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Compression Stroke - How Do You Find It?

  • Thread starter Thread starter 68Blue302Coupe
  • Start date Start date Sep 7, 2009
6

68Blue302Coupe

New Member
Jul 30, 2005
74
0
0
Fairfax, VA
Sep 7, 2009
#1
  • Sep 7, 2009
  • #1
Hi Everyone,

I am getting ready to start my '68 for the first time in 6 years. I've swapped th I6 for a 302 and had to install a new distributor without and reference marks. I installed it with both valves on the #1 cylinder closed, timing pointer at TDC, piston at the top of the stroke, and the rotor pointing to the #1 spark plug.

I am trying to determine if I have done this correctly. Aren't there are two points when the the cylinder is at the top of the stroke and both valves closed--one on the compression and one on the exhaust stroke? How can I determine if I have this set on the correct stroke?

I could just give it a shot but would rather elminate as many variables as possible if (er... when...) it does not start.
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
Sep 7, 2009
#2
  • Sep 7, 2009
  • #2
If you screw a compression tester hose into the #1 spark plug hole, and rubber band a rubber shop glove to it. When you get the compression stroke, the glove will inflate.
 
T

TT670

Founding Member
Jul 10, 2001
360
9
28
Sep 7, 2009
#3
  • Sep 7, 2009
  • #3
Youve got it correct!
 
6

68Blue302Coupe

New Member
Jul 30, 2005
74
0
0
Fairfax, VA
Sep 7, 2009
#4
  • Sep 7, 2009
  • #4
Interesting idea, I'll have to try that. I also thought that I might be able to watch for when the intake valve opens/closes (valve cover off), and the the next TDC would be the compression stroke. Would this work? Oh, um, basic question, the intake valve is the one closest to the front of the engine?
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
Sep 7, 2009
#5
  • Sep 7, 2009
  • #5
68Blue302Coupe said:
Interesting idea, I'll have to try that. I also thought that I might be able to watch for when the intake valve opens/closes (valve cover off), and the the next TDC would be the compression stroke. Would this work? Oh, um, basic question, the intake valve is the one closest to the front of the engine?
Click to expand...

That works, but requires removing the valve cover. The intake manifold runner lines up with the intake valve.
 

shoguun

New Member
Jul 28, 2009
184
0
0
Sep 7, 2009
#6
  • Sep 7, 2009
  • #6
Google Image Result for http://www.lunatipower.com/Images/Tech/Pistons/DeckHeight.gif
 

Wicked65

Member
Aug 10, 2003
490
3
19
NORCAL
Sep 10, 2009
#7
  • Sep 10, 2009
  • #7
Put a big socket on the crank nut. Attach large ratchet. remove Number one spark plug. Put your finger over the hole. Start Cranking on the ratchet "in the direction the motor goes ofcourse".
When you get on the compression stroke, you will feel air start blowing by your finger. You should then be able to feel when the air stops, or use a pensil or something like that to see when the piston stops moving. you should be able to reference your timing indicator and balancer when you get to this point.
 
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