While checking and adjusting valve lash this past weekend, I encountered a strange issue while turning the engine over clockwise (cw) by hand, with the sparkplugs removed.

As I approached TDC for cyl. #2 the engine locked. I tried a moderate amount of pressure on the ratchet, but it would not turn. Then I reversed direction, turning counter clockwise (ccw) just a few degrees of rotation. Returning to normal (cw) rotation, it would then turn over. This really got my attention!

I checked carefully, all tools and fasteners accounted for, nothing dropped into the engine.

Oddly, if I rotated the engine (cw) quickly it wouldn't lock. If I rotated it slowly, as is needed to line up the timing marks, it would lock most times. When it locked, it was always at the same spot, BTDC for #2.

But wait, there's more... The engine ran last on Friday evening when I changed the oil and filter while the engine was hot. I started the valve lash check on Saturday afternoon, when I could rotate it (cw) slow as I liked with no locking. I had to stop before I was finished. I resumed the valve adjustment on Sunday morning when the locking issue occurred for the first time. I bring up this last part because I have a feeling the duration of time is key.

I'm hoping this is i-VTEC related and normal for some reason unknown to me. Residual oil pressure bleeding off in the flux capacitor or sumpin...

Has anyone here heard of this before?

 

Nobody?

(sound of crickets chirping)

Well I finally got to talk to a master Honda Technician at my local dealer. He said, you guessed it, never heard of such a thing.

Then after a minute he said something like that has happened with Toyotas in their shop. After the engines sat for a couple of days with the sparkplugs out, pieces of carbon came loose from the head and dropped onto the piston crowns. The squish is tight enough that the carbon stopped the pistons.

The engine still hasn't run since Friday. I either tear it down to inspect it, knowing it ran fine before I got my hands on it. Or I crank it up, keeping in mind that it turned over fine when I turned it fast.

And I know ya'll are waiting in suspense...

Help Mr. Wizard!

 

I had something VERY similiar happen to me when installing my built motor. I bought a car with the built motor already installed and running (I helped build the motor roughly a year or so before i aquired the car) upon swapping it into my CRV, I was doing a valve adjustment just like you and ran into almost the exact same problem. I thought FOR SURE one of my kids had dropped something down in the cylinders during the time I had both motors out of both cars sitting on the garage floor.

Mine was getting stuck just before TDC on cylinder 1. I used lights, flexible magnets, air, etc etc to try and find or remove the item in the cylinder...no luck at all. I ALMOST tore the engine down, but since I have an 84mm ls/vtec it requires a Golden Eagle Headgasket and they are $100+.

When it would get stuck, I was barely turning the motor over....while troubleshooting the issue, I went in the house to get a drink...my buddy that had just came over was left in the garage....when i came back out, he was like "dude i've turned the motor over like 5 times, where does it get stuck at??" My heart sank, i thought whatever was stuck or lodged, was broken and in a bunch of pieces in my newly aquired engine. At that point i was like screw it...whats done is done, lets fire this thing up and see what happens.

8k miles later its still running VERY strong, (just did a time attack in it this weekend) compression tested it several times since (174-181 lowest to highest) and ive leak down tested it too (3 cylinders tested exactly the same at 2%, one cylinder tested 5%)

so, i never did figure out what the issue was, and the motor turns over just fine now....

weird issue for sure...the carbon thing does seem to make some sense to me though...my engine had about 15k miles on it before i aquired it.

 

The part about your buddy cracks me up! That's some funny sheet there.

He probably got down a spun it around with no hesitation. He must have thought you were nuts.

I feel a lot better after reading your reply, thank you for posting that.

 

Its funny now, yea lol....i freaked the eff out when i walked out into the garage and saw him cranking on the crank pulley...i was like "STOP!!!! WTF ARE YOU DOING!!!!!" It was a total panic moment, but like i said, so far so good....never did figure out what it was getting caught up on.

 

Hi I'm a new member and I know this is old but I know EXACTLY what causes that. No guesses or theories.

The "locking up" is when a piston touches a valve that has yet to move out of the way, and here's why:

In the service manual for the first gen CRV the instructions make it clear to only turn the crankshaft counterclockwise (when turning on the crankshaft pulley).

This is because the timing belt drive pulley will pull directly on the timing belt camshaft pulleys VIA the timing belt. However if you turn the crankshaft pulley clockwise, the timing belt drive pulley will pull directly on the belt-tensioner VIA the timing belt, removing slack that was taken up by the tensioner, and THEN pull on the timing belt camshaft pulleys.

Counterclockwise results in camshafts and crankshaft turning in unison, but clockwise results in camshafts turning at delayed timing, possibly enough for a piston to touch a valve.

No lasting harm should come of it unless you were to really crank hard when it "locks-up". However your valve adjustment may end up being slightly off.

I'll see if I can post a pic to make this clear.

 

Welcome to the forum!

Thanks for the (late) feedback, however, mine is not a first gen CR-V, but an '07 model, as shown in my sig. line. The direction of rotation on mine is CW at the crank pulley on the right side of the engine.

I was turning the engine CW, by hand, when the "locking" occurred. I only turned the engine backward (CCW) a very few degrees, probably less than 5 degrees to back it off of the obstruction. When I resumed CW rotation it turned past the previous stop point.

The cause remains a mystery, but 20,000 miles after that valve adjustment the engine runs as well as it did when new. But what else would one expect, it's a Honda!!??

 

i just tore down a b20 the other day that had this "Locking up" at TDC you're describing. it was a bent rod.

 

no big deal.........

 

Ha ha Sorry. I looked at fast2camciv's post and saw his 98 crv, but didnt notice yours. My Bad