So, today, while changing out the spark plugs in my Buick 300, I felt that sick sensation on number 5 cylinder of the threads letting go when I installed the spark plug. I use anit-sieze, and chase the threads before installing the plugs. Was wondering what everyone else has done to fix the threads in their aluminum heads, while not having to remove it. Was thinking heli-coil, but being 2019 is there a better more permanent fix? By the way I have a spare aluminum top end from another 1964 300 but don't want to go that route, as my 300 was rebuilt 3 years ago with most parts from T/A performance(Thanks again Tim for all your help, much appreciated).
https://www.ebay.com/itm/M14-x-1-25...934387?hash=item4692b34af3:g:6E8AAOSwpzJaSyud https://www.ebay.com/itm/SPARK-PLUG...:U70AAOSwcY5cjH9u:sc:USPSPriority!33772!US!-1 I don't like helicoils. You may want to do all of them while your at it. Attach a piece 1/2 pvc pipe to a vacuum to get as many metal pieces out as possible. Put the engine at the bottom of compression stroke and turn it with the starter to blow the rest out.
I dont like helicoils either! What does work much better than helicoils is Gardsert: https://www.gardspecialists.com/gardserts/spark-plugs/individual-packages/ While I have not used these specific ones for spark plug repair, I have used their other thread repair solutions. The Gardserts are harder than grade 8 and these inserts are self tapping. Not sure if you can make this repair with-out pulling the head because you need to drill out a larger hole to allow the Gardsert to self tap.
Took the hood and left front fender off today, lots of room to do a repair, with nothing in the way, so I can tap the threads. Seems like the main thing to do is make sure the tap is STRAIGHT into the hole, and lots of grease to catch the aluminum filings. Also need to turn over the engine when done to blow out filings. Hope this works, thanks for all the threads, don't think I will need to tap the other 7 holes, or should I?
Probably the best repair I have done on aluminum heads was the one where I simply tapped it out to the next larger size. That meant I had to come up with the right heat range of plug for the one hole, but I never had any problems with the threaded insert coming out with the spark plug like I did before. Jim
I would personally put a bunch of oil in the cylinder and vacuum it out after, that will catch most of the filings.
Interesting thought. Probably would work pretty well too. Anyway the chips will be aluminum, very small and light, so they'll get blown out with the exhaust in short order, and while they are in there they won't be substantial enough to do any damage. Jim
something I have heard and have used a couple time is shaving cream/foam . had my neon top end all together and stripped out one of the cam hold down threads . clean , foam , drill n helicoiled , vac'd up the foam . seemed to catch all the metal shavings fine . I think I would run the piston all the way up and then foam it ? strong vac , small nozzle .
