Piston won't move.

[5150DSM]

Pulled the head today to replace it because of bent valves. 12 Valves are bent and pistons 2-3-4 have pretty good score marks in the top(s). Piston 1 is clean but when I was rotating the crank to get pictures of the dings in the pistons I noticed that #1 wasn't moving. I haven't pulled the pan and looked at the bottom end yet, its getting dark and cold outside.
The crank spins freely and the other pistons move correctly but #1 just stays in the same exact place, not moving at all. Anybody have an idea of what I should be looking for when I drop the pan in the morning? I was thinking spun bearing but why is the crank spinning freely? Car is the one in my profile... Bone stock 91' GSX w/auto tranny. Timing recently jumped and bent the valves at 118,xxx. I don't have anymore history as I just bought the car. Thanks in advance for any info.

 

[Jeff99GS]

Sounds like you broke a rod, or broke the rod bolts causing the Rod Cap to come off the crank.

Time for a full rebuild...check the block for HOLES/ Cracks

I'd LOVE to know what you think is COLD in Sacramento hahahaha. Is it like 65 degrees?

Well it's like 12 degrees here with white out snow flurries
I'll Trade you locations?

 

[5150DSM]

Yeah I was also thinking broken rod or cap but it's strange that I don't hear any clunks when I rotate the crank. I bought the car last week for $400 under the understanding that just the time had jumped and bent the valves. I have a replacement head, head gasket and timing set on the way. I wasn't counting on having to rebuild the block for a while. (like after I get a new job)

And about the cold...
I just spent the last 15 years in Hawaii. 65 is sweatshirt weather to me. It's much colder in the evenings and early morning here. Ususally drops into the mid to hight 30's or low 40's.

 

[tqmx1]

Well fingers are crossed for you. I had a Yamaha FJ1200 that snapped a rod the top of the rod stuck in the piston and ended up all the way in the top of the bore the lower 2/3rds twisted just enough that it locked it self to the counterweight (doing almost no damage) If thats the case you might get lucky and a piston&rod swap will be all thats required.

 

[91gvr4gsr]

sorry to hear that ......o well time for a build

 

[5150DSM]

Crank was cooked. #1 rod is snapped off inside the cylinder wall. #1 piston is jammed in the bore. Rebuild time.

 

[tqmx1]

5150 I just went out to Pick&pull sunrise import there is a 4g63nt short no pistons or rods sitting out there the cylinders boars have slight rust (last time I saw the engine less than 2 weeks ago it was a long block) and it has just over 100k on it seeing as I robbed the cluster out of the car.

It just might be what you need to build up another engine.

 

[booostedGSX]

When you do rebuild, do it right, do it once. You'll be kicking yourself later if you use inferior parts and have to go in again to replace rod bolts etc.

 

[mindset]

Time to stroke it and make it a 2.3

 

[5150DSM]

Got a bare block and a crank on the way from a tuners guy. Got pistons and rods today and bearings coming tomorrow. Just got to pick up some rings and a couple of gaskets and I'm golden. Fu(K P&P, I'm not going to bother with them anymore, I'd rather just deal with trusted and knowledgeable tuners members.

Now all I have to do is build it.

 

[tqmx1]

Just a quick one. The toasted block are the ballance shaft bearings still intact? If so would it be possable to ge the old block off of you to rob some parts out of it?

 

[5150DSM]

Just a quick one. The toasted block are the ballance shaft bearings still intact? If so would it be possable to ge the old block off of you to rob some parts out of it?

I don't know if the BS bearings are intact, though I kind of doubt it. You are more than welcome to the block after I pull what I need off of it. I'll be using the oil pump(hopefully), the front cover and the water pump and accessories. I'll probably do the BSE on the new block so...