Im doing a 3.5 swap on my 4th gen. I switched all the timing stuff over, now when i turn the motor over by hand it goes smooth then just stops. Like its hitting a valve or something. I know the timing is set right, checked it and reset it a few times. I can get it to turn over completely its just rough in that one spot. I pulled the plugs and looked in the cylinders, there clean.
Idk any ideas?

 

What if you turn the other day? will it stop too? does it have any give or its a sudden stop?

The last time I experienced something like this was a motor we were putting together, turned out to be so much carbon buildup that it did not the let piston reach TDC. If your 200% sure nothing else is hitting, that might be your issue.

 

Yup if i got clockwise or counter clockwise its the same, and always in the same spot. I guess ill have to throw her in and see what happens... Lol

 

No, dont do that! if it does not turn, your going to break it when you try to start it, guaranteed. You have to figure out whats stopping it from turning. If nothing else is hitting and your sure the timing is perfect (and you didnt mix the rear and front cams) then its probably carbon buildup, so remove the heads, and check.

 

3.5s have left a bad taste in my mouth.

 

I agree with you bro, if I ever do another 3.5 on another max, im stripping it down to the bare block and putting it back together to make sure everything is good. These junk yard motors cant be trusted.

 

Theres gotta be an easier way then striping down the motor. If it was just stoping dead and unable to move id tear into it. But it just hangs up enough to make me have to muscle in by. Idk...

 

did you happen to remove the oil pan? its really hard to tell what the problem is on the bottom end without tearing it down, checking bearing's rod and main's. there can be a loose connecting rod cap causiing it not to spin, again its hard to chime in you would really have to tear down the motor for a accurate diagnosis. something is obviously hitting preventing from revolving the motor.

 

I didnt pull the pan, that sounds a little easier then the heads tho. If the bottom end looks to be in order in it goes.

 

oh I thought you said it stopped completely, so it does make full turns? just hesitates a lil bit at one point? are sparkplugs in?

 

Exactly Streetz, If the spark plugs are in turning it by hand will be harder to muscle in areas due to trapped air. That's prob the case here.

 

TDC can be hard to turn through because of compression even without spark plugs. I know mine felt difficult at that point, but the motor worked fine.

 

I'm putting an '07 quest motor in a 5.5 gen right now, ****ing thing had 36K on it & I had to take the timing covers off & do the secondary guides & chain, 36K miles!! I've seen 3.0's with 360k miles that didn't need anything done to them.

The last motor swap before that was on an '02 pathfinder, it had a rough spot just like your describing.......... I put it in without doing some further tests & that was a very bad idea. Had to pull it out due to a #2 misfire, 90psi max on that cylinder even after putting 150+ miles on it to make sure it wasn't something stupid like carbon or a stuck ring.

I never got to pull it apart because of the whole junkyard warranty thing, but I'm pretty sure the cylinder wall rusted to **** after the small engine fire from the donor truck was put out.

 

Plugs are out, and it is hard right before TDC.

 

Maybe if i can get a hold of a snake camera ill take a look down into the cylinders.