Piston Stop Tool?

[Mikel2000]

Has anyone used the summit piston stop tool, I put in cylinder #1 and turned the motor over and it stops, what seems to be about 180 degrees off from where the white line is at, I have 2 lines on my harmonic balancer one with a white line and another on the other side without a white line and it stops at right before the 12 mark, any suggestions, I tried pulling out the tool turning it a little then putting it back in and then turning it over again and it stops at the same exact place?

 

[denny]

Re: Piston Stop Tool?

It is a new build? Maybe yoe set the timing chain on wrong. The dubble roller gear set have 3 marks.
Check the rotor in the distributor, is it pointing to the #1 cylinder?

 

[Mikel2000]

Re: Piston Stop Tool?

nope, what originally happened was I took the distributor out without marking where it went, and now I dont know where the actual TDC is at, I moved the mark to 0 and set the distributor facing the #1 piston, but it never ran right?

 

[denny]

Re: Piston Stop Tool?

There are some cases where the harmonic balancer would spun.
The piston stop should be correct, I would use the piston stop to find tdc, place a mark on the balancer, then set the distributor to point to # 1 cylinder.

 

[Mikel2000]

Re: Piston Stop Tool?

TDC only occurs once for every 360 right?, if I was to stick something in the spark plug hole like a clothes hanger would the piston be right there?

 

[leroy]

Re: Piston Stop Tool?

Has anyone used the summit piston stop tool, I put in cylinder #1 and turned the motor over and it stops, what seems to be about 180 degrees off from where the white line is at, I have 2 lines on my harmonic balancer one with a white line and another on the other side without a white line and it stops at right before the 12 mark, any suggestions, I tried pulling out the tool turning it a little then putting it back in and then turning it over again and it stops at the same exact place?

It's not clear from what you wrote, but the correct method is to line up the timing marks, then go past about 10-15 degrees. Install your stop to find the top of the piston, and mark the alignment on your balancer somehow. Now rotate the engine slowly and gently by hand, until you feel the piston stop. It should stop about 10-15 degrees before the timing marks. Mark the balancer again, and TDC should be in the middle of the 2 marks. You may have to do it a couple of times to get the feel for it.

That only tells you where TDC is. It doesn't tell you if it's the compression or the exhaust stroke. You can look at your valves....#1 intake and exhaust should both be closed for the compression stroke. If you don't have your valve covers off, hold your finger over the #1 spark plug hole, and you will feel the pressure on the compression stroke.

HTH,
Jim

 

[vortecfiero]

Re: Piston Stop Tool?

Has anyone used the summit piston stop tool, I put in cylinder #1 and turned the motor over and it stops, what seems to be about 180 degrees off from where the white line is at, I have 2 lines on my harmonic balancer one with a white line and another on the other side without a white line and it stops at right before the 12 mark, any suggestions, I tried pulling out the tool turning it a little then putting it back in and then turning it over again and it stops at the same exact place?

the piston is at TDC twice...
end of the compression stroke
and end of the power stroke..

I think you need to release the stop and rotate the engine once around again

 

[Robert Lone]

Re: Piston Stop Tool?

the piston is at TDC twice...
end of the compression stroke
and end of the power stroke..

I think you need to release the stop and rotate the engine once around again

I'm w/ him... :tup:

 

[denny]

Re: Piston Stop Tool?

That only tells you where TDC is. It doesn't tell you if it's the compression or the exhaust stroke. You can look at your valves....#1 intake and exhaust should both be closed for the compression stroke. HTH,
Jim

This too...

 

[Mikel2000]

Re: Piston Stop Tool?

thanks for the help my buddy and i found it, it was actually one of the other marks on the balancer, and it was 180 off

 

[Don W.]

Re: Piston Stop Tool?

the piston is at TDC twice...
end of the compression stroke
and end of the power stroke..

:rant: Minor point but you misspoke. TDC occurs at end of the compression stroke and at the end of the exhaust stroke. End of the power stroke would be BDC.

BTW The "power" stroke has long since ended by the time the piston reaches BDC. Look at any valve timing diagram and see where the exhaust valve opens. 65* before BDC for example would be the end of the power stroke. In other words the the piston is making power through only 115* of crank rotation. Reason being once the angle between crank and rod become less than 90* (which is before 90* of rotation) power (IE torque) applied to the crank goes down rapidly. :rant:

 

[vortecfiero]

Re: Piston Stop Tool?

:rant: Minor point but you misspoke. TDC occurs at end of the compression stroke and at the end of the exhaust stroke. End of the power stroke would be BDC.

BTW The "power" stroke has long since ended by the time the piston reaches BDC. Look at any valve timing diagram and see where the exhaust valve opens. 65* before BDC for example would be the end of the power stroke. In other words the the piston is making power through only 115* of crank rotation. Reason being once the angle between crank and rod become less than 90* (which is before 90* of rotation) power (IE torque) applied to the crank goes down rapidly. :rant:

oops

of course you are correct lol
i was in a hurry and over simplifying as I didnt want to confuse him (or me lol)

or another way to put it...
if you look at it the 4 cycles as suck, squeeze, bangand blow
the piston is at the top after the squeeze
and also after the blow

heyyy we are talking about engines here !!! NOT..... ummmm ahhhhhh oh nvm