You can occasionally still find Geman Bosch on eBay but I got tired of hunting them down, now I obsess on other things
Critique the condition of these spark plugs please
- Thread starter Stevehose
- Start date
Better?
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That’s a Japanese plug- note the zen like uniformity.
I've always liked this writeup on spark plug reading.
www.4secondsflat.com
FBO Ignition - Home of the HRR688 - Spark Plug Reading
www.4secondsflat.com
Better?
Pretty. Very pretty.
Steve--My triple Webers seem to be running rich. Soot still coming out the tailpipe. The car runs & accelerates great. The shop installed new plugs when all of the carb work was done months and about 500-700 miles ago. I pulled out # 2 and #4 plugs to see the electrodes. The plugs are DENSO # IW16 Iridium Power. #2 looks darker than #4. They don't look fouled. My pics are below. Ever hear of these plugs in an M30 engine--1986 head and 3.3L on the block. I'm calling Korman tomorrow to see what plug they put in a stage 2 engine. Drew
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I don't know those plugs, I use NGK BP4ES - a hot plug for city driving. Also BP5ES (less hot) and BP6ES (lesser hot) work well. Do you have an AFR gauge installed? Your plugs don't look bad although a closeup would be better. Black tailpipe is also a byproduct of the crappy gas these days. If your engine is running well and you don't have an AFR gauge I'd be careful of changing anything other than the lean idle adjustment.
My e24's are supposed to have silver (silber) plugs. I do not run them in my E3/E9 but why silver for my 86 M30 and not my 73M30? I am plug-dumb BTW.
Dunno but silvers have never worked well in my coupes and others have had similar experience. DeQ has had sucess with NGK Iridiums but I haven’t tried them as I am satisfied with the regular NGK’s
+1 for NGKs
I talked to Carl Bennett at Korman about the Denso plugs. He said they use Bosch WR8DC in a stage 2 M30 engine with 3 DCOE Webers. The heat range of this Denso IW16 is the same as the WR8DC. I mentioned the NGK BP6ES that you use. He said the heat range of that plug is between the Bosch silver WR8DC and the colder WR7DC. He said to check the fuel pump pressure. It should be between 3 and 3.5 PSI. I had a gauge ,but the shop removed it since the Pierce Manifold pump they installed is supposed to run at 3.5 PSI. I don't have an air/fuel/ratio gauge (AFR) either. I think we should confirm the fuel pump pressure and the lean idle adjustment. Here are better pics on #2 and #4 plugs.
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One does look a little darker but not too bad, the other looks fine. You should check all the plugs and compare them in order 1-6 since sidedrafts have a single barrel for each cylinder it is possible that one or more mixture screws are out too far. From the manufacturer charts I've seen the eqivalency is:
WR8DC=BP5ES
WR7DC=BP6ES
My BP4ES are hotter than the WR8DC.
Imho I would not use Bosch plugs unless they are NOS German made ones, and ones that are not resisted like mentioned above. The ones to look for are the W8DC or W7DC. I used to hunt them on eBay but have given up this obsession to go with the NGK's which are easy to get, less expensive, and of equal if not better quality than the German Bosch and certainly better thna the Indian or Brazilian made Bosch which is all you get if buying new in the USA.
WR8DC=BP5ES
WR7DC=BP6ES
My BP4ES are hotter than the WR8DC.
Imho I would not use Bosch plugs unless they are NOS German made ones, and ones that are not resisted like mentioned above. The ones to look for are the W8DC or W7DC. I used to hunt them on eBay but have given up this obsession to go with the NGK's which are easy to get, less expensive, and of equal if not better quality than the German Bosch and certainly better thna the Indian or Brazilian made Bosch which is all you get if buying new in the USA.
Korman likes the Bosch plugs. The shop installed the Denso plugs since they think they are excellent quality Iridium type. My car seems to run very well on my 30 mile curves and high speed weekend runs.(The traffic down here is heavy after 10 AM so I just want the roads clear when I drive.) They also checked the fuel pressure (3.5 PSI) back when the carbs were sorted. Thanks again for your advice.
Fixed it, I don't know why some go away, they are still there when I hit the edit button but only will come back if I repaste the link, @dang is this a Google thing or? Doesn't happen to all of my old pics that are linked, just some of them....
Not sure but it may be how you linked to the image. If I right click on an image in Google Images and "copy image location" and paste that URL into a message using the Insert Image feature it works fine. How are you linking to the image?
Yes that's how I've always done it. What's weird is that the image is still there when I go to edit it.
Could be a forum image proxy thing. The only sure way to do it is to save the image locally and upload it as an attachment.
I need new plugs and am wondering if I should go with hotter BP5ES, I have some oil fouling with BP6ES plugs and don't run my coupe enough to burn the deposits off. Would a hotter plug be a good idea?