Denso Iridium Plugs Legendary Det Resistance...

http://www.sxoc.com/vbb/showthread.php?t=134070

Scary stuff!

Bri.

oooo looks expensive

Had exactly the same happen with HKS 40's (rebadged i think) Use cheapo NGK's and replace every 3000 miles. they NEVER break. (we use these on Kawasaki race engines for exactly the same reason)

Dont really think that can be blamed on the plugs this time,if the fuel pump wasnt relocated on its bracket properly, and sucking air at High Revs then i dont think ANY spark plug would be able to cope with that for a prolonged period of time.

If you look at the thread you will see the guy himself actually puts the blame down to the Fuel Pump fitting fault and not actually the plugs.

Michael

Dont really think that can be blamed on the plugs this time,if the fuel pump wasnt relocated on its bracket properly, and sucking air at High Revs then i dont think ANY spark plug would be able to cope with that for a prolonged period of time.

 

If you look at the thread you will see the guy himself actually puts the blame down to the Fuel Pump fitting fault and not actually the plugs.

 

Michael

But the det caused did not melt the pistons, only the electrode tips on the plugs which in turn damaged the pistons...

Electrodes breaking off dont melt pistons mate but they can damage them as we see........it takes a hell of a lot to melt a piston though.

If the car was running lean because the pump wasnt sucking up fuel,as it was, and the plug tips HAD remained in tact.........the pistons would have still been knackered cos of the heat in the cylinder in turn melting a piston or two maybe more in time, no ? So if the plugs HAD remained in tact..........the damage would possibly have been substantially more with melted pistons and a fooked block / bores ?

So the plugs arent really in the equation. Because the AFR problem was the main factor in the chain of damage. The plug damaged the top of the pistons.....but it could have been worse if they had kept in one piece and the car had kept running lean.

The damage caused to the piston in this instance is physical.......as in chunks out of it................not heat related from a lean AFR which was apparent in this car,this in turn caused the plugs to overheat by the looks of it and tips to break off. The problem isnt plug related, it was AFR related due to a fuelling prob.

Michael

I can't see how you can blame the plugs either ???

Mine wasn't running lean at the time, but the tip broke coz of det. which was caused by a massive overboost (2.3 bar) due to the AVCR failing.

The det causes a high frequency resonance that can damage the superthin electrodes on this type of plug.

Had exactly the same happen with HKS 40's (rebadged i think) Use cheapo NGK's and replace every 3000 miles. they NEVER break. (we use these on Kawasaki race engines for exactly the same reason)

One thing that was mentioned to me a while back:Is it advisable to have plugs that require such regular changes? After all, the car was designed for long-life plugs, and wear could be an issue over time. Thoughts?

I didn't 'blame' the plugs

Just illustrating that these iridium plugs seem to be a little on the frail side. Perhaps playing devils advocate here but I reckon good 'ol NGK coppers would have withstood the abuse from the actual problem. Who's to know if the owner would have realised there was a problem before there was det damage to the pistons though....

I didn't 'blame' the plugs

 

Just illustrating that these iridium plugs seem to be a little on the frail side. Perhaps playing devils advocate here but I reckon good 'ol NGK coppers would have withstood the abuse from the actual problem. Who's to know if the owner would have realised there was a problem before there was det damage to the pistons though....

Ah got u now, agreed...........kinda lol

One thing that was mentioned to me a while back:Is it advisable to have plugs that require such regular changes? After all, the car was designed for long-life plugs, and wear could be an issue over time. Thoughts?

I would agree with the theory of the car being designed to use long life plugs but in the majority of cases, the car is rarely kept as design and therefore the parameters would change.

Syed - what wear could the plugs cause? They either fire or they don't. IMHO fit coppers and pay a fraction of the price of iridiums, any misfires just replace, I personally would change the plugs every 2nd or 3rd (depending on interval) service. The benefit of this is getting an insight into how your car has been running, once you see the used plugs.

Syed - what wear could the plugs cause? They either fire or they don't. IMHO fit coppers and pay a fraction of the price of iridiums, any misfires just replace, I personally would change the plugs every 2nd or 3rd (depending on interval) service. The benefit of this is getting an insight into how your car has been running, once you see the used plugs.

Got to agree with tDR on that one, unless you are running a crazy powered Drag Car or the likes, theres no point using Iridium plugs. Its all a big con put into our heads by the big tuning companies. Copper ones do just as good a job, and as long as you have the correct heat range of plugs, or one range colder on uprated engines, 99% of the time you wouldnt know if you had copper or iridium fitted anyways.

Michael

It was more along the lines of wear/damage to the plug threads on the head itself with such regular changes, than the type of plug used. Hence the reasoning for longer life plugs. Would not be a consideration for the weekend cars, but how about those clocking up 10K+ per year?