LS swap into a 240z using Sanderson shorty headers. Spark plug boots #s 3 & 5 are getting burned (right through the boot). I've installed DEI sleeves but that didn't prevent it from happening again. I even hammered a little dent into #5 tube for clearance. I'm thinking I may have to re-route #3 and #5 header tubes unless someone has a better idea.

 

pretty common to switch to 90* plug boots. The clearance on these headers is a joke though, for what they cost. I know, I have a set in a box in my shop.........

 

I wouldn't think 90* boots would fix the problem, the tip of the plug is right next to the tube. The burn through is happenning at the bend. I am going to need new wires after this so suggestions would be appreciated. MSDs are on it now, any other brand handle heat better? The MSD boots are crumbling.

 

Accel makes shorty plugs. not sure if they make a listing for the Gen III/IV engine.. try searching.

 

I'm running a set of Sanderson headers from JTR on my 240z. MSD makes a set of multi angle boot plug wires for LS motors that allow you to bend each plug boot to any angle you want. No sleeves needed. 8 mm wires and only $60 per set too. I have zero issues.

 

The tip of the plug on #5 is at most 0.5" away from the tube. Is this the same on your car? I'm assuming we have the same header design but I could be wrong of course. The combo of shorter spark plugs and adjustable boots would definitely help, or completely solve the problem.

 

Yeah, that one is pretty tight. I remember having to use a wrench on the top of the plug socket instead of a ratchet to get the plug in. But the MSD wires bend right at the top of the plug. Mine clear. You can kind of turn the coil plug to help angle the wire away from the header. The JTR headers could really be improved, but at least someone makes them for our cars.

 

^^^^^^^Wow, I don't get it. My MSDs have about a 60* boot and they were angled as far away as possible. The set up looked virtually identical to yours. #5 boot literally crumbled like a piece of cornbread and the engine started misfiring. This was on my test drive! Forget about a track day, there would be cornbread everywhere. The wires are brand new too.

 

Would the stock metal spark plug shields help?

 

I had to modify my Sandersons for fitment in my chassis. I finally re-routed #3, it does have a right angle boot. #5 looks close to the pipe, but it really isn't, just the camera angle. Since doing that no more problems after 15k miles.

Pat

PS those are Taylor wires and components made to make the longer one.

 

Looks pretty roomy in there around your plugs, nice job. I think that's what I'm going to have to do.

 

Probably, but if I run the car hard (which I will), heat soak will eventually win.

 

Wow, you must have gotten a bad set or something. One of my plug boots is melted a bit from it hitting the pipe. But the boot is still pretty rubbery, not brittle. 3 years old.

I could see where some headers might be closer than others, but like I said I can't get a socket and ratchet on that plug so mine is pretty close too. Only other thing is maybe your tune is off causing higher than normal exhuast temps. But even still, crumbling silicone doesn't sound right to me. Hope you didn't get some cheap MSD knock offs.

You know if you still have a receipt I would give MSD a call and see if they will replace the wires

 

Yeah I'll do that. I doubt they are knock offs, they came in an MSD box with literature. Maybe they had a bad run of boots or something.

 

Thought I'd update this thread. The solution for me was to perform a little header surgery. I re-routed two tubes on the driver side and one tube on the passenger side and wrapped them both. Amazing how tough that ceramic coating is! I thought I could use the TIG torch to cook it and then sand it off. No way, had to file, grind, and sand it off.

Thanks for everyones input.

Passenger header:


Forgot to take a pic of the driver side, too bad, I was actually proud of that one.

 

I'm using 2 of these: http://wrenchrat.com/sparkarm/

One of them is arcing though. Not sure if I'd 100% recommend them for this reason, but supposedly it's because the LS coils are too powerful (or at least that's what I was told when I called about the problem).

 

I haven't seen those before. Is it arcing straight through the side?

 

No, it's arcing at the swivel joint. It's only one of them, and it's only in the #2 position.

I swapped the 2 I had, and it didn't arc for a while. I noticed a little popping one day, went out and looked, and sure enough, it was arcing on #2 with the good one that hadn't sparked on #4.

Maybe I'll swap the coils on #2 and #4 some day to see it it doesn't make the other one arc.

Not sure what I'll try next, but I really don't feel like pulling the header. Although, I am dropping the trans next week, so the exhaust will be unbolted... Hmmm....

 

Yeah maybe a little header surgery in your future too.

 

Weld done!