Running on 3 cylinders | 356 Speedster, 550 Spyder, Replica, Automotive Community

Former Member

Started out on a Sunday drive. Turned out to be a short one. Blew a plug that had been helicoiled 20 years ago. Without seeing my car, can anyone tell me if a second helicoil can be inserted, or would a blown one mean a cylinder has to be sleeved and redrilled? Lord knows, option one is alot cheaper. Engine is a Super 90 Porsche.

10/19/084:24 PM

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Former Member

Started out on a Sunday drive. Turned out to be a short one. Blew a plug that had been helicoiled 20 years ago. Without seeing my car, can anyone tell me if a second helicoil can be inserted, or would a blown one mean a cylinder has to be sleeved and redrilled? Lord knows, option one is alot cheaper. Engine is a Super 90 Porsche.

10/19/084:24 PM

LeonChupp

Jim....There are a number of different "Helicoil" manufacturers....The only way I know of checking thread damage is to visualy inspect the hole it came from....Hole diameters are not exactly the same among many of the different inserts....If it blew the insert out of the head, chances are good it demolished the threads it had cut originaly.....Good luck....

10/20/084:59 AM

Former Member

Thanks Leon. I just spoke with my regular mechanic who said basically the same thing. He's got two different helicoil sizes depending upon the Porsche, and said that as long as the head isn't cracked, it will probably do the job. Jim

10/20/0810:19 AM

Michael McKelveyAnn Arbor Supporting Member

How, if at all, does a helicoil affect the heat transfer from the plug to the head?

10/20/0811:55 AM

Gordon NicholsMassachusetts 1993 CMC Supporting Member

Just like it wasn't even there.

10/20/084:18 PM

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