HELP! Engine won't rotate 360 degrees

Tincup

Tincup

Full Access Member
Joined
Feb 3, 2014
Messages
221
Reaction score
106
Location
MA.
Just getting ready to install my engine & trans for good, and while installing the converter bolts, I noticed the engine rotates ( by hand ) about 340 degrees then stops. I hits something hard. I can go backwards the same amount, and it hits again. I removed the trans, and the heads, and the oil pan, and can't find anything wrong. The inside looks like brand new ( it should with only 31K on it ), nothing in the oil pan. I'm stumped, any guesses would be appreciated...20200201_155013.jpg
 
No, I removed the trans, and no change. Right now it's only the long block, no heads, no oil pan.
 
rottenronnie said:
What's the deal. Was it running before, you just buy it???
Click to expand...
I bought a rolling chassis several years ago to use for my build of a 67 Dodge D100 pickup. It was supposed to be a good running motor with 31K on it. They even sent me compression test numbers, and a video of the (an) engine running. It's been in my shop taped up and used for mockup for my build. Unfortunately I never had any way to start it, I did spin it by hand, (but obviously I never went 360). The bottom end looks like new, nothing in the oil pan. I guess I'm going to have to remove the front of the motor next, there has to be an explanation..
Here is a link to my build. Thanks for your interest.

https://www.vtcoa.com/threads/project-cottonmouth.60443/
 
There really isn't much left...
If your short assembly is doing it's thing the pistons are going up and down when the crank (tries to) go around and 'round,
there must be some kind of issue inside the timing cover. The oil pump is driven off the front of the crank but it would have to be in really bad shape to stop the engine dead.
That's why I asked if it was running. Hopefully it WAS the engine in the video.
Good luck with it.
 
You don't state the year of the block but based on the crank trigger hole in the rear webbing I'd guess it's an 03-04. Good news if true eliminates one issue.

The only thing I can think of that might behave that way is the cam position sensor which reads the back side of the cam gear. It's possible the adjustment has moved or it has broken along the way and is jamming on the lobe on the back side of the cam gear. Again, something behind the timing cover like the oil pump. Try pulling the cam position sensor out completely and see what happens ?
 
It's actually an 05, but I will try pulling the sensor, can't hurt. Thanks
 
The cam sensor is pretty particular about how far it is away from the cam so, take note of it and save yourself some grief.
 
The math here is pretty simple. The cam on the back of the cam gear is about 50%. The cam gear is a 2:1 ratio to the crank. So there's 360' rotation if it's being stopped by the sensor. Add in the thickness of the sensor and there's your loss of the 20'.

Ronnie is right, the depth of that sensor is critical, so make sure you mark it -- assuming it's not broken. Factory is no longer available though I was able to find some 3rd party. And if you take a look at the FSM the install process is kind of weird.
 
I'm going to pull the sensor tonight. The strange part is that the sensor is the same one that came in the motor when I purchased it, (supposedly running). It's solid gray molded plastic.
 
Pull out the crank sensor. Maybe it was hit and is to far into the block...…
 
You may have something on top of a piston pull plugs and get a scope and look in each cylinder The cam sensor if out of adjustment should only allow 180 degrees and its plastic so a breaker bar will usually bust the cam gear through it Did you drop the pan? Listen for a clunk while turning and try to Isolate You could have a piston skirt hitting the crank. Good luck.
 
It was the F-ING sensor! Pulled it and she spins over like a charm. Thank you guy's so much for the help, I really appreciate it.
 
rottenronnie said:
Nice!!
A zeo-cost "repair"
Click to expand...

Well, not quite. $260 for head gaskets , another $65 for new bolts, $45 for base pan gasket, $140 for new "Correct" sensor. But, in the grand scheme of things, I'm not complaining, could have been much worse.
 
You must log in or register to reply here.

Latest posts

Support Us

Become A Supporting Member Today!

Click Here For Details

Random Media

3974.jpg
image
004
sitting purty
Back
Top