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1998 Big Bear 350 Possible Blown Engine

1518 Views 5 Replies 2 Participants Last post by  ryan313
Yesterday I picked up a 98 Big Bear 350, I am not gonna lie it is a bit of a roach. I got it for $150, knowing that it had an engine problem. I got it from a buddy, he never messed with it, but said he thinks it dropped a valve. Somebody has messed with it before, the jug bolts are only in a few threads, the valve cover bolts are loose, the recoil cover is missing. I figured for $150, I would take a gamble and see if I can get it running.

I put a socket on the crank, it turns about half a revolution, and just stops. I put a screwdriver in the plug hole, the piston is moving up and down. I pulled the valve covers, I can see the lobe inside moving, but it does not hit the valves in the current position. Any ideas what I can check? I know I will probably have to finish taking off the head, but it looks like whoever took the bolts out didn't finish removing it. I didn't have much time to mess with it, before it got dark out. I wanted to ask the experts (reading up and researching before I post, it seems like you guys are) so I have a game plan for tomorrow. Thanks!!
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This could be one of many things wrong and locking it up.
You first need to pull the cylinder head and go from there.
I do not know why someone would pull the cylinder mounting bolts before removing the timing chain. The timing chain/cam gear must be removed first.

If your going to be digging this deep into this machine, if you haven't got a service manual, get one. It's less than $20 off tradebit.com.
The timing cover screws are loose, so they took that off too. The chain and gear is still on though. I will get the manual and dig into it more. Thanks!!
Would It be easier to pull the engine out to try and figure out the issue? Any Expert opinions??
Pull the cylinder first. That's easy. If the problem is in the bottom end, then and only then will you need to pull the engine.
I spent only a few minutes trying to figure out how to take the head off, I watched several videos and it looks pretty simple. In the machine, it looks like there isn;t enough room, I cant even get the head bolts to clear the frame to remove them.
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