plugfouling

[william vd Sman]

I just checked the plugs (NGK8ES) on my 1200 HF and observed that cilinder 1 and 3 (longer inlet poort) plugs were much darker compared to nr 2 and 4. sometimes in heavy traffic one cilinder even cuts out due to a wet plug.
Is this normal and due to the concept or can this be solved?
I have Dell Orthos's which are perfectly balaced using a 4 barrel digital vacuum tool.
previously I used Bosch super 4 plugs and never had problems with fouling in warm city traffic but now with the NGK one plug occasionally fouls and the car runs on three cilinders.

[P. de R. Leclercq]

William,

The BP8ES is a very hard plug; are you sure that you need something as "cold"?

I know that you are running quite high compression, but BP7ES is perfectly satisfactory in the turbo-charged Integrales and Themas, so I suggest that you try a set of these and see how they work.

Paul

[william vd Sman]

I used the BP8ES because this plug is in the list supplied to viva-lancia.com technical Q&A by Andrea Nistri for the 1300HF wich has about the same spec as my engine.
Even if they are to cold for my engine it does not explain the difference in soot build-up between 1&3 and 3&4.

[P. de R. Leclercq]

Well I think it's probably a bit hard - otherwise there would probably be no fouling. What do the unfouled ones look like?

The difference could be a function of the port length, the modifications you have made etc. I recall that one tuner used to run 2 and 3 a bit richer because tests on the exhaust manifold (on the dyno) showed that those two cylinders run hotter!

Paul

[Huib]

First, I put together the list of sparkplug from the Lancia documentation such as workshop manuals and user booklets. The NGK type numbers were provided by NGK.

Note that the www.ngk.de now has a list giving the correct types for most Lancia's from the Artema onwards.

Click here for the 1.3HF

You probably have oil consumption. Did you hone the cilinders and put new piston rings when you re-assembled your engine?

[william]

Why the assumption that I have oil consumption? The story is this: The headgasket blew on the track a few weeks ago. When I had the head skimmed I asked the machinist to install valveseals on the guides which were original Lancia and not prepared for seals. The reason was suspected oilseapage through the guides. Before I had this trackevent I changed the Bosch super 4 plugs for the original BP8ES (following the list on Viva-Lancia Q&A) because I found the Bosch plugs very black with soot and oil. No misfiring or fouling ever occured with these plugs though! The contamination of all 4 plugs was the same. With the NGK's the difference in collor between 1/3 and 2/4 was very pronounced. I tried to compensate for the black plugs by weakening the mixture with the mixturescrews 1,4 turn in. This did not help and in heavy traffic one plug stopped working altogether. Yesterday I changed the NGK's for the Bosch plugs and the engine ran better immediately. Even idling for 15 minutes didn't seem to bother my beloved HF.
I will check the plug tomorrow. But it seems that the Bosch plug are the preferred choice by my engine.

[Huib]

Why the oil consumption? Well, you say so yourself! Changing the mixture did not help. The soot is not falling from the sky. What remains is oil.

[william]

I allways thought that soot is fuel and carbon buildup is oil. But tomorrow when I check the bosch plugs I will know if the valveseals helped.

[Huib]

I am not sure it is that clear cut.

The misfiring will probably disappear by changing to a hotter plug like the BP7ES or BP7E or BPR7EVX or BPR7EIX or Beru UX56.

I assume you have the carbs set up and adjusted correctly. BTW it is important to arrive at the desired mixture screw setting from the bottom up. However the mixture screws affect the mixture at idle and low power settings.
If you spend more time driving than idling the float levels and jetting are more important.

If the float levels are incorrect you would have the problem on 1 and 2 or 3 and 4 or all 4. If there is dirt in one of the air jets, you would have the problem on 1 cilinder only

[william vd Sman]

I just removed the Bosch plugs and they are all the same! Very strange this, as the NGK's (BP8ES) show very different for 1/3 and 2/4. The idling is much smoother with the Bosch plugs also after long idling which indicates good combustion. Surely the type 8 is to cold for the Fulvia but I wonder if the hotter 7s would improve much...