low compression

joeyfast13 · Posted: Fri Mar 04, 2011 6:12 pm Post subject: low compression

i have recently took my motor out and put all new gaskets on..
and now my compression reads 30 psi on one cylinder one and the rest lower the motor ran great before i pulled it
any ideas?

this is a f134 i checked the intake valves and adjusted them

Cacti_Ken · Posted: Fri Mar 04, 2011 7:29 pm Post subject:

So you had the motor out and just replaced gaskets and thats it?
_________________
Tropical Veteran
35th Inf. Reg. "CACTI" 4th I.D. VN
Amateur Radio K5XOM

DJ · Member Joined: Apr 15, 2005 Posts: 289 Location: Wis.

Did you check compression before you took it out?

joeyfast13 · Posted: Sun Mar 06, 2011 1:02 am Post subject:

i took the motor out and replaced all gaskets and painted it and put in a new clutch

the compression was 90 before i pulled it

wesk · Posted: Sun Mar 06, 2011 10:40 am Post subject:

Can you give us a list of what gaskets you changed, what parts you removed and reinstalled on the engine and what adjustments you made on the engine?
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

joeyfast13 · Posted: Sun Mar 06, 2011 11:06 pm Post subject:

i got a full fel pro gasket kit i didnt replace my rear main i just put the oil pan, timing cover, front plate both sides both valve cover gaskets carb gasket, head gasket, exhaust manifold gasket, water pump, pretty much everything..

i had to remove the cam gears but i did line the dots back up
i have adjusted the intake valves because they had play its acting like the valves arent closing cause the compression is just to low like the valves are open on the compression stroke

wesk · Posted: Sun Mar 06, 2011 11:14 pm Post subject:

Try doing a leak down test on it. That will pinpoint where the leak is. If you have never done a leak down test check here:
http://www.carcraft.com/techarticles/116_0406_cylinder_leakdown_tester/index.html
http://www.wcengineering.com/articles/leakdown.html

Did you set the valves at .014 or .016 gap? Did you set them cold or hot?
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

joeyfast13 · Posted: Sun Mar 06, 2011 11:20 pm Post subject:

Well i dont have a leak down tester

wesk · Posted: Mon Mar 07, 2011 12:04 am Post subject:

They are simple to make. The simplist is an air pressure regulator w/gage, a quick coupling, a hose adapter from a compression tester for the spark plug hole.
http://www.650motorcycles.com/LeakDownTester.html
http://www.top-fuel-racing.com/leak.asp

Bring each cylinder up on compression then apply 10 pounds of air to push the piston to bottom center and raise the pressure to about 50 pounds.

Listen and look for the air leak source:

Carb for intake valve leaks
Exhaust pipe for exhaust valve leaks
Bubbles in the radiator for water jacket and head gasket leaks
Dipstick tube for bad ring leaks
around the edge of the head gasket for external gasket leaks.
the other spark plug holes for leaks between cylinders

What gap setting did you use for your valves?
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

joeyfast13 · Posted: Thu Mar 10, 2011 10:24 pm Post subject:

I just took the slack out i haven't set it to specs
I lined the dots up on the gears is there more than one way

wesk · Posted: Thu Mar 10, 2011 11:18 pm Post subject:

The jeep 4 banger has solid lifters. They must have the correct running clearance or one of two things will happen to each valve. If set too loose it will stay closed too long and the exhaust valves will get too hot and burn. If set too tight the valves will not always close fully and leak. You only remove lash (" just took the slack out ") on engines with hydraulic lifters.

Are you referencing the correct engine serive manual for your engine? If not the correct one is available to you free to download in PDF on our downloads page.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

joeyfast13 · Posted: Sat Mar 12, 2011 2:10 am Post subject:

But if i lined the dot up on the gears is there a wrong way to do it

wesk · Posted: Sat Mar 12, 2011 2:44 am Post subject:

Lining the dot up on the gears only sets the cam gear in time with the crank gear.

joeyfast13 · Posted: Sat Mar 12, 2011 4:55 pm Post subject:

Well thats what i think it is when number 1 comes up one its compression stroke maybe the cam is off and opening the valves...

But i will adjust the valves to spec and ill post back

wesk · Posted: Sat Mar 12, 2011 5:22 pm Post subject:

If you used the manual and set gear marks correctly then when #1 is TDC on compression both valves will be closed unless they are adjusted too tight.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php


Create an account	Home · · Forums · · Articles · · Downloads · · Photo Gallery


PHP-Nuke Copyright © 2005 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.