Spark plug gap

[vilant]

I was told from the auto parts store clerk that NGK recommends .05" gap. But in Solutions it says .043" on a 91'. I have a '90. My question is: What gap size is correct .05" or .043"? TIA

[efnfast]

This was the answer I got from Mr. Haibeck

Hi Steve,

For high load operation I recommend a spark plug that is one AC heat range cooler than the OE plug. The best spark plug is the NGK TR7IX. Part number 3690.

It has a tapered seat. All LT5's are machined for both tapered and flat seat plugs. Carefully open the gap to .050"

Best of luck.

Marc

[vilant]

Thank you very much.

[efnfast]

Originally Posted by vilant

Thank you very much.

Piece a cake. That's what I did, with no regrets.

[vilant]

He wasn't kidding about being careful. How're you suppose to bend the ground without breaking that tiny tip? I'll try needle nose.

[efnfast]

Don't break 'em, they're expensive. My gaping tool had an end to open the gap, but yes, be careful.

[efnfast]

I also read somewhere that not all the heads were tapped for both. The plan was to over torque by 25 pounds to kinda make a tappered seat.

Marc has seen plenty of heads and I would ASSUME he's right. I think I over torqued some, maybe not 25 pounds, backed them out and retorqued.

[scottfab]

As with many issues this has been covered as far back as 98 on the mail list. (and maybe earlier) Unfortunately the archives on the Club pages only go back to 2000.
This is the earliest found there:
http://maillist.corvettemuseum.com/c...R1NET&P=R21105

[vilant]

Thanks, fellas. The new plugs had the same end as the old ones. I torqued them to 22 ft/lbs, per the FSM.

[scottfab]

At least you don't have to worry about the gap effecting the dwell or timing.
Ah the 60s ... =D>70s.
Some things really have improved.