shorty plugs?

[rrubel]

Thanks, black_81_vette. I'll have to check around; my closest AutoZone is a smaller store, and doesn't seem to stock less-common items. There's another store about 10 miles from here that is much larger. The r44TS is an AC Delco part?
[RICHR]

 

[rrubel]

My local (smaller) AutoZone did indeed have the Bosch Supers that corresponded to the R44TS. I also picked up the set of Accel header plugs that I ordered. Lo and behold, they too cross-listed to the R44TS (actually one set crossed to the R43TS and the other to the 44). So is there really and truly a difference between a plug for an AL head and a plug for an FE head, or is it just based on the seat being tapered or flat?

And Mic got the header leak taken care of (as long as the weld stays ) so looks like I can at least try those - without a Y-pipe, I can start it in the garage but would hesitate to actually take it on the street.

[RICHR]

 

[Hib Halverson]

After readin' this thread some comments on plugs.

First, the issue of racing cylinder heads with stock exhaust manifolds. That might be an insurmountable problem, no matter if you can get so-called shorty plugs or not. Racing heads aren't designed with the idea that anyone is going to run stock exhaust manifolds on them and the plugs may be placed and/or angled with headers in mind.

91 Corvette Small-Block heads use a 14mm, 5/8-in. hex, 3/4-in reach, flat-seat, projected-tip, resistor plug. Don't use anything other than that, if you want the car to perform well. The only exception to that might be a pure race engine with no computer controls which might use non-resistor plugs. Here is some more plug info:

53-69 iron heads use 14mm, 13/16-in. hex, 3/8-in reach, flat seat, std. tip, resistor plugs.
67-72 alum. heads use 14 mm, 13/16-in. hex, 3/4-in reach, flat seat, std. tip, resistor plugs
70-86 iron heads use 14mm, 5/8-in. hex, .460-in. reach, taper seat, projected tip, resistor plugs.
86-91 alum. heads use 14mm, 5/8-in. hex, 3/4-in reach, flat seat, projected tip, resistor plugs.
92-05 alum. heads use 14 mm, 5/8-in hex, .708-in reach, taper seat, projected double platinum or iridium tip, resitor plugs.


Taper seats are not unusual for aluminum heads. Many GM alum. heads made since the late-80s have used them. In fact, the Corvette was one of the last platforms to get taper seat aluminum heads in 1992. Today virtually all GM alum. heads use taper seat plugs.

Best to use for hi-po street/mild racing in all Small-Blocks, Gen 1-4 is the AC 2, NGK 6 or Denso 20 heat range. Generally that's one or two heat ranges colder than stock. They should not be used in an engine that sees starts without warm-ups.

Don't try and put a .460-in reach plug in a head requiring .708-in reach, nor should you do the opposite. Don't try to use a taper seat plug in a flat seat head nor should you do the opposite.

As for non-projected tip and "retracted" tip, that may be marketing and it might be reality. There are some very specialzed racing spark plugs that could be characterized as having retracted tips but most Corvette DIYs will never some in contact with them.

As for plug gap...while it is generally correct that a wider gap and smaller/thinner or cut-back electrodes are better because they give the charge air better access to the plug, the gap issue is impacted by the strength of the ign. system. Yeah a .060 gap is great...but only if the ign. is powerful enough to fire that gap.

 

[rrubel]

Hib, once again you're a wealth of information. The biggest issue I'm facing (other than the fit/won't fit part) is that the heads aren't stock and the manufacturer hasn't yet answered my emails (they're in New Zealand, so I hesitate to phone them). I'll investigate the AC 2's.

Wish you were local...

------
Pfff. Ok. Called the place I bought them from (yes, the manufacturer is now out of business - very suddenly about two months ago). I was told that while I may see a slight chamfer in the plug seat, it's DEFINITELY a flat seat. I need 3/4" reach, Champion C57C-compatible plugs, and as long as I'm not using domed pistons an extended tip is preferable. Love it when I get different stories each time I call... Back to the charts... the Accels are not going to cut it after all.

Thanks.
[RICHR]

 

[Moonunit 451]

ad

 

[Ken]

You alright Colin? :L

 

[rrubel]

I think he's just expressing frustration for me...

Today, thanks to lots of help from Mad-Mic and Sothpaw, we dropped the stock exhaust again and got the headers in (needing to pull the starter on the passenger side). All 8 plugs are now easy to put in, though one (#6, I think) is proving to be impossible to tighten. I've bought a cheapo plug socket and I'm cutting it down in hopes that it will clear the pipes.

Next, distributor!

[RICHR]

 

[Moonunit 451]

I think he's just expressing frustration for me...

Today, thanks to lots of help from Mad-Mic and Sothpaw, we dropped the stock exhaust again and got the headers in (needing to pull the starter on the passenger side). All 8 plugs are now easy to put in, though one (#6, I think) is proving to be impossible to tighten. I've bought a cheapo plug socket and I'm cutting it down in hopes that it will clear the pipes.

Next, distributor!

[RICHR]

Great news Rich! Now all you have to do is keep from frying wires like Ken

I didn't get any distributer gasket with my gasket kits, but I think you should have one or you're likely to have a leak there. I'd at least put the one from your old engine in, if it's not trashed. Mic must have access to one

I'm rootin' for ya to get her goin' tomorrow :cool

 

[rrubel]

Believe it or not, there WASN'T a gasket with the old distributor...

As for frying wires, it looks like there are two cylinders that might be an issue, but the rest aren't even close to the pipes.

Probably won't get it done today, though - have a birthday party to take the kids to, and if it's not raining then I need to mow the lawn and do some other house stuff I've been neglecting. We'll see.
[RICHR]

 

[Ken]

I knew if I looked hard enough I'd find it!

... Then I have people like my TEC3 rep who say I should run the gap closer to 0.028 rather than wider for this setup. You think you want someone with authority to speak up??

I just came across the section in the book where it describes why Electromotive recommends a closer gap on the plugs ...

The load at which a spark plug fails is different for all spark plugs. With the Electromotive TEC3's charging circuit, the more load you put on an engine, the more voltage will be applied to the plug. This is a beneficial situation: for a high-compression engine, the voltage at the plug will be inherently higher (since there is more load). The detriment is that the spark plugs and wires are only rated to a certain voltage (30-40,000 volts is typical), and can begin to "blow out" at around 40,000 volts. If that voltage is exceeded by a large amount for a long enough length of time, the spark plugs will either blow out, break down, or arc to somewhere other than the electrode (often through the insulator directly to the engine block).

The solution is to run smaler plug gaps on high-compression engines. This is perfectly acceptable with our ignition charging method, since the high load of the cylinder pressure will allow the voltage to be quite high at the electrode, but with a small gap will keep the plug from seeing an over-voltage situation. Use the recommendations below as a guideline for spark plug gaps:

• Stock engine -- 0.045"-0.060" (1.1 mm-1.5 mm)
• High Performance Street -- 0.030"-0.035" (0.75 mm-0.9 mm)
• Alcohol High Compression -- 0.025" (0.65 mm)
• High Power 75-115 HP per cylinder -- 0.025" (0.65 mm)
• Over 115 HP per cylinder -- 0.022" (0.55 mm)
• Over 12:1 CR or Over 14 psi boost -- 0.022" (0.55 mm)

The bottom line is this: the TEC3 system uses an inductive (long duration charge at battery voltage) charging method for the coils, which is completely different than the capacitive (short duration charge at the higher-than-battery voltage) charging method used by several other aftermarket manufacturers. What may work well for these systems may not work well with ours.

 

[WhalePirot]

Rich. I bought a set of Accel shorties (876S)which turn out to be the same length as the Bosch, at least reaching from my straight plug aluminum Dart Pros to the headers. As recommended by TPIS, my Vette pro had to 'dimple' #7 tube a bit. Nice. I remain NOT impressed.

I solved the wire burning with porcelin boots. The only continual problem was on #7, but others were quite close, too. Mine came with a very pricey set of wires, but I was told that snowmobile shops might have just the boots.

BTW, the header wrap did nothing to lessen underhood heat nor reduce arcing nor boot burn-through from my ceramic coated headers.

mike

 

[rrubel]

Oh wow, that's tight... I don't have anything near that close, so hopefully won't have the same issues. I did see some arcing between #1 and the headers last time I had it running, but twisting the boot seemed to make it go away.

Those Accel shorties you bought sound like the ones I got (and couldn't use). I *think* they're for cast-iron heads and have a different seat. I was mistakenly told that I needed a tapered seat for my plugs. They were also shorter reach than what I needed. You've got the heads that I probably should have bought (AL Dart Pro One's, right?).

If I get wire burning, I'm probably going to get silicon plug wires which claim to be good to 6000 degrees. Don't think it'll get QUITE that hot under there .

[RICHR]

 

[Mad-Mic]

Oh wow, that's tight... I don't have anything near that close, so hopefully won't have the same issues. I did see some arcing between #1 and the headers last time I had it running, but twisting the boot seemed to make it go away.

Those Accel shorties you bought sound like the ones I got (and couldn't use). I *think* they're for cast-iron heads and have a different seat. I was mistakenly told that I needed a tapered seat for my plugs. They were also shorter reach than what I needed. You've got the heads that I probably should have bought (AL Dart Pro One's, right?).

If I get wire burning, I'm probably going to get silicon plug wires which claim to be good to 6000 degrees. Don't think it'll get QUITE that hot under there .

[RICHR]

you'd be surprised

3 sets later after header install i went with the accel 9000+ wires. seem to holding up to the challenge

 

[WhalePirot]

My experience is that any silicone boots will burn. Your rotation of the problem boot probably temporarily fixed the arcing problem, because the new area of the boot had not deteriorated yet. Been there..........

I bought 8 Bakelight boots from a VW place, but didn't use them because I found (finally) the ceramics, which are LOTS shorter due to the 90* shape. OC Speed was the only place to stock them (I've raved about their knowledge B4).

I arrived at a place where I was happy to spend a pair of C-notes to end the problem. My solution was to get Magnacore 8mm, EMI suppression, metallic core wires. Stray EMI has caused me problems before in this electronic car; moreso than radio noise.

If you are running the HEI, I would expect that resistor plugs are called for to develop a healthy spark, but I am hardly an ignition expert.