Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing GDI plug examination May 2020

We've been talking about the Ford 4cyl plugs for a while on and off. The Duratec seems to have a remote coil pack, whereas the GDI has four coil packs - one over each spark plug.

When I did this job on my Duratec, it showed some water ingress, and the plugs were progressively more corroded front to back.

When we took delivery of our new GDI at BHM, the journey home was in torrential rain, as it often has been in this Morgan. within 500 miles, I fitted an engine cover to keep water away from the plugs. This was 2016. Since then we've done 7,500 miles. I reckon that over 4,000 of those miles has been in heavy rain. One of the great delights of Morgan, is to drive roof down in rain. I do it when I can. Once coming back from Oakmere we had heavy snow over the Snake Pass, and that was great fun, but the roof was up.

Anyway, to check the plugs, first I removed my engine cover, which is two nuts. Then the coil packs are fastened using a single set screw on each. The electric plug is a three pin latched connector, and the unlatching tag is white. With these disconnected, the coil pack pulls up and out. The plugs are deeply recessed, and need a small modern plug socket with a medium length extension, and ratchet handle. It's important to hold the tool exactly vertical to undo without damaging the plug. They all came out easily, with no trace of water or corrosion.

I've always used coppaslip on plugs, but it seems that ceramic grease may be preferable. Either way, note that lubricating the threads may affect torque wrench settings. Personally I use "feel" based on many years experience, sometimes having sheared things off in the distant past. This time I used ceramic grease.

Before applying the grease, I cleaned the threads. There was brown gum about half way up the threads, and using a bit of WD40 and a fingernail/rag combo, most of this can be removed. When unscrewing, the threads were "tight" and sticky. Refitting the plugs went in all the way easily by hand. Take a bit of time to start each plug, keeping the socket absolutely vertical. Plugs with a taper seat lock onto the taper immediately they tighten up from finger tight. It's not the classic quarter turn you use with conventional compressed washer plugs, so literally a tiny nip with the socket from finger tight is all it takes.

Then, replace the coil packs, and fastener on each, and reconnect the electric plugs. It's that simple. Around a leisurely hour of "Lockdown Engineering" time.

Image 1: Engine cover removed. Four years on, and lots of wet driving...….you just wouldn't know.



image 2: Plug number four, usually the least affected by corrosion and water ingress. Plug type is CYFS12Y1



Image 3: Plug number 1. The most exposed, and often the most corroded.



Image 4: Cleaned plug with coil pack.



So the thing is, if you fabricate an engine cover to keep the water out, it also keeps the engine remarkably clean. And checking the plugs is quite a simple job.

Ultra high temp ceramic grease is the correct stuff to use. With EVERY new car I acquire one of the first things I do is remove the plugs, apply ceramic anti-seize coating and replace. Then I know they will come out easily in a few years time. Lubricate the rubber connectors with a litttle silicone then they will slip over the plugs more easily. The other essential job to do with any modern GDI engine (which means basicly all latest generation gasoline engines) is to run the crankcase breather pipe (from the rocker cover on your GDI) to atmosphere or a can open to atmosphere and securely plug the inlet manifold port. This is to eliminate totally well-documented inlet tract and inlet valve fouling problems.

Interesting topic on breather discharge.

What is the car makers reason for returning the crankcase breather into the inlet?

Back in the day the engine breather, with or without catch tank, served to reduce internal pressure build up.

Is this all related to reducing emissions? Any potential MOT test issues? Any influence on performance and/or mpg?

From my point of view it is still the case today. returning the crankcase breather into the inlet I would maintain. I am not familiar with today's GDI engines with the exception of the people carrier whare I make no modifications. As Griffo writes, there can be a conflict of goals. Coking vs. reduce internal pressure build up.

Yes, it must breathe but that is achieved either by venting through the inlet, or to a catch tank. Emission control is why manufacturers feed back into the inlet so that the fumes get burnt. However, GDI engines do not have any fuel in the inlet tract, it’s air only as the fuel is injected straight into the cylinders. This means that the backs of the inlet valves do not get a wash of petrol, only air. So if you introduce crankcase fumes to the inlet tract, over time (50k miles?) carbon can build up excessively on the backs of the valves and seats.
Manufacturers are driven by emission control rather than engine longevity!

Deejay is absolutely right. Though, depending how the car is driven (short journeys make it worse), it can happen in less than 50k miles. Heinz, there is no conflict of goals -- if the breather is effectively open to atmosphere there can be no internal pressure buildup.

Thanks for explanation, Deejay and griffo. I was not thinking about the differences which come with the design of the direct injected engine.

Dave, simplest and safest way to refit deep recesses spark plugs is to get yourself a short length (6-8”) of rubber or plastic straight hose where the internal diameter is sufficient that the plug ceramic is a push fit and hold the plug tight enough that it won’t fall out.

Use this as a plug ‘holder’ to insert and start the thread, it makes it most unlikely you will cross the threads as your hose will turn rather than the plug if it starts to get tight!

The hose can be used to screw to hand tight then you use your rubber insert type plug socket and extension to nip up the plug until it bottoms. I then also don’t use a torque wrench and give them a 1/8th turn and that’s it.

BR
Colin

Thanks for the explanations guys. Feel a small project is about to break out!

I did the mod to my plus 4, blanking off the inlet and routing the cam cover hose to a catch tank and then to atmosphere via a filter. I’m sure I posted some pics on here when I did it but no idea how to find and link them here.

If anyone is interested I’ll try and find the photos. It’s an easy mod.