1986 - 6.2 - crankshaft/balancer/pulley issues

Happy Father's Day to tall the Father's out there. I hope all is well with the rest of the community as well.

I am reaching out to you all in hopes for my M1008. I am questioning whether to pass on this motor and plug in a new one, go grab a used one, or keep moving forward with this one. It "Says" it has 89,000 on it... probably 189,000. The pulley has, and has had, a fair amount of wobble. I recently pulled apart and installed a new Dorman balancer, seals and all. After a few thousand miles, running good, I have now noticed the same amount of wobble to the balancer. I realize I could have and should have replaced the pulley when I replaced the balancer. Any thoughts to this? I have also just put in a new power steering pump. Would a bad balancer disrupt a timing chain and vice versa?There are no leaks to this motor or other said parts. When it runs... it runs good. Well taken care of. I am wondering if the crankshaft is the major problem... I am not sure. I have always said that I can fix anything... diagnosis not so much the same. %96 at mechanical... %60 at diagnostics.

Mahalo in advance for all input and responses...

Dorman balancer made with substandard rubber. Replace again while cursing "globalization ".

Thanks for your reply... You really think it is the 3/16" rubber inner ring? I thought of that... but ****.

It would make a little sense. Centrifugally speaking...

There is not a spot of oil anywhere and that leads me to believe that the crank is still okay, but maybe going. I dunno...

I am also curious if a bad balancer would disrupt a timing chain and vice versa...

What NDT said. Replace balancer before doing anything else!

Get a fluidamper and never do it again.

Make sure your sitting down when you price them though.

Okay.. I will pull the balancer, again, and replace with another new one. After that, If the balancer is wobbling immediately to 500 miles... should I be convinced the crankshaft is done? Like I pointed out, there are no leaks, which is why I have a little faith left in the fact that I am okay. My timing chain will be replaced at the same time, as they are somewhat a unit, is this correct as well?

The balancer failing will cause the crankshaft to break and you will know it! I would not replace the chain. Others here have had repeated failures of Dorman balancers.

ACDELCO still makes an exact replacement.
Mine was marked made in USA.

My M1028 was used sparingly on a National Guard base in Arizona for 25 years until I acquired it in 2010. All rubber parts were dry and cracked from that heat. And I mean all rubber parts including vacuum lines and window rubber. When i first drove it I noticed a distinct vibration in the engine and upon examining the balancer, sure enough, that rubber was hard and brittle as well. So I was faced with the decision of which new balancer to get. And since I am retired and spending my daughters inheritance, I opted for the Fluidampr (hail my daughter would never know). I’m not joking, I could not believe the difference in how my engine felt and ran. All vibration was gone completely and it made a believer out of me.
However having said that, in the case of the OP’s situation, I’m not sure of the wisdom of installing a $500 Fluidampr on an engine which could already possibly be on life support. I belive if it were me, with that engine, I would install a new AC Delco balancer and drive it as far as it would go.
Just my 2 cents.

dom1986ck30 said:

............ After a few thousand miles, running good, I have now noticed the same amount of wobble to the balancer. I realize I could have and should have replaced the pulley when I replaced the balancer......

Click to expand...

What exactly is wobbling? If it's the whole assembly, torsional damper including the belt pulley, then this part might be fitting way too loose on the crankshaft nose. In that case both parts may be worn out beyond limits, already.
Loosen the crank front retaining bolt and try to wiggle the damper & pulley to see if there is any play. If so, then the crank needs to be checked for excessive wear.

Now, if it was only the outer ring portion of the damper; if the damper itself (and pulley) felt tight on the crank even after loosening that bolt - and if the damper rubber insert is still intact and feels soft(!) - only then... you have three options:
1) leave it alone, as is (because even wobbling, it still does its function as torsional damper);
2) put the damper in a press and push the ring back in place until you get zero runout (use a lathe to control) [done this many times; even new parts are not always perfect(!)];
3) replace the damper, possibly with something better than Dorman... but don't spend $500(!).

Are you keeping the truck? Then I see no reason not to get a fluid damper, I have heard as you have seen said here... they make a huge difference.

The balancer is a big thing to kill these engines, if the budget allows I see no reason not to get one. I have 2 cucvs, and if I knew I was keeping them (I want to but what I want and what life allows who knows) they both would have fluid dampers. You can always take it off and move it over to the next truck, engine, whatever.

I look at it this way, what is going to be cheaper, get a overkill balancer, or have the crank break at some point leaving you stuck, getting a new motor, installing it, etc etc.

And even if the balancer does not solve you current issue, what harm does it do?

AC delco is a parts rebrander now (as far as I know), I've ordered ac delco stuff and the box has a sticker over the "made in usa" section that says "made in china" so.

I would *never* ever put a dorman balancer on, I have one sitting on the shelf for 3 years now (waste of money) and I will never ever install it. Not after the problems I have read about breaking the crank. Not after the people I've see who had motors redone and broke the crank in 100's of miles... with, a dorman balancer.

If I ever replace a balancer it will be with a fluid damper one with peace of mind.

Mahalo Matt5 and everyone else above. I am stuck on this one a little as I sit here and ponder the "What if that sound I heard rattling WAS the crank?" The rattling just stopped on the last start-up. It kind of just ticked... and then disappeared. I thought, at first, it was a simple timing chain situation. Now I am back to diagnostics. Sounds are hard to identify. Rattled under my firewall, or maybe it was from the vibrations up front at the timing chain. I am willing to grab a Fluidampr, but I think I will open it up at the oil pan first. Check out the crank, or inspect, I should say. From there... I will decide I presume.

Diesels make weird noises for sure.
Assume you’ve crawled over/underneath and checked all mounts and bolts, etc.
I mean everything. Not just on the engine.
Doesn't sound like a crankshaft issue, but I’ve never had a 6.2 apart either.
I would exhaust all possible sources before tearing into the engine.



The original design harmonic balancer has worked fine for decades.
Guys who don’t replace them after the trucks been sitting and hardly used are the ones who have had issues.
Hard and cracked rubber and/or oil soaked.
Buying cheap inferior parts also will do it.

The ACDELCO harmonic balancer I installed had “Made in USA” cast into the metal.
It was an exact replacement down to all the casting numbers.
It was not old stock either.
No stickers and have never seen a Made is USA sticker covering up a M-I-C sticker on a ACDELCO part.
I use ACDELCO as much as possible.

$500+ for a harmonic balancer?
Not for me and it isn’t a cost issue.
Yes I’ve read the threads raving about how great they are.
If I did a complete engine rebuild, new everything, and had thousands invested.....then yes I would install one.
But for an original 155hp stock 6.2, like mine, the acdelco part works just fine and as designed.

Dayco makes a Australian made stock balancer and a performance one. I had doubts that it was no better than the delco Rey China ones. I called dayco and they referred me to this on the road salesman who has been with the company for years. He reassured me the rubber in the Dayco was not the substandard China rubber. I ordered one from Rock Auto part# pb1102n upon inspection the rubber did smell different. OPTION 2 call Bill Heath at Heath Diesel he can order current production parts for our 6.2 diesel. He has never steered me wrong. Heath Diesel 877-894-6266

Hope this helps!