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ksollinger

1976 Intro....

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Hey All,

I just wanted to introduce myself so sorry if this is long winde. My name is Kelly and my wife Jennifer and I are the new owners of a 1976 sierra brown 2002. The car has a weber 32/36, header, sunroof, aftermarket exhaust and wheels, a beautiful tan interior, all the original tools and paper work and finally...were the second owners. Yes thats correct we are the second owners and I even have a picture of the original owner standing in front of the car at his brother in-laws dealership in Bethesda. I've been all over the car and the only rust I can find is some minor surface on the body and a little in the spare tire well but nothing major. The one big problem with the car is the motor, it's not working.

The story with the motor is about 8 years ago the owners friend adjusted the valves and over tigthened them causing something to go wrong with the motor. He thought it was a spun lower bearing so he removed the oil pan (it was in the trunk when I bought it) but never went any further on fixing it. I've never heard of this happening but I dont claim to know everything so Im looking for some advice, a nudge in the right direction or any other words of wisdom someone might share with me.

I figured the first order of buisness would be a leakdown test, dry and wet to see if this will point me in the write direction. After that I'll crawl under and see what I can find.

Thanks in advance everyone!

-Kelly

Roswell GA

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-= o u c h ! =-

NOT RUNNING WHEN PARKED

Your wife must be a saint !

i'm sorry we had to meet under these circumstances.

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your thinking is on the right track

LOOK under and into the bottom of the motor (crank bearings)

before you roll out the compressor for the cylinder leak test.

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Welcome! First, a question: Who decided the problem was in the bottom end and what were the symptoms as best he can remember all these years later? Loud hammering noise? Quit running? Etc. If a pro told your friend the problem was in the bottom end, it probably is. If, in fact, there is bottom end damage, the valve adjustment was probably coincidental to it. Bottom end problems are usually pretty easy to find. First, climb underneath with a flashlight, look at the connecting rod big ends (where they are fastened to the crankshaft) and see if any of them look blackened. Often when a bearing spins or cooks the resulting friction is so great that the heat literally darkens the entire connecting rod visibly. If there is nothing obvious, try to move each connecting rod laterally (perpendicular to the crank). There should be no looseness. There may be a tiny bit of movement fore and aft, don't be concerned about that. If you don't find obvious damage, remove the rod bearing caps one at a time, paying careful attention to their orientation and check the condition of the bearing shells as well as the journals on the crank. Respond to your original post with your findings.

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So I crawled under this afternoon and wiggled all the ends and three of them had the same amount of lateral movement and only number 2 had any vertical movement. I pulled off the 2 nuts that hold the connecting rod on and pulled the bearings out of number 2 and took these pictures. If anyone has any information as to why this would have happened and how I can remedy the situation please let me know. Im hoping this is my only lower end problem and I can simply replace the bearings and get on to the next phase of getting it running. Im going to go pick up a leak down test kit from harbor freight or somewhere on wednesday and see what else I can find out.

Thanks skipsfcr for pointing me in the right direction!

-Kelly

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Oil starvation or contaminated oil (not changed properly etc.) is usually the culprit. That's a pretty ugly rod bearing. Without even seeing it myself, I can say that your crankshaft will probably have to be machined .010"" (.25mm) to clean up. The rod that shell came from may well be trash also. No biggie as they're cheap in good usable condition and readily available from any number of '02ers here. Now it's decision time...do you want to spend a significant amount of time and money rebuilding your engine or do you want to find a decent used engine? The parts wanted / for sale pages here at the FAQ can be a great resource.

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Not what I wanted to hear.

The crank itself feels smooth, just the bearings a little rough. What are the odds that if I put in a new bearing in it will run for a while until I find a suitable donor engine? Is there any way to tell if the connnecting rod is trashed?

Thanks

Kelly

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Get the manual and a nice micrometer to tell you whether you have cut the journals or you have galling which is when the bearing material attaches itself to the crank journals - if you have more diameter than called for you have galling which I used to solve with emery cloth and then polish on some 240 and 300 MB diesels I used to restore.

To be sure check the undamaged journals and move the micrometer around the axis (remember to keep it always perpendicular) to get a true reading.

If the crank is NG take it out and over to a qualified machine shop for a look see. Make sure they and you know what overside is possible.

When you do this you should also do the chain, tensioner and while the pistons are out check for wear and damage - and of course the head, new springs, seals and for me- new valves.

In short - it's a complete engine job which don't forget a new oil and water pump as well.

Is the car so solid you can put this much money in it and still be OK? I have driven many BMW's which have all rusted before the engines needed this kind of work so dont fall in love with it unless it's solid.

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The major concern for me at this point, aside from the obvious damage, would be the connecting rod big end no longer being round. Very likely if the engine was hammering pretty good, and there's no "in car" fix for that. The locating tab missing from the bearing shell is a strong indication that the bearing did, in fact, spin. Also the bearing materia can, at times, plug up the oil hole in the rod so you need to look at that too. An M10 crank IS pretty damn hard and, as Anschauer pointed out, you may simply have bearing material bonded to the crank. I've seen them cleaned up and run for 100K. Try and have a better look at the crank and go from there. You might get lucky, but I wouldn't count on it.

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If push comes to shove my M10 should be coming out of my 75' 02' soon for an M42. I really have no idea how many miles it has on it and it definitely doesn't run perfectly but I'm thinking it may be a carb issue (it's got a 32/36), but if you're just looking to get it on the road it'll do the job for sure. I'm over in Suwanee so just give me a shout if you do end up needing a motor. (It's still in so you can hear it run, and possibly get a ride!)

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Kelly,

LOL .... the crank journal feels "smooth" .... it wouldn't take long to pound out a new bearing, should you put one in. Everything in there has to be perfect for the bearing to survive. And how a set of rod bearings can take all that punishment for years and decades without self-destructing ..... one of the mysteries of the universe in my mind.

Anyway, looking at that bearing: the crankshaft journal is probably trashed, we're talking just a few thousandths of an inch between "good" and "trash." Not to mention what else may be damaged, as discussed by others above.

In a situation like this, the only way to regain reliability is to fix it right. Definitely a bummer, but that's what it is when a rod bearing looks like that.

Cheers,

Carl

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