Repaired the spark plug threads with insert

[Cusser]

1835 DP, single Weber. About 1.5 years ago the rebuilder-installed heli-coil came out with spark plug #2, and I purchased a kit of four different-length aluminum inserts and a tap at Checker/Schuck/Kragen. The tap was the same size as that used for the heli-coil, so I used red Loctite and installed the insert and the plug. Noticed today rough running, and #2 plug wire was off, and #2 spark plug loose. I unscrewed it and the bottom half the aluminum insert was missing. I was going near a BAP (Arizona) shop so I stopped in and purchased a set of four EMPI inserts for about $3.50, which were a different metal than previously. I sprayed brake cleaner on the cylinder head threads, and wiped the threads clean with a rag. I screwed one of the inserts onto the plug (with a little anti-seize) and put new red Loctite on the outer threads of the insert, and screwed them in. After two hours I tried unscrewing the plug, and it readily loosened, so I tightened the plug and started it up, and sounded great. I had been to CarQuest also today (after BAP), and found that they stocked a heli-coil brand of solid threaded insert (which may have been the best of the bunch) but I had already used BAP's. Hopefully this insert will last longer or I'll need to try CarQuest's.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[74bug]

i've been running insert on one of my cylinders (#3) for about the last 6yrs, and the trick i found is to NOT try to put the insert in permanantly. Basically i don't torque that plug really tight, and when i do change plugs it allways comes off with the plug, it has a raised shoulder and i just put some large vicegrips on the shoulder and remove the insert and re-use it on the new plug. Locktite won't hold, the heat just makes it loosen, and the insert allways comes out with the plug. Those empi inserts are good, and really cheap, i'm planning on eventually giving the motor a rebuild (actually soon) and i'll most likely get new heads anyhow, since they have ALOT of miles on them. I guess what i'm trying to say is just use the insert, if when you change plugs the insert comes off with the plug, re-install it on the new plug or just leave it on the plug if your just checking them or cleaning them. and i allways put a little antiseize on the insert and the plug so nothing gets seized up, you can deal with the issue properlly when you pull the heads off next time. Also resist the urge to exceed the reccommended torque, and maybe even use a little less because if you strip the threads now your really out of luck.

[Cusser]

Update: 8.5 years after this repair, the same spark plug blew out November 2015.

I used a brand new insert (had 3 left over from pack of four), and a new spark plug. I used the red Loctite on the insert's outer thread again, and a little anti-seize on the spark plug threads. But this time I now had a click-type torque wrench, so i actually torqued the spark plug to the factory setting, something I had not done earlier. My guess is that I was a little "timid" back then and didn't get tight enough.

So now April 2016, that is still holding up fine so far, don't give it a second thought. If this happens again I'll go the Time-Sert route or just pull the engine and put on a new pair of cylinder heads, engine deserves that, the 1835 heads and engine haven't been apart since 1986.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Cusser]

Update: Last weekend just drove my VW 140 miles away last weekend in 100F heat to the Jerome VW Bus show, was fine, about 300 mile total mile trip. No spark plug issue, no issues at all.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[mark tucker]

I wonder if any body makes a few thou over size indcert that could be installed when the engine is hot....but it might grab the plug.. hell when all else fails ford used a biger size plug thread...13/16" thread I think..not sure there is enough head for it but ... also you might try twisting the plug wire the other way so it keeps the plug tight......and or make a tab that bolts to the intake flange to hold the plug in....or...try screwing a lug bolt in the hole then drill it for a 10mm plug....or....hmm I wonder if you head is cracked... I have a set of heads that were on my bug when I got it in 02, that have somuch welding on them it's unbealeavalble that somebody did it and thought they were making $$$ that was when the heads were about $40 each.... or less. kinda skeerey. the entire chambers had been re done, the sparking bolts re done, the guide bosses redone...they didnt say gex but I think it had a PIR or somethinmg like that. pure stupididitty.or wood that be conyea outwest?

[Cusser]

[theKbStockpiler]

What about the punch method where you take a pointed punch and place it inbetween the head spark plug bore and the insert outter edge. When you give the punch a whack with a hammer it creates a divit that stops the insert from spinning.
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My beetle is not competing with your beetle. I have the yellow beetle in my town. There is a red one, a green one ......
Use all safety devices including a mask.

[Cusser]

[mark tucker]

sometimes wacking cast items just makes it worse. I think cusser is cussen me again....fer what Im not sure other than my fingers being out of sync with my brain.....among other things. but if thats all you didnt get I think I done good as did you. I not a fan of inserts. so..why are certs(the breath mints) spelled with a c and inserts spelled with a s? german?

[Cusser]

I just drove the VW again yesterday (Feb. 2021), still no issues with that solid threaded insert. But I didn't go over 75mph (65 zone on freeway).
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Cusser]

Still fine, Sept. 2023 !
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297