tjenkins Posted December 11, 2002 Share Posted December 11, 2002 Could someone confirm that the gap is .060" on stock plugs (R45LTS6) for 90 coupe?--Tom Link to comment Share on other sites More sharing options...
padgett Posted December 12, 2002 Share Posted December 12, 2002 Am certain some would have a different opinion but I wouldn't gap a plug over .045, partcularly with a stock Motorolla ignition. I also have a preference for #3 Rapidfires. Link to comment Share on other sites More sharing options...
Charlie B. Posted December 12, 2002 Share Posted December 12, 2002 Per the owners manual, the spark plug gap is <span style="font-weight: bold">.060</span> Link to comment Share on other sites More sharing options...
Roadster90 Posted December 12, 2002 Share Posted December 12, 2002 Because of different opinions I had the same question several months ago and I called A/C Delco. As Padgett suggests, the factory also suggests that the gap on #3 s be .045 (with the Motorolla coil pack). Link to comment Share on other sites More sharing options...
Guest EDBSO Posted December 12, 2002 Share Posted December 12, 2002 the Rapid Fires should not be regapped!# 3s are pregapped at .45#14s are pregapped at .60I use #14s with the Jacobs coil. Link to comment Share on other sites More sharing options...
Guest Posted December 13, 2002 Share Posted December 13, 2002 If using stock plugs, the gap should be as the underhood emissions lable, .060". If you are changing to any kind of plug with a raised pad on the electrode, i.e. platinum plugs, the gap should be decreased .010". It is important to use a round wire gage on these large gaps, as flat gages can give false readings. A lot of owners swear by twisting the side electrode so that it lines up perfectly over the center of the plug. There does not seem to be any downside to this if done carefully. Bob Rich Link to comment Share on other sites More sharing options...
tjenkins Posted December 15, 2002 Author Share Posted December 15, 2002 Faced with R/R of the three items, I choose to go Delco, and, purchase the cheaper of the three - spark plugs and wires.Got 'em at GMPARTSDIRECT, and even with the $7 "handling fee" total was very competative.It seems to idle/accelerate smoother - time will tell on the low gear 'pull'. I've got a half-tank of premium gas, I need to burn that off.Should I still get the hesitation in 4th, I'll R/R the coil pack - also with Delco.Thanks to all for your immediate help, knowledge and trusted experiences.--Tom Link to comment Share on other sites More sharing options...
Filobedo Posted March 5, 2004 Share Posted March 5, 2004 Just changed Spark Plugs from AC-Delco .060 to AC-Rapidfire #3 .045 {Per a few members advise}. Which resulted in an imediate loss in power and acceleration. The old Plugs were clean and white when removed. Maybe it allready has the coil upgrade? I dont know... But, I doubt it. Next time I will use #14 Link to comment Share on other sites More sharing options...
Guest EDBS0 Posted March 5, 2004 Share Posted March 5, 2004 Interesting. I have used both plugs, the 14s most recently with the Jacobs "brick".The gap is not adjustable.They should provide more response, easier, quicker starts, smoother idle etc. Link to comment Share on other sites More sharing options...
Filobedo Posted March 5, 2004 Share Posted March 5, 2004 I must admit that it runs better & the idle is smoother but, Im talking about a "Significant" loss of power & acceleration.Also on the first couple of starts it wanted to cut out.Something that has never happened until the plug change.Problem has been resolved by driving & computer adjustments.This car was a neglected mess when purchased.So im inclined to think that there was no coil upgrade.The .060 gap plugs were a year old & like new upon removal.Which convinces me that the .060 gap #14 is corect for my car. Link to comment Share on other sites More sharing options...
padgett Posted March 5, 2004 Share Posted March 5, 2004 Doesn't make a lot of sense. On the one hand the larger gap will result in a fatter but very slightly retarded spark. On the other hand it will require more power from the coilpack.Since am now curious and have installed the later Delco ignition, think I'll pick up some #14s and see what happens. Link to comment Share on other sites More sharing options...
Guest wally888 Posted March 6, 2004 Share Posted March 6, 2004 Some owners have reported power loss, etc. after plug replacement and the cause turned out to be improper placement of the sheilds on the rear plugs. Lots of spark lights/jumps when observed in pitch dark! Link to comment Share on other sites More sharing options...
padgett Posted March 6, 2004 Share Posted March 6, 2004 Any reason not to just leave shields off ? Link to comment Share on other sites More sharing options...
2seater Posted March 7, 2004 Share Posted March 7, 2004 I don't know if the manifold heat would bother them or not, but I assume so, or the General wouldn't have spent the money to install them. There isn't much air flow on the back side of the engine so I would imagine the radiant heat builds up. I am using Accell's Extreme 9000 plug wires which have silver reflective boots. I used the Ford style 110 deg. boots which point the wires approx. straight up from the plugs, and even with my revised rear manifold, which is pretty close to the plug boots, I have not experienced any problems with them. My manifolding is all ceramic coated, but there are no heat shields, and the turbo really builds heat in the pipes. Link to comment Share on other sites More sharing options...
Guest wally888 Posted March 7, 2004 Share Posted March 7, 2004 Mine were off for the winter but will probably put back on soon. Think a lot of people/mechanics just throw them away! Several times when changing plugs I have had a brief knuckle twister getting them on right, once one kept the wire end from completely seating but the engine missfire notifies you immediately. Link to comment Share on other sites More sharing options...
Guest EDBS0 Posted March 8, 2004 Share Posted March 8, 2004 My shields have been off since the first plug change many thousands of miles ago. No problems with MSD or Magnicor wires. Also took them off my SC Riviera with no problems. Link to comment Share on other sites More sharing options...
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