Stupid plug gap question (?)

[Finnerty]

I'm replacing the plugs in my 1977 Mercrusier 454, as per the manual, but the plugs I bought have a gap of .025, whereas the Merc manual says .035, should I regap or leave them as is? To put it another way is the correct plug gap SPECIFIC TO THE PLUG OR TO THE ENGINE?

 

[Don S]

Re: Stupid plug gap question (?)

What spark plugs did you buy?

 

[Finnerty]

Re: Stupid plug gap question (?)

I bought NGK BR6FS (from my local Mercruiser dealer).

 

[ziggy]

Re: Stupid plug gap question (?)

but the plugs I bought have a gap of .025, whereas the Merc manual says .035, should I regap or leave them as is?

regap them. spark plugs never come gapped to what is needed. least not any i've ever got... gap to mercruiser spec.

 

[Don S]

Re: Stupid plug gap question (?)

Odd they all were at .025 that NGK plugs normally come pregapped to .032, but yes they need to be regapped to .035.

 

[Finnerty]

Re: Stupid plug gap question (?)

Odd they all were at .025 that NGK plugs normally come pregapped to .032, but yes they need to be regapped to .035.

Only checked two of the eight plugs before posting, thanks for the advice...Dave

 

[sschefer]

Re: Stupid plug gap question (?)

.035 standard gap for all GM carb'd engines with HEI ignition. Actually, now that I think about it, .032-.035 it's pretty much standard for all gas engines that use that style of spark plug. If it's not I guarantee it will still run decent with that gap. Anyone remember this... a matchbook cover is .017 thick, set your points with one thickness then fold it over once and set your plug gaps. We always had a book of matches but could never remember where the dang'd feeler gauge set was.

 

[Don S]

Re: Stupid plug gap question (?)

Anyone remember this... a matchbook cover is .017 thick, set your points with one thickness then fold it over once and set your plug gaps.

Yeah, I remember it, and it was a very long time ago.. When was the last time cars used points?

 

[Silvertip]

Re: Stupid plug gap question (?)

Yeah, I remember it, and it was a very long time ago.. When was the last time cars used points?

Depending on the engine HEI showed up in 1974 and was standard on all engines in 1975.

 

[Don S]

Re: Stupid plug gap question (?)

Depending on the engine HEI showed up in 1974 and was standard on all engines in 1975.

Yeah, I know that, probably should have finished the statement with how many people carry around a book of matches these days.

 

[Bondo]

Re: Stupid plug gap question (?)

Yeah, I know that, probably should have finished the statement with how many people carry around a book of matches these days.

Ayuh,.... Where can ya even Find a book of matches anymore,..??