View Full Version : Harmonic balancer and/or timing chain
LeadHead
01-26-2007, 10:11
What a great web site! There is a ton of info here and it makes for some good reading.
My ride is a '98 Suburban 6.5 TD with 233,000 miles. This week I discovered that the harmonic balancer is bad so I have a job to do tomorrow. My question is whether I should just replace the timing chain at the same time or should I not worry about it. Is it a difficult job since I'll have the balancer off anyway? Does anyone know of a walk-through that I could print out for either or both of these procedures?
Thanks in advance.
Welcome to the forum Pb82head...................
At 233kmi, most definitely do timing chainset along with the defective balancer - also verify the accessory drive-pulley rubber is not heat-cracked and deteriorated.
Might also cast a rather jaundiced eye on the waterpump, if not recent - if it lays about while the repairs are in progress, you'll be doing it a short while thereafter due to leaking seals.
If the wp is recent, turn it upside down on a 5-gal pail for stability, pour engine coolant in the ports to cover the impeller shaft seal.
Also the nylon rocker-arm keepers are known to heat-crumble, more on the turbo-side, but 233kmi is pushing the limits for the cool side - valve covers are black RTV-sealed.
If you have a need to spend more money :D , this would be a good time to consider the Phazer gear drive...
LeadHead
01-28-2007, 13:32
Unfortunately having the need to spend extra money usually isn't a problem for me...:(
We got the job done yesterday. We went and bought the harmonic balancer, timing chain & gear set, a water pump (just in case) and serpentine belt (again, just in case). It turned out that the outer weighted ring on the harmonic balancer was completely loose from the rest of the unit and could spin freely. When we got to the timing chain, it had approximately 5/8" to 3/4" slack in it! It's amazing how smoothly the engine ran with is this loose, though.
Everything is now back together and it runs, but it's quite a bit louder than before and it is totally gutless. It's obviously out of time and we didn't realize you have to use a scanner to time the injection pump on one of these engines. Obviously I want to get this done ASAP, but in the mean time will it hurt anything if I need to drive it to town with it running like this? Does anyone know approximately what a shop will charge to time the injector pump?
Check the scuff marks made by the nuts on the IP flange - move the IP so the nuts are in the same positions, for the same timing
Or, make sure the ESO solenoid is exactly vertical - should be very close to correct timing.
billschall
01-28-2007, 17:58
If the wp is recent, turn it upside down on a 5-gal pail for stability, pour engine coolant in the ports to cover the impeller shaft seal.
GMCTD, how long do you think a water pump can sit dry before this becomes an issue? I'm redoing my top end and it's taken several weeks so far due to one having just too many irons in the fire.
-Bill
Depends on age of pump - check the weep-hole for leak-sign.
If none, try plugging the bypass and intake , then submerge the shaft seal in coolant until you're ready for it.
Insert the shaft in the fan\clutch assy, stand that on it's face - cannot leak silicone as the thermacoil shaft will be above level of the reservoir channels.
LeadHead
01-28-2007, 19:35
GMCTD, I'm not sure what the ESO solonoid is. Could you please explain?
Engine Shut Off solenoid - the shiny vertical cylinder, top front your Inj Pump - IP is usually in time if the ESO is vertical.
FYI - never use it as a lever when rotating the IP for timing adjustments.
LeadHead
02-01-2007, 11:15
Ok, I have some more info. Was planning on taking the truck to the dealer to time the injector pump since it's next to impossible to find anyone else around here who wants to tackle the job. As a precaution, I stopped by AutoZone to have them scan the engine codes. I'm getting 2 of them, a P0216 ("Injection Timing Control Circuit Malfunction") and P0236 ("Turbocharger Boost Sensor A Circuit Range/Performance"). I'm assuming the 236 is a result of the 216 error but please correct me if I'm wrong. My main question is, am I safe to assume that the 216 error is simply a matter of the IP being out of time or should I look for something else (in other words, more expensive)?
Again, thanks for the valuable advice.
According to my online service manual, a 216 code can result from improper timing, but can be other things as well (Crankshaft sensor, bad IP, etc. - it has quite a lengthly troubleshooting procedure). Probably get it timed first and see if it comes back.
As for the code 236, I don't think it should be related to the 216 - it has to do with the boost/map sensor on the top intake plenum. It could indicate a faulty boost solenoid, but it could be as simple as turning the key on/running the truck with the map sensor disconnected. I know I've got this code before by just turning the key to "on" with it unplugged.
Hope that helps.
Joe.
LeadHead
02-01-2007, 14:03
Ok, I'm guessing the 216 is a result of being out of time considering the timing chain/gear swap.
As for the 236, I may have a sensor problem. A while back I was getting a "check engine" light and I think it was "P0237 Turbocharger Boost Sensor A Circuit Low", but that one didn't show up when I had it scanned today.
Guess I'll get to the Chevy stealer and get it timed.
LeadHead
02-02-2007, 15:56
Well, I just paid the Chevy dealer about $165 to tell me that the injection pump was 24 degrees out of time. Apparently we did get the timing chain one tooth off from where it should be.
I'm waiting to hear back from him whether it needs to be retarded or advanced from where it is now. He doesn't work on too many of these 6.5's so he wasn't sure what to tell me as far as which way we need to adjust the chain on the sprocket. If it needs to be advanced one tooth, which way do we need turn the camshaft in relation to the chain?
UPDATE
Before I could finish this posting, the mechanic just called back again and said that since they cleared out the memory to time it, now the truck will hardly run and is undrivable. Guess I'll have to have it towed.
He also just told me that the truck is now getting a P1218 code. Apparently there is a resistor that plugs into the driver module on the injection pump, and that resistor is missing for whatever reason. According to him, there are about 10 different values of resistors and you don't know which one it needs without trying different ones. I'm at the end of my rope...
The resistor is probably in the socket of the last PMD you had. It should go with the pump. If you can't find it, put a 5 or 7 in and forget about it. It really doesn't matter that much. 5 is middle of the road and what they "shoot" for when setting up the pump. 7 will give you a little more fuel and ensure you haven't under configured it.
If the engine was loud and rattley then you probably missed by 1 tooth in the advanced direction, but best bet is to take the cover off and set it up right. Your cam could be off too, which is bad....
LeadHead
02-02-2007, 17:45
Yes, the engine was noisier and had sort of a low-pitched rumble when driving. We're most definitely pulling it apart tonight to look at it, it's just that this is the first time either of us has been inside a 6.5 diesel so we're not familiar with it. I'm not much of a mechanic myself, but my buddy is pretty good so I thought I'd ask for an educated answer as to which way to turn things. If it's the cam that is off a tooth (which I suspect), how can you tell if it's lined up properly? My Chilton's is at home at the moment and I hadn't planned on driving 40 miles out of my way tonight but it looks like I'll have to.
As for the resistor problem, I found out that the driver module was replaced between Thanksgiving and Christmas of '94. I can't help but wonder if the resistor is even an issue since it's never seemed to throw that P1218 code before; rather, could it be a result of the engine being so far out of time? The mechanic said it was 24 degrees instead of the usual 3.5. It's amazing how well it ran for being that far out!
Also, since the shop zero'ed out the computer to time the injection pump, will I have to take the truck back in to them to time it again, even if the mechanic put the pump back where it was originally? Fortunately he marked it before starting the work.
Patrick m.
02-03-2007, 11:02
i would think the engine would not tolerate the cam being off by a tooth, (valve to piston clearance is insufficient). Either way, with the front cover off turnning the engine untill the dots align is in order.
If the dots wont align at "6 and 12 oclock" the valve timming is off.
If they do align simply align the pump gears.
LeadHead
02-03-2007, 20:32
Well, we got started on the engine last night about 11:00PM and finished this morning a little after 4AM. We had indeed gotten the cam and crank one tooth off. The stamped marks were SOOO faint we could hardly see them but finally could make them out. After it was all together it fired up but of course still runs horribly since the dealer zero'ed out the system with the scanner. So, another $65 for towing it back to the dealer, and probably another $165 labor fee to have it timed. Hopefully it'll straighten out the problem.
Also, the old vacuum pump was indeed shot. There was no compression whatsoever when we would spin the shaft.
All this for a $50 harmonic balancer....
Thanks again to everyone for their advice.
billschall
02-03-2007, 23:07
All this for a $50 harmonic balancer....
Thanks again to everyone for their advice.
Leadhead,
How'd you keep the crank from spinning when breaking/loosening the nut that holds the dampner (balancer) on?
-bill
LeadHead
02-04-2007, 14:53
My buddy has an air impact tool. Dunno how else you would do it in a practical manner, Bill.
Drop the flywheel cover, lock the starter teeth against the bellhousing - you'll need to do this when torquing the crank bolt to 200ftlbs.
Not a good idea to impact-torque the bolt under any circumstances
LeadHead
02-07-2007, 07:42
Why is that, gmctd?
Ok to remove the crank bolt with an impact, however -
The hub is cast-iron, and the crank is cast-iron, which means the threads are cast-iron - installing the HB requires a smooth steady pull across both keys, as does torquing the hardened bolt into the cast-iron threads.
The hammered anvil gives the operator no feel for what is happening between the bolt, the crank, and the hub, where the lever of the torque-wrench allows the user to 'feel' the progress of the procedure, and can pause for a recheck prior to the assembly being destroyed.
Namely, the cast-iron hub is easier to split than you may imagine, and the cast-iron threads are easy to gall and crumble.
Impact off, apply smooth torque for installation and final torque.
Install a stud full depth into the crank, use a hardened washer and nut to install the hub onto the crank, such that all the threads in the crank take the compressive load and twisting torque.
And, never beat the hub onto the crank with a hammer and block.
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