distributor shaft doesn't turn when engine cranked

keats · Last edited by keats on Mon May 28, 2018 6:28 pm; edited 1 time in total

Going to a parade this AM and the m38 justed stopped running. would crank fine but not start. Got it home and did some troubleshooting. Getting gas at carb. 24 volts to distributor primary wire plug.

Took the cap off and looked around. tried to get points on shaft cam but noticed the shaft wouldn't turn. tried with cranking engine and shaft doesn't turn.

put rotor back on and can't turn shaft by hand only a slight bit , and can see the weights under the plate moving as they should.

broken shaft? Jammed somehow?

I guess the next step is to remove distributor but wanted some advice first.

can I remove distributor by marking rotor direction on dist. case and putting it back in with rotor pointing at the same direction?
_________________
Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B

dpcd67 · Member Joined: Nov 25, 2016 Posts: 187 Location: Iowa

Yes and the distributor only goes in one way. Get out your TM and read it.

keats · Posted: Mon May 28, 2018 6:27 pm Post subject:

Update:
took distributor out and once out the shaft was turning cleanly and smoothly.

tried to turn oil pump slot with long screwdriver but couldn't

Next step?

Next I think checking if cam is turning by looking thru side cover?

broken teeth on cam timing gear?
_________________
Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B

dpcd67 · Member Joined: Nov 25, 2016 Posts: 187 Location: Iowa

You can't turn the oil pump shaft when it is installed as the cam turns it via gears. I would remove the oil pump and check the gears on it; if those are bad, or the cam gears are broken, well, that is rare, and bad.

wesk · Posted: Mon May 28, 2018 10:09 pm Post subject:

Before you start any major teardown, do two things.

1 - Stick that long common screw driver in the oil pump slot and hold the screw driver with light hand pressure while someone turns the crank. If the screw driver does not turn, pull the oil pump.

2 - Make sure the anti-rattle clip is still on the distributor shaft tip and not laying at the bottom of the hole wedged against the oil pump shaft stopping the distributor from fully engaging with the oil pump drive slot.

_________________
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

keats · Posted: Tue May 29, 2018 9:42 am Post subject:

anti-rattle spring was still on the dist. shaft when I pulled it.

Oil pump would not turn at all when pressure added while turning crank.

removed oil pump and found 3 teeth broken. (photos below) No pieces fell out when pump removed. I took the cover off the pump and found one of the gears inside had a tooth broken off (the gear riding on the fixed shaft.)

How can I tell if cam gear or timing gear is damaged? can't really see up the pump bore clearly.

where would the chips go? oil pan?

next steps besides getting a new pump?

Cam gear hardened enough to take this abuse?

_________________
Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B

RICKG · Member Joined: Aug 31, 2010 Posts: 1740 Location: SO IDAHO

Hi Gary, I went thru this with an L134 I'm using for my CJ3A project.

You will find the broken teeth in the oil pan (at least I did).
Being a project jeep I had clear access to view the cam gear thru the oil pump shaft hole to determine it was not damaged. Sensible engineering would dictate the cam gear being more hardened than the pump gear bit I don't have a source confirming that. At any rate I would not install a new pump without first inspecting the cam gear.

It's good you determined the root cause of the failure being a busted gear inside the pump.
_________________
keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a

LTDan · Member Joined: Oct 13, 2017 Posts: 32

Your real question should be "What caused the gear to fail in that way?"

Something caused your camshaft and oil pump to bind and the force had to go somewhere.

I have a feeling that the oil pump would have been seized in order to cause such a failure.

RICKG · Member Joined: Aug 31, 2010 Posts: 1740 Location: SO IDAHO

[quote="keats I took the cover off the pump and found one of the gears inside had a tooth broken off (the gear riding on the fixed shaft.)

[/quote]

That would do it..
_________________
keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a

keats · Posted: Tue May 29, 2018 2:49 pm Post subject:

a mechanic friend of mine took a look at the pump and noticed a nick in a tooth in the pump... Conjecture, but maybe the gears had something caught in them breaking the inner gear first which then jammed the inner gears which led to the teeth being broken off the pump shaft.

will next take off the manifolds to get a good look at the cam gear. It feels whole and intact but need to get a good look through the valve cover.

If it looks OK I will put another new (NOS)? pump in and see how it runs.

Otherwise its a major overall anyway.

Any ideas?
_________________
Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B

RICKG · Member Joined: Aug 31, 2010 Posts: 1740 Location: SO IDAHO

It's been a while since mine was apart but I don't think you'll see the cam gear by taking off the valve cover.
http://willysmjeeps.com/v2/modules/gallery/albums/album70/Lt_side_001.jpg
_________________
keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a

keats · Posted: Tue May 29, 2018 3:35 pm Post subject:

I can feel it thru one of the drain holes right behind the manifold so I should be able to see it once the manifold is off. Worth a shot to get a good look at the gear. If no luck then it’s probably a major tear down to get the cam out and about to much above my pay grade to attempt. I will report what I find
_________________
Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B

wesk · Posted: Tue May 29, 2018 9:59 pm Post subject:

I had my doubts, but went out to the garage and looked at my L134 on the engine stand and lo and behold!

_________________
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

keats · Posted: Wed May 30, 2018 1:45 pm Post subject:

Took manifold off and had a perfect view of cam gear. Checked it several times while crank was turned and saw no chipped or damaged teeth.

Might have got lucky!!

At this point I just plan to get an oil pump (any suggested brands?) and a bunch of gaskets and put the jeep back together and see what happens.
_________________
Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B

RICKG · Member Joined: Aug 31, 2010 Posts: 1740 Location: SO IDAHO

That's good news Gary! FWIW I run Melling pumps on both my L134's with no problems.
_________________
keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a


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