Spark plugs and glow plugs are both screwed into the cylinder head and both are about starting and running an engine, but they do opposite jobs on opposite engines. A spark plug ignites the mixture on a petrol engine, every cycle, for the life of the plug. A glow plug heats the combustion chamber of a diesel so it will fire when cold, and then mostly stops working. Confusing them wastes a service; ordering the wrong reach or heat range damages the engine. This article covers both, what the markings mean, and how to read a used plug.
Spark plug သည် ဓာတ်ဆီအင်ဂျင်အတွက်၊ glow plug သည် ဒီဇယ်အင်ဂျင် အအေးစက်နိုးရန် ဖြစ်သည်။ နှစ်မျိုး လုံးဝ မတူပါ။
In This Article (ဆောင်းပါးအကြောင်းအရာများ)
1. Two different jobs on two different engines
2. Spark plugs: reach, heat range and gap
3. Reading a used spark plug
4. Glow plugs: how they fail and how to test
5. Replacement intervals
6. Fitting — the mistakes that cost a cylinder head
7. How to order from Win Auto Parts
1. Two Different Jobs on Two Different Engines
မတူညီသော လုပ်ဆောင်ချက် နှစ်မျိုး
| Spark plug | Glow plug | |
|---|---|---|
| Engine | Petrol | Diesel |
| Job | Provides the spark that ignites the mixture, on every power stroke | Heats the chamber so diesel will ignite on a cold start |
| When it works | Continuously, whenever the engine is running | Mainly before and shortly after a cold start |
| Electrical | High voltage from the coil | Low voltage, high current from the battery through a relay |
| Failure shows as | Misfire, poor running, hard starting, higher fuel consumption | Hard or impossible cold starting, white smoke and rough running when cold |
| မြန်မာ | ဓာတ်ဆီအင်ဂျင်အတွက် မီးပွား | ဒီဇယ်အင်ဂျင် အအေးစက်နိုးရန် အပူပေး |
2. Spark Plugs: Reach, Heat Range and Gap
Spark Plug — အရှည်၊ အပူအဆင့်နှင့် အကွာအဝေး
| Specification | What it is | What goes wrong if it is wrong |
|---|---|---|
| Thread diameter and pitch | The thread that screws into the head | A wrong thread destroys the head — an expensive repair |
| Reach | How far the threaded portion extends into the chamber | Too long: the plug can contact the piston, and carbon builds on exposed threads. Too short: poor ignition and a carbon-filled thread pocket |
| Heat range | How quickly the plug sheds heat to the head | Too hot: pre-ignition and possible piston damage. Too cold: fouling and misfire |
| Seat type | Gasket seat or tapered seat | A tapered plug in a gasket-seat head will not seal and can loosen |
| Gap | Distance between centre and earth electrode | Too wide: misfire under load and coil strain. Too narrow: weak, incomplete burn |
| မြန်မာ | Thread, အရှည်, အပူအဆင့်, seat နှင့် gap | တစ်ခုမှားပါက အင်ဂျင် ပျက်စီးနိုင်သည် |
Do not "upgrade" the heat range on a standard engine
Heat range is matched to the engine, not to how hard it is driven in normal use. Changing it without a reason from the engine builder causes fouling at one extreme and pre-ignition at the other. Fit the specified range.
အပူအဆင့်ကို အင်ဂျင်အတွက် သတ်မှတ်ထားသည့်အတိုင်းသာ သုံးပါ။
3. Reading a Used Spark Plug
သုံးပြီး Spark Plug ကို ဖတ်နည်း
A removed plug is a free diagnostic report on the cylinder it came from. Lay them out in cylinder order before you look.
| What you see | What it means | |
|---|---|---|
| Light grey or tan deposit, even across all plugs | Normal running | |
| Dry black soot | Rich mixture, or a lot of short cold journeys. Check the air filter and the fuel system | |
| Wet black oil | Oil entering the chamber — valve stem seals, guides or rings on that cylinder | |
| White, blistered insulator, eroded electrode | Running too hot: too-lean mixture, wrong heat range, or ignition timing too advanced | |
| Melted or broken electrode | Detonation or pre-ignition. Find the cause before fitting new plugs | |
| One plug different from the rest | A fault in that cylinder, not a whole-engine problem | |
| မြန်မာ | အနက်ရောင် ကောက်ညှင်း — ဆီပို၊ အဖြူရောင် — ပူလွန်း | တစ်လုံးတည်း ကွဲပြားပါက ထို cylinder ၌ ပြဿနာရှိသည် |
4. Glow Plugs: How They Fail and How to Test
Glow Plug ပျက်စီးပုံနှင့် စစ်ဆေးနည်း
- They fail open circuit. A failed plug simply stops heating, and on a four-cylinder engine one dead plug is often unnoticed until the weather turns or two have failed.
- Test with a multimeter. Measure resistance from the terminal to the plug body — a healthy plug reads very low, typically under a few ohms. An open circuit reads infinite.
- Check the relay and its feed before condemning the plugs. No supply looks exactly like four failed plugs.
- Replace them as a set. They have the same hours and the same heat cycles; replacing one is a false economy given the access.
- Do not over-torque. Glow plugs are slender and snap easily, and a broken plug in the head is a cylinder-head-off job.
- Suspect them when a diesel starts poorly cold, runs rough for the first minute and blows white smoke, but is perfectly normal once warm.
Glow plug ကို multimeter ဖြင့် resistance တိုင်း၍ စစ်ပါ။ အားလုံးကို တစ်ပြိုင်နက် လဲပါ။ တင်းလွန်းပါက ကျိုးတတ်သည်။
5. Replacement Intervals
လဲလှယ်ရမည့် အချိန်
| Type | Typical interval | Notes |
|---|---|---|
| Standard nickel spark plug | 20,000–40,000 km | Shorter with poor fuel or a lot of idling |
| Platinum or iridium spark plug | Considerably longer — follow the manufacturer figure | Do not gap fine-wire plugs unless the maker allows it |
| Glow plug | On condition, checked when cold starting deteriorates | Test before winter or the cool season rather than after a no-start |
| မြန်မာ | ပုံမှန် spark plug — 20,000–40,000 km | Glow plug ကို အအေးစက်နိုးရ ခက်လာမှ စစ်ပါ |
6. Fitting — the Mistakes That Cost a Cylinder Head
ဦးခေါင်းပိုင်း ပျက်စီးစေသော အမှားများ
- Only remove plugs from a cool engine. Alloy heads expand; pulling a steel plug from a hot alloy head strips the thread.
- Blow out the plug wells first. Grit that falls in goes straight into the cylinder.
- Start every plug by hand, several turns, before any tool touches it. If it will not start by hand, stop — it is cross-threading.
- Torque to specification. Over-tightening stretches the shell and can crack the insulator; under-tightening lets the plug run hot and blow out.
- Use anti-seize only if the manufacturer specifies it, and reduce torque accordingly — on many modern plugs it is explicitly not wanted.
- Replace plug leads or coil boots that are cracked while you are there; a tracking lead misfires exactly like a bad plug.
အင်ဂျင် အအေးမှသာ ဖြုတ်ပါ။ လက်ဖြင့် အရင် လှည့်သွင်းပါ။ သတ်မှတ် torque အတိုင်း တင်းပါ။
7. How to Order from Win Auto Parts
Win Auto Parts မှ မှာယူနည်း
Win Auto Parts stocks spark plugs and glow plugs for the petrol and diesel platforms common in Myanmar.
- Call 09 5105768 with the make, model, year and engine code.
- Say whether the engine is petrol or diesel — it is the first question we will ask.
- Quote the code printed on the old plug if you can read it; it identifies the plug exactly.
- Or email support@winautoparts.com with a photograph of the old plug.
- Order a full set. Trade rates apply from five units.
အင်ဂျင် code နှင့် ဓာတ်ဆီ/ဒီဇယ် ဖြစ်ကြောင်း ဖော်ပြပြီး 09 5105768 သို့ ဆက်သွယ်ပါ။
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