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blue89 Member

Joined: 23 May 2006 Posts: 3482 Location: Bellingham/Eugene
1986 Chevrolet Camaro RS
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Posted: Sat May 01, 2010 5:20 pm Post subject: Plugs |
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The 454 needed some new plugs and exhaust gaskets so I've spent the afternoon dinking around with it. Making due with my craptastic headers until I can move the subframe around to fit the long tubes. Anywho...
So I did some research on plugs and came across the following info:
| Quote: | AC spark plug codes.
42 = Racing --- Cold plug
43 = Street & Get by for racing
44 = Good all around street plug
45 = Getting into the hot range (for an old loose engine)
46 = Will damn near ignite diesel fuel (real hot)
HEI set them at .045, if it has points set plugs at .035" |
The set in there were AC R43TS and I found a set of AC MR43T at the parts shop. Seems like it should be alright? The engine is around 8.5:1 with an HEI. I'm not exactly nice to this thing so I justified the 43's instead of the 44. What do you think? _________________ E30
86 RS - 7.4L V8 SOLD
89 RS - 3.25L V6 REMOVED
89 RS - 5.7L LT1 SOLD
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Twilightoptics Hardcore (12sec Club)

Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Sat May 01, 2010 5:55 pm Post subject: |
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I run Autolite 25s in my Camaro. It's the perfect heat range based on visuals.
Put it this way, all the TPI motors that had more power than TBI stuff.... ran 24s or colder.
Too cold they foul, too hot they increase ping chances. With 8:5-1 I'd run a hotter plug because you aren't getting alot of efficiency with that low compression and old chamber. _________________ A redline a day keeps the carbon away! |
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blue89 Member

Joined: 23 May 2006 Posts: 3482 Location: Bellingham/Eugene
1986 Chevrolet Camaro RS
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Posted: Sat May 01, 2010 6:38 pm Post subject: |
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| I see. I'll get a set of 45's and see how the engine responds. I read that if you get too cold then the engine will loose power sooner, can you elaborate? |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Sat May 01, 2010 8:30 pm Post subject: |
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| blue89 wrote: | | I read that if you get too cold then the engine will loose power sooner, can you elaborate? |
Too cold of a plug will foul quickly, causing a misfire that gets worse over time. |
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redlava Member

Joined: 02 Feb 2007 Posts: 448 Location: Bremerton
1986 Chevrolet Camaro Z/28
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Posted: Sun May 02, 2010 8:20 am Post subject: |
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| Quote: | blue89 wrote:
I read that if you get too cold then the engine will loose power sooner, can you elaborate?
Too cold of a plug will foul quickly, causing a misfire that gets worse over time. |
I got the recommended racing plugs, when I got my heads. Little did I know that they foul quickly and I couldn't figure WTF was wrong cause they were brand new ~300 miles. Engine had like 5 fouled plugs. Replaced with some bosch platinums been running great ever since.
I would recommend you look at the length of the spark plug at the store. Make sure you get shorter ones, it may not look like much of a difference but will save you a bunch of head aches. That was one of the main reasons I got the bosch platinums to begin with was the decent price and almost as short at the accel spark plugs. |
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Twilightoptics Hardcore (12sec Club)

Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Sun May 02, 2010 10:47 am Post subject: |
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"race" plugs are for very high compression and power levels. _________________ A redline a day keeps the carbon away! |
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blue89 Member

Joined: 23 May 2006 Posts: 3482 Location: Bellingham/Eugene
1986 Chevrolet Camaro RS
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Posted: Sun May 02, 2010 11:28 am Post subject: |
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| So race plugs are really short cause of high rpm and high engine load? Never really got into spark plug stuff, just checked them from time to time to make sure they weren't fouled. |
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chevymad Master B
Joined: 11 Jan 2004 Posts: 5476
1987 Pontiac Formula
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Posted: Sun May 02, 2010 11:36 am Post subject: |
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The insulator length has nothing to do with whether its a race plug or not. A hot plug will burn off contaminants where a cold plug wont. But if you use a hot plug in high compression or rpm it will act like a glow plug. The heat will actually pre-ignite the fuel mix causing detonation and destruction. You want a plug thats just hot enough for what you're using it for. Too cold and it will foul, too hot and you'll get pre-ignition.
The short insulator length just makes things easier when you have headers. That has more to do with brand then anything else.
Race plugs are generally colder in heat range, and have a heavier duty construction then standard plugs. They're also usually tossed after a short amount of time. So I doubt they're made for daily use. |
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blue89 Member

Joined: 23 May 2006 Posts: 3482 Location: Bellingham/Eugene
1986 Chevrolet Camaro RS
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Posted: Sun May 02, 2010 12:38 pm Post subject: |
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Can you avoid fouling a colder plug by opening it up with some WOT pulls every time you go for a ride? Cause I do that anyway  |
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izcain 9sec Club
Joined: 09 Sep 2006 Posts: 1306 Location: Port Angeles WA
1983 Chevrolet Camaro Z/28
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Posted: Sun May 02, 2010 1:49 pm Post subject: |
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| blue89 wrote: | Can you avoid fouling a colder plug by opening it up with some WOT pulls every time you go for a ride? Cause I do that anyway  |
That will help with keeping them from fouling out.
Whatever you do stay away from platinums they are not designed for that style of ignition system. I can't even count how many times I get misfires in the shop because someone thought they were doing their car a favor by installing platinum plugs. Sometimes I think the parts counter help should be smacked up side the head since I hear them pushing them all the time.
43 T's will work well for what your doing but with the low of compression your not going to hurt anything going to something a touch hotter.
There are many other things that will help with keeping the plugs clean..... Wheres the timing set at and what kind of A/F are you getting? those things alone can keep the plugs nice and clean.
If you really want to get fancy you could get the shims and bust out the sharpie and make the marks and index all the plugs per cylinder and gain power.  _________________
1983 Z28 383 + 201ci more = New Heart for this season!
9.17 @ 148 |
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blue89 Member

Joined: 23 May 2006 Posts: 3482 Location: Bellingham/Eugene
1986 Chevrolet Camaro RS
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Posted: Sun May 02, 2010 2:40 pm Post subject: |
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| Where do you get spark plug shims? Parts store guy couldn't find anything. |
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Twilightoptics Hardcore (12sec Club)

Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Sun May 02, 2010 2:52 pm Post subject: |
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Hehe yeah shimming is a more power thing... but for the work involve... that .5HP isn't worth it. _________________ A redline a day keeps the carbon away! |
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chevymad Master B
Joined: 11 Jan 2004 Posts: 5476
1987 Pontiac Formula
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Posted: Sun May 02, 2010 3:10 pm Post subject: |
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| Twilightoptics wrote: | | Hehe yeah shimming is a more power thing... but for the work involve... that .5HP isn't worth it. |
Especially when you gotta do it all over again next time you buy plugs! |
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