Twin Plug Question
 

Hi,

I'm looking to twin plug my car and wonder if one would typically use the same plug (as before twin plug) for both top & bottom?

And just to be sure - would the bottom cover/cam tower cause any clearance issues with the plugs?

TIA...

please search in the engine rebuilding forum. Some smart people suggest using a 12mm plug on the exhaust side. you can also weld up the original plug hole and set it up for a 12mm as well.

There are no clearance issues if you have the work done by a good porsche machinist. I would search on the forum for names of such people as well.

Cheers,

Thanks for the response Andy. Will do a search in the engine rebuilding forum.

My question came from a good Porsche machinist who suggested that on some cars, if I'm to keep the same plugs the cam tower might need to be shaved a little to clear the socket. Unless I am willing to go with smaller plugs - which will be more $$$ and a pain (in my mind). Hence the question to see what others have done.

You could use a standard 14 mm - 3/4" reach plug that uses the 5/8" hex to alleviate the clearance problem with the lower plugs.

I have the standard plugs on the bottom (didn't know any better at the time). I had to replace the head stud nuts next ot those plugs with "reduced wrench" sized nuts i.e. 10mm nut that takes a 15mm wrench instead of the standard 17mm wrench. Some plug sockets interfere with the cam towers. I don't think the factory plug socket (that comes in the toolkit) does though.
-Chris

Thanks for the reply guys... I have also found this thread thru the search -
http://forums.pelicanparts.com/showthread.php?s=&threadid=171111&perpage=20&highl ight=twin%20plug&pagenumber=1

After reading all of these, it sounds like 12mm plug is the way to go. Especially if Chris(Bennet) said that he needs to replace one of the head stud nuts - I'm planning on going with ARP studs so don't want to have to anything special.

I think you are right about going with a smaller plug.
The nut size thing is a non-issue though. The ARP studs are the same threads as the factory and you use them with the factory nuts. From the looks of them, the ARP nuts would clear the plugs as well.
-Chris