chaseincats

Update: I picked up Costco's Interstate battery (1624505 this one) for $120 and it works great.

I remember the days when batteries came with a 10 year warranty

Sold - group 24 it is

Is the head thread pitch/thread length identical for all s30 heads? If they are different, then my guess is that would be the cause. Regarding NGK plug part numbers I found the bpr6 to be 7133 and the bpr7 to be 5534. Just putting this in here in case people look for those NGK part numbers in the future.

So go for a group 24 instead of 24f? I didn't know there was a difference, I'll grab one, thanks.

It seems that plug doesn't fit my head. Amazon and O'reilly's site says its not compatible with the car. Does that make sense to anyone?

Interstate MT24 has the positive terminal under the inspection flap. Having it the other way around makes sense, but my wires wont reach.

Hey gang, So it's time for a new battery - my Interstate MT-24 from 2018 has thrown in the towel. Should I just get another one of those or is there a commonly agreed upon better one to go with, without breaking the bank?

Yep to the right plugs or yep to it being pre-gapped to the right spec (or both haha)?

so, these would be what I'm looking for? The -11 means that it is pre-gapped so I just pop them in, right?

The engine is absolutely running leaner which adds heat. The TPS on a stock car basically keeps the car in WOT configuration at almost all pedal pressure we discovered earlier on in this thread, and since we bent that pin out a bit, the car will be in cruise mode longer (highway speed). So maybe a 7 would be a good test in this case?

So if I'm understanding this right. When running leaner, it's better to use a BP5 plug since it will absorb cylinder heat better than a BP6?

Will do - curious why I shouldn't change to BPR5 or BPR7?

Well, the whole point of this thread was learning how to tune the stock system but thanks for letting me know.

is that something you just pop in or does it require a lot of supplementary tuning?

Never heard of that let alone it being used as a metric for engines. @madkaw

Sorry if this is a dumb question, but what does KPA stand for?

The air/fuel gauge connected to the o2 sensor that was installed gives you load readings that I listed above though.

I believe it burns some oil, but whatever it burns it isn't enough to affect oil level over the course of a year. @dutchzcarguy@jonbill Understood on the spark plug material. Which heat rating though (bp5, bp6, bp7)? Plug reading really isn't the way to go as long as you have an air/fuel gauge to see what the engine is actually doing. It's running at a 13.8-14.2 idle, 12.3 WOT, and 14.7 highway cruise. I will say, the other day I did catch it running VERY lean (in the 17s) so I pulled over and fiddled with it - not sure if that's when the plugs started looking like this or not though

Spark plug question. Plug image below. NOTE: cylinder 3's plug's ceramic was cracked so I pulled the valve cover and noticed that cylinder's exhaust valve was loose by at least .004 and has now been fixed. All other valves were sitting at factory spec. I pulled the plugs (they've been in there for a few years) and they're white on the top. I have been using NGK Iridium BPR6EIX-11 plugs. Since the car is running leaner than stock 280zs (14.7), should I change the plugs' heat to BP5, keep them at BP6, or change to BP7?

gotcha As a side note, there is some old/crunchy looking oil bits in there, should I try to pick those out or is that also, just an age thing?

Thanks for all the info! This whole thing spanned from me looking at my cam and seeing small lines on all the lobes. They are small enough that you can't catch your nail on it and wasn't sure if it was damage or 45 years of wear. I made a video of my cam with the valve cover off here: https://www.youtube.com/watch?v=MYNc7lrVUWk What do you guys think?

Gotcha and to make sure the hole is spraying properly I could just use a bent out paperclip and move it around in there, correct?

Hey gang, On a '78 I'm told the cam is 'internally oiled' (instead of using the oil spray bar). What does that mean and are there holes somewhere on the cam that spray oil while rotating or something? I looked but didn't see any... -chase

The air temp sensor is showing readings to spec on both the old and newer afm per the fsm which is good. I never found that sensor did much if anything since starting this process which I always found odd. Regarding adding a potentiometer on the coolant sensor, doesn't that only have ability to add resistance to the coolant sensor thus increasing richness? I don't believe you can lean the car out with a potentiometer on the temp sensor but I could be wrong.