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  #1  
Old 03-07-2003, 12:51 AM
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How to tell if an engine is any good

Just bought a package deal of a 84 SD with good trans and bad engine originally from an 82 300D with a broken camshaft and god knows what else wrong. I also got the original engine and trans. My plan is to put the extra trans in my 82 SD and hopefully resurrect the original engine. Its supposedly low miles approx 130k, told it was running when pulled but making horrible noises that they thought was from the bottom end. Turbo is seized which I think would make it run very badly but I dont know what kind of noise it would make? What can I look for to give me an idea if it can be revived. Turns over easily and had oil in it, half way between marks on dipstick. I have a compression tester on the way so will do that in next few days. Would it be feasible to try and start the engine when its on a stand. Any advice gladly accepted.
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Old 03-07-2003, 01:21 PM
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The bearings are probably shot. Low oil pressure probably starved the turbo due to excessive clearance in the bearing journals. Definately sounds like it is worth rebuilding.
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Old 03-08-2003, 01:26 PM
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Jhal, thanks for the reply, am going to pull the pan and check bearings, apart from obvious scoring what should I look for and do I need to check the rod bearings as well? Seems checking diesels is not very common on the diesel forum so any help you can give is appreciated, really want to get this engine running instead of having to hunt for a used one.

Bob
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Old 03-08-2003, 08:53 PM
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Try this for a start:

Check for scoring on the crankshaft. If is is scored, it will have to be reground. Oversize bearings are available.

If it is not scored, measure with a micrometer and compare readings to wear limits in repair manual.

P E H
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Old 03-09-2003, 01:39 AM
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From what I remember, having the crank reground on a turbo is going to be difficult to do, since the crank is hardened steel, and requires a special procedure. A new crank, after all the bills are paid, may be close in price to the regrinding price.

just my two pennies.
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Old 03-09-2003, 12:50 PM
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When taking it apart.... if the crank has no scoring visible when you take the rod caps and crank bearings caps off... immediately stick Platigage on the bearings and re tighten the caps... then take off and read the size on the package ... this will be an easier measureing situation than trying to use a micrometer ...
The stuck turbo is worrisome... but can fail without the oil supply being the cause... and noises can be other stuff down low... so a careful inspection as you take it apart is very important to economical use of what is good and what needs help....good luck...
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Old 03-09-2003, 01:39 PM
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Leathermang,

Plasticgage will only tell the total clearance between the bearings and the crankshaft. So you don't know if it is the bearings or the crankshaft journals that are worn.

You can check crankshaft wear by using new bearings and plastic gage but the crankshaft should be checked at multiple places around the journals to find if there is any out of round areas. The same holds true when using a micrometer.

P E H
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Old 03-09-2003, 02:12 PM
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PEH, That is true,,, but I thought since it is very cheap to do it would be good practice and something to compare to when putting the engine back together.... when you would naturally use the plastigage .
Also, many people are going to be at a disadvantage with respect to owning a micrometer big enough to check the crank...and it is not as easy to get a good measurement with a dial indicator... 'feel' harder to maintain between readings...
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Old 03-09-2003, 02:48 PM
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I just thought of another thing. If the camshaft is broken, the timing chain probably jumped a tooth or 2. That means the timing chain has elongated beyond where the chain adjuster can keep it tight or the adjuster is bad.

Some of the valves may be bent from hitting the pistons. If there is good compression and the valves can be manually pushed down and return from the spring force, the valves are probably OK. Are the cam towers broken too? They usually break first and protect the valves and camshaft from breaking.

Of course you will have to get the camshaft and valves working to check the compression. Don't let the timing chain slip into the engine or you might have trouble timing the injection pump to the engine. Clamp vise grips on it or use wires to keep it from slipping away from you when you replace the cam.

P E H
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  #10  
Old 03-09-2003, 08:13 PM
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PEH, thanks for all the info, the engine with the broken cam is in the car right now, the one I am working on is the original engine that was pulled when it started making a lot of noise. I am not even going to bother with the broken camshaft engine.

thanks

Bob
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