How to measure piston protrusion?

[JoshH]

I'm trying to figure out what thickness gaskets I need, and I want to make sure I'm measuring correctly. How do you make sure the piston is at exactly TDC? Can it be done correctly with a set of vernier calipers?

 

[tylerrustLB7]

We use a indicator that sit's on the deck of the block. But it should be correct with calipers.

 

[TrentNell]

I'm trying to figure out what thickness gaskets I need, and I want to make sure I'm measuring correctly. How do you make sure the piston is at exactly TDC? Can it be done correctly with a set of vernier calipers?

use "dial indicater"........ use the deck and set up so deck is zero next to piston........... then swing over so the rod for the dial is in line with the highest part of the piston .... then turn over motor by hand slowly waitching the dial and the highest reading is your protrusion # . i have never used a caliper maybe some one else can chime in on if it will work .

 

[S Phinney]

Dial indicator is the proper way.

 

[JoshH]

I was afraid of that. I guess I'll have to find a dial indicator. Thanks guys.

 

[1slow01Z71]

I have my dial indicator I use to build all my LS motors if you cant find one locally you can borrow it for the shipping cost...

 

[JoshH]

I have my dial indicator I use to build all my LS motors if you cant find one locally you can borrow it for the shipping cost...

Thanks. I'll keep that in mind.

 

[IOWA LLY]

Here are both pieces you need to measure protrusion properly,

http://www.jegs.com/p/JEGS/958139/10002/-1

http://www.jegs.com/p/Proform/969803/10002/-1

 

[malibu795]

i have used
dial inditcatior
depth gauge
verinal dial caliper


preferd is dial indicator

 

[Trippin]

I would buy both of the tools here:

http://www.jegs.com/p/Proform/969803/10002/-1

 

[MMLMM]

Just rub your hand across it. If it feels like a good bump go with a thicker gasket.















J/K, get yourself a Dial indicator, there a handy tool for other projects too.

 

[JoshH]

I found a dial indicator with a magnetic base at a local parts store. Do I really need the across the bore bridge thing in the Jegs links?

 

[Fingers]

The Dial indicator is the proper way, but for the poor fool who is going cheap....

Place a piece of bar stock across the bore. Now bring the piston to TDC. Use a feeler guage to measure the gap under the bar. Measure both sides.

Even with a dial indicator, if you place a parallel across the piston bore, zero the indicator on top of the parallel, then run the piston up. It gives you a good number without having to move the gauge around.

JMO