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Discussion Starter · #1 ·
Hey Guys,

I have a bit of a problem/question for you guys. I just bought another rappy, in rough shape, but running for a grand but it smokes. So I got it home and did a compression check and it came in at 100ish at first 120 with some oil in the cylinder. So I decided that was too low and tear it down, when I get to the cylinder I notice that the piston is in great shape, cylinder is smooth as can be and I noticed that someone must have just put this in.

The problem I think is that the jagoff that did it must have stripped one of the cylinder-->crank studs and didn't put it back in, the threads look pretty beat up, it was one of the back ones that are a little shorter. The head gasket looked pretty good though.

My question to you guys is, do you think that stud not being there could screw the head gasket???? I don't see how it could. Or do you guys have any other suggestions???

Thanks
 

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I am unique
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22,621 Posts
Hey Guys,

I have a bit of a problem/question for you guys. I just bought another rappy, in rough shape, but running for a grand but it smokes. So I got it home and did a compression check and it came in at 100ish at first 120 with some oil in the cylinder. So I decided that was too low and tear it down, when I get to the cylinder I notice that the piston is in great shape, cylinder is smooth as can be and I noticed that someone must have just put this in.

The problem I think is that the jagoff that did it must have stripped one of the cylinder-->crank studs and didn't put it back in, the threads look pretty beat up, it was one of the back ones that are a little shorter. The head gasket looked pretty good though.

My question to you guys is, do you think that stud not being there could screw the head gasket???? I don't see how it could. Or do you guys have any other suggestions???

Thanks
The two bolts with the dimples in the head go to the timing chain side of the engine.........
 

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if it stripped, and isn't getting a good seal then yes, you'll lose compression. It's not uncommon for someone to put the wrong bolt in the wrong hole, as willy is eluding to. A helicoil or tinesert should resolve the problem, and while you're at it go ahead and replace the OEM bolts with new ones.
 

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Discussion Starter · #4 ·
Update

Hey guys,

I got a bit of an update with nothing solved, so I got all new cylinder bolts and regasketed the whole top end.

So I finally got the thing back together and it solved nothing, the compression is still low and smoking like a mofo and the oil is milky in like 1 minute of running.

The cylinder and piston/rings looked fine. I suppose I'm going to have to take a caliper to the cylinder and check it out. But I wonder if you guys have any thoughts. Cuz I'm stumped. I will rebuild and bore out the top end but I was wondering why the oil would go bad so fast if it just needs new rings. I can get pics of anything anyone would want if you could help me out.

thanks

jbi
 

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You may need a new seal on your waterpump. When you put the cylinder back on, did you replace the large base o-ring? Just because the cylinder and rings "look good dosent mean they meet specs. Was the cylinder rehoned befor the new piston and rings were installed? Were the rings gapped correctly? If you just put rings in a "glazed" cylinder, they wont seat correctly and you can get oil blowby and low compression. Sounds like the last owner did not repair the engine correctly. You have to go back to the start. Mike the cylinder and see where you are compared to stock specs.
 

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Discussion Starter · #7 ·
Yeah, I'm gonna get a bore gauge from my friend. The water pump wouldn't make it smoke, but it would make the oil milky. I believe what thumper said is probably the problem and a terribly botched job last time. I think I'm gonna test the bore, but I'm gonna end up boring it out to 101mm I think.

Thanks everyone. Any recommendations for an oversized piston set???
 

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I am unique
Joined
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22,621 Posts
Hey guys,

I got a bit of an update with nothing solved, so I got all new cylinder bolts and regasketed the whole top end.

So I finally got the thing back together and it solved nothing, the compression is still low and smoking like a mofo and the oil is milky in like 1 minute of running.

The cylinder and piston/rings looked fine. I suppose I'm going to have to take a caliper to the cylinder and check it out. But I wonder if you guys have any thoughts. Cuz I'm stumped. I will rebuild and bore out the top end but I was wondering why the oil would go bad so fast if it just needs new rings. I can get pics of anything anyone would want if you could help me out.

thanks

jbi

How far down did you tear the engine down, did you at least look at the piston's skirt and cylinder walls..........
 
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