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Spark Plug Hole Protective Cap

$0.29/Each
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Part# 15-06003
MFR Model# VC937-16 BLK

Overview

Note: These are not for 18mm plugs.

#9721 Spark Plug Hole Caps. Seal your Spark plug hole openings with these inexpensive tapered fit plastic caps. Prevent debris from accidentally entering ports and creating damage or mischief. Ideal for sealing for winter storage, preventing moisture from corroding internal engine parts. Also can be used to seal ports for leak testing, an important procedure that locates potential air leaks before they cause costly engine damage. Tapered fit provides positive seal for either vacuum or pressure testing, Tapers from 0.482" to 0.526".
   
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Reviews

Robert W Verified Purchase

Spark Plug Hole Protective Cap

September 28, 2024

Purchased the spark plug hole cap for use on a Ford small block 351W engine. Plug hole is 14mm and the caps fit perfectly.

Chris T Verified Purchase

Spark Plug Hole Protective Cap

December 10, 2022

Product exactly what I was looking for. Great service, product and pricing,

Alf S Verified Purchase

Spark Plug Hole Protective Cap

December 7, 2021

These fit my small block Chevy (after-market heads) spark plug holes perfectly, in preparation for painting of the newly finished engine. My order was filled immediately, and the parts arrived MUCH sooner than I expected. THANK YOU.

Brian E
December 31, 2018

Spark Plug Hole Protective Caps are way to small they came loosely packed in a small plastic bag unsealed, twist tie around it. I ordered 30 received 28. Would appreciate a refund. Thank you. Order # VC937-16-BLK

David R Verified Purchase

Spark Plug Hole Protective Cap

May 19, 2022

Guys, change the description! I wish I would have read the reviews first, no they dont even come close to fitting an 18mm spark plug hole, which is why I wanted them for shipping engines. No I need to scramble to find some that do fit!

Advantage A
June 2, 2022

These plug hole caps do not fit aircraft engine spark plug holes (18mm)

Cliff R
March 5, 2020

If you order these, you will receive T-5 Cap Plugs (Stock No. 04-00048), these will probably work on the spark plug holes in a Ford 289, but not on an O-320! T-8 Cap Plugs are O.K. ( Stock Number 04-00050) work with the 5/8-24 spark plug holes, typical of most engines.

Greg W
June 22, 2018

Way way too small for the typical 18mm spark plug hole common in aviation. Might work for 14mm, but if you’ve got a typical Lycoming or Continental, don’t bother with these.

Morgan
January 30, 2018

Too small for 18mm spark plug holes.

Zane J
December 16, 2017

Q&A

Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

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