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Best Spark Plug?

There has been a lot of talk about double, triple, and now four electrode (split electrodes) spark plugs. So what is the best to use on a carbed 914? I have heard one should go one or two plugs cooler than on stock fuel injection. That has worked well for me, but I am interested in trying the split electrode plugs if they are at all what the ads make them out to be in terms of performance improvements. Anyone have experience here to share?

(I am running a 1.8 with Dells and MSD-6 ignition)

While we are at it, how about the best plug wires that work with stock Bosch distributor caps?

Also, how much of a difference do indexing washers make in terms of performance or even running. (indexing washers are a set of washers of different thickness that allow you to effectively position the plug such that the electrode faces away from the center of the cylinder and thus does not "shield" the spark from the center point of the combustion). Again, experience is the best reference. Anyone got experience with these? Seems they would no make any difference if you used the new Bosch 4 prong plugs.

Thanks and happy new year!

Old 12-28-1999, 05:53 PM
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IMHO indexing would be good IF you had a motor to benefit from it....a stock 1.8 would with carbs not be such a subject.....don't waste your time or money.
Old 12-28-1999, 06:34 PM
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After using Splitfires, I must conclude it's mostly a lot of hype and very little if any benefit.

The best plugs I have found,however, are Autolite and also happen to be the cheapest.
They beat Bosch, NGK, Beru and even Splitfire. And I'm not even getting paid to say so. Besides, if it's good enough for my 86 Carrera, it's got to be good enough for my Oldsmobile 98 and Pontiac Bonneville.
Old 12-28-1999, 07:49 PM
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Surely there must be more opinions on spark plugs...

(Hey Mike, quit picking on my 1.8L...)
Old 12-30-1999, 05:32 PM
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Conerning SplitFires, I have to strongly insist it is ALL HYPE and no substance, for two reasons.

First of all, one of the MOPAR magazines did a whole series of dyno tests on a 'crate' motor, and found that BOSCH Platinum, 'plain' ones (the test was 3 or 4 years ago) were better than just about anything else in most of their dyno runs! I had been using BOSCH Platinums since 1987 and had been very happy with them in place of the factory-recommended Champion N-9Y in my '68 340 'S' Cuda, which has a rather 'warm' engine notoriously hard on plugs!

If the SplitFires were even a few percent better than the competition, auto mfrs would know it by now, through testing, and would UNDOUBTEDLY be equipping them as OEM! To my knowledge, nobody, not one mfr has swithched to them!

------------------
Warren Hall
1973 911S Targa
Old 01-03-2000, 03:14 PM
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Pete I wasn't pickin' on yer 1.8.

I wouldn't even consider indexing on my 3.0. Indexing in MY opinion would be worth while if you were racing against similiarly prepared cars in a specific race with the driver's all having the same ability. THEN ever little edge counts. Street or autocross....go ahead,you won't know the difference.
Old 01-03-2000, 03:27 PM
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Bosh platinums in all our cars. They seem to burn pretty clean, but then I try to keep mixtures adjusted close. The race car 914 runs at full throttle mostly and they hold up well to the MSD spark produced at high RPMs.
Old 01-03-2000, 09:07 PM
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I use Bosch WR7DP extended reach Platinum plugs @ .045". 74 2.0 with 96mm P&C's cam and Webers. Pertronix in the dist. and a Crane HI-6 CD unit. After a rebuild 2 years ago (PO's mech didn't locktite or stake the cam drive gear bolts and they ate the oil pump) we tried the standard depth Bosch copper plugs, at standard gap and at .045, car ran poorly. Extended reach platinums made a much smoother running engine. I've heard that some people have reported the extended tip hitting the pistons, but I havent had any problems. Plan to try the new NGK platinums in the spring, but they are significantly more expensive, a bit over $8 a plug.
Harvey
Old 01-04-2000, 04:43 AM
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I use Bosch WR7DP extended reach Platinum plugs @ .045". 74 2.0 with 96mm P&C's cam and Webers. Pertronix in the dist. and a Crane HI-6 CD unit. After a rebuild 2 years ago (PO's mech didn't locktite or stake the cam drive gear bolts and they ate the oil pump) we tried the standard depth Bosch copper plugs, at standard gap and at .045, car ran poorly. Extended reach platinums made a much smoother running engine. I've heard that some people have reported the extended tip hitting the pistons, but I havent had any problems. Plan to try the new NGK platinums in the spring, but they are significantly more expensive, a bit over $8 a plug.
Harvey
Old 01-04-2000, 04:44 AM
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Are the Plantiums the ones that have the electrode encased in ceramic?. May the gods of internal combustion help you if you foul them just a wee bit. I used to have those things in my 914 this was before I got it sorted out. The car would foul them at some point and then no matter how much I heated them or did anything with them they would work. I dont see the benefit of that kind of design. I read an article in Circle Track magazine (this is a pretty good magazine when it comes to the techy stuff of automobiles and easier to read then a text book) they had done a test on various plugs and their designs. There was absolutely no benefit to the fancy shmancy desings of sparkplugs. Zero. All you need is an electrode and the thingy that stick out at the end where the spark jumps across. In fact they said that the more of those thingy's that stick out at the end there are. The more it will 'confuse' the spark and reduce its strength. Reason being is that when the spark makes it's jump it only jumps to one of those thingy's. It doesnt make a multiple jump. Once and thats it. Until the next revolution.
As far as brands go I have the regular Bosch' on my 914 and wanted to get the regular Bosch' for my Volvo 240 but my chain FLAP's (NAPA, Need Another Part As$#*%#) said that Bosch doesnt make them. So to my chagrin I got NGK's, they seem to be pretty good so far but I dont think I'd use them on my 914. The 914 likes Bosch plain very much. My uncle use to use Champion on an old Buick he had once (86 LeSabre with 350) he said that the Champions were very sensitive to any foriegn matter in the combustion chamber (like oil or something, not that he had alot of oil in the chamber).
Old 01-04-2000, 06:28 AM
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The WR7DP is a flush tip, the NGK's I got for the spring are not. With the multi spark capacitive discharge from the HI-6 unit I haven't had any problems with fouling. I've got to let the carbs fill and play with the accelerator pumps since there is no choke, but other than that it starts right up.

Sorry for the previous double post.
Harvey

[This message has been edited by HarveyH (edited 01-04-2000).]
Old 01-04-2000, 04:09 PM
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To quote the old drag racer types: Ignition systems won't give H.P., they just take it away. If you make a change and the engine runs better, you are just correcting an existing problem. If everything in your ignition system is right on, the type of spark plug probably won't matter at all. If there is a weakness somewhere in your spark, the fancier types may help, kind of like a band-aid. The split-fires are hype, as was indicated by the class action lawsuit that forced them to pay a certain amount and to stop the deceiving advertizing. Having said all of that, I use the Bosche platinum in my turbocharged motor, running two ranges colder than stock. The cold plugs last better under boost and help fight knock, but can foul if not careful. Before I rebuilt this motor, it smoked like a cheap BBQ. Both oil and over rich mixture, and never fouled a bosch plug. That was when I was still running points. The plugs were so black that I couldn't see the electrode tip, and there was 1/8" of carbon built up on the heads in some places, but no fouling. As far as I'm concerned, that's all I can ask from a plug. Are they any better? I have no idea, but I won't switch from bosch platinum even if they are giving the others away. Just my .04

Last edited by turbo2.0; 01-31-2008 at 12:13 PM..
Old 01-05-2000, 08:40 AM
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The results that every body has had are very interesting. Mine have been very different. I currently have the following cars and here are my plug choices:

1972 914 2.0 - Bosch super 90
1972 911s - Bosch super 90
1966 Shelby GT350 - Autolite
1952 MGTD - Champion
1993 Isuzu Rodeo - NGK

I have used the platinum plugs before and had nothing but bad results. I used to drive a 1991 Audi 100 Quattro and it literally ran like it had a bad tank of gas when the platinums were installed. The 914 was a similar result. I did run a set of mutliple electrode Bosch plugs in an GTI I had in college and did notice some improvement, but as stated in an earlier post, that probably was helping old wires, cap and rotor, etc.. The MG runs twice as good on the $.99 Champion plugs than on the platinums, and there is no discernable difference in the Mustang. The truck is Japanese, I think it would run well even if you just jammed the plug wires into the spark plug holes sans the plug!(that truck has just shy of 190k on it and, knock on wood, has needed nothing but tires, brakes and oil changes - great car).

Just My $.02
-Scott S

[This message has been edited by S Schroeder (edited 01-05-2000).]
Old 01-05-2000, 11:03 AM
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I worked in a parts store for a few years and my prefrence for selling plugs was based on where the car was from; ie: bosch for german, ngk for japanese, ac for gm, etc. I have talked to many reps and for the most part a spark plug is a spark plug. All are mass produced and there are many sold with poor connections internally. Platinum plugs came out because of the new high capacity ignition systems, the tips wear longer thus giving car companies the ability to claim 100,000 mile tune-ups. But like a catalitic converter the platinum reacts to the heat and keeps the plugs cleaner at a lower temperature.
Old 01-05-2000, 12:30 PM
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Platinum plugs should never give bad results. Your's were probably mis-gapped. The gaps are set at the factory, so the clerk making $5/hr most likely gave you the wrong ones. I've used Bosh Platinum's in all of my cars except the one I'm driving now. I've tried Split Fire and A C Delco's Rapidfire and they both sucked a$$. Then bosh came out with the new platinum + 4's, they kick a$$. I installed them with a new K&N filter and got 6 mpg better. I know what you're thinking, maybe it was the filter. Well in my wifes vette I installed the platinum +4 and got 4 mpg better on the highway. Not to mention the smoke I had on start-up is gone. Platinum is a wonful electrode. It burns hotter and cleaner than any regular plug will do PERIOD!!! I'm not getting paid to say this either, however when I use a product, that I enjoy, I will tell as many people as I can. The fact that you never have to replace the plugs is worth the money alone. Thats my .02 cents worth, maybe I'm the only one out there who is getting results, but then you wouldn't see the product on the shelf would you???
Old 01-05-2000, 02:39 PM
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Remember that there are at least three different kind of Bosch Platinum plugs, and they are different.

One kind, I think it's the oldest, is rather expensive. It was spec'ed for some of the older 911s or 944 Turbos, I believe. Those are evidently high-quality plugs that work VERY well.

There is also the kind with the microscopic speck of platinum. Those are somewhat more recent, and a lot of parts stores really pushed them hard. They are much cheaper. Quality is fairly uneven, from what I hear. There have been a number of cases where the little sliver of platinum has slid out and bridged the electrode gap completely. This from my mechanic, who has seen it a number of times. He also tells me they foul easier than standard plugs.

All I know is that my old 1.8 would *not* start. I had it towed to him, he replaced the plugs and sternly told me to NEVER use the cheap Bosch Platinums. That (and one or two other things) got the car started and running fine.

The third type of Bosch Pt plug seems to be the same as the second, but with three more electrodes. I won't use it--you can if you want to. It's your car.

--DD
Old 01-05-2000, 09:53 PM
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I've only seen 3 types of Bosch plugs, I dont think dave is referring to all of them. I also thought that platnium meant that they were only encased in ceramic. But when I installed the platniums which are encased in ceramic to sort out the FI in my 4cyl 2.0 they were all but useless to me. The car would start and work but if I fouled them there was nothing in the world I could do to revive them. I tried putting them under an actylene torch which would help a little but then it happened all over again. Once I bought the plugs withouth the ceramic encasement it was easier for me to sort out the FI. The ceramic ones are probabably more suited for cars that are in excellent tune but to start they are not a good choice.
They are actually better for newer cars with EI.
Now that the 2.0 runs pretty good I can even run it so rich that I get black smoke coming from my exhaust (I only did that once when I had disconnected the MPS and forgot to reconnect it). I may also have been using the wrong tempreture on the ceramic ones which could also have contributed to it not running properly. If that was the case then maybe they would be benificial since like Dane says they work better in higher tempretures. But I find that highly unlikely it seems to me that it is the kind of plug that is overly sensetive.
But like I've harped before and Brain K had clarified there arent any benefits to multiple electrode designs. Except longevity, that makes sense, but its only a selling point for the mouthpieces of the plug manufacteres to crow about. It should be an excuse to maintain ones automobile.
Old 01-06-2000, 07:14 AM
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Well, it seems people either swear by or swear at Bosch Platinum plugs and that splitfires are definitely on the out. Guess I'll just keep running my Bosch W8DC's (one step hotter up here at a mile above sea level, than the W7DC's spec'd for the car). Never fouled one. Runs clean. Passes emissions with flying colors with the MSD-6A. Thanks for all the experience and commentary.

Pete
Old 01-06-2000, 02:27 PM
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