3 Node Spark Plugs

[ChrisG]

Not so much a question, but something I have found out.
On my 72 1.7 I am currently using 3 Node Plugs by NKG.
Instead of having a single tip which is used to create the spark, these have three (!) tips which create a strong and reliable spark.
Since fitting them I have had no misfire, blow backs or backfires!
If anyone is interested I will try to find the part code out.

Chris

[Dave at Pelican Parts]

Are you planning to do a back-to-back test, NEW "standard" plugs versus the (also new) triple-electrode plugs? I would be interested in hearing the results of that!

--DD

[ChrisG]

I originally fitted a set of standard plugs which were in the car for around 8 months.

One of the plugs fried! Tip melted and blew.
Generally over a period of time, the engine performace dropped significantly as the plugs began to choke with minor carbon build up.

When I fitted the new triple core plugs, the engine reacted much better - the power difference was amazing.
Those have been in 8 months now and even though I think they will need a clean up soon, they still work and the engine is running fine.

I would love to back to back test the plugs in comparison with another 914 doing similar mileage but to be honest I think I will have trouble finding another 914 owner over here.
I know of a few locally (ie 50+ miles away), but we don't talk often. There are only 100 examples on the road over here (at last count)so popping down to a mates house to check on his 914 is an impossiblity! LOL!

Lets just put it this way - I have tested the new plugs against the old plugs in a minor sort of way - I took it down to a local garage where they put it on a CO Meter and tested the percentage of unburnt fuel.
The result on the standard plugs was higher than that on the three core plugs. More fuel was getting burnt hence a minor increase in BHP is expected.

Hope that helps

Chris

[This message has been edited by ChrisG (edited 03-16-99).]

[Patrick]

I have always wondered if there was really something to those plugs. My old Audi 4000 came from the factory with the Bosch equivalent and my VW Cabrio came with the NGK's.

[Bobbitt]

Multi-tip spark plugs have been around for a while. They are pretty common on aircraft engines where misfiring/stalling due to a fouled plug could be bad (fatal). I have seen plugs with up to 8 tips. I don't know if the extra reliability comes from less likelyhood of fouling all tips or if there is some scientific reason. Either way, they do work. Of course, going to a platnum plug can really help too. The platinum does not erode as quickly, so the gap remains consistant.

[Dave at Pelican Parts]

One thing about platinum plugs--there are two main kinds that Bosch sells: the inexpensive ones that everyone tries to sell you, and the VERY expensive ones.

The latter are OEM spec'ed for some hi-po cars like 944 Turbos (if I remember correctly), and at least some of them have multiple electrodes. They work just great and apparently have little or no problems. Except for being rather pricey.

The cheap ones, however, are something my (admittedly rather conservative) mechanic just HATES. There have been real QC problems with them in the past, and he's seen several where the sliver of platinum has slid out and bridged the gap completely. He has seen others with different problems that I don't recall offhand. He also claims that they are more prone to fouling in a rich-running motor than most plugs. He thinks they're fine for modern closed-loop FI cars, but not for older carbed or open-loop FI (that's all 914s except for a very few Six conversions!) cars that tend to run a bit rich.

I was talking to the owner of a 55 'Vette today, and he said that when he installed platinum plugs, they fouled very quickly. One more data point.

If they work fine in your car, that's great. But I know several people who won't use them for the reasons stated above.

--DD

[This message has been edited by Dave_Darling (edited 03-17-99).]