NGK Plugs in GM Engines

[Russ]

Yay or nay? I was changing the plugs on my girlfriends 88 Suburban with a 350 engine, and the guy at O'Reilly's advised me that NGKs are most beneficial for imports and bikes, and the best thing
for my application would be AC Delco Rapidfire (I went for plain AC Delco plugs - budget issues

)
I, myself, have had a good experience with NGKs, but in a Mitsubishi, and Ford 302 engines.

P.S. The same salesperson recommended that the gap
on the plugs for this engine be set at .045. I have listened to him, trusting his judgement/expertise.
After finally looking up the spec,

I found it to be
.035 in every single source I can find (online catalogs for O'Reilly's, Advance Auto Parts, hard
copy catalogs at various parts stores). The engine runs fine, but my current plans are to re-gap the
plugs to .035 the first chance I get. Any thoughts on this issue?

 

[novadude]

I've used NGKs in 350s and they have worked well. However, plain old AC plugs are hard to beat in Small Blocks. They offer the best performance per dollar, IMO.

As for the gap, The 75-? large cap HEI systems generally called for 0.045". I suspect yours has a small cap with a remote coil. Maybe this explains the 0.035" gap? I know the pre-HEI chevy engines all used 0.035" (breaker points).

 

[Matt_S]

I don't see why you wouldn't use them. We had a discussion about this a short while ago and I think we determined that NGK actually supplies some of AC Delco's spark plugs, most notably the platinum and probably the iridium, too. I know a lot of guys use them in the 3800, I'm strongly considering it myself. See the "AC Delco Spark Plugs" thread further down the list in this topic area.

BTW, auto store spark plug gap information is notoriously wrong. I would never trust it. My advice is to try to find the plug your manual specifies (or an exact replacement) and use the same gap and stock wires. That way, you can be assured the engine will at least run the way it was designed. GM's ignition systems are pretty efficient off the line and typically don't need modification.

 

[SSDude]

There are some people who you should never listen too and this guy is one of them. NGK plugs are actually one of the favorites of LS1 owners. They are great plugs.

 

[T-Keith]

GM uses NGK plugs, if they don't have AC delcos available, so their OK to use. I prefer AC delco my self, because they have more defined heat ranges and are available in more styles.

The Rapidfires are a very good plug for the price. They have ways of making old engines run great.

-T

 

[jthorner]

The AC-Delco plugs (100,000 mile platinum type) which I bought for our Olds Minivan have NGK embossed on the actual metal portion of the spark plug.

In the old days the common wisdom was to put Bosch on German cars, NGK on Japanese and whatever the factory used on 'merican cars.

Today I think that those rules of thumb are worn out.

NGK makes an excellent quality product and I would not hesitate to use them in any application which the NGK catalog calls for.

John

 

[Patman]

I used NGK plugs in my LS1 Formula and have them now in my LT1 Formula, they are great plugs.

When I get my C5 soon, I'll be swapping it over to NGKs as well. I've got a set of TR55 platinums sitting right here.

 

[GT Mike]

I have NGK plugs in my car right now. They're working ok, though I can't say they're any better or any worse than another brand. I liked the AC Rapidfires too. When these come due for replacement, I'll probably go back to the Rapidfires.

 

[Jimbo]

Always use the plug gap specification on the underhood emissions sticker. Way to much bad information is in spark plug catalogs and repair manuals. Too small of a gap (Chilton manual) caused me problems on a Ford Duraspark I system.

Bosch and NGK are both OEM for BMW. The NGK last a little longer in that application. I found AC Rapidfires to be really good for old point-type ignition systems.

 

[Matt_S]

Just as a quick follow-up to this, I just bought 6 AC Delco 41-901 plugs for my Monte Carlo SS. Guess what I found stamped right on the side of the steel base of the plug? "NGK Japan". "AC Delco", along with the GM part number was printed on the ceramic insulator.

If there was ever a doubt about using NGK plugs in your GM, this should erase that, so long as you use the correct plug.

 

[Matt_S]

Sorry, wrong part number, should have been 41-101, not 901.

 

[crashz]

There wouldn't be any problems using NGK, but I've never had good luck finding them. As novadude suggests, the good old copper core plugs run great in the old chevy small blocks. In fact I switched out my platinums for plain old motorcraft copper core plugs and my idle smoothed out a bit.

 

[DJ]

NGKs are a favorite on the RDW Impala boards a few of us here frequent, for the most part that engine is just a 350 chevy with a little twist, but really not all that drastic a change.