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Discussion Starter #1
I have a adjustable pointer that i am unsure if its pointing where it should so thought id make sure it was pointing right.

Just wanted verification that i did the process correct.

Turned motor over until on compression stroke of #1
installed piston stop
Turned until piston touched stop, made mark where pointer was pointing
reversed and turned the other way until piston stopped, made mark where pointer was pointing
divided in half to get middle of each mark which "should" be TDC?

Now i make a mark where the half way point is for TDC, turn motor by hand so pointer is pointing at new TDC mark
then loosen and adjust pointer to point at 0?
 

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Absolute best way to set an adjustable timing pointer is with the cylinder head off.

Use a dial indicator on the piston to see true TDC.

I wouldn’t trust the way you are doing it to be even close to accurate.


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$15 piston stop That goes in the spark plug hole.

turn one way until the piston hits piston stop and mark, turn opposite way until the piston hits piston stop and mark.

tdc is between the two marks,
 

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I have a adjustable pointer that i am unsure if its pointing where it should so thought id make sure it was pointing right.

Just wanted verification that i did the process correct.

Turned motor over until on compression stroke of #1
installed piston stop
Turned until piston touched stop, made mark where pointer was pointing
reversed and turned the other way until piston stopped, made mark where pointer was pointing
divided in half to get middle of each mark which "should" be TDC?

Now i make a mark where the half way point is for TDC, turn motor by hand so pointer is pointing at new TDC mark
then loosen and adjust pointer to point at 0?
That's the way I did it. Worked good and everything seems to be accurate.
 
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I used a spark plug non fouler and tapped it for a 3/8 nc bolt, was a cheap way to make a piston stop.

The way Rob stated is how I’ve always done it, if the heads are on.
 
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The cylinder head being off to check true top dead Center makes sense to me. The guys on this forum are very knowledgeable and helpful.
 

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Stick a dial indicator through the spark plug hole.

ks
 

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Discussion Starter #8
$15 piston stop That goes in the spark plug hole.

turn one way until the piston hits piston stop and mark, turn opposite way until the piston hits piston stop and mark.

tdc is between the two marks,
The way you described is how i did it. Once i had my mark made in the middle of the two marks i turned the motor so the timing pointer was pointing to the new TDC mark then adjusted the pointer to 0
 

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If you are degreeing your cam, you need to be absolutely certain of TDC, and chances are that the heads will be off while degreeing a cam. I just put my engine back together with a new crank and need to find TDC, so I used the dial indicator on the piston along with a degree wheel on the crank. Once I found TDC, I made some marks on the back of the crank / oil seal so that I could easily get back to TDC after the cam was in and the timing cover was installed. Then, I installed the harmonic balancer and timing indicator, aligned the marks on the crank / seal to get back to TDC and verified that TDC on the balancer is aligned with the pointer. In my case, I was lucky and things lined up as they should.

If you are installing a new balancer on an engine that has the cylinder heads installed, the piston stop method will get you close enough.
 

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The piston stop method is 100% accurate.

Just curious what is your method for finding tdc with a dial indicator with the heads off?
 

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If you are degreeing your cam, you need to be absolutely certain of TDC, and chances are that the heads will be off while degreeing a cam. I just put my engine back together with a new crank and need to find TDC, so I used the dial indicator on the piston along with a degree wheel on the crank. Once I found TDC, I made some marks on the back of the crank / oil seal so that I could easily get back to TDC after the cam was in and the timing cover was installed. Then, I installed the harmonic balancer and timing indicator, aligned the marks on the crank / seal to get back to TDC and verified that TDC on the balancer is aligned with the pointer. In my case, I was lucky and things lined up as they should.

If you are installing a new balancer on an engine that has the cylinder heads installed, the piston stop method will get you close enough.
I think more people end up degreeing a cam with the heads on than off. Piston stop will get you spot on if done correctly.
 

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The cylinder head being off to check true top dead Center makes sense to me. The guys on this forum are very knowledgeable and helpful.
It really is the only way to find true TDC. The way the others are doing it with a piston stop will get them in the ballpark, but those adjustable pointers should be setup when the short block is being assembled.

.02


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It really is the only way to find true TDC. The way the others are doing it with a piston stop will get them in the ballpark, but those adjustable pointers should be setup when the short block is being assembled.

.02


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This is false. A piston stop will find tdc IF used correctly.

If a dial indicator is not used properly, it will give inaccurate readings. There is piston rock and dwell when it gets to the top of the stroke.

If the heads are off, this is another option. You can always make your own easily.
1066947
 

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This is false. A piston stop will find tdc IF used correctly.

If a dial indicator is not used properly, it will give inaccurate readings. There is piston rock and dwell when it gets to the top of the stroke.

If the heads are off, this is another option. You can always make your own easily.
View attachment 1066947
Correct, but if you understand dwell and piston rock then you will understand how to equate that into finding TDC.


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