Just rebuilt a B18C1, everything was torqued to spec, new bearings, new P30 pistons, plastigauged it, etc. We timed it right too.

We started it and it ran great for about 5 seconds and then started making a loud knocking sound. We tried turning it over by hand to see if the timing belt had jumped some teeth, and it went about half a revolution then stopped and we can't move it any further. Any ideas?

We might make a video here in a little bit. It's just a loud knocking sound.

 

We're taking the head off to see if it was the pistons contacting the valves.

 

not trying to hijack your thread, but did it sound anything like this?

http://www.youtube.com/watch?v=BAreLQB0i6I

listen to the knocking sound right after he starts the car. his goes away after a couple seconds. that's the sound mine makes permanently. it sounds like it's coming from just underneath the valve cover, so i'm praying it's not a rod bearing. i'll be tearing into it a little bit tomorrow.

edit: any chance a rocker arm could be making that noise from the video?

 

I think it was louder than this, and it's constant.

 

so it's the same symptom as mine. i would take a sound clip of mine, but i doubt a cellphone cam would do it justice. did you guys try and listen for where the sound was coming from (bottom end, top end)?

 

No we got worried and turned it off lol. Tried to check the timing but couldn't turn it over by hand.

 

lemme know how you make out. i'll be tearing into the head later on to try and find my problem. hopefully i won't have to actually remove the head, we'll see.

btw, stock valve train?

 

Yes stock valvetrain. We just took off the head and everything looked good. So we're going to take out the block tomorrow and tear it down to reveal the problem... again.

 

Ended up being a pressure plate bolt that came loose and pretty much welded itself to the bell housing. So the pressure plate was hitting it. That's why it was so loud. We found an extra pressure plate bolt so we'll use that. We spun the engine a few times and it spins freely now so it should be good to go. We're about to put the engine back in.

 

haha thats an odd problem but im glad you got it resolved, excellent work!

 

*WHEW

 

dayum. sure didn't see that coming lol

 

Haha, yeah neither did we, we were ready to buy new bearings and have the crank polished!

 

Started the engine, runs perfect.

 

good ****. discovered my problem and fixed it too. it's actually embarrassing to think it might have been something internal after finding out what it actually was.

 

Im the owner of the b18c1. It runs like a champ. Drove it around town today it was great.
Still cant believe it was only a clutch bolt, really glad that it didn't break anything.
Episode what was your knock from?