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Technical Info: 2nd Gen 12 VALVE DRIVETRAIN Technical discussion of second generation (1994 - 1998) 12-valve engine and drivetrain questions, solutions and upgrades.
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  #1  
Old 12-21-2012
Biodieseler Biodieseler is offline
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Default Engine knocking

I'm helping maintain a friends truck (see the '98 12 valve in my sig.) and have been trying to help with a plan of action. Right now one major concern with this truck is the engine has been making a bad knocking noise. Usually only noticable to the driver when rev'd up (approx. 2000+ RPM) Feel free to look at the previous topic I started on it.

We had a diesel mechanic/friend look at it and he figures there's something seriously going wrong, like a rod bearing. It's most noticable at the back of the engine while underneath (he figures either cyl. 5 or 6 and in the bottom end. Engine starts and runs fine, but this knock has been getting a little worse. Valve clearances have been checked and are within spec. everything seems to look okay from up top. I know every engine will eventually have problems, but this engine in the truck has approx. 300,000 km (not crazy high miles) and at stock power output. I've just never heard of a Cummins with major problems in the bottom end like this. But could it be?

So here's the question. Is it likely worth getting the oil pan off and inspecting the bottom end? We're willing and prepared to change the engine if needed. We have the original engine that was overheated/seized that we are tempted to rebuild, or we're considering buying another used engine to drop in. We can get a rebuild kit for about $2000 and along with time to rebuild the original engine we would have something we know is good. (we own a machine shop and can bore out the cylinders as needed, etc.) The other option is to buy another used engine and take our chances with that. For example, we currently found a '98 12V Cummins engine for sale for $1000 out of a wrecked freightliner truck (in an accident)... The guy selling it says it claims it would bolt into a 12V dodge just fine. Can't hear it run though as it broke the fuel filter mount and an injector line. otherwise apparently it's a good engine with 158,000 km for $1000... It's tempting to go that route for the sake of saving some time/money, but more risky there could be a problem than with a rebuilt engine.

Sorry for the long post, trying to explain the whole scenario.

The options I see are:
1- start tearing the engine currently in the truck apart to see if we can find cause of this knock, and then consider what to do to fix it. (no idea how far we'll have to look into it to find anything or if it'll be worth fixing)
2- rebuild the original engine that was seized (expensive and time consuming, but we'll know we've got a good engine)
3-find another used engine and take our chances again

What would you do if it were your truck?

Thanks in advance!
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1999 Ram 2500 4X4, DTT trans & TC, Smarty, 150/95 FASS, 100 HP Maxsticks, Snow performance stage 2 water/methanol injection, DSS steering stabilizer bar, Lukes Links, Cold air intake, Silencer ring MIA. 4" turbo back exhaust split to duals half way back, 6" lift, lots of gauges

1998, quad cab, 12 valve, 4x4, auto converted to 5 speed, engine out of a 98 freightliner truck (still 12 valve 5.9L CTD) pacbrake exhaust brake, Runs on waste vegetable oil.
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Old 12-21-2012
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Chris H. Chris H. is offline
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I wouldn't worry about it, the world ends today right?

Since you have had such good luck with engines in this truck, buy the rebuild kit and ensure you are starting out fresh. It is a lot of work pulling these motors, so make it worth your time.
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Old 01-02-2013
Biodieseler Biodieseler is offline
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Thanks Chris. Not to go against your advice, but as it turns out we did buy the used engine. It's beautifully clean and are willing to take our chances it's okay to save about $1000 plus labour to rebuild the original.

There are a few things that need swapped, like the exhaust manifold located the turbo differently on the engine out of the freightliner, and some small stuff like that, but the main engine is the same from all we can tell.

One thing I'd like to know more about is the flow of coolant through these engines. There are some differences in what coolant ports are used between the engines and I don't want to re-plumb things wrong.
Does anyone have a coolant flow diagram or something like that?

Thanks
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1999 Ram 2500 4X4, DTT trans & TC, Smarty, 150/95 FASS, 100 HP Maxsticks, Snow performance stage 2 water/methanol injection, DSS steering stabilizer bar, Lukes Links, Cold air intake, Silencer ring MIA. 4" turbo back exhaust split to duals half way back, 6" lift, lots of gauges

1998, quad cab, 12 valve, 4x4, auto converted to 5 speed, engine out of a 98 freightliner truck (still 12 valve 5.9L CTD) pacbrake exhaust brake, Runs on waste vegetable oil.
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Old 01-02-2013
whiskers whiskers is offline
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Before you pull the engine swap the lift pump out. I had this happen on a '98 with 260k on it. Thought it might be a rod bearing but put on a new lift pump even though the old one pumped just fine. It was definitely the arm worn down and it was knocking just like a rod. You got extra's, try one first. You didn't say what the mileage was on the suspect motor, but even if it;s higher and you change it out, you'll know if you need to rebuild this one or it's ok to sell as is.
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Last edited by whiskers; 01-02-2013 at 06:40 PM..
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Old 01-02-2013
Biodieseler Biodieseler is offline
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Thanks Wiskers. I've been advised to check into that before, and if we were running the stock lift pump I'd definantly try it first, but this truck has a FASS fuel pump and the original lift pump has been removed and just has a block off plate in it's place.
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1999 Ram 2500 4X4, DTT trans & TC, Smarty, 150/95 FASS, 100 HP Maxsticks, Snow performance stage 2 water/methanol injection, DSS steering stabilizer bar, Lukes Links, Cold air intake, Silencer ring MIA. 4" turbo back exhaust split to duals half way back, 6" lift, lots of gauges

1998, quad cab, 12 valve, 4x4, auto converted to 5 speed, engine out of a 98 freightliner truck (still 12 valve 5.9L CTD) pacbrake exhaust brake, Runs on waste vegetable oil.
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Old 04-04-2013
Biodieseler Biodieseler is offline
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Just to give a little update on this topic, we FINALLY got the engine swap completed and drove the truck out of the shop yesterday. Engine out of the freightliner runs beautifully. Could use a little tuning to get a few more HP but I'm not worried about that! got it cleaned up too with some body work done and a bit of paint, re-vamped the vegetable oil fuel system, and all looks good. Only issue we have now is that the seat belts won't retract out of the seats. I did a search and understand there may be a black box under the center seat and make sure it's level. otherwise, any ideas why the seat belts wouldn't come out of the seats?

Cheers!
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1999 Ram 2500 4X4, DTT trans & TC, Smarty, 150/95 FASS, 100 HP Maxsticks, Snow performance stage 2 water/methanol injection, DSS steering stabilizer bar, Lukes Links, Cold air intake, Silencer ring MIA. 4" turbo back exhaust split to duals half way back, 6" lift, lots of gauges

1998, quad cab, 12 valve, 4x4, auto converted to 5 speed, engine out of a 98 freightliner truck (still 12 valve 5.9L CTD) pacbrake exhaust brake, Runs on waste vegetable oil.
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Old 04-04-2013
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J_R_R J_R_R is offline
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Quote:
Originally Posted by Biodieseler View Post
Only issue we have now is that the seat belts won't retract out of the seats. I did a search and understand there may be a black box under the center seat and make sure it's level. otherwise, any ideas why the seat belts wouldn't come out of the seats?

Cheers!
I had the same issue, sometimes everything worked fine, other times I could not get the belts to come out.
There is a little black box under your seat. The issue I found was one of the contacts was intermittent on sending power to release the belt. While waiting for one from the $tealer, I found out where the bad contact was with a volt meter. Bent the contact, re-installed, put the new one in the glove box and have not had any issues in the last two years.
They only used the black box under the seat for two years, I believe. I found they are difficult to get. Expect a 4 to 6 week delivery.

John
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Old 04-05-2013
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So what did the bottom end of the other motor look like ?
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Old 04-05-2013
Biodieseler Biodieseler is offline
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Quote:
Originally Posted by MAXTORQ View Post
So what did the bottom end of the other motor look like ?
My brother took the oil pan off and found some little piece of metal in the bottom. Not sure what it was from, but something was definitely coming apart in there. We didn't look too far into it because our focus was on putting the new engine in.
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1999 Ram 2500 4X4, DTT trans & TC, Smarty, 150/95 FASS, 100 HP Maxsticks, Snow performance stage 2 water/methanol injection, DSS steering stabilizer bar, Lukes Links, Cold air intake, Silencer ring MIA. 4" turbo back exhaust split to duals half way back, 6" lift, lots of gauges

1998, quad cab, 12 valve, 4x4, auto converted to 5 speed, engine out of a 98 freightliner truck (still 12 valve 5.9L CTD) pacbrake exhaust brake, Runs on waste vegetable oil.
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Old 04-22-2013
v8440 v8440 is offline
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I had a customer with a truck that had 430,000 miles on it. It had a knock similar to what you describe. I narrowed it down to being related to #6 cylinder by loosening the injector lines one at a time while it was running (do not EVER do this on a common rail engine!!!) until the noise went away. I dropped the pan, took that rod cap off, and replaced the rod bearing. I got it done easily in one day, the total cost in parts was less than $100 including the oil change I did at the same time. Truck runs great today. That was over a year ago. If this ever happens to you again, it's worth checking into.
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1998 quadcab 5 spd 12v 2wd dually, SB 3250 dd sintered iron clutch, no plate, CPP 7 x 10 injectors, htb2 64-13 turbo, 4" exhaust, detroit locker, wastegate set at 50psi, internally stock and original motor, has run 14.67 at 98 mph granny shifting, dynoed at 450/920 on VERY stingy dyno in 4th gear.

2009 rcsb 2wd hemi truck, runs 13's stone stock
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