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Old 07-14-2005, 01:49 PM   #1786
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Ok I took the motor apart this afternoon to see how things were going. See if I could find some problems or anything. Seems still pretty tight when I turn it. I looked at the sleeve. It still has those criss cross markings all over it. Im guessing this is indicating it still needs more time to break-in?

The other thing is the backplate has scratches on it from the con-rod or crank. Is this normal to an extent or normal always a bad sign?

I did notice something odd when I opened the motor to inspect it before breaki-n. The con-rod had space between the top and bottom of the crank pin? Whatever the con-rod connects to. But the con-rod brass circle wasnt completely circular and as well the brass was kinda flaking from it....but didnt think it would cause any trouble or hit anything.

Would this indicate that possibly the con-rod wasnt right from the factory?

I thought maybe thats how they are and it would round...cant really tell now as its got oil in it and didnt check to see if there was any play. But I can later and will take pictures if anyone wants to see so they can perhaps let me know whats up.

Let me know, thanks again.
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Old 07-14-2005, 02:14 PM   #1787
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Quote:
Originally Posted by Artificial-I
Ok I took the motor apart this afternoon to see how things were going. See if I could find some problems or anything. Seems still pretty tight when I turn it. I looked at the sleeve. It still has those criss cross markings all over it. Im guessing this is indicating it still needs more time to break-in?

The other thing is the backplate has scratches on it from the con-rod or crank. Is this normal to an extent or normal always a bad sign?

I did notice something odd when I opened the motor to inspect it before breaki-n. The con-rod had space between the top and bottom of the crank pin? Whatever the con-rod connects to. But the con-rod brass circle wasnt completely circular and as well the brass was kinda flaking from it....but didnt think it would cause any trouble or hit anything.

Would this indicate that possibly the con-rod wasnt right from the factory?

I thought maybe thats how they are and it would round...cant really tell now as its got oil in it and didnt check to see if there was any play. But I can later and will take pictures if anyone wants to see so they can perhaps let me know whats up.

Let me know, thanks again.
Hi AI, by "con-rod brass circle" you mean the brass rod bearing, right? If you do it sounds like you need a new rod. Pictures would help.

cheers

edit: you say before break-in. I'm not sure then.
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Old 07-14-2005, 03:02 PM   #1788
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you need to measure the the rod and the crank.
The measurements are posted earlier...
You will probably need a crank and a rod. which is common for as tight as these engines are..
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Old 07-14-2005, 04:34 PM   #1789
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Quote:
Originally Posted by Hesky
Hi AI, by "con-rod brass circle" you mean the brass rod bearing, right? If you do it sounds like you need a new rod. Pictures would help.

cheers

edit: you say before break-in. I'm not sure then.
Yeah lol thats what it was. The rod bearing, just didnt think of it cause its not the traditional bearing..at least to me.

Yeah the rod bearing was oval and the brass was kinda chunking, it still looks a bit weird. My camera can get ultra close, ill have a photo up in a bit.

Thanks for the reply Hesky.

Last edited by Artificial-I; 07-14-2005 at 04:55 PM.
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Old 07-14-2005, 06:10 PM   #1790
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Quote:
The other thing is the backplate has scratches on it from the con-rod or crank. Is this normal to an extent or normal always a bad sign?
yes that is NORMAL, the back plate is designed to keep the rod in place, if there wasnt a back plate the rod would slide off
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Old 07-14-2005, 06:42 PM   #1791
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Quote:
Originally Posted by BigBadJabba
yes that is NORMAL, the back plate is designed to keep the rod in place, if there wasnt a back plate the rod would slide off
yeah, when I looked at the exploded diagram of the motor a while bk, I was thinkin the only thing that held the crank in place is the back plate and the flywheel collet. so I guess if you were to have excess crank end float the crank pin could make contact with the back plate.
AI, did you put the washer between the front ball bearing and flywheel collet? I dont think that makes a difference though.
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Old 07-14-2005, 10:09 PM   #1792
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Quote:
Originally Posted by Artificial-I
Ok I took the motor apart this afternoon to see how things were going. See if I could find some problems or anything. Seems still pretty tight when I turn it. I looked at the sleeve. It still has those criss cross markings all over it. Im guessing this is indicating it still needs more time to break-in?

The other thing is the backplate has scratches on it from the con-rod or crank. Is this normal to an extent or normal always a bad sign?

I did notice something odd when I opened the motor to inspect it before breaki-n. The con-rod had space between the top and bottom of the crank pin? Whatever the con-rod connects to. But the con-rod brass circle wasnt completely circular and as well the brass was kinda flaking from it....but didnt think it would cause any trouble or hit anything.

Would this indicate that possibly the con-rod wasnt right from the factory?

I thought maybe thats how they are and it would round...cant really tell now as its got oil in it and didnt check to see if there was any play. But I can later and will take pictures if anyone wants to see so they can perhaps let me know whats up.

Let me know, thanks again.
measure the size of crankpin,wrist pin and 2 rod's bushings
new crankpin is 4.29mm and rod bushing is 4.30mm
new wrist pin is 3.89mm and rod bushing is 3.90mm
If the 'play' is bigger than 0.05mm,it is dangerous.
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Old 07-15-2005, 02:46 PM   #1793
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I need to get a digital caliper. Ill let you know once I get that.

Is the scratches on the backplate ok?

Does the criss cross effect on the sleeve indicate that there still needs to be broken in more? Will that go fully away or will it always be there somewhat?
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Old 07-15-2005, 05:09 PM   #1794
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Quote:
Originally Posted by Artificial-I
I need to get a digital caliper. Ill let you know once I get that.

Is the scratches on the backplate ok?

Does the criss cross effect on the sleeve indicate that there still needs to be broken in more? Will that go fully away or will it always be there somewhat?
Backplate scratches are normal. The cross-hatching on the bore is there from new and is only worn down where the piston is pinching the sleeve, so from the top of the exhaust port and higher. Below that it will remain in most cases.
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Old 07-15-2005, 05:16 PM   #1795
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Quote:
Originally Posted by AMGRacer
Backplate scratches are normal. The cross-hatching on the bore is there from new and is only worn down where the piston is pinching the sleeve, so from the top of the exhaust port and higher. Below that it will remain in most cases.
Right on AMG, and also the cross hatch is there, so oil film stays on between piston and sleeve. Be worried when there is no cross hatch, because that is when engine has poor lubrication and starts to heat up, and eventually give problems in carburation and finally dies.

AFM
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Old 07-15-2005, 06:05 PM   #1796
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Quote:
Originally Posted by AMGRacer
Backplate scratches are normal. The cross-hatching on the bore is there from new and is only worn down where the piston is pinching the sleeve, so from the top of the exhaust port and higher. Below that it will remain in most cases.
Sweet thats exactly what I noticed.

Oddly enough I have two os motors. One has the cross marks the other is completely smooth.

Both run great and have around the same numbers in compression.
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Old 07-15-2005, 06:35 PM   #1797
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Yeah, it looks like you have some abnormal main rod bearing wear. the contact occurs only on upper half of the bearing towards the end of the crank pin. I guess the crankshaft pin is not running true in the rod bearing. Either the crankshaft pin is bent or the bearing is not aligned correctly in the rod. The rod does look a little messy. Probably still tight but just wears funny.
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Old 07-15-2005, 06:38 PM   #1798
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8-0 not looking healthy. The backplate from my first STS, a D5 purchased at the start of 2004 (has many many hours of use and I still use it) only has light "scuff" marks , yours look like a deep groove?

I dont know what to say about the conrod - I've not had a problem like that before. The conrod oil hole is not blocked? Gap looks kinda big - you can see oil movement I assume..
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Old 07-15-2005, 06:49 PM   #1799
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Im thinkin dodgy connecting rod
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Old 07-15-2005, 11:25 PM   #1800
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Quote:
Originally Posted by Artificial-I
Yeah this is how it came. So im not sure what my next step is. Guess I shouldnt have run it at all really.

Yeah I think the rod bearing was kind of oval at the start. Now it seems one side has the gap and the con-rod has moved upward so the pin is now to one side of that oval...leaving the gap on the other side.

Im hoping a new con-rod is all thats needed. What do you guys think?
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