Profile Picture

Timing

Posted By Pops57 9 Years Ago
You don't have permission to rate!
Author
Message
Ted
Posted 9 Years Ago
View Quick Profile
Co-Administrator

Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)

Group: Administrators
Last Active: 14 hours ago
Posts: 7.4K, Visits: 205.0K
Pops57 (7/5/2016)
Opened her up and found #2 cylinder pushrod was out. That would cause no compression right? Can I just pop it back in and check it or do I need new pushrod? Is this something common that happens?

If it was an intake pushrod, then there will be minimal compression on that cylinder.  An exhaust pushrod being off will have the engine popping back through the carb.  Just stick the pushrod back in place if it's not bent and recheck the compression on that cylinder.  If it's bent, replace it.


Lorena, Texas (South of Waco)


Pops57
Posted 9 Years Ago
View Quick Profile
Normally aspirated

Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)

Group: Forum Members
Last Active: 8 Years Ago
Posts: 17, Visits: 67
Opened her up and found #2 cylinder pushrod was out. That would cause no compression right? Can I just pop it back in and check it or do I need new pushrod? Is this something common that happens?
Ted
Posted 9 Years Ago
View Quick Profile
Co-Administrator

Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)

Group: Administrators
Last Active: 14 hours ago
Posts: 7.4K, Visits: 205.0K
Pops57 (7/5/2016)

How do I perform a leak down test

A leak down tester puts air to the cylinder while both valves are closed and gives a percent value for the air leaking past rings, valves and/or gaskets.  A cheap test is to simply put air pressure to the cylinder and see if you can hear air come back out the carburetor, exhaust, or oil fill tube.  Having the rocker arms off while you do this eliminates the need to have the piston at exact TDC on the compression stroke.  By doing this you know in advance where to look once you start pulling the engine down.


Lorena, Texas (South of Waco)


Pops57
Posted 9 Years Ago
View Quick Profile
Normally aspirated

Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)

Group: Forum Members
Last Active: 8 Years Ago
Posts: 17, Visits: 67
How do I perform a leak down test
Pops57
Posted 9 Years Ago
View Quick Profile
Normally aspirated

Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)

Group: Forum Members
Last Active: 8 Years Ago
Posts: 17, Visits: 67
I've had it off and they all move valve lash is .019 .As I was pulling spark plugs #2 was dirty and oily
Ted
Posted 9 Years Ago
View Quick Profile
Co-Administrator

Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)Co-Administrator (13.1K reputation)

Group: Administrators
Last Active: 14 hours ago
Posts: 7.4K, Visits: 205.0K
A Leak Down Test would help to isolate why the cranking compression is ‘low’ on cylinder #2.  Without the leak down test, check the valve lash and make sure you don’t have one that’s too tight.  Oil in the cylinders and repeating the test for cylinder #2 can help to determine if the rings and/or the piston is the problem.  Assuming the oil in the cylinder and the valve lash checks out okay and based on the very low test value, I’m betting on a valve sealing problem on cylinder #2 which will require the cylinder head to come off in order to fix.
 
The valve stem seals remaining in the raised position on the valve stems is normal.  Once the head(s) is pulled, then the condition of those seals can be verified and replaced if needed.

Lorena, Texas (South of Waco)


miker
Posted 9 Years Ago
View Quick Profile
Supercharged

Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)

Group: Forum Members
Last Active: 4 days ago
Posts: 1.8K, Visits: 190.6K
I'd pull that valve cover, and see if #2 has the valves visibly moving, or a thrown pushrod. If it's a valve stuck open or a pushrod off and stuck closed, I wouldn't just replace the pushrod until I knew the valve would move. Then I'm afraid the head comes off to see what you've got.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ
Pops57
Posted 9 Years Ago
View Quick Profile
Normally aspirated

Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)Normally aspirated (38 reputation)

Group: Forum Members
Last Active: 8 Years Ago
Posts: 17, Visits: 67
So I ran a compression test today.what should I do next as #2 is shot?thanks in advance.
Talkwrench
Posted 9 Years Ago
View Quick Profile
Supercharged

Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)Supercharged (1.6K reputation)

Group: Forum Members
Last Active: 4 Years Ago
Posts: 898, Visits: 23.2K
Wipers work good - great. Shouldn't the gauge be a steady reading of 16-20 it rapidly bounces at 19-20 If you are checking the lines off the fuel pump I would say it may bounce around as its a small diaphragm that's working. If your checking the engine you need to get manifold vacuum from below the carb butterfly or out of the manifold direct. The dizzy lines goes to bottom of under the bowl. ..What carb are we talking about original or new style Holley , Eddie????
Both valves are closed/up position. Intake was last one to come up felt air coming out of spark hole. Pistons at TDC rotors at #1 on cap balancer is at like 50degrees

http://forums.y-blocksforever.com/Uploads/Images/02c74785-3ce2-4b80-a66c-f31f.jpg

"Came too close to dying to stop living now!"
miker
Posted 9 Years Ago
View Quick Profile
Supercharged

Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)Supercharged (4.1K reputation)

Group: Forum Members
Last Active: 4 days ago
Posts: 1.8K, Visits: 190.6K
Measuring the vacumn at the double acting fuel pump wil show the "bouncing" and high vacumn. It's made to run the wipers at WOT when vacumn is low. The 15" reading, if steady, isn't bad. I don't know if the carb on the motor used manifold or ported vacumn to the carb. But it sounds like you're looking at manifold vacumn. Any cam over stock will read a little lower.

If it runs good, make a mark on the balancer where the timing pointer is at TDC. If it's slipped, you need to be able to find it again. also mark the the TDC line on the balancer so it show well with a timing light. Start it up, and check the timing. Remember to disconnect the dizzy vacumn advance. Start it up and take a reading. If it's running good, and you've got a mark 50 degrees off, it's a slipped balancer. Not a big deal right now, and now you've got a mark that works. If it shows up on the original mark, the balancer's good, and you didn't find TDC. Make sense?

Either way, you've got a mark that works for now. Now you can add a couple degrees, or back off a couple, but at least you can get back to your starting point. Now you can advance or retard it, looking for the highest vacumn reading, and test drive to see if it pings.

Mark everything, write it down, use two colors of paint. I can't tell you how many times I've regretted not having a base line, and not knowing what to go back to.



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ


Reading This Topic


Site Meter