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

Password

Don't have an account yet? You can create one here.

Navigation
· Home
· Article Archive
· Article Submit
· Downloads
· FAQ
· Forums
· Members List
· Photo Gallery
· Private Messages
· Web Links
· Your Account

Search Articles



Forums

FS - Early M38 horn
M38 grill hinges
M38a1 / m170 shifter boot installation
Engine stay cable
45 M Willys, what is a reasonable price
Tub Vendors
HELP needed with M38 top bow mounting locations!!
M38 CARBURATOR KIT ?
Say hello to: CJV-35(U)
Industrial lamp Corp lid , driver side

Willys M Jeeps Forums


willysmjeeps.com :: View topic - What have I done, what have I done,
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

What have I done, what have I done,

 
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Technical Knowledge Base
View previous topic :: View next topic  
Author Message
jeeptj1
Member


Joined: Aug 20, 2010
Posts: 137
Location: Illinois

PostPosted: Sun Sep 29, 2019 3:06 pm    Post subject: What have I done, what have I done, Reply with quote

Been wanting to check the compression on the m38. So I took all the plugs out and such as the tm said. Installed the compression gauge and only got like sixty pounds. Took the gauge out to see if it could have been plugged since it hasnít been used in thirty years. It was ok. Put it back in and got zero compression. So hereís where I figured out what an idiot I am. The compression gauge has a couple of adapters on it. The one I used was longer than the short one that should have been used. So now I have no compression on number one and 110 on the other three. The piston doesnít look like it has any damage so Iím pretty sick about being so stupid. What happened to number one? Did it break a valve etc. oh if it does start, itís pop crackle stuff. I will check the manual when Iím done pouting. Stupid John jr, arrrgh
_________________
52 m38
Back to top
View user's profile Send private message Send e-mail
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 14449
Location: Wisconsin

PostPosted: Sun Sep 29, 2019 7:07 pm    Post subject: Reply with quote

Just about all the compression gauges I have ever seen (55 years worth) have only 5 to 10 threads. None of these would be long enough to strike the piston so what exactly did you stick in the plug hole? Post us a photo of this weird gauge.
_________________
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
Back to top
View user's profile Send private message Send e-mail Visit poster's website
jeeptj1
Member


Joined: Aug 20, 2010
Posts: 137
Location: Illinois

PostPosted: Mon Sep 30, 2019 4:08 am    Post subject: Reply with quote

Wes the gauge is just a regular gauge. The longer adapter was definitely hitting the top of the piston as there is a mark not a dent from it. Also the bottom of the adapter shows that it was hitting. Canít post pics so let me know if thereís some other way to get them to you. Thanks John jr

Here's John's photos edited by me:


_________________
52 m38
Back to top
View user's profile Send private message Send e-mail
charlesfitton
Member


Joined: Jun 07, 2010
Posts: 65
Location: Maryhill On

PostPosted: Mon Sep 30, 2019 5:31 am    Post subject: Reply with quote

take off the tappet cover and see if the valves are still moving correctly.

If you done see a hole in the piston, there likely isn't one.


one step at a time

f
_________________
M38 CDN 52-30105
M38 CDN 52-30883

and other green crap...
Back to top
View user's profile Send private message
jeeptj1
Member


Joined: Aug 20, 2010
Posts: 137
Location: Illinois

PostPosted: Mon Sep 30, 2019 6:11 am    Post subject: Reply with quote

Pretty sure Iím going to have to end up doing that but thereís a lot of stuff to take off to get to it first!
_________________
52 m38
Back to top
View user's profile Send private message Send e-mail
bbloom
Member


Joined: Apr 23, 2008
Posts: 90
Location: Kansas City

PostPosted: Mon Sep 30, 2019 7:06 am    Post subject: Reply with quote

Pretty sure you bent the valve.
_________________
Bill
GP, GPA, GPW, M38, M38A1
Bantam T-3, M100
MVPA #1196

Photo Album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=album327&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
mdainsd
Member


Joined: Oct 20, 2017
Posts: 313

PostPosted: Mon Sep 30, 2019 8:16 am    Post subject: Reply with quote

First off refer to the manual TM-9 1804A, graciously provided in the downloads above.

First off a long compression gauge adaptor cannot strike the pistons. Period.

Referring to the manual and looking at the cross section views (both). You can see that the spark plugs are located over the valves, not the pistons. You have bent a valve in cylinder number one. They actually bend fairly easily and since yo left a mark and you have zero compression that is what happened.

The good news is that most likely you will not need a full tear down to rectify. Follow the same manual and do the tear down as far as getting all the stuff off of the head and the valve side of the engine. The head will have to come off as will the tappet adjustment cover. But from there on you can replace the bent valve quite easily.
_________________
'52 Dodge M37, '42 GPW, '48 FrankenJeep CJ2A/M38, '50 CJV-35(U), '51 M38, '42 WC-57 Command Car Undergoing factory original restoration, '44 WC-51 Weapons , (2) M1941 Sperry 60" Anti-Aircraft Searchlights, John Deere M-gator
Back to top
View user's profile Send private message
jam51m38cdn
Member


Joined: Feb 06, 2008
Posts: 61
Location: Findlay, Ohio

PostPosted: Mon Sep 30, 2019 8:21 am    Post subject: Reply with quote

Hum, I cannot reach the pistons from the spark plug holes on any of my engines. Sounds like number 1 exhaust vale is not closing to get the compression. I would loosen that tappet and readjust the tappets
Back to top
View user's profile Send private message
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 14449
Location: Wisconsin

PostPosted: Mon Sep 30, 2019 9:53 am    Post subject: Reply with quote

John,

This will illustrate the geometry of the spark plug hole/valves/piston and you should be able to see now that you hit the valve not the piston.


_________________
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
Back to top
View user's profile Send private message Send e-mail Visit poster's website
jeeptj1
Member


Joined: Aug 20, 2010
Posts: 137
Location: Illinois

PostPosted: Mon Sep 30, 2019 10:31 am    Post subject: Reply with quote

Thanks for all the info guys. John jr
_________________
52 m38
Back to top
View user's profile Send private message Send e-mail
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 14449
Location: Wisconsin

PostPosted: Mon Sep 30, 2019 12:15 pm    Post subject: Reply with quote

And if you bent the valve the next step is removing the head. Then removing the side valve cover to expedite the valve change.
_________________
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
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Technical Knowledge Base All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB © 2001 phpBB Group
Forums ©

 



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.