Piston & Ring Kit (.030) – Fits Evinrude/Johnson Vanguard V-Twin (Replaces 5006669, 394018S)

$0.00

Shipping calculated at checkout.

Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This is a an aftermarket Piston & Ring Kit (.030) – Fits Evinrude/Johnson Vanguard V-Twin (Replaces 5006669, 394018S). It is a .030" oversized assembly designed for cylinder position #4 in compatible Evinrude/Johnson Vanguard V-Twin engines and certain John Deere models with Briggs & Stratton engines.

It serves as a direct replacement for Evinrude/Johnson part numbers 5006669 and 394018S, as well as John Deere part number LG394018.

Precisely engineered for cylinder position #4.
Includes piston and a set of .030" oversized rings.
Constructed from a durable aluminum and steel blend.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number	Notes
Evinrude/Johnson	5006669
Evinrude/Johnson	394018S
John Deere	LG394018
Briggs & Stratton	394018S	For cylinder position 4

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For John Deere models, this kit fits various lawn tractors that utilize the Briggs & Stratton Vanguard V-Twin engine.

For Briggs & Stratton, this kit is specifically for the Vanguard V-Twin engine series requiring a .030" oversized piston for cylinder #4.

Brand	Model	Rated HP	Stroke	OEM Part No.	Notes
John Deere	GT235	18–20	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
John Deere	GT235E	18–20	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
John Deere	LT166	16	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
John Deere	LT170	17	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
John Deere	LTR166	16	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
John Deere	LX288	18	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
John Deere	SST16	16	4-Stroke	LG394018	Briggs & Stratton Vanguard V-Twin engine
Briggs & Stratton	Vanguard V-Twin	16–23	4-Stroke	394018S	For cylinder position 4

Technical Specs

Product Type: Piston & Ring Kit (.030 Oversize)
Installation: Cylinder Position 4
Housing Material: Aluminum/Steel
Dimensions: 5.38" L x 5.38" W x 5.63" H
Oversize Specification: .030" (0.76mm)

What’s in the Box

1 x Piston Assembly with Rings (.030 Oversize) (5006669/394018S)

Installation Notes

Disconnect the battery and ensure the engine is cool.
Drain engine oil and coolant.
Remove the engine cover, intake, exhaust, and cylinder head assembly.
Carefully rotate the crankshaft to access and remove the old piston from the connecting rod.
Inspect the cylinder wall for damage. Ensure it has been properly bored to accept a .030" oversized piston.
Install the new piston rings onto the new piston, following the correct order and orientation.
Generously lubricate the new piston, rings, and cylinder wall with fresh engine oil.
Compress the rings and carefully guide the new piston assembly into the cylinder.
Re-install the cylinder head, intake, exhaust, and all other components using new gaskets where required.
Refill the engine with the correct type and amount of oil and coolant.
Reconnect the battery and test the engine, checking for leaks and proper operation.

Troubleshooting & FAQ

How do I know if I need an oversized piston kit?

Oversized pistons are required when a cylinder has been machined (bored) to correct for wear, tapering, or scoring. This .030" oversize kit is for cylinders that have been bored 0.030 inches larger than their standard diameter. Always measure your cylinder bore before ordering.

Is this kit for a specific cylinder?

Yes, this piston and ring assembly is specifically designed and balanced for use in cylinder position #4 of the V-Twin engine.

What are the signs of a failing piston or rings?

Common symptoms include excessive oil consumption, blue-colored smoke from the exhaust, a noticeable loss of engine power, poor compression test results, and a tapping or knocking sound from the engine.

Can I install just the rings on my old piston?

It is not recommended. This kit provides a matched piston and ring set. Using new oversized rings on a worn standard-sized piston will result in poor sealing, low compression, and premature failure.

What's the main difference between OEM and this part?

This is an aftermarket component engineered to meet or exceed original equipment manufacturer (OEM) specifications for performance and fit. It provides a cost-effective solution without compromising on quality materials or manufacturing standards.

What is your shipping policy?

We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

What is the warranty and return process?

Our parts are covered by a 1-year warranty against manufacturing defects under normal use. If an issue arises, contact support with your order details. Returns are accepted within our standard window for unused items in their original condition. Please see our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

Payment & Security

Payment methods

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.