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Spark plugs



Now that I have the car open again, I have chosen to tinker around under the hood. What is the concensus on spark plug choice. The car will be a daily driver, NGK, Splitfire, Bosch, or AC? I took one out its an AC #906. If there is a prefered performance plug out there let me know.
I forgot the Spec's

By the way the car is a 95' LT1 6 speed coupe...
I stayed with AC/Delco Platinums. I went to several parts stores in the area and no one recommended Bosch and no one thought that the Splitfires made any improvement in performance. Only one place sold NGK and that was all they offered so obviously they were biased.

A few days ago one of my wires got against the manifold and burned a hole in it. My local Chevy dealer was going to charge me $450 for a set of wires, or $170 just to replace the damaged wire. They also quoted me $350 for new spark plugs. GEEEZ

So I'm getting the parts myself for them to install for $150. With the distributor located where it is I didn't want mess with that myself.

I spent $50 for AC/Delco Platinums and I have on order an MSD wire set for about $85. All of the part stores recommended MSD but they didn't carry the LT4 in stock. So I went online with MSD at www.msdignition.com] and ordered them myself.
Nice car

Great job with the car Mike. I like the road race style wing, I'm sure it plants the rear end at speed. I just returned from autozone, I replaced all the vacum fittings & the (3) port check valve on the R/H side, mine were all shot, & the check valve was cracked. They carried all the stuff under the "Help" name brand.
Anyway while there I checked on plugs, they had all the major brands including the AC Delcos @ $4 Ea. The Bosch platinum +4 plugs look like a very high quality item @ $6 Ea.
Argh! I spent all WEEKEND looking for that 3-port check valve. Four stores, three companies. No dice! And they all carried the "Help" brand stuff.

I spent Friday morning replacing my plugs (86 L98) with Bosch +4's. Yes, they were $6 each, but they're lifetime- supposedly I'll never have to buy another plug again. And $6 is CHEAP. The NGK platinums for my Subaru are $17 :cry EACH at the dealer and *$18* each at Pep Boys. I think the whole plug itself is solid platinum painted to look like steel and ceramic :).

Found one bad connection with the distributor - some numbnut who worked on the car before me had the plug end of one wire on the dist. and the dist end on the plug and it wasn't making full contact (very loose, no click of the wire cap, and the plug was blackened).
Buddy of mine who recently had his plugs and wires changed was charged $380, but it was for a Camaro. I was like, "You should've done it yourself for that kind of money." I checked out some AC's, I think they were in the $35 neighborhood for plugs. Not too bad. I think I'm going to go with Bosch when I do my plugs and wires in a few weeks.
Who would have thought

I thought those Elec. plug ends were all fool proofed. There is always someone that will find a way though. Did you look in the "Help" product line when you were shopping for the 3 port check valve? Earlier today I ran over to O'Reiley auto parts & I noticed they had that valve also, again it was in the "Help" section, the price was a whopping $2.99. How do you like the Bosch +4 plugs? Any difference in idle quality, power, or economy?
What's the recommended mileage to change the plugs and wires?
Maintenance Schedule

Upon review of my owners manual, I find that in both schedule #1 and schedule #2 the recommended mileage to change the plugs is 100K. They recommend inspecting the plug wires at every 30K, but there is no suggested replacment interval on the wires. I assume their (GM) opinion is that as long as the resistance is within Spec. they don't need replaced.
I put the Bosch +4s in my92 about 6mo ago. They work fine. I wouldn't say they are better or worse than the factory plugs I pulled out. Never noticed a difference in perf, idle, mileage. I'm going to brave changing my plug wires in the spring time. The factory ones still look good but I'm almost at 80K mi now so it seems reasonable to change them. I'm debating over the MSD or Magnacore wires.

go with AC delco
My AC Delcos got 92,000 miles still revvvvvving:r

I did not know about the Bosh 4, are they really lifetime??? It sounds like a good deal to me
words of wisdom

Maintenance costs are cheaper than repair costs.
I put Bosch +4's in mine. work fine. Installed Taylor Spiro Pro wires at same time. $50 at Speed Demon Motorsports. They fit the stock wire looms. It is a lot easier to change plugs if you remove the back side of the inner wheel wells. If you have never changed the plug wires in an LT1/4 be prepared for a lot of frustration and beer breaks. I finally had to get a friend with small hands to install the last two wires on the left side. I already had the alternater off and the A/C compressor laid aside to install headers. I ended up removing the flex intake ducting and the belt tensioner pulley and still could not get my hands in far enough. I could touch the terminals but couldn't do anything else. After a couple of days and an untold number of. :drink I finally called by buddy for help. It IS do-able, just don't get discouraged.

took my 95 to the chevy dealer...1.5 hrs and $69 later....I had my car back with new AC plugs. No scraped knuckles, no cursing, no beers (unless you count the A&W I had whilst waiting).... Not into the S&M scene;)

I guess I'll give the S&M scene a try. I just returned home with $50 dollars worth of toys (Bosch +4 Plugs). I suppose that 1.5-hour installation time will be my goal for the evening. I will post the results later tonight.
The plugs are in!


S&M isn't that great. I like to never got plug #8 (rear Pass. side) out or in. Pulled front wheels, dropped the drivers side wheel well, pulled plugs #1-3-5-7 & reinstalled (45 Min). Went to the Pass. Side. Left the wheel well in place as plugs #2-4-6 were a piece of cake (45 Min). The A/C evaporator case kills you on plug #8. Scraped every knuckle & cussed up a storm. Spent a full hour on it alone. So 2-1/2 hours is what it took, without reassembling the drivers side wheel well yet (20 Min). I had to stop & have a drink after plug #8 and believe me it wasn't an A&W Root beer! My advice would be to do plug #8 first, after you win that battle the other (7) plugs will make you smile!
Firing order

Could someone please tell me the firing order of the cylinders? It doesn't go 1 through 8 does it?

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