spark plugs.... Over thinking!

[SirRobyn0]

Ok got a fun little story for ya, then a question for 305 owners.

So when I got the truck it had ACDelco CR43TS spark plugs in it.

Listed in the ACDelco catalog for 1984 C20 - 305 LG6 says CR43TS plugs or R45TS no notes about when you should use which plugs. My truck had the CR43TS plugs in it when I bought it so I have continued to use them even though I'd describe the "read" on the plugs as a little cold. Like most high mileage SBC I get a puff of blue at start up, and on Friday I fouled out #7, oil fouled. No one in town had the CR43TS plugs in stock and I needed the truck this morning so I got a set of NGK UR4 6630. When I got home I cross referenced them to the ACDelco's The CR43TS I had before would cross to an NGK UR5, and the ones I just got cross to and R45TS. So I've just upped the heat range, which is probably fine. I'll pull the plugs after a few hundred miles to read them and see if they are acceptable. I can always run the cooler plugs in 7 holes and one hotter one in #7 to keep it from fouling.

So I curious now what other 305 owners are running for plugs or have run and what have your experiences been? Thanks.

 

[bucket]

I know in the past I have ran the 43's and the 45's. And also Accel 576S a couple times. I don't recall any of them working better or worse than the others. The 576S plugs are shorties for use with headers.

 

[fast 99]

Believe CR43TS plugs are a commercial plug. They will work fine. I usually used R44T or TS plugs in most GM vehicles. There is or was such a thing as a spark plug anti-fouler extender. It helped with the fouling a little bit. Might have one and can post a picture if you want to try one.

 

[80BrownK10]

Believe CR43TS plugs are a commercial plug. They will work fine. I usually used R44T or TS plugs in most GM vehicles. There is or was such a thing as a spark plug anti-fouler extender. It helped with the fouling a little bit. Might have one and can post a picture if you want to try one.

They have them on the "Help" or "Motormight" isle. I think Motormight might have been the name we had at pepboys? It was re branded Help if so.

 

[bucket]

They have them on the "Help" or "Motormight" isle. I think Motormight might have been the name we had at pepboys? It was re branded Help if so.

Yeah, the anti-foulers are still available by one of those companies. They come in a pack of two.

 

[SirRobyn0]

I know in the past I have ran the 43's and the 45's. And also Accel 576S a couple times. I don't recall any of them working better or worse than the others. The 576S plugs are shorties for use with headers.

No headers here so won't be needing the shorties. I have a suspicion on 43's vs 45's I'll get to that in a moment.

Believe CR43TS plugs are a commercial plug. They will work fine. I usually used R44T or TS plugs in most GM vehicles. There is or was such a thing as a spark plug anti-fouler extender. It helped with the fouling a little bit. Might have one and can post a picture if you want to try one.

Yes, the "C" in CR43TS is for commercial. IIRC:
C = Commercial
R = Resistor
43 = Heat range
T = Taper seat
S = Extended tip

But what the heck is the difference between the CR43TS and R43TS, which is also made but not specified for the 305? Frankly I haven't a clue. And why would two different heat ranges be specified for the same engine? I'm thinking the commercial plug is for a engine that sees heavy duty use. Just like they use to recommend one or two steps colder for a 350 run in heavy duty use. Why the CR43TS vs R43TS IDK, maybe it's just method to quickly identify that those are for heavy duty.

They have them on the "Help" or "Motormight" isle. I think Motormight might have been the name we had at pepboys? It was re branded Help if so.

I've seen the extenders before, but have never used one, and might try one out if it seems like that is the way to go. Also might be able to go to a plug without the S designation. In the end I'm going to run these plugs for a couple hundred miles and re-assess. If they appear to hot when read, or if they seem to cause ping, I'll order the CR43TS and get 2 sets to have extras on hand. Now that I know most of my oil control issue is with one cylinder, it's not hard to just replace that one spark plug a little more often than the others if that's what's needed.

I know I could do valve stem seals, but the overall oil consumption is not bad at all, and I'm not really looking to spend a lot of time or money inside this 305, as when it is done I'll be opting for either a 350 or possibly a 383. I've got a local company, well relatively local, they are actually 200 miles away in Spokane, that I've used a couple of times at the shop for older chevy engines, and one AMC motor too. S&J engines. Anyhow I've been talking to them about doing me up a 383 when the time comes, with mild manners and setup for towing. Anyhow I'm rambling, that's not happening until the 305 is done. Thanks Guys.

 

[Turbo4whl]

Since you plan to buy extra plugs, why not try to index them? Fact for me, indexed plugs last longer. This will help with the fouling plug/cylinder too.

The easiest way that I have found to index the plugs, small white or yellow paint line opposite of the gap opening. This way when they are tight, look for the mark to be straight up, or close to up. If it is not up, try a different plug. I would not use indexing washers.

I put the paint mark right on the plug wire contact, never on the plug porcelain. If you put the mark on the hex drive end it is hard to see.

 

[SirRobyn0]

Since you plan to buy extra plugs, why not try to index them? Fact for me, indexed plugs last longer. This will help with the fouling plug/cylinder too.

The easiest way that I have found to index the plugs, small white or yellow paint line opposite of the gap opening. This way when they are tight, look for the mark to be straight up, or close to up. If it is not up, try a different plug. I would not use indexing washers.

I put the paint mark right on the plug wire contact, never on the plug porcelain. If you put the mark on the hex drive end it is hard to see.

Something to think about.... I'll be honest I don't particularly enjoy indexing plugs, but may consider doing the one that is having fouling issues.

 

[fast 99]

The ground electrode is wider on the C plug. Center electrode doesn't appear much different, but it could be another material. I used C plugs on 2 tons and larger where the motor was under a hard load most of the time.

 

[SirRobyn0]

The ground electrode is wider on the C plug. Center electrode doesn't appear much different, but it could be another material. I used C plugs on 2 tons and larger where the motor was under a hard load most of the time.

I never noticed that but never compared them side by side either, make sense though.

 

[80BrownK10]

No headers here so won't be needing the shorties. I have a suspicion on 43's vs 45's I'll get to that in a moment.

Yes, the "C" in CR43TS is for commercial. IIRC:
C = Commercial
R = Resistor
43 = Heat range
T = Taper seat
S = Extended tip

But what the heck is the difference between the CR43TS and R43TS, which is also made but not specified for the 305? Frankly I haven't a clue. And why would two different heat ranges be specified for the same engine? I'm thinking the commercial plug is for a engine that sees heavy duty use. Just like they use to recommend one or two steps colder for a 350 run in heavy duty use. Why the CR43TS vs R43TS IDK, maybe it's just method to quickly identify that those are for heavy duty.



I've seen the extenders before, but have never used one, and might try one out if it seems like that is the way to go. Also might be able to go to a plug without the S designation. In the end I'm going to run these plugs for a couple hundred miles and re-assess. If they appear to hot when read, or if they seem to cause ping, I'll order the CR43TS and get 2 sets to have extras on hand. Now that I know most of my oil control issue is with one cylinder, it's not hard to just replace that one spark plug a little more often than the others if that's what's needed.

I know I could do valve stem seals, but the overall oil consumption is not bad at all, and I'm not really looking to spend a lot of time or money inside this 305, as when it is done I'll be opting for either a 350 or possibly a 383. I've got a local company, well relatively local, they are actually 200 miles away in Spokane, that I've used a couple of times at the shop for older chevy engines, and one AMC motor too. S&J engines. Anyhow I've been talking to them about doing me up a 383 when the time comes, with mild manners and setup for towing. Anyhow I'm rambling, that's not happening until the 305 is done. Thanks Guys.

Yea if it was me I would run the same plug I was happy with and just replace the failed one when needed.

 

[SirRobyn0]

Yea if it was me I would run the same plug I was happy with and just replace the failed one when needed.

I looked in my maintenance book and I got 8K out of that plug. So changing that single plug out every other oil change at 6K shouldn't really be that big of a deal. I've got the NGk's in there now, because that's what I could get and I needed the truck, so until I read them I'm going to run them and then take it from there. The one thing, I'll add that no one including myself has said, the one that fouled, is if it's building up like that on the plug, then it's on the valves and top of the piston to some degree as well, so a hotter plug might help with that some. When I do my read, I should probably run my borescope in there just to see.

Weather (flooding) looks likely to be an issue this week. If it isn't I might be able to get close to 200 miles on by the end of the week. So possibly able to read them this coming weekend.

 

[fast 99]

Getting a look inside is a good idea. Not sure when GM started to cut the heads for PC seals but if it ends up being valves and the heads are cut, PC seals are fairly easy to install. Those seals will really slow or stop oil consumption past the guides.

 

[ghopp24]

I use E3 plugs in my 86' 305 with zero issues and runs perfectly.

 

[SirRobyn0]

Due to crazy busy and trying to drive the square a little less because of gas prices, I only got around to pulling a couple plugs today. 7 of them look fine. It's clear the NGK's are burning a tiny bit hotter than the A/C CR43TS were but I still see a bit of tan on the porcelain and no blistering so for now I'm not concerned about that but will go back to the CR43TS, one of these days.

What I am concerned about is #7. Take a look.

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It's a little hard to see but in the second picture that is blurred a little bit there is a lot of oil deposits, and this is the slightly hotter NGK plug, so I think that I will be stopping for one of those anti-fouler extenders today when I'm in town.