I bought my truck not running and took it to the local deisel shop to have them check it out. The OPS was bad and once it was running they said it had a lower end knock. Assuming it needed a motor i towed it home. I put a new OPS in it just so i can move it around without pushing it.

Now that is running i can hear the knock myself. It doesnt seem like a rod knock to me. I think it just needs injectors. Upon start up it puffs a little white as if you had some bad glow plugs but not as bad and continues to slightly puff white during idle.

Also the oil pressure is a little above 40 at idle. This seems odd to me. Ive never seen an engine with a rod knock hold that much oil pressure at idle. Could it be that i only need injectors? There is also a cylinder imbalance on number 3,4, and 7. What do you guys think?

swap out those injectors before you melt holes in pistons from overheating them.

You may have stuck injectors that are "nailing" which can sound like a knock. A road knock is a very deep and loud thump thump thump sound. Its hard to mistake that sound, as its the sound of an engine in pain. :eek:

An example of a 6.2 diesel with an Injector nailing problem. does your truck sound like this?

http://www.youtube.com/watch?v=YCvj7S5kN1k

Thanks for the vid. After seeing that though im pretty sure i have a rod knock. The sound is much deeper than that. To post a vid i just need to put it on you tube and make a link to it in the post right?

That's correct. post up the video so we can hear the sound. IF you do indeed have a rod knock, i'd repair it before it gets worse. These engines have a very tight area between valves and piston when the piston is at TDC.

High Sierra 2500's old 6.2 developed a rod knock on the front 2 cylinders, after someone drained his oil out and the motor seized for the first time. A short while later it started to develop a rod knock on the front 2 cylinders and then the front 2 cylinders hammered the valves since the rod bearings were gone, and that little bit of extra clearance was there.

http://www.youtube.com/watch?v=orbbourGCOQ

http://www.youtube.com/watch?v=C4ZMaJxInIw

Well here it is. I dont think its a rod knock now. I hadnt listened to it run in a while and i thought the sound was deeper. It sounds just like the video you posted.

First off, all that coughing and smoke on startup points out an obvious problem. Looks like you've either got bad glows or worn injectors.

How many miles on the truck/engine and do you have any records of the injectors being replaced? they should be done every 100K miles as they wear out and can cause serious issues.

EDIT: that really sounds like an injector nailing to me. Do you always get faint white smoke out the tailpipe? if the injector is stuck open it'll fire early and cause that knocking sound. A bottom end knock in a 6.5 sounds more like this. In this vid he says he spun a bearing, and it sure sounds like it. http://www.youtube.com/watch?v=fhCjJ8EnJwA

Im sure it does need new glows as well as injectors. The truck has 305k on it and i dont have any service records. I bought it not running from a small corner dealer that knew nothing about diesels. They were ready to send it to the juckyard. Good thing i saved it.

This is only the second time i had it running since i bought it. Im really dissappointed in my diesel shop. They told me it was a definate lower end knock even when i kept asking if it was injectors. Why wouldnt they want to fix it? At least you confirmed my suspicion. The shop i took this thing to is the number one diesel shop in milwaukee and this really took them down a notch in my book.

Maybe they wanted to sell you a rebuilt engine, or maybe they wanted you to sell the truck to them 'for parts' or maybe they just didn't want to work on it. Just a thought. H.

305K is 3 times the life for injectors. Just a reminder that cheap injectors are junk. Get either Stanadyne's from Heath, or get Bosch ones from a reputable dealer(not ebay).

Also, since this came up recently, Herzog does not make 6.5L injectors, so if you see any that say such, it is not true.

Thanks a lot dave. This help really saved me some money. The shop wanted to sell me a jasper crate motor for 11,000 installed. What a joke. I was going to do the rebuild myself but now i dont have to. For now at least.

I will most likely be going with heath injectors and as long as im in there new glow plugs. Also a new CDR and glow plug controller. Thanks again!

Do i need a special socket or anything for the injectors? Do you know of wny threads that can walk me through the injector replacement? Im very mechanically inclined just never done injectors on a 6.5 yet. Ill search and see what i come up with.

Yes you need a special 30MM socket. Its narrowed out on the top so you don't bust off the return barbs.

Injector swaps on these trucks aren't that difficult. Just unscrew the injector line from the top of the injector(do not bend the injector lines) and then put the socket over the injector and remove it. do the reverse for the new ones. Make sure you follow how the return lines are hooked up. take pictures of the setup before you get started if you wish, it may help you more than you'd think.

I pulled my turbo off to change the passenger side injectors. Wasn't that bad w/ the turbo removed, and it came off fairly easy even with 168K miles in rust bucket Rhode Island.

I would order injectors from Heath personally, as he really stand behind his stuff. Cheap injectors can have inferior parts that can fail and do major damage to piston crowns(like overheating/melting them). You can also order the socket you need from him, and return it when your done for a full refund of the socket purchase price. Also you may want to do a compression test of your rig with that many miles on it, just to get an idea of how well the combustion chamber is sealing.

This topic is great. Awesome to have some people that know how one that runs is supposed to sound. I just uploaded one, ( it hadn't processed yet just a minute ago), it is really short, taken from inside the cab, and with the hood down. In addition, the oil pressure starts out good then falls about 30 seconds after startup. I haven't let it get below 35 without shutting it off, so I don't know how far it will drop. If I give it 3 or 4 minutes (to let the oil drain back to the pan? - maybe plugged returns?) it will do the same thing all over again. I also have terrible blow-by. I don't think any amount of blow by would hold the oil in the valve covers though. I can take more video's tomorrow when it is light outside. Any insight would be greatly appreciated.

http://www.youtube.com/watch?v=lR_BdMnoppM

Thanks.

Dave

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First off, all that coughing and smoke on startup points out an obvious problem. Looks like you've either got bad glows or worn injectors.

How many miles on the truck/engine and do you have any records of the injectors being replaced? they should be done every 100K miles as they wear out and can cause serious issues.

EDIT: that really sounds like an injector nailing to me. Do you always get faint white smoke out the tailpipe? if the injector is stuck open it'll fire early and cause that knocking sound. A bottom end knock in a 6.5 sounds more like this. In this vid he says he spun a bearing, and it sure sounds like it.

Mine sounded nowhere near that bad. It ran great and didn't smoke once it warmed up a few minutes. Photos of the insides of the engine are in my .sig. I started out to change head gaskets due to pressure in the cooling system when engine was cold, and decided it was just about as easy to pull the engine. Both heads were cracked beyond repair. I had the engine align-honed and decked, crank polished. Installed new rings, bearings, timing set, and Fluidampr. I've almost got it back running. Stupid weather. I only work on it when the weather isn't too hot or too cold.

Here's the vid.

http://www.youtube.com/watch?v=_L6dp8rOD6E

I am hoping this video isn't the poster child for a 6.5 diesel rod knock, but I think it probably is. 3.5 minute video this time.

http://www.youtube.com/watch?v=Jn0RRaUtQ-c

This thing puts out 45 psi oil pressure off of the starter, puffs smoke, knocks, rattles, has blow by. I'm not sure if its a broken/cracked piston, spun bearing, head gasket? Oil level actually rises, I am assuming I get fuel in the oil, coolant would be white/creamy... still just looks like oil. Not sure why it surges either. no one touched the throttle throughout the video. I didn't mean to let the oil pressure drop to nothing... turned it off when I saw the gage.

bearings...
and rings/hole in piston allowing diesel fuel into cylinder

I have some strange sounds too, one video before I changed the lift pump and one video after. Do you think its injectors

http://www.youtube.com/watch?v=P9zX40hpwXs

http://www.youtube.com/watch?v=17ScJ-8iNGI

Based upon the last post an the response, which I believe is accurate...

Where is the best place to get one of the newer beefe up long blocks? I am looking at 6-5liter dot com for $4090 . I saw international diesel for much less, but I cant tell if its the better designed block & heads... also, does anyone offer a forged crank? I can't believe these didn't have forged from the factory. I am really considering pony'ing up 4K , but I don't want to have to screw around with this again later. I am also thinking I could drop a 454 in an put $2500 towards the poor gas mileage.

Please let me know if you have any experience.