Head Gaskets and Engine Gasket Sets — Grades, Bolts and Fitting

A head gasket is the highest-loaded seal on the engine: it holds combustion pressure, coolant and oil apart across the same joint, through every heat cycle the engine sees. When one fails the cause is almost never the gasket itself — it is a distorted head, a surface that was never cleaned properly, or bolts that were reused when they should not have been. This article covers what is in each gasket set we sell, what to check before fitting, why head bolts are usually single-use, and how to identify the right gasket thickness.

Head gasket သည် အင်ဂျင်ရှိ အဖိအားအမြင့်ဆုံး အဆက်အသွယ် ဖြစ်သည်။ ပျက်စီးမှုအများစုမှာ gasket ကြောင့် မဟုတ်ဘဲ ပြင်ဆင်ပုံ မမှန်ခြင်းကြောင့် ဖြစ်သည်။

1. Which Set You Need
မည်သည့် Set လိုအပ်သနည်း

2. Symptoms of a Failed Head Gasket
ပျက်စီးမှု လက္ခဏာများ

3. What Actually Caused the Failure
အမှန်တကယ် အကြောင်းရင်း

Fitting a new gasket without finding the cause is how the same job is done twice. Look for these before the head goes back on.

• Overheating. Almost every head gasket failure starts here. Find out why it overheated: thermostat, radiator, water pump, fan, or a blocked core.
• A warped or distorted head. Check it with a straight edge and feeler gauges across several axes; skim it if it is outside limits.
• A pitted or eroded fire ring land on the block or head, usually from coolant that had no corrosion inhibitor.
• Stretched or reused head bolts that cannot reach clamping load.
• Poor surface finish — too rough, or polished glass-smooth by an aggressive disc, which some gasket types will not seal against.
• Detonation from poor fuel or wrong timing, which hammers the fire ring until it fails.

အပူလွန်ကဲခြင်းက အဓိက အကြောင်းရင်း ဖြစ်သည်။ Head ကွေးနေ မနေ စစ်ဆေးပါ။ အကြောင်းရင်း မရှာဘဲ လဲပါက ထပ်ပျက်မည်။

4. Head Bolts Are Usually Single-Use
Head Bolt များကို ပြန်မသုံးသင့်ပါ

Many engines use torque-to-yield bolts, which are tightened past their elastic limit on purpose so they hold clamping load evenly. Once stretched, they cannot do it again.

• Check the workshop procedure. If it says "torque to X, then turn 90° plus 90°", the bolts are torque-to-yield and are single-use.
• Measure the shank if in doubt — a stretched bolt is visibly thinner along part of its length, and it will be longer than a new one.
• Buy the bolts with the gasket. They are inexpensive against the labour of doing the job twice.
• Clean the threads in the block with a thread chaser, not a cutting tap, and remove oil and coolant from the holes — hydraulic lock in a blind hole cracks the block.
• Oil the threads and under the head of each bolt exactly as the procedure specifies. Dry threads give a false torque reading.

Torque-to-yield bolt များကို ပြန်မသုံးပါနှင့် — gasket နှင့်အတူ အသစ် ဝယ်ပါ။

5. Gasket Thickness and How It Is Marked
Gasket အထူနှင့် အမှတ်အသား

Several diesel engines are built with head gaskets in two or three thicknesses, chosen at the factory to set piston protrusion correctly. Fitting the wrong grade changes the compression ratio and, on some engines, lets a piston touch a valve.

• Look for notches or holes along one edge of the old gasket. One, two or three marks identify the grade.
• Measure piston protrusion above the deck with a dial gauge if the engine has been rebuilt, and select the grade from the manufacturer table.
• Do not assume the old grade is correct if the block or pistons have been machined or replaced.
• Record the grade when you remove the old gasket — it is the easiest time to see it.
• Tell us the grade when ordering, or send a photograph of the marked edge.

Gasket အနားရှိ အမှတ်အသား (ချောင်း) အရေအတွက်က အထူအဆင့်ကို ပြသည် — မှာယူစဉ် ဖော်ပြပါ။

6. Fitting — Surface, Sequence and Torque
တပ်ဆင်ခြင်း — မျက်နှာပြင်၊ အစီအစဉ်နှင့် တင်းအား

• Clean both faces without gouging them. Use a plastic scraper and a solvent, not an angle grinder or a coarse abrasive disc.
• Check flatness with a straight edge across the length, the width and both diagonals.
• Fit the gasket dry unless the manufacturer says otherwise. Modern multi-layer steel gaskets are coated and must not be sealed with paste.
• Observe the TOP mark and the dowels. A gasket fitted upside down can block a coolant passage.
• Follow the tightening sequence and stages exactly, working from the centre outwards. Angle stages need an angle gauge, not an estimate.
• Refill with the correct coolant and bleed the system fully. An air lock will overheat the engine and destroy the new gasket on the first run.
• Re-check torque only if the procedure calls for it. On torque-to-yield bolts, re-torquing is usually wrong.

မျက်နှာပြင်ကို သတ္တုတိုက်စက်ဖြင့် မခြစ်ပါနှင့်။ တင်းရမည့် အစီအစဉ်နှင့် ထောင့်ကို တိတိကျကျ လိုက်နာပါ။

7. How to Order from Win Auto Parts
Win Auto Parts မှ မှာယူနည်း

Win Auto Parts stocks cylinder head gaskets, upper and lower gasket sets and full overhaul kits for the Japanese and commercial engines common in Myanmar.

• Call 09 5105768 with the engine code — not the vehicle model, which can cover several engines.
• Say which set you need, and the gasket grade if the engine uses graded gaskets.
• Ask for the head bolts at the same time if the engine uses torque-to-yield bolts.
• Or email support@winautoparts.com with a photograph of the old gasket showing the marked edge.
• Or browse the engine range at winautoparts.com.

ကား model မဟုတ်ဘဲ engine code ကို ဖော်ပြပါ။ Head bolt အသစ်ကိုပါ တစ်ပါတည်း မှာယူပါ။

Related Articles
ဆက်စပ်ဆောင်းပါးများ

• Piston Ring Sets — What Is in a Set and How to Select One
• Measuring the Bore and Choosing Oversize Rings
• Pistons and Piston Pins — Sizing, Pin Types and Fitting
• Engine Internals — Frequently Asked Questions
• Fitting Piston Rings — Common Mistakes
• Engine Valves, Guides and Seats — Diagnosis and Selection