Some time back I had the local Nissan dealer install a set of NGK laser iridium plugs cause they have a tech who has done it on my car before; tough access due to my Stillen manifold and is a pain to do. He had noted that I had a slight oil leak on the pass side valve cover (may have fouled a plug or two); I declined the repair due to cost at that time.

I am going to get the Z in to them and get that gasket replaced. I will have them check all plugs and "if" one or more on the pass side are fouled at all due to oil issue would it be ok to have them install 1 or 2 stock NGK iridiums (one step colder)? Or would that mess things up having 4-5 lasers with one or two regular iridiums?

I thought I'd run this past you intelligent experts here so I can be ready to possibly need to have an entire set of plugs replaced. These Laser models that are in the car cost quite a bit with not many miles on them, but there had been at least one plug prior that had some oil leak issues that had traveled down and maybe caused some fouling; the plug looked bad when I examined it. Thanks in advance!

*I asked the service guy a minute ago and If I need a whole set, they would sell them to me for $18 per, which is basically what they cost; I had figured that a dealer might double that price.

 

No answer for ya Randy; but, how badly fouled could they be that a good cleaning couldn't fix 'em? Now I realize that we exist in a "throwaway environment" these days but back in the day, we all used to have those little "spark plug cleaners" that ran off the cigarette lighter - wait, excuse me, the "accessory plug" - and they did the trick on our typically oil/fuel fouled ignitors. No, I no longer clean spark plugs either; but in a case like this, a good solvent soak and wire brushing maybe? Oil fouling shouldn't ruin a relatively new plug.

Reminiscing sidenote: My first job at the parts counter, we used to sell Champions for a buck a piece. Few years later when I was at Datsun, the "exotic" NGK Platinums came along and they went for a whopping $2 a plug! But we had to have the latest and greatest! (And still fouled them cuz we couldn't ever get our CARBURETORS right!) Laff....

 

I'm inclined to agree with Mic, the Chevy I drove as a teenager fouled the plugs regularly and I had a can of gas or mineral spirits and a wire-brush bc I was broke and the plugs were fine, not baked-on. However in your case you do not want to pay a shop 1/2 hours to clean fouled plugs, cheaper to buy new @ $100/hour shops charge for time. I cannot imagine a problem from mixing plug types, and the -1 colder is what your Vortech kit should run. As complicated as the modern engines are, plugs are not rocket-science. Metals and shapes may change but still the same concept.
Let us know what you decide, and how it goes!

 

Oh right... that's a good point. Was thinking DIY. If it's in the shop for all the work then yeah, just drop some new, off-the-shelfers in.

 

Thanks for the input guys! Yeah I used to have a little kit and would keep them clean. My main issue is to get the valve cover leak taken care of and try to work with them as to how oil could be getting into the tube leading to the plug/s.

Have you guys heard of this sort of thing happening on a Z33; oil leaking from valve cover causing issues with a coil pack or down to the plug itself? I think I'll stop by the dealer and try to get an explanation as to why they had recommended that the "valve cover be replaced on pass side" (from my invoice) and take it from there.

*Man I miss how easy it was to work on my '77 280Z!

 

Yes. it's common. The valve covers have built in non-replaceable seals for the spark plug tubes. When they start leaking, you have to replace the entire valve cover.

 

Thanks a lot i8acobra! I spent quite a bit of time looking around online and I didn't realize that there are 3 seals on each of the 3 spark plug tubes both sides. That now makes sense to me; I had assumed possible issues with the valve cover gasket and that is not the problem. I guess that I've had some oil leaking into one or more tubes on the pass side. Yep, it requires full replacement of the cover.

The car is running strong, but I'm going to call and get an apt. made today and get this taken care of. Their quote from Feb. was a good $800+ but looking around at covers there are some cheap crappy ones; OEM run about $300, so now the quoted price sounds more reasonable with all of the labor required to access that pass side cover, etc.

 

And herein Randy explains why all of my "projects" are 40+ years old. Haha!

Changing oil/filter, plugs, wires, adjusting valves and replacing the VC gasket (psh on valve COVER replacement!) on my S30s: 35-40 mins (total including jacking and jackstand placement). and cost about $30. (Then again, newer cars don't really require valve lash adjustments. )

 

Cool stuff Mic!

Yep, I'd go grab plugs, cap + rotor, wires for $25. and basic minor tune up in 1/2 hour! *I'll always love those straight 6's and still think it's one of the coolest/toughest engines that were mass produced, plus all of that room to access + work! A friend of mine who is a master mechanic and now owns 4 shops in No. Utah worked on my '77; he raced cars also and does full performance builds and I'll never forget him telling me that these Z engines (back in the day) were "bullet proof" and had always been one of his favorites.

*Got an apt. for Mon. a.m. to get the valve cover replaced. They will also inspect the 3 plug tubes and plugs for any oil and clean it up if needed.

*Edit: Got it all done; a lot of labor costs due to my Stillen manifold, etc. being in the way on that pass. side, but nice to have that cover replaced with spark plug tubes sealed and their best tech giving the all good on his inspection.