Showing results for 
Search instead for 
Did you mean: 
Hagerty Employee

Wrenchin’ Wednesday: how to build a DIY piston stop for $5

Setting Top Dead Center (TDC) is a major step during engine work as it is the point at which all mechanical events are timed to. 

We're going show you how to build a quick and cheap piston stop using a generic spark plug anti-fouler, which costs under $5. These tools can be found online and in many speed shops, but are becoming less common in local parts houses, so we'll dive right in on a DIY solution!


Read the full article at

New Driver

I made one 40 years ago. I broke the porcelain out of a old plug and used a carriage bolt with the curved head so didn't damage the piston. Nut on each side of the shell. Just another way. 

Intermediate Driver

Sorry just noticed your comment after posting an almost identical one myself. What’s interesting is that I’m in the U.K. so minds across the ocean!

Intermediate Driver

I made a simple tool for this purpose over forty years ago merely by knocking out the ceramic part of the spark plug itself and adapting a suitable rod to go through the centre. Screw it in and off you go.

New Driver

you know it doesn't matter if it's on the compression stroke or not

Pit Crew

So @extech your timing marks are on the exhaust stroke?

New Driver

so you know tdc happens twice inthe 4 stroke cycle . once with both valves closed and once when there is a transition from ex to in
Intermediate Driver

Nice to see a reference to a "flat blade" screwdriver when so many call it a "flat head" screwdriver.

Advanced Driver