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360 domed pistons hitting spark plug #1411473 03/30/13 04:20 PM 03/30/13 04:20 PM
Joined: Oct 2011 Posts: 319 Fort Collins, Colorado C CoDart OP enthusiast
CoDart OP enthusiast C Joined: Oct 2011 Posts: 319 Fort Collins, Colorado	Im assembling my stock stroke 360 magnum and came upon a "snag". The pistons are hitting the spark plugs, even with the .093" thick head gaskets. The heads are RHS indy heads and the pistons are made for this type head. Pistons are the IC743. Here are some pictures of the setup. How do I go about this? Thanks

Re: 360 domed pistons hitting spark plug [Re: CoDart] #1411474 03/30/13 04:30 PM 03/30/13 04:30 PM
Joined: Dec 2010 Posts: 1,035 Missouri U.S.A. 7 71yelladustr super stock
71yelladustr super stock 7 Joined: Dec 2010 Posts: 1,035 Missouri U.S.A.	Looks like you are going to have to grind some spark plug "dimples" in the dome of your pistons and maybe some colder heat range plugs with a shorter electrode and ground strap. 392 gen III hemi on E-85 727 trans Dana 60 10.02@134

Re: 360 domed pistons hitting spark plug [Re: CoDart] #1411475 03/30/13 04:36 PM 03/30/13 04:36 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Two choices... shorter/retact electrode ot cut a trench in the pistons... I like to cut the piston to give it a easier flame travel

Re: 360 domed pistons hitting spark plug [Re: 71yelladustr] #1411476 03/30/13 04:38 PM 03/30/13 04:38 PM
Joined: Feb 2005 Posts: 20,279 PA. pittsburghracer "Little"John
pittsburghracer "Little"John Joined: Feb 2005 Posts: 20,279 PA.	Would you be ok with this style of tip. http://www.ngksparkplugs.com/products/spark_plugs/racing.asp 1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.38@138.67 Livin and lovin life one day at a time

Re: 360 domed pistons hitting spark plug [Re: pittsburghracer] #1411477 03/31/13 08:26 AM 03/31/13 08:26 AM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	If indexing the plug doesn't fix it,bring each piston up TDC,screw the plug in untill it touches and marks the dome.With a diegrinder and sanding roll grind a fire slot into the dome at the same angle as the plug.Make sure that the dome is thick enough and only remove the amont necessary.You can even do this with the pistons in the block if you cover everything and seal it up with duct tape and keep it as clean as possible. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: 360 domed pistons hitting spark plug [Re: B G Racing] #1411478 03/31/13 08:39 AM 03/31/13 08:39 AM
Joined: Nov 2009 Posts: 2,177 ill D dennismopar73 top fuel
dennismopar73 top fuel D Joined: Nov 2009 Posts: 2,177 ill	Quote: If indexing the plug doesn't fix it,bring each piston up TDC,screw the plug in untill it touches and marks the dome.With a diegrinder and sanding roll grind a fire slot into the dome at the same angle as the plug.Make sure that the dome is thick enough and only remove the amont necessary.You can even do this with the pistons in the block if you cover everything and seal it up with duct tape and keep it as clean as possible. I agree !! Hard to believe that the plug is hitting??

Re: 360 domed pistons hitting spark plug [Re: dennismopar73] #1411479 03/31/13 11:22 AM 03/31/13 11:22 AM
Joined: Oct 2011 Posts: 319 Fort Collins, Colorado C CoDart OP enthusiast
CoDart OP enthusiast C Joined: Oct 2011 Posts: 319 Fort Collins, Colorado	What spark plug number would you guys recommend?

Re: 360 domed pistons hitting spark plug [Re: B G Racing] #1411480 03/31/13 12:20 PM 03/31/13 12:20 PM
Joined: Sep 2003 Posts: 2,008 Sweet Home Alabama M MRMOPAR622 top fuel
MRMOPAR622 top fuel M Joined: Sep 2003 Posts: 2,008 Sweet Home Alabama	Quote: If indexing the plug doesn't fix it,bring each piston up TDC,screw the plug in untill it touches and marks the dome.With a diegrinder and sanding roll grind a fire slot into the dome at the same angle as the plug.Make sure that the dome is thick enough and only remove the amont necessary.You can even do this with the pistons in the block if you cover everything and seal it up with duct tape and keep it as clean as possible. We used to have to do that to the Old TRW-L2295 pistons.It worked so good I think TRW changed the cast to have the groove cut in their pistons.This would be better than trying different plugs to get your clearance as it will give you a few more Horse-Power by the plugs having a better flame travel. PS When doing this I like to make the V-groove a 1/4"-3/8" wide for better flame travel,just be careful on the dept you cut them. Last edited by MRMOPAR622; 03/31/13 12:24 PM. "To Be The Man'You Have Got To Beat The Man" "T/D and Pro-Bracket Racer"

Re: 360 domed pistons hitting spark plug [Re: MRMOPAR622] #1411481 03/31/13 01:24 PM 03/31/13 01:24 PM
Joined: Oct 2011 Posts: 319 Fort Collins, Colorado C CoDart OP enthusiast
CoDart OP enthusiast C Joined: Oct 2011 Posts: 319 Fort Collins, Colorado	If i cant find the right plugs then ill cut a groove in the pistons. What should the minimum clearance be from spark plug strap to piston?

Re: 360 domed pistons hitting spark plug [Re: CoDart] #1411482 03/31/13 03:16 PM 03/31/13 03:16 PM
Joined: Aug 2003 Posts: 44,180 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 44,180 Bend,OR USA	Quote: If i cant find the right plugs then ill cut a groove in the pistons. What should the minimum clearance be from spark plug strap to piston? I would use .060 and hope Better yet go to a retracted gap spark plug type or even a side gap plug type Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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