Calculator Inputs
Example Data Table
| Case | Hole Diameter | Labor Hours | Parts Cost | Hourly Pay | Use |
|---|---|---|---|---|---|
| Small piston crown hole | 4 mm | 6 | $250 | $15 | Light estimate |
| Moderate crown failure | 8 mm | 9 | $420 | $15 | Common planning case |
| Severe melted piston | 14 mm | 15 | $850 | $18 | Major repair estimate |
Formula Used
Piston area: A = π × (bore ÷ 2)²
Hole area: H = π × (hole diameter ÷ 2)²
Area loss: Loss % = (H ÷ A) × 100
Engine volume: Volume = piston area × stroke × cylinders ÷ 1000
Repair subtotal: Labor + parts + machine cost + diagnostic fee
Total: Subtotal + supplies - discount - warranty credit + tax
Pay periods: Final repair cost ÷ gross pay per period
How to Use This Calculator
- Enter the piston bore, stroke, hole size, and cylinder count.
- Add the compression ratio for a basic severity estimate.
- Enter labor hours, repair rate, parts, machine cost, and fees.
- Add tax, supplies, discount, and warranty coverage.
- Enter hourly pay and pay period hours.
- Press calculate to view the result above the form.
- Use the CSV or PDF buttons to save the estimate.
Repair Planning Guide
What This Calculator Does
A hole in a piston is a serious engine problem. It may come from detonation, overheating, lean fuel mixture, broken rings, or wrong ignition timing. This calculator helps you estimate the repair cost and compare it with pay period income. It also gives a simple physical damage view using piston area, hole area, cylinder volume, and compression information.
Why Piston Area Matters
The piston crown receives high pressure during combustion. A larger bore has a larger crown area. A hole removes part of that area and creates a path for pressure loss. Even a small hole can lower compression. It can also push heat, oil, and gases into places where they should not go. The area loss percentage is not a full engine diagnosis. It is a planning signal.
Cost and Pay View
Repair cost often includes teardown, inspection, new parts, machine work, fluids, gaskets, taxes, and supplies. Labor can become the largest part of the bill. The pay section compares the final estimate with gross earnings per pay period. This helps a worker plan how many pay periods may be needed before the repair is covered.
Advanced Use
Use the warranty field when part of the repair is covered. Use the discount field for coupons, shop reductions, or negotiated savings. Use the shop supplies field for seals, cleaners, rags, and other service items. Adjust labor hours for engine access difficulty. Transverse engines, turbo systems, and tight bays can require more labor.
Important Limitations
This tool gives an estimate only. It does not replace compression testing, leak-down testing, borescope inspection, or professional diagnosis. A piston hole may damage cylinder walls, valves, bearings, plugs, injectors, and the catalytic converter. Always inspect related systems before approving repair. Use real shop quotes for final decisions.
FAQs
What is a hole in piston repair calculator?
It estimates piston damage severity, repair cost, tax, discounts, warranty credits, and pay recovery time using physical and cost inputs.
Can this calculator diagnose engine failure?
No. It provides planning estimates only. A mechanic should perform compression, leak-down, and visual inspection before repair decisions.
Why does hole diameter matter?
Hole diameter estimates lost piston crown area. Larger holes usually mean greater compression loss, heat damage, and repair urgency.
What does pay periods needed mean?
It shows how many gross pay periods may be required to equal the estimated repair total.
Should I include taxes and shop supplies?
Yes. These charges can affect the final bill. Add local tax and typical shop supply percentages for better estimates.
What is warranty coverage percent?
It is the portion of the subtotal covered by a warranty, service plan, or repair agreement.
Can I download the result?
Yes. After calculation, use the CSV or PDF buttons shown under the result table.
Is the severity score exact?
No. It is a simple estimate based on area loss, compression ratio, and labor time. Use it only for planning.