camaroguy7

I found a set online for cheap, I contacted the seller and he said they came pre gapped at .59'...is that the right gap? Or should I lower it? Bone stock 04 gto with 139k on the clock.

Russ K

iTrader: (1)

GM has a TSB about a change up plug with a .040 gap. So you need a TR5.

Russ Kemp

camaroguy7

Sorry when was this posted? Hmm Iv been hearing a lot of good things about the tr55...so .40 is the way to go with the tr5?

96capricemgr

iTrader: (1)

Same plug, different pre-gap.

camaroguy7

So either plug is fine? With the .40 gap

Russ K

iTrader: (1)

No, the TR55 is designed for a .060 gap. Bending the ground strap to make it a .040 gap will make for a very crooked plug gap. Just get the TR5.

Russ Kemp

camaroguy7

Will do, thank you!

Robert Cantu

iTrader: (2)

I gap my TR55 on my 02 WS6 to .054.

96capricemgr

iTrader: (1)

According to NGK the TR55 is .054.
The GM TSB specifically states the change in gap is due to the OEM spec changing from platinum to iridium so why would you apply that to a plug of a third electrode type?

Russ K

iTrader: (1)

Because the TR5 is the correct plug as per NGK's application chart.

Russ Kemp

96capricemgr

iTrader: (1)

Such things are often a loose guide, why would you want such a small gap with a copper plug when we know old distributor setups with less coil potential are fine with larger gaps.

Not to mention OEM plug guidelines are for 100k tuneup interval and have to leave some room for gap erosion, not saying TR5 is a bad plug choice, just saying there is more to understand than you are even willing to consider.

Robert Cantu

iTrader: (2)

When I checked mine were at .055 to.057 gaped mine all at.054. I've heard anything from .050 to.060 is optimal for the LS1 and TR55.