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

Wiper motor...which is the correct one?
Lead additive, one more question.
M31C mount with or without replica weapon
Backfire and Hesitation
Wanted: Steering column and shaft for M38-1952, or late CJ2A
2024 CT. MILITARY VEHICLE SHOW AND FLEA MARKET- JUNE 15,2024
Brake Line
How to link full size photos in posts
Clutch release bearing support cast tab for return spring
T90 case replacement required?

Willys M Jeeps Forums


willysmjeeps.com :: View topic - M38 Engine Sound
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

M38 Engine Sound
Goto page 1, 2, 3, 4  Next
 
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Technical Knowledge Base
View previous topic :: View next topic  
Author Message
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Thu Jul 26, 2018 6:44 pm    Post subject: M38 Engine Sound Reply with quote

I recently resurrected a '51 M38 with 12v and got to the point of moving it for the first time. Sorry for the fat ass belly, but it was 90 degrees.

First movement from a buildup from scratch. I rebuilt everything except the motor which I was told was rebuilt and ready to go. During my first movement/brake test, I noticed a noise at the end of the video. What do you think it is? The sound in question is when I get back in the garage and ready to shutdown....the thumping sound...disregard the belt squeal...I'll get that fixed.

https://www.youtube.com/watch?v=s7fe20uovZg
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 16225
Location: Wisconsin

PostPosted: Thu Jul 26, 2018 11:45 pm    Post subject: Reply with quote

That's easy. It's a rod knock! What was the oil pressure gauge reading?
_________________
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
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Fri Jul 27, 2018 5:00 am    Post subject: Reply with quote

20 psi I think...wonder why it did it after returning into the garage and not going out.

I'll try it again this afternoon and double check the oil pressure. Thanks Wes.

I also need to purchase a new tach/dwell meter and get it on there to verify rpm and timing.
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 16225
Location: Wisconsin

PostPosted: Fri Jul 27, 2018 8:52 am    Post subject: Reply with quote

It had a milder version of that knock the instant you started it up and while you were backing out. The camera up front was in a better position to hear it then you were.

Good sense says pull the pan and physically check the rods before you do any more runups.
_________________
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
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Fri Jul 27, 2018 9:01 am    Post subject: Reply with quote

Thanks Wes...good advice. I think I will instead of ruining the engine.
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Fri Jul 27, 2018 2:36 pm    Post subject: Reply with quote

Wes...Would dwell at 43 and timing off contribute to the rod sound? I just purchased an electronic analyzer, hooked it up and discovered dwell at 43. Going to search for dwell angle now....I was thinking it was around 20.
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Fri Jul 27, 2018 4:33 pm    Post subject: Reply with quote

I have dwell at 42, point gap at .020, and timing at 5 BTDC. Noise quieted down some but moving 100 yards the oil pressure went below 20 psi...was around 40 during run-up and initial movement. I think oil pressure is my culprit...needs to be up around 40. I'm going to drop oil pan and check rod caps for tightness, then I may move to the oil pump.

FYI...I purchased this engine with word from previous owner that it was rebuilt by an engine shop...this is my third issue with the engine (no bolts to mount flywheel, missing front pulley spacer). And to top it off, Wes informed me that the serial number indicates it was a Willy's station wagon engine...dang!
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
Mike_B
Member


Joined: Dec 10, 2017
Posts: 336
Location: Southern Maryland

PostPosted: Fri Jul 27, 2018 6:51 pm    Post subject: Reply with quote

You're loosing oil pressure because the bearings are loose/worn. Raising the oil pressure will not fix your rod knock problem.

Mike B Smile
_________________
Mike B
1953 M38A1 Brush Truck
1952 M38
1951 M100 Trailer
Back to top
View user's profile Send private message
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Fri Jul 27, 2018 7:26 pm    Post subject: Reply with quote

Mike_B wrote:
You're loosing oil pressure because the bearings are loose/worn. Raising the oil pressure will not fix your rod knock problem.

Mike B Smile


Well, thanks for the wonderful news. Sad
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 16225
Location: Wisconsin

PostPosted: Fri Jul 27, 2018 9:44 pm    Post subject: Reply with quote

I would advise you to stop running the motor for timing checks and get the pan off and physically determine if you have a loose rod or not!!!!!!
_________________
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
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Sat Jul 28, 2018 4:30 pm    Post subject: Reply with quote

Gettin' after it Wes...again, thanks for the advice.

This week I'll get-r-done thinking if only 3 quarts of oil come out and 1 quart in oil filter, then maybe low on oil. (hopefully) I'm not confident on the engine oil stick, yea it looks good, but is it accurate? Else, I'll pull the engine and replace crank and cam bearings and inspect the oil pump.
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
Ray101
Member


Joined: Jun 03, 2015
Posts: 41
Location: Forest Lake, MN

PostPosted: Mon Jul 30, 2018 9:59 am    Post subject: Reply with quote

Low oil level will not cause low oil pressure until it gets low enough for the pickup tube to suck air, and the it will be zero or fluctuate alot.
Better listen to Wes and pull the pan.
_________________
1950 M38
Back to top
View user's profile Send private message
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 16225
Location: Wisconsin

PostPosted: Mon Jul 30, 2018 11:26 am    Post subject: Reply with quote

Quote:
I'm not confident on the engine oil stick, yea it looks good, but is it accurate?


Two important things I have learned wrenching on and buying vehicles the last 60 years.

Establish baselines on fresh rebuilds and newly obtained vehicles.

Simple Things:

With a newly obtained vehicle I always put a full gas can in the trunk and drove it til it ran out of gas. From that point on I always new exactly when the gauge meant EMPTY. Of course be careful with the newer fuel injected cars that do not behave well if you run the pump dry.

With oil dipsticks it's similar, I always check the stick at the end of an oil change to see what it reads vs the quantity of oil I serviced. Then make a noticeable note somewhere if a correction factor is needed.
_________________
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
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Mon Jul 30, 2018 12:35 pm    Post subject: Reply with quote

Good advice...makes sense. Thanks!
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
MarkR1951M38
Member


Joined: Aug 22, 2016
Posts: 117
Location: Huntsville, AL

PostPosted: Thu Aug 02, 2018 10:51 am    Post subject: Reply with quote

Wes and others...I have removed the oil pan and all rod and main caps were tight. However, only 3.5 quarts of oil came out and what did come out was as black as coal. Maybe attributed to before the carburetor was rebuilt...it was running very rich before the carb rebuild.

When draining oil without draining the oil filter, should you get 4 full quarts? Guess I'll dump in 3.5 - 4 more quarts of clean oil and see how it runs before I just go and remove the engine.
_________________
1951 M38 MC 22731
(Converted 12v, Carter WO carb, single action fuel pump, electric wipers)

http://www.willysmjeeps.com/v2/modules.php?set_albumName=album527&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Technical Knowledge Base All times are GMT - 6 Hours
Goto page 1, 2, 3, 4  Next
Page 1 of 4

 
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.