glowplug confusion

[bifft it]

I'm confused as to what glowplugs i should be using in my trucks. i have been using ones called "fireball" but they are junk. 3/5 are junk/bad right out of the package, so heres my info.also have a couple stock HPI plugs R3 i believe

2-savage .25,1-savage x f4.6,1-savage x SH.28,1-savage xl lrp .32 (never started)

i live in North Dakota. most days are in the 70,s with low to medium humidity. summer is here 80,s to low 90,s with medium humidty. had the 4.6 and SH out the other day in high humidity upper 80,s and they ran terrible. 4.6 kept"popping" and the SH wouldnt even hardly run. also may have had bad fuel as that jug was 1/4 full and has been opened and closed quite a few times

 

[SchrodeMode]

General rule of thumb:

Hot plugs for low nitro % fuel
Cold plugs for high nitro % fuel.

The plug has very little to do with overall engine temp, and ambient temp has little to do with the plug you should use.
As always, there are a few exceptions to every rule.

What fuel % are you running?

 

[HPIguy]

Here are some helpful guides on choosing a plug

http://www.osengines.com/accys/glowplugs.html

http://www.osengines.com/accys/choosing-glowplugs.html

 

[Zdragon71]

I just read a 5 page article on this subject and this is accurate from what I've learned. If you run 24% or less nitro you need a hotter plug. 25% or more you need a cold plug. Reason. Eing that the less nitro the fuel has you need a hotter plug to burn off the more % of methanol in the fuel and vise versa. The liquid the comes out of your exhaust is the excess oil from the fuel. The oil in the fuel is what cools and keeps engine lubricated. Hints the smoke as well. That is what oil is being burnt if combustion. It aslo touched on burning a cold plug on days below 32* f. Which that I'm still not understanding. I need to read more into the rumor of cold plugs cold days and hot plugs hot days. Hope this helps clarify a bit more for you. And I'm glad someone finally posted a thread on this subject also.

 

[HPIguy]

It aslo touched on burning a cold plug on days below 32* f. Which that I'm still not understanding. I need to read more into the rumor of cold plugs cold days and hot plugs hot days. Hope this helps clarify a bit more for you. And I'm glad someone finally posted a thread on this subject also.

That's exactly backwards, you want a hotter plug on cold days, and colder plugs on hot days. Read the article I linked to, OS has been in the game a LONG time and have a great reputation.

 

[Zdragon71]

Well thats why i was wanting to read more on that hot cold topic. Hotter plug on cold days made better sense to me from the start. That is a good link you posted and it definitely clears it up for me now. Thanks^^^

 

[bifft it]

I'm running losi/vp 20% now. when i break in the .32 i will switch everything to 30%
i bought 12 os8 plugs today. hope they work better for me than what i have now