Evening all,

 

After having my zed back on the road for about two days, it’s now back off the road. Although this time it’s for planned maintenance.

 

When I purchased the car I was made aware of a small oil leak from one of the valve cover gaskets. I started the process of removing the plenum yesterday, but was held up by crappy weather and an injector connector. Today I managed to get the plenum completely off and replace all four valve cover gaskets and half-moon (or half-circle) seals.:biggrin:

 

Anyway, the reason for this thread is because I noticed one or two things I was unsure of when I had the plenum off. Firstly, the plenum seemed to have quite a bit of oil in it, with some cylinders having more than others. I’ve tried to take some pictures below, although I think the lighting doesn’t show it very well.:blink:

 

Does anyone know where this would be coming from, and is this something I should be concerned about?

 

 

 

 

Next, I noticed that the spark plugs had seen better days. Is there any particular make/model that people recommend? I’ve only brought OEM for previous cars so don’t really know what ones to go for…

 

Thanks

Spark plugs NGK PFR6B-11B

If you have the stock PCV system oil is constantly ingested through the inlet track, in vapour form. If you look at the PCV location you will see its towards the rear half. A thin coating of oil in the plenum is therefore normal. If the plenum is swimming in oil and blue smoke is resultant then further investigation is required. If you've got a few quid, they are fairly cheap, I'd suggest replacing the PCVs while your there. In fact replace what you can.

Priority to;

The fuel line that connects the rails, these shrink and leak during winter.

Ohm test the injectors, if ones starting to fail it's so much easier to sort now then once back together.

Any small coolant pipes, such as heater matrix pipes.

 

Oh and I'm sure you won't but don't reuse the plenum gasket.

Edited June 12, 20169 yr by Stephen

Unless it is excessive amounts of oil it is normal, stock sparkplugs are best NGK PFR6B-11C suit UK fuel and driving conditions.

Jeff

Thanks guys.

 

Some of the cylinders had a thin coating, whereas others seemed to be coated in quite a bit of oil. There was a fair bit of oil in the plenum, so I’m going to give that a clean before putting that back on the car. Anyone have any suggestion/experience cleaning inside one?

 

I’ve looked on Z centre and seen that they do a PCV silicone hose kit with PCV valves. Going to contact them tomorrow and see if this will fit my NA engine. I want to do the hoses anyway as they’re rock hard and seen much better days.

 

Have a new plenum gasket to install and I’m also going to replace the IACV gasket and probably the balance tube O-rings. Looking at silicone hoses for the IACV and brake vacuum hoses (in addition to the PCV hoses) as the rubber doesn’t look in great shape

 

Also going to look at ohm testing the injectors as per Stephen’s suggestion…

Give Mike at MJP a call for your OEM parts mate..... Best source on the forum and certainly a great service!

Give Mike at MJP a call for your OEM parts mate..... Best source on the forum and certainly a great service!

 

I thought Mike was still outta action?

I thought Mike was still outta action?

 

Is he; I've no idea mate....?

Me either. I certainly haven't heard he's back to normal.

I got parts off Mike a couple of weeks ago do unless he's had complications he's about

I know many people have posted to your reply already, but I use iridium NKGs

 

http://www.ebay.co.uk/itm/Z32-300ZX-FAIRLADY-6-x-Ultra-Colde-NGK-Iridium-Spark-Plugs-UPGRADES-8-/160856266849?fits=Model%3A300+ZX&hash=item2573c7d861:m:mgO5rHmvH4Ptmg-ZBPlbYMw

I ended up getting a few things from Z Centre, including a set of NKG iridium plugs. I ordered silicone hoses from Z1 Motorsport. Luke didn’t have the silicone PCV or air idle hoses in stock when I called so they’re coming from the states.

 

I’m waiting for all my bits to arrive before I put the car back together. According to FedEx my parts are currently in Memphis, TN.:sad:

 

I decided to spray inside the plenum and lower manifold with some intake/carb cleaner, which did a good job of removing most of the oil (and one or two spots of red paint :crying:)

 

I read a little while ago that Mike was not around and I haven’t seen anything since to indicate that he is now available. Don’t know what was up with Mike so I didn’t want to risk annoying him with questions about car parts…