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Discussion Starter · #1 ·
Sitting at idle i was just relaxing just thinking and I started hearing what sounds like a rod knock. it sounds like a rod but when I get my stethoscope it quiets down obviously but when i put it up to the valve covers i don't hear anything out of the ordinary. I crawled underneath and didn't hear anything unusual either i could just hear the crank moving around but nothing like a knock. The oil pressure as some of you know in a previous topic has been all over the place but lately its been behaving for the most part. In the morning when its cold its at like 50psi idle and 70psi on the road but when it warms up its like 30-40 on the road and 15-30psi idle. I'm thinking of replacing the oil pump this weekend to be on the safe side since that isn't to hard just annoying. Is there anything else I should look for when I pull the pan or something i should look at first before i pull the pan off? And what oil pump should I get? The ones on the shucks web site look like the ones found in SBC motors but those attach to the bottom of the distributor which the 6.2 obviously doesnt have. Recommendations will be much appreciated.
 

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Well, I kind of doubt it has a knock. If it had one it would probably be pretty easy to tell. No harm in being cautious, though...

The oil pump probably isn't causing problems. While I'm on the subject, the 6.2 doesn't have a distributor, but it does have a vacuum pump. The oil pump is driven off of the vacuum pump drive. I don't know if the oil pump is the same as a small block, though.

Your oil pressure readings sound good (although if you are using the stock pressure gauge it is hard to tell how accurate they are). Keep in mind that there are many things that can cause a knocking sound besides the engine itself and that these engines do make a lot of knocking noises.

If you are still pretty sure you've got some sort of a knock and want to investigate it, you can drop the pan and have a look around. The oil pump isn't the main focus of the investigation, though. Pull some bearing caps and have a look at them. If there is copper showing or severe wear on the bearing you should consider replacing the bearings... They aren't actually all that expensive.

Also be aware that a loose wrist pin can cause a knock...
 

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Discussion Starter · #3 ·
I need to find a good book on diesel motors cause im still a noob on them. I know lots about gas engines and Chevy small blocks since I used to have a built 350 in an S10 and a 406sbc in a 73 K20. I just want to be sure on everything cause I get nervous really easy on little sounds and stuff. Im thinking of making a custom dash and put in mechanical oil and water temp gauges but thats a ways down the road since I have other things to fix. Well the temperature gauge doesnt work at all unless this engine always runs at 100 degrees which i doubt.
 

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You'll get used to it. It took me a while... Before I bought my truck I had never touched a diesel, driven anything powered by one, or even paid attention to them. There's a lot of noises and smells and things to adjust to, but now I can't stand the smell of gasser exhaust at all and I didn't even notice it had a smell before... ):h

One thing I found that helps a lot is listening to other diesels in trucks, big rigs, and heavy equipment. If you listen closely you will hear that they all make noises that would be really scary if you heard them coming from a gasser... Some diesels sound like they've got a real bad main bearing knock, but that's just how they sound.

Mechanical gauges are a very good idea. It is hard to get a good idea of what's going on from the stock electric gauges.

EDIT: By the way, a good book on these diesels is the Haynes Diesel Engine Repair Manual. It covers the 6.2L and 5.7L GM diesels as well as the Ford 6.9L and 7.3L engines in great detail. Lots of pictures and information to be found there.
 

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Discussion Starter · #5 ·
Thanks that puts me to ease a bit. I never paid attention to diesels before I got this. I actually like the smell of diesel exhaust i don't care much for the exhaust of gassers but diesel is better in my opinion.
 

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diesels have their own clatter, just how they are. with the exhaust smell, wait until you run some homemade biodiesel through there. i was smelling long john silvers at red lights in my old f250, makes ur stomach growl.
 

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Yeah, the funniest thing I've noticed about running biodiesel/WVO is when you pull up to a light and you can see the people in the car next to you looking for the restaurant... ):h
 

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Something I found that helps was to pull the cold advance wire off the IP when the engine is cold. You should hear the knock quiet down then you know it is just a diesel noise. The cold advance wire is the green wire on the passenger side of the IP near the top.

Another thing to do is depress the advance lever with the truck at idle and see if the engine starts to stumble. You should also here a change in the knock. This also tells you if you advance it working ok as well as you timing being set close to where it should be.
 
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