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Discussion Starter #1
I'm currently fitting a 6.2 into my 85 chevy dually. I bought a scrap suburban to get all the parts and have it in and running however I'm a little worried by the amount of clatter from the engine. we have another 6.2 in our GMC suburban, it has done very low miles but doesn't clatter any where near as much as the dually. I've scanned through post on here and gain much info. during the transplant the engine was partially stripped and cleaned. I wondered if the pump timing was out, I've tried disconecting the cold advance and it makes no difference. could the timing be too advanced?

I know the engine has done a good few miles but reconditioning the pump would be hard as we are in the UK and our local diesel workshops know nothing about the 6.2 so I don't really want to throw money at it if it isn't that important. the truck will not be hauling much and will be lucky to cover 3000 miles per year.

what should I try? should I retard the pump a little? the clatter is real loud and at times there appears to be a knock but I have very good oil pressure so doubt theres a major problem with the bottom end.

cheers
Cliff
 

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Welcome to the forum! :welcome:

Just one note since you are in the UK... I will refer to the "driver's side" and the "passenger's side..." What I mean by driver's side is the left side of the truck when you view it fro the rear. Since the "driver's side" is on the right in the UK I just thought I'd make that clear so that it doesn't get confusing.

Try this... This is an idea for a quick timing check that I must credit D.Camilleri for coming up with:

On the passenger side of the injection pump there is a lever about 3-4 inches long that goes down and moves a plunger in and out. This is the timing advance lever. It varies the injection timing with throttle position. Reach in there with the engine running (I like to use a screwdriver) and push the lever in all the way. If the engine slows down but continues slows down but continues to run smoothly, the timing is too far advanced. If it starts to run rough the timing is about right or a little too far retarded. If it doesn't change at all when you push the lever in, the advance piston in the injection pump isn't working. That's a common problem. It won't cause it to rattle excessively and it isn't really a big deal (the advance piston on the injection pump in my truck has been nonfunctional for some time).


If your advance piston isn't working, you will have to time it with the trial and error method (you might want to try this whether or not the advance piston works)... Loosen the bolts that hold the injection pump on (engine turned off, of course) and rotate the injection pump. To retard the timing you would want to rotate it counterclockwise (when you view the truck from the front. Go a little bit and see if it helps. If it does, go a little bit further. The only thing that happens if you retard it too far is the truck will start to smoke and power will be reduced, so don't be afraid to go a little too far... You can always move it back.

Another thing... I have noticed that some 6.2s are much louder than others. As far as I can tell, a lot of it depends on how much compression the engine has left... Ones that don't have many miles seem to be quite a bit louder than high mileage ones.

Hope this helps! :)
 

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byt;1599193; said:
I'm currently fitting a 6.2 into my 85 chevy dually. I bought a scrap suburban to get all the parts and have it in and running however I'm a little worried by the amount of clatter from the engine. we have another 6.2 in our GMC suburban, it has done very low miles but doesn't clatter any where near as much as the dually.
cheers
Cliff
Are you sure it's a diesel knock? And, does it knock at idle? Does the knock go away when you turn the steering-wheel? I ask, because - if the engine you are using is 1985 or newer - it will probably have a rubber-buffered bottom crankshaft pulley. That type of pulley has a relatively short lifespan (usually 100K) - and when the rubber breaks - it's knocks something awful. By turning the steering wheel, you are putting demand on your power-steering pump which will usually make it get quieter - if that IS the problem.
If it is indeed a diesel knock - too much advance, a bad injector, or too much carbon buildup - will do it. It is possible for something to go haywire and make your injection pump advance way too early. On the back of the injection pump there is a fuel transfer pump that runs the timing advance. It has an adjustable pressure regulator. If someone turned up the pressure, the advance will be way too early.
If an injector is causing the knock - it will sound like it's coming from one place, and not "jumping all over the place" like a traditional diesel knock.
 

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Discussion Starter #4
cheers guys, will give the suggestions a try today and let ya know.

wife's 6.2 is very low miles yet is very quiet but this one I've put in the dually is prolly high miles and real loud that's why I'm cautious.

don't think it's the front pulley, it came out of an 83 burb and I did have the pulley and balancer off and never noticed any faults however I also have a none working power pump, it worked fine in the last vehicle and was only cleaned and painted but now it doesn't pump at all. I have a spare so gonna swap that today.
 

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Discussion Starter #5
tried the lever and it slows and hessitates so I guess the timing is about right, I also noticed it smoked a little more (grey) with the lever pushed. I'm guessing I could advance it a little more.

the crank pulley is fine, and now that I've swapped the pump I have power steering/brakes again.

I drove it out the workshop and up and down the long drive to help warm it up and it seam fine, and it appears to be getting quieter, I'm now begining to think that I was worrying about nothing. the engine has stood for a while and I think the injectors ain't 100% so maybe some cleaner added to the fuel might do it some good.
 
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