world products spark plug reach

[engineman1642]

i have a set of older sportsman II heads for a customer and the plugs are about 2 threads too short. calls for .460 reach..do i just grind back chamber to right depth or does some one know of another fix.

[PRH]

I just ground the chamber on the ones I’ve done.

[gruntguru]

Is extending the counterbore (sink the plug gasket face) on option? Would extend the plug further towards the chamber centre. Too close to piston crown?

[PRH]

Is extending the counterbore (sink the plug gasket face) on option? Would extend the plug further towards the chamber centre. Too close to piston crown?

The older ones I was doing(they were new at the time) used tapered seat plugs.
I don’t know if they’re still that way or not.

[engineman1642]

they are taper seat but don't think machining the tapers would be an option for customer.

[BOOT]

My newest set needs index washers or grind a thread off the plug, yes I am using the short .460 plugs.

[Walter R. Malik]

they are taper seat but don't think machining the tapers would be an option for customer.

That would be the bset answer however, simply chamfering the plug hole in the chamber to remove those threads wold work.

[BlitzA64]

Is a cutter made correct/repair the taper seats? I have run across some seats that could use some "tweaking" for the correct plug depth

[PRH]

These heads were pretty common to see in the shops I worked at 25-30 years ago.
Selling new ones, or freshening used ones.
That was a while back for sure, but the way I remember it is...... that was pretty standard fare for those heads.
The plugs always looked “short” in the chamber.
I remember thinking, how can they constantly get that wrong?

Pretty much all the used ones I had come in had been run that way with no one the wiser.
Some customers had it corrected, some didn’t.

[engineman1642]

customer has had problems with pre ignition ,so just trying to eliminate as many factors as i can.

[6.50camaro]

I'm just about finished working a set of these for a 383 bracket motor, out getting milled back to the cc's I want . I ground the chamber and layed back the area around the intake valve . I think the problem arises when the heads are drilled for straight plugs . It appeared to me that the chamber shape was really designed for angled plugs. Dan

[engineman1642]

these are angle plug heads.just did what Walter suggested,chamfered from combustion side ,deburred moved on .Thanks