Engine bolt backing out while tightening...

So I put my engine all back together yesterday and expected to be able to turn her over and get started on carb syncing. I tourqued down the first cylinder head nut with no problem at all. The second one, however, started backing the engine bolt out of the crank case the more I tightened the nut. Not what I was looking forward to. What the hell do I do now?! The bolt in question appears to be backed out an 1/8th of an inch higher than the one to the right of it and that's after I tightened it back in. Don't know if that makes too much of a difference but how do I keep that thing from moving? Anyone else have this problem? I put high-temp RTV sealant on my base gasket ONLY. I'd rather not remove it a day later and replace the gasket again if I can just pull the bolt through the cylinder block.

Also:

I had to rent a torque wrench and already returned it. Not too stoked about that either. I read on here recently that you should tighten the cylinder nuts down but not all the way, run the engine a while and THEN torque them to specs after it's cooled? I need to know if this is standard procedure so I know what to do once I fix that bolt. Sorry for the information overload but I wanted to get it all out there in one post.:S

Is the bolt turning in the threads or stretching? I don't know what particular bolt your referring to..

If it is stripping you might need to put a Helicoil or tap it out and put a cert in it.

If its turning in the threads you can back it out a bit, put some loctite on it and tighten it down. Let it set up a bit and continue on.

As far as a Torque wrench, you can get one for $14 or so from Harbor Freight. Not the best quality but if the values you need are mid range on the wrench it should be close enough. You can mail order them off the web or if your lucky they might have a store locally.

When torquing, its best to go a bit below what the end value should be and torque your bolts down, wait 30 minutes, up the value and repeat. This usually results in things setting up better.

although i m not in the big league as far as motor rebuiding, i ll try to help....if the studs go in clockwise and the nuts tighten clockwise, the only explanation would be that the threads for that stud are junk.....as you are cranking down, the stud is pulling up from case....not good....stock studs?.....what bike?....rtv should nt make a diff, but i would put it on dry....when tightening head bolts, torque to fact specs with stock studs, higher with ape(30 to start)...and run it to temp and back to cool a few times and re-torque....like i said , i m no pro, but i did mine and no leaks....just trying to help......good luck.....keith...
ps....harbor freight has a torque wrench stupid cheap....i bought one and it worked fine...just a thought........

Let's hope I'm wrong, but it sure sounds like the stud is pulling out of the crankcase which means the crankcase is probably stripped or if you're very lucky the stud is stripped. The only other thing I can think of is the stud stretching, but it seems like we're talking about a lot of stretch here. How much torque were you able to apply before the stud started pulling up? Ed

C, obviously something is wrong. the two most probable are pulled threads in crankcase, or a weakened stud. i would, remove stud.either by double nutting or extactor. in either case, be gentle. a failed stud will have a skinny area somewere in body. pulled threads leave remnants in thread channels.... stud failures are rare, but possible..if there is evidence of pulled threads from cases it becomes a discresionary call as to wether to attept to re-seat deeper or repair threads. luck g

The threads in the case are stripped out. You will have to take the head and cylinder block back off and repair this. When you torque down the head nuts start with the center ones and work your way out. Do not go to full torque value the first time work your way up to it. Once the engine has been run and heat cycled then retorque them.

Colossus wrote:

I read on here recently that you should tighten the cylinder nuts down but not all the way, run the engine a while and THEN torque them to specs after it's cooled?

I recommend you do a progressive torque when you assemble the engine first: follow the tightening sequence and torque to 50% of spec, then repeat at 75% of spec, then repeat at 100%.

AFTER YOU RUN IT: I always retorque the head after it runs maybe an hour and every time, they needed it. Follow the tightening sequence and torque every bolt to 100% of spec.

you always tourque in stages exactly like bountyhunter has said it does sound like the studs are pulling out of the cases aso the threads in the case will have to be either timeserted or helicoiled the time sert is the best option of the two also the cylinder head has to be tourqed to spec don't leave any bolts or nut's loose if you do that your asking for trouble after you have gone through a few heat cycles then do a retourque also like was mentioned as well start in the middle and work your way out. follow the bolt patterns exactly don't do it willy nilly there are a couple of reasons for this one you can actually cause warpage if not tightened correctly and also that way you won't get confused as to where you started and finished.

Thanks for the help and replies. That torquing info is crucial! As for the stud I don't know when I'll get to it. My bike budget is drained and I wanna ride! I had perfect luck with everything else so far so in the true spirit of DIY I guess it just makes sense.:laugh: