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I just swapped the NGK BPR 6ES plugs which were in my car, with the recommended BP (not R) 7ES plugs and gapped them to 1,0 mm
Car runs great, noticably smoother (power dip around 3000 rpm is gone, and it feels even torquier in lower revs).
However I noticed the engine sound also changed? With a little throttle applied I dont notice a big change, but with > 30% throttle it has a more pronounced , bit of ticking sound. Not like valve lifter ticking, more like leaky exhaust manifold
It really happend right after swapping the plugs.
I doublechecked if I did not cause any vacuum leaks (not the case).
Perhaps I bent/loosened the air-pump --> cat pipe when removing the intake plenum?
I have a air pump bypass, with the valve still in place.
Could this be the case, or is it normal for the car to sound a bit different?
Did a quick search on the forum, and suspect I might have loosened/damaged one of the emission-diagnosis pipes (with the blue caps on them, behind the intake).
Thought about the problem all night and decided to jack up the car this morning, and .. yes.. I found a snapped of emissions test port, close to the exhaust manifold.
Tapped some M7 thread inside the original bolt, and capped it off with a nice M7 bolt.
While I was under the car, I also noticed the outer passenger cam-seal is accessible from underneath, so I changed that as well.
Took it for a drive and it is GREAT. The plugs really make a noticable difference and no more oil-leak from the cam.
Thought about the problem all night and decided to jack up the car this morning, and .. yes.. I found a snapped of emissions test port, close to the exhaust manifold.
Tapped some M7 thread inside the original bolt, and capped it off with a nice M7 bolt.
While I was under the car, I also noticed the outer passenger cam-seal is accessible from underneath, so I changed that as well.
Took it for a drive and it is GREAT. The plugs really make a noticable difference and no more oil-leak from the cam.
I put in a set of BP7ES gapped to 0.9mm recently, to see if I could make more HP with the smaller gap (vs. 1.0mm).
I've done quite a few logging runs since then. Overlaying before and after logs, with similar weather, shows that the smaller gap is consistently slower over 4000 rpm, the rpm lines diverging more and more all the way to 6700. It's not huge, but it indicates that the larger gap makes a little more HP.
I would try going even wider, say 1.1mm, but NGK recommends only gapping 0.2mm (0.008") over the plug's initial 0.8mm pre-gap (else the electrode will no longer be parallel to the anode).
There is a BP7ES-11, with a 1.1mm pre-gap, but it is not available locally.
I put in a set of BP7ES gapped to 0.9mm recently, to see if I could make more HP with the smaller gap (vs. 1.0mm).
I've done quite a few logging runs since then. Overlaying before and after logs, with similar weather, shows that the smaller gap is consistently slower over 4000 rpm, the rpm lines diverging more and more all the way to 6700. It's not huge, but it indicates that the larger gap makes a little more HP.
I would try going even wider, say 1.1mm, but NGK recommends only gapping 0.008" (0.2mm) over the plug's initial 0.8mm pre-gap.
There is a BP7ES-11, with a 1.1mm pre-gap, but it is not available locally.
FWIW it's not uncommon for domestic 2-valve V8's to have a plug gap over 1mm.
86 Super Charged 424 Hp to wheels
Old thread
I have a colder plug Bosch Wr5D but having trouble finding Wr5D its replacement 7992 is not the same I was told Nkg maybe more available and a better option. What plug number from Nkg would you replace this with, is this my best choice need to make sure it’s not too hot for my application.
Thanks
I just ordered a set of Bosch WR5DC to change out the standard plug...Ken don't dun me but yes I was running stock plug with your chips, upgraded airbox temp sensor and full exhaust....is the NGK that much better that I should send back the Bosch units and get the NGK's? I don't race it but redline it usually once while I'm out with it....
Well this is weird.....I got the WR5DC: Ken's recommendation but they aren't german...they are made in Russia...the plug boxes are perfect. says made in Russia right there. Plug metal part is stamped with the correct plug model/type...looked on an old plug and that metal part has "germany" stamped on it as well....new plugs are stamped "Russia" in same place...
They aren't hiding at all the plugs are made in Russia. Quality appears to be just as good....weight and how they look on outside....all 8 came in a Bosch box as well as being individually boxed. The threads/electrodes had their own little cardboard protector sleeve on them...
On the removed plugs: I've done 4, and apart from some oil on the threads of 2 of them, they are all a medium to slightly dark medium gray...with one being a little lighter....all electrodes dry and free of any buildup...so far so good there...I guess I'll find out I'll update again with results from the other plugs but she always starts right up and runs evenly with good power so I'm expecting the same.
FYI I gapped them all at .813...its what my feeler guage had...all were too small....a thousandth of a mm would be snug but would fit...none of them would allow the feeler gauge in until I'd done some seesawing to open things up. Also, the 4 old plugs I've pulled are all overgapped....one was so wide I could put the gauge in and still move it up and down.... stay tuned for more...or as they used to say on the evening news: "Film at 11".
Has anyone else bought Bosch plugs for our cars and they were made in Russia?
I'll also update this thread with how it starts up from stone cold and how she runs...Russian Bosch plugs...who knew? I believe they are genuine though....human nature tells me a Chinese copy would stamp Germany all over it...not Russia.
Update: drivers side plugs replaced. Cylinder closest to firewall and one next to it had some carbon build up but it was around the base....the electrode still looked good. I had the stock WR7DC's in and put in the correct plugs for Ken's chips, WR5DC. As per the old plugs on the passenger side...all were overgapped.....I had an .813 mm gauge and on one of them there was daylight shining through with the gauge in there...in zero cases was there any drag whatsoever on the gauge with the old plug.
How did the Russian made Bosch WR5DC's run? Great. Car runs smoother..esp at lower rpms its more docile. It's a tad sluggish cause it's got 93 in it but it runs beautifully and still every bit as responsive...going to run it till the light comes on and put the 91 in...looking forward to it. Cleaned up the intakes a little bit as well...although the metal has been treated for oxidation a film will still form on them...they turn a tad yellowish...they don't look bad..but when you polish them, the rag is black...anyway here's a current pic...you'll have to excuse the excess polish...I'll get to it at some point...
Vendor sent me BPR7ES and I just noticed they are not BP7ES. Since they are resistor plugs and it is too late to send them back, should I gap them at .8mm?
07-28-2012, 07:30 PM
