete kits for your application..

nortster · 07-20-2012, 09:53 AM

Depends on your compression.
Had a bud with a high compression shovel, blew out the insert.

Lower compression, the insert probably would still be working just fine.

Scooter · 07-23-2012, 01:18 PM

How bad is it? My rear (pan) head is a little corrupt. Everytime I remove the plug I have to chase the threads with a spark plug hole thread chaser that I've had for years. You can probably pick up a thread chaser and try that first. Been babysitting this marginally threaded head for years without having to do a major repair.

LowRiderCustom · 07-23-2012, 06:01 PM

I bought a nice tap with solid inserts on Ebay for around $30 and it worked great on the stripped spark plug hole on my daughter's car. I put thick grease on the tap to stop the metal shavings from going into the cylinder and I didn't have to pull the head.

Larbaldi · 07-23-2012, 09:04 PM

Time Sert is one of the best options ... while many others work I think this is the way to get it done. Good Luck with your repair.

http://www.timesert.com/html/sparkplug.html

LowRiderCustom · 07-23-2012, 09:10 PM

Any solid insert will work, it doesn't have to be a $150 time sert. I'm a tool & die maker/machinist so I know they are all the same.

Nahanhoku · 07-24-2012, 12:31 AM

I am with Scooter. If the threads aren't too bad, you can chase them with a spark plug threader. Thread it until you feel moderate resistance then bring it back out and clean the residue off the tool and start again. Then if that doesn't work, tap and use an insert or heli-coil.

panman69 · 11-12-2012, 11:38 AM

I have a insert in my front pan head, high compression, the problem is there was/is an oil galley next to the plug hole and the insert got into the oil galley and I had oil coming out of my spark plug hole inside and out.

Jeffytune · 11-12-2012, 12:50 PM

Okay, here is how to repair it correctly.

1) Remove the head.

2) Take it to a quality machine shop and have them fix it.

3) Reinstall the head.