Just a note to let all know how a simple change of plugs can improve an engine's behaviour.I changed out the AC's I had been using to NGK BPR4ES (recommended by Jim Weise in an old thread) on my Stage 2 headed GS.The old AC's were likely too cold and were breaking down at full boogie.The NGK's work great at full throttle but an unexpected bonus is the stability at idle.I can now idle the engine at about 750-800 RPM in low stall with no fear of it falling off or stalling.Went out for a 50 mile run today with another GS and it could not have worked better. Just wanted to thank JW for his usual great advice and to put in a "plug" for these sparkers. Rod
Which A/C's were you running? I have a miss in my Stage1 motor that I recently put in. I was pulling wires to figure out which plug it may be and found that I could have several wires off at the same time andnot affect my idle. A little background, motor purchased from and built by Mike Garrison. Origonally put in in HEI, but went to stock with a Crane XRI, new Accel 8mm spiral wires and AC R44TS plugs. Also new brass fitted cap and rotor button. It definately has a slight miss, and I suspect plugs. Both front cylinders are definately noticable when removed, the others on drivers side are slightly and back 3 on passenger side seems dead. I will be swapping them around to look for a change, but I am curious if it is the type of plugs as well.
Hi Michael, The plugs I was using were the equivalents to the R43TS.I had to use the washer 13/16 type,not the 5/8 type due to the Stage 2 heads.The 44 heat range sounds right for a Stage 1 or warmed over motor.Your ignition system sounds up to the task.Is the miss only at idle or is it evident under throttle? I would need a bit more detail before I could give a sensible response.If it is the plugs NGK's or Autolite 24's appear to work well.I went to a local Ford dealership a couple of weeks ago with my friend's Stage 1 and we put in the Autolites right in the yard and they work super.The operator of the "fast lane" operation there is a GM guy all the way! Stranger things have happened,I suppose. Rod
Well the miss is at idle up through around 1800 m- 2000 RPM's. It is very noticable when staying in first, and just keeping the RPM range steady around 10 -15 MPH, there is a miss as well. When I throttle it, it seems to be pretty strong to me. Then again, I have not been behind HP's for a while. She will chirp pretty good hitting second with a peg leg 2.56 and 255/60's. She will also rip loose at a roll of 10 - 15 MPH as well, so it seems to hav power overall. I was talking to Mike G. and we were thinking my gap being at .045 may be a little excessive and causing a lower RPM miss. I swapped plugs (#2 & #8, and the #8 plug was wet when removed), and the problem stayed at #8. Then I swapped the wires, and 8 was still dead, but it seemed to not be as much of a difference on #2, but that could have been me. I am going to meter from the cap post to the plug connector tomorrow, hopefully. And go from there. I may get some new plugs and go with a .040 gap and see if that helps. Thanks for the reply and any suggestions are very welcomed and appreciated... Mike
You are going about it in the proper manner.Heavy loads usually bring out the worst in plugs not light engine loading.I agree that the gap should be no more than 40 thou.I set mine about 35 to 38 just to be on the cautious side.I would use the meter on those wires and after that and plug replacement look at the carb. Good luck-Rod
NKG recommends a gap of .030" on their wedsite for the BPR4ES plugs. Would this be correct for 455 with stock heads? I've purchased a set of the plugs and want to install them only once.
Depends on 2 things, your ignition system, and compression ratio. MSD's and other HEI's can fire bigger gaps(up to .060). The higher compression(or boost), the smaller the gap must be.
Gee, I was afraid it would get technical! I have a GM HEI, 9.5-1 compression, Stage 1 Cam, some porting on '73 heads with Stage 1 valves.
Nahh, not that technical :laugh: :laugh: I would go with .045, the HEI will fire that easy with 9.5:1. Only problem might be the plugs themselves. Making the gap bigger, sometimes results in the ground electrode not being at a 90* angle to the center electrode. Plugs are manufactured with a gap range. Usually, you can increase or decrease the recommended gap .008. You might want to contact NGK for their recommendations, or to see if they have the same plug with a bigger gap.
Edelbrock problem If you have an engine miss, check every threaded hole in your edelbrock manifold. SOME BREAK THROUGH and suck air. Mine had 3 holes through and sucking air. Two were in the holley bolt pattern holes and one an accessory hole toward the back. A friend just discoverd a broblem with his also. It was in the Q-Jet bolt holes. Had been that way for four years and said he knew something wasant right in the tunning and lean popping when cold.
Anyone have a recommendation for a NKG plug for my vehicle? 350, TA290-94H cam, TA intake, qaudrajet. They have multiple plugs so I was wondering if I should just go with the: Standard OEM plug, Laser platinum OEM, Laser Iridium OEM, V-Power, or G-Power. It's not a race car but built for street/strip. http://www.ngksparkplugs.com/products/spark_plugs/index.asp?mode=nml Thoughts?
Im not familiar with these plugs. I use ngk ur5. Whats the diference and also are these hotter or colder than mine. I have a heavy car,70 electra, but its had head work to that of stage 1, no porting though. usinng 290-94h cam,performer,holley,msd,thanks,marty
The higher the number in NGK, the colder the plug. Your plugs are a bit colder on paper than the NGK BP4ES. However, you have the UR-5, which is a projected nose plug, and projected nose plugs have a wider heat range, and they place the gap further into the combustion chamber. IMHO, they are better plugs for the street. You have the right plug for your car.
thanks larry,by the way my car i a runnin son of a b. finnally have all together except a//c and top,marty
OK I will jump in... time to replace the plugs on my bone stock 68 GS400. What NGK's or other plug do you suggest? I will also be replacing the wires, cap, rotor. Any brands better than other?
You can try the NGK UR-5 plugs. They are roughly equivalent to the R43TS or R44TS. The UR-4 is a bit hotter, like an R45TS or R46TS. I find the projected nose plugs give me a perceptible increase in throttle response. I can tell the difference. As far as wires go, I think it's hard to beat the MSD super conductor wires in black. They have gray multi angle boots, and they look great IMHO. I like the universal kit. You can get them perfect that way. Delco has a premium cap with brass contacts. It's of noticeably heavier construction.
Should I use the factory gap of 0.030"? Stock ignition system except for Petronix and Flame thrower coil.
