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 - My new project: 1964 USMC M38a1
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

My new project: 1964 USMC M38a1
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8  Next
 
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Jeep Project Threads
View previous topic :: View next topic  
Author Message
wilfreeman
Member


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Thu Apr 12, 2018 6:28 pm    Post subject: Reply with quote

This morning I stopped at O'Reilly Auto Parts and picked up 8' of 7/32" vacuum line and a couple of 5/16" fuel line fittings (I have extra 5/16" fuel line at home). When I got to the shop, I replaced all of my vacuum hose - only needed about 7' of it. Started the engine and - NOTHING - they didn't even try to move. I sprayed a little WD40 in the air inlets and worked them a little - no change. Oh well, at least it has new hoses now - I guess it needs more vacuum! I looked at my other Jeep and noticed I had put 1/4" hose on it - maybe that's why those wipers don't work so well with all new components? I will be changing those hoses out at a later date.

Next, I made up a new short hard fuel line to go between the fuel shutoff and the flex hose, but I could never could get it to stop leaking where the flex hose threaded on the new short hard line. I am guessing the flex hose threads are messed up - I ran out of patience (and time) with it. It doesn't leak until you stop the engine - pretty sure it is pulling air from there. I will probably go back to the setup I had before I bought the new flex hose (rubber fuel line hose clamped to the short hard line and a nipple in the fuel pump fitting) for the time being. I'll order a hose and install it if it gets here in time.

After I made the new hard line and installed it, I went for a drive - started acting up when it warmed up, so I reached down and took the gas cap off - didn't help, but that was before I knew I still had a gas leak.

Got back to the shop and checked the timing - about 12 BTDC, so I adjusted that to about 7 or 8. Idled like it is missing - adjusting the mixture screw on the carb didn't help and had to adjust the idle screw a LOT to get it to idle.

With that said, I am thinking that my valves are too tight, causing it to start missing as it warms up. I only have about 8-10" vacuum also. This engine is VERY quiet compared to my other one - can hardly hear ANY valve noise! What do you think? This will probably be my first area to check.
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Mike_B
Member


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

PostPosted: Thu Apr 12, 2018 8:15 pm    Post subject: Reply with quote

If your fuel leak is after the pump it can't be sucking air as that's the high pressure side, all it can do is leak out...that's not your problem...

Sounds like you need to check valve clearance, you should hear a little ticking as the valves close...

My .02 cents

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


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Thu Apr 12, 2018 8:43 pm    Post subject: Reply with quote

The leak is between the shutoff valve and the flex line - before the pump.

Yeah, check/adjust the valves are the first order of business Saturday morning - not looking forward to pulling the dude valve cover!
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
mdainsd
Member


Joined: Oct 20, 2017
Posts: 444

PostPosted: Fri Apr 13, 2018 8:41 am    Post subject: Reply with quote

8 to 10" of vacuum is not very good.

Both of my M38s and my M37 run 20 to 21"

There should be a little bit of valve noise, I liken it to a nicely oiled and running sewing machine.
_________________
'52 Dodge M37, '42 GPW, '48 FrankenJeep CJ2A/M38, '50 CJV-35(U), '51 M38, '42 WC-57 Command Car, '44 WC-51 Weapons , (2) M1941 Sperry 60" Anti-Aircraft Searchlights, John Deere M-gator, '44 White M3A1 Scout Car
Back to top
View user's profile Send private message
wilfreeman
Member


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Fri Apr 13, 2018 9:17 am    Post subject: Reply with quote

I knew it wasn't good - figured tight valves might be causing the low vacuum. Mine is as quiet as a new OHC engine. Actually as quiet as all of my vehicles. I'll be pulling the covers to check tomorrow - I just have a feeling.
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Mike_B
Member


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

PostPosted: Fri Apr 13, 2018 1:44 pm    Post subject: Reply with quote

Fuel leak before the pump WILL suck air...put Permatex II on the threads to seal then up.

There's a good valve adjusting on YouTube...should be an easy job...once the covers are off!

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


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Sun Apr 15, 2018 8:50 am    Post subject: Reply with quote

Update from yesterday's work on the Jeep.

I adjusted the valves to .016" exhaust and a "loose" .016" intake. Took a test drive and once again, after it warmed up it started missing, running rough and a slow idle that you had to throttle it to keep it running.

While I had the side cover off, I cleaned and painted the cover, bell, fording valve and PCV valve. After the test drive I noticed a fairly loud hiss which turned out to be multiple vacuum leaks. I tightened up the fording valve/PCV valve (which loosened the nipple to tee connection right after the PCV valve). These connections haven't been loosened in MANY years, so you can imagine what a PITA they were to break loose without stripping! I 2 more leaks at the vacuum port elbows (bottom of the pump) - I removed the elbows and added Teflon tape so that I could get them to a point that they were tight and at the angle I needed. This fixed my vacuum leaks, which helped the idle. While I was down there, I removed the flex fuel line (that I couldn't get to stop leaking), installed a nipple on the fuel pump inlet elbow and installed a rubber fuel line and hose clamps - definitely not sucking air there anymore.

I took another drive - same result after it warmed back up.

I was running out of time, so I decided to put the original distributor back in. This one has the breakerless ignition module in it, so I could rule out the condenser. Once installed, I set the air gap with the provided plastic feeler gauge. I installed the distributor adaptor to connect a dwell meter and connected a timing light. I fired it up and adjusted the timing to 5deg BTDC and idle to 700rpm. I adjusted the carb for the smoothest running. The dwell showed 30. Correct me if I'm wrong, but the dwell angle only matters with points, correct? It was showing 38 with the other distributor installed - it is supposed to be around 45 with points, right?

I took another test drive and although it ran better, once it warmed up it started doing the same thing! It runs fine as long as I keep the rpms up, but once you slow down to a crawl it starts surging and wants to cut off.

I am running out of ideas on this Jeep. I didn't try disconnecting the fuel line before the pump to try pulling gas from a gas can to rule out sucking air from the rest of the line. Nor did I try re installing my "redneck" gas tank to gravity feed the carb to rule out fuel pump problems. I checked all of my coils last year, and they show in spec.
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 16227
Location: Wisconsin

PostPosted: Sun Apr 15, 2018 9:23 am    Post subject: Reply with quote

Assuming you are 100% good on coils and air leaks.

Check compressions hot versus cold. You may have a piston fit issue. Or with the engine cold apply tension to the belts and turn the engine over by hand. Then run it till hot and try turning it by hand again.

If you can get your hands on a thermal radiation style heat meter compare head temp at base of carb to head temp at the thermostat and again to block temp. If you have a wide spread in temps with some quite high you may have clogged water passages getting the head too 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
Back to top
View user's profile Send private message Send e-mail Visit poster's website
4x4M38
Member


Joined: May 30, 2014
Posts: 3440
Location: Texas Hill Country

PostPosted: Sun Apr 15, 2018 1:30 pm    Post subject: Reply with quote

Your heat riser valve is operating correctly, right?
_________________
Brian
1950 M38
MC11481
http://www.willysmjeeps.com/v2/modules.php?set_albumName=album372&op=modload&name=gallery&file=index&include=view_album.php
Back to top
View user's profile Send private message Send e-mail
wilfreeman
Member


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Sun Apr 15, 2018 8:01 pm    Post subject: Reply with quote

Good idea - I'll check temps when I get off on Friday. I also want to check the air flow across the coil to make sure it's not overheating.

No heat riser on the a1 Brian.
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
m3a1
Member


Joined: Aug 13, 2017
Posts: 97

PostPosted: Sun Apr 15, 2018 8:28 pm    Post subject: Reply with quote

Sounds like it might be getting air into the mixture after the carb from somewhere, creating a lean condition. Have you explored that possibility?
Back to top
View user's profile Send private message
wilfreeman
Member


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Mon Apr 16, 2018 9:31 am    Post subject: Reply with quote

The other week I found a MAJOR leak in the carb - manifold gasket. It would hardly run. I replaced the gasket and it runs a LOT better - until it gets hot. I didn't check the carb base while I had it off - I guess I could check that and check the mounting nuts again.
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
wilfreeman
Member


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Fri Apr 20, 2018 2:08 pm    Post subject: Reply with quote

This afternoon I checked all of the vacuum line connections and tightened a few a little. Also made sure the distributor line was clear and had the oriface in the tee end. Then I got the wild idea to check the fuel pressure. I hooked in at the hard line before the filter before the carb (I know it should be checked at the pump, but I don't have a 1/4" barb fitting - figured this would be just as good since it is a hard line). I cranked it over and only got 2 - 2.25# of pressure.

Here's a link to a video of it not running right:

https://youtu.be/UMKJHTWWNrk
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
wesk
Site Administrator
Site Administrator


Joined: Apr 04, 2005
Posts: 16227
Location: Wisconsin

PostPosted: Fri Apr 20, 2018 4:13 pm    Post subject: Reply with quote

Does your pump have the spacer between it and your block?
_________________
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
wilfreeman
Member


Joined: Mar 13, 2006
Posts: 1079
Location: Richburg, SC

PostPosted: Fri Apr 20, 2018 4:15 pm    Post subject: Reply with quote

It has the 1/2" spacer on it Wes. I'm leaning toward a worn out fuel pump lobe. I might pull the pump tomorrow to check that.
_________________
Matt
1953 M38a1
1964 USMC M38a1
'51 USMC M100 trailer, '54 M100 trailer, '90 M101a1 trailer
Http://wilfreeman.wordpress.com (M38a1 build blog)
http://m38a1usmc.wordpress.com (USMC M38a1 rebuild blog)
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Display posts from previous:   
Post new topic   Reply to topic    willysmjeeps.com Forum Index -> Jeep Project Threads All times are GMT - 6 Hours
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8  Next
Page 7 of 8

 
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.