Terms of Service

Effective September 29, 2026

These terms cover your use of Engine Walk (the website at engine.college and any app version of it), including buying Full Access or a Classroom License. By using Engine Walk or buying access, you agree to them. If you don't agree, please don't use the site.

“Engine Walk”, “we” and “us” mean the person who runs Engine Walk. “You” means you, the person using it. You can reach us at enginewalk@gmail.com.

1. What Engine Walk is

Engine Walk is an educational tool. It shows interactive 3D teaching models of engines that you can run, take apart and look inside. The models are simplified illustrations built from published specifications. They are not service manuals, and their dimensions, timing figures, temperatures, torque values and procedures may be approximate or simplified.

Safety. Don't rely on Engine Walk to repair, modify or operate a real engine or vehicle. Always follow the manufacturer's service manual and safe shop practice, and get help from a qualified mechanic when you need it. Working on real engines can cause injury or damage, and you do so at your own risk.

2. Free and paid access

Free: one engine is free to use, with no account needed.
Full Access is a one-time purchase that unlocks every engine on the site, including engines added later, for your own personal use on your own devices.
Classroom License is a yearly subscription for one teacher to use every engine with their own students, on a projector and on students' devices, for teaching. It renews each year until cancelled.

Prices are shown on the site before you pay. We may change prices for future purchases. That won't affect what you've already bought.

3. Payments

Payments are processed by Lemon Squeezy, which acts as the merchant of record: it takes the payment, handles sales tax and VAT, and issues your receipt. Lemon Squeezy's own buyer terms also apply to the payment. We never see or store your card details.

4. No refunds

All sales are final. Full Access and Classroom Licenses are digital products that start working the moment you pay, so we don't offer refunds. The V-twin is free with every feature, so you can try Engine Walk fully before you buy.

Classroom License: you can cancel at any time and keep access until the end of the year you've already paid for. After that it won't renew. We don't refund the current year.
Billing mistakes: if you're charged twice, or charged without authorizing it, email us at enginewalk@gmail.com and it will be put right. As merchant of record, Lemon Squeezy may also refund duplicate, fraudulent or unauthorized charges.
If a purchase is refunded or charged back for any reason, the access it gave ends.

Nothing in this section takes away any right you have under the consumer law where you live that can't be waived by agreement.

5. Your account

You can create a free account with your email and a password at any time, or you're signed in automatically with the email you pay with. A purchase only unlocks an account whose email has been confirmed, either by buying from that account or with a code we email you. Keep your password to yourself; you're responsible for what happens under your account. You can delete your account at any time from the account menu, or by emailing us.

6. Fair use

Please don't:

share your account, password or license key with people outside what your purchase covers (Full Access is for you; a Classroom License is for one teacher and their students);
copy, download, extract, resell or redistribute the models, renders, text or code, or build a competing product from them;
try to get around the paywall, overload the site, or break its security;
use Engine Walk for anything unlawful.

We may suspend or end access, without a refund, for anyone who seriously or repeatedly breaks these rules.

7. Ownership

The Engine Walk models, renders, text, design and code belong to Engine Walk. Buying access gives you a personal, non-transferable license to use them on the site, not ownership of them. Screenshots and short screen recordings for teaching, reviews or sharing on social media are welcome if you credit Engine Walk.

8. Trademarks and independence

Engine Walk is independent. It isn't made by, affiliated with, sponsored by or endorsed by any engine, vehicle or motorcycle manufacturer. The engines are described by their layout (for example “45° V-twin” or “small-block V8”), and any maker's names mentioned are used only to describe well-known designs. All trademarks belong to their owners.

9. Availability and changes

We work to keep Engine Walk running and improving, but we can't promise it will always be available or error-free. We may add, change or retire features and engines.

10. Disclaimer

Engine Walk is provided “as is” and “as available”. As far as the law allows, we make no warranties of any kind, express or implied, including that the content is accurate, complete or fit for a particular purpose.

11. Limit of liability

As far as the law allows, Engine Walk won't be liable for any indirect, incidental, special or consequential damages, or for any loss or injury arising from using (or being unable to use) the site or from relying on its content. Our total liability for any claim is limited to the amount you paid us in the 12 months before the claim. Some places don't allow these limits, so they may not all apply to you.

12. Children and schools

Engine Walk is meant for general audiences and classrooms. Purchases and accounts are for adults (or a parent or guardian on a child's behalf). Students using a Classroom License don't need an account of their own.

13. Changes to these terms

We may update these terms. The effective date above shows the latest version. If a change is significant, we'll say so on the site. Continuing to use Engine Walk after a change means you accept the new terms.

14. Governing law

These terms are governed by the laws of the State of New York and applicable United States federal law, without regard to conflict-of-law rules. Any dispute that can't be settled informally will be heard in the state or federal courts located in New York, unless the consumer law where you live gives you the right to bring it where you live. If any part of these terms can't be enforced, the rest still applies.

15. Open-source credits

Engine Walk is built with three.js (MIT License). It uses the Saira Condensed, Source Sans 3 and JetBrains Mono fonts (SIL Open Font License) served by Google Fonts. Thank you to their authors.

16. Contact

Questions, billing or anything else: enginewalk@gmail.com.