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Your cart is empty.COMP Cams Top Dead Center Stops are designed to positively stop the piston in order to find top dead center. The bolt style screws into the spark plug hole, while our universal plate type bolts across any cylinder bore when the heads are off.
J. Lewis
September 3, 2025
I give the quality, and utility of this tool 5 stars, but it cannot be used on Ford 4.6, and 5.4 engines, as the tool is too short. The 4.6 & 5.4 have deep spark plug holes, and this tool won't work, as it won't even begin to thread into the cylinder head. The threads on the the spark plugs for these engines, are from the beginning of the threads, to the shoulder of the spark plug, 5/8 of an inch long, whereas the threads on the tool, from the beginning of the threads, to the shoulder of the tool, are only 3/8 of an inch long, which means, the tool is 1/4 of an inch too short. If you need a piston stop tool for one of the above mentioned engines, you will need to go to a specialty tool company, such as Modular Motorsports. Hope this helps.
Steven Edwards
September 1, 2025
Worked great on a Pontiac 400.
Rod
August 10, 2025
Ahh the joys of classic car ownership !got the 84 vette, was running rough, turns out gm harmonic balancers are bonded with rubber in 2 pieces, the outer piece slips due to age, and your timing marks are way off, to determine where TRUE TOP DEAD center is you need a piston stop which is waaaaay more accurate than using a screwdriver or straw or whistle to know where exactly true top dead center is on the compression stroke.Fit like a glove and i was able to re mark on the balancer true top dead center using this tool and i was able to time my engine to factory spec of 6 degrees before top dead center with the est wire unplugged. Car runs great now !!!Great price, super fast free shipping !
Customer
August 5, 2025
Great product
William Miller
July 27, 2025
Used it on motorcycle, with a degree wheel, to check ignition timing.
GP
July 18, 2025
Did not fit my 14mm Vespa.
Dr. Righteous
June 4, 2025
Really, this is the ONLY way to determine what you TRUE TDC of your engine. And this is essential.On my old Dodge Ramcharger the actually timing mark had shifted. I had previously set the timing by that and it was low on power so I suspected there was a issue. Timing using the piston stop I found the stock timing mark had shifted several degrees retarded.I use some timing tape and set the advance to a reasonable 8* and the sleepy (stock) 360 woke up!
EmTee
May 13, 2025
but otherwise it does its job. If you're trying to find TDC within range of a timing chain/belt tooth, you should be fine. After that you can use valve timing marks to get a good mark for a timing light etc. for ign. timing, or a trigger wheel, hall sensor, pos sensor what have you. I used it very far from TDC, and bracketed interval, going from both sides, narrowing it down, making sure marks on both sides spaced similarly, just as a sanity check.Don't use it extremely close to TDC, you could damage something, spark plug hole, piston etc. Just go halfway between your final marks.
Ben Misko
May 7, 2025
Kind of expensive for what it is but whatever it works. Used this to install a timing pointer on my LS to verify timing on my Dominator ECU
Alex Hansen
April 18, 2025
This piston stop worked great on a Chev 454 with flat pistons and 1971 292 heads.
Lahaie
March 22, 2025
expedié rapidement ,bonne qalité
Wendy Campbell
March 14, 2025
great
JT
February 7, 2025
good quality. Haven't used it yet but should be no problem.
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