Chingy Posted November 28, 2014 Report Share Posted November 28, 2014 Hi What would be the best Spark Plugs? Spec- 4kc head, compression at 11:1 Electronic Ignition Worked engine cam, overbore etc etc Thanks Quote Link to comment Share on other sites More sharing options...
Taz_Rx Posted November 28, 2014 Report Share Posted November 28, 2014 Should be nothing wrong with a stocko bp5ey Quote Link to comment Share on other sites More sharing options...
Chingy Posted November 28, 2014 Author Report Share Posted November 28, 2014 Should be nothing wrong with a stocko bp5ey Thank you, .... sorry to sound stupid and may be over complicating it, but am I right in thinking there are long reach plugs for the 4kc head, will this cause a problem now that the head has been skimmed to increase the compression. I am sure it's an obvious answer :) Quote Link to comment Share on other sites More sharing options...
parrot Posted November 28, 2014 Report Share Posted November 28, 2014 You might want to go one plug colder in the heat range. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted November 28, 2014 Report Share Posted November 28, 2014 I don't think you could skim a head enough for pistons to hit the plugs. What you really should do is fit all four plugs and make sure they protrude into the combustion chamber the same amount. Use shim spacers to get them even. Then do your combustion chamber sizing to get all four chambers the same volume using those plugs, so you have 11:1 on all four cyl. Parrot's right, you should try a heat range colder. If it fails when cold or at low revs you can always go back up.. Quote Link to comment Share on other sites More sharing options...
Chingy Posted November 28, 2014 Author Report Share Posted November 28, 2014 Thank you guys for all your advice. As always another problem resolved here :) Quote Link to comment Share on other sites More sharing options...
springersrolla Posted November 28, 2014 Report Share Posted November 28, 2014 Youll never hit the plug the valves will go first. Another old school trick is to face the spark to the exhaust port Quote Link to comment Share on other sites More sharing options...
TRD ke70 Posted November 28, 2014 Report Share Posted November 28, 2014 Always found the twin electrde worked very well. Quote Link to comment Share on other sites More sharing options...
Chingy Posted November 29, 2014 Author Report Share Posted November 29, 2014 Thanks again, any particular brand or model of the twin electrode? Quote Link to comment Share on other sites More sharing options...
styler Posted November 30, 2014 Report Share Posted November 30, 2014 (edited) What you want to do a on a worked motor is find the correct plug to suit, the plugs trap heat to burn off deposits so a standard plug works in a standard motor. When you increase the motors performance the combustion chamber temperature goes up and you use a colder plug so the plug will operate at the correct temperature. Its all in the plugs trap area, its bigger for hotter and smaller for colder, the rest of the plug is the same. Hot burns off deposits, too hot breaks the plug down Cold keeps the plug together, too cold causes fouling from deposits Best to buy 2 heat ranges colder from standard using a basic cheap plug and go from cold to hot until the plug stops fouling. Then buy your fancy electrode style plugs if you like or replace the basic ones more often. The shim and facing thing may refer to spark plug indexing, where you buy a set of shims to allow all the spark plugs to face in one direction to improve performance. The shims just allow indexing, the extra height spacing is irrelevant. May improve by a small amount in some applications but often dismissed in lower hp builds. I prefer ngk over bosch, personal thing I guess! Edited November 30, 2014 by styler Quote Link to comment Share on other sites More sharing options...
Chingy Posted December 1, 2014 Author Report Share Posted December 1, 2014 Awesome, thank you for taking the time to share, great advice much appreciated Quote Link to comment Share on other sites More sharing options...
philbey Posted December 8, 2014 Report Share Posted December 8, 2014 I"m running big comp on my 5k and I've never had any issues with the bp5ey. I did go with some BP6eys for a while but not really any difference. It's tuned well as well. Quote Link to comment Share on other sites More sharing options...
styler Posted December 8, 2014 Report Share Posted December 8, 2014 Yeah if it doesn't foul or burn up its good to go! Running from cold to hot plugs is the safe way of finding out :) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.