I got a call last night that the '96 had lost it's crankpulley. I grabbed a spare and headed out. When I looked I could see the pulley was close but it was the harmonic. It had slipped the outer ring off the urethane and counter balance and was banging against the crankpulley and block.

Well since I didn't bring a harmonic and it was late at night, I cleaned the inner and outer ring surfaces with carb cleaner where it had been glued to the urethane, whipped it down good with a clean towel then coated the urethane donut with urethane industrial strength bonding agent and put it back together and let it sit till this morning. When we cranked it up, the HB was functioning well enough to drive it.

Now I know this is not a long term fix, but it got us down the road.
but then GM just glued it too, so what did I do that was different?

The balancer should be weighted and keyed according to crankshaft position..

Yes. It still is. The outer ring didn't change that. I ordered a HB from rockauto for $58 usd with ship. I could have pulled it and put the HB from my '93 on but the old man was determined to run it 'till the new one comes. He said if urathane was good enough for GM, it will hold for another week.

did the outer diameter slip on the inner diameter? If so, how can you be sure it is still in the correct position? I guess it dont matter since your replacing it anyways

It did just that. The outer slipped on the inner, the urthane strip was still intact on the outer. It had a depression machined on one surface that I lined up with the key when I glued it back on. And yes It's getting switched real soon with a new one.

I could have pulled it and put the HB from my '93 on but the old man was determined to run it 'till the new one comes. He said if urathane was good enough for GM, it will hold for another week.
They are different on mechanical pump engines.

I'm glad I didn't bother then. nothing like doing the work to swap it and then getting that D'oh feeling when it doesn't work. Like two or three years back when I tried to swap the cartridges on a gm-4 with a gm-7. It's close but no cigar.
this is the '93

I got a call last night that the '96 had lost it's crankpulley. I grabbed a spare and headed out. When I looked I could see the pulley was close but it was the harmonic. It had slipped the outer ring off the urethane and counter balance and was banging against the crankpulley and block.

Well since I didn't bring a harmonic and it was late at night, I cleaned the inner and outer ring surfaces with carb cleaner where it had been glued to the urethane, whipped it down good with a clean towel then coated the urethane donut with urethane industrial strength bonding agent and put it back together and let it sit till this morning. When we cranked it up, the HB was functioning well enough to drive it.

Now I know this is not a long term fix, but it got us down the road.
but then GM just glued it too, so what did I do that was different?



Dude you scare me...

I know.
An uncertain future is always scary, JK or so it seems...

Dude you scare me...And I was think that QM Inspried me ;)

Another great place with great prices for GM parts like a HB is gmpartsdirect.com

I ordered a HB from rockauto for $58 usd with ship. I use them extensively and have never had a problem. Plus you get GM parts for the price of Pepboys.

Just an FYI for everyone.

-John

I would go ahead and pull the timing chain cover while I was there and replace the timing chain. Use a 92-93 year set and reuse the crank gear. Save a whole bunch of money and make the engine run better too. Now which highway was I supposed to land on?http://www.skypark.org/images/747Rand2.jpg

Yeah, the '96 is pushing 250,000 and I don't know what the service history was before 180,000. A timing chain couldn't hurt. What's the advantage on the '92-'93 set vs. the '96? price only?

Just curious, since I've never replaced either the HB (mine passes the visual tests) or the timing chain... Which of these parts (from Rockauto) are needed to do the timing chain?

Timing Chain Sprocket ($26)
Timing Chain ($33)
Timing Cover Gasket Set ($11.40) w/ seal & sleeve ($16)
Timing Cover Repair Sleeve ($5.40)
--Repair Sleeve Tool ($26)
Timing Cover Seal
--Oil Seal ($7)
--HB Sleeve ($10)
--Redi-Sleeve ($30)
Timing Crank Sprocket ($62)
Timing Set ($92)
Timing Sprocket ($28 or $35)

Timing set ($92) might have the chains, gears and gaskets but I'd find out first. did it show a picture?

No picture. There's three different items listed under Timing Set. Two are Cloyes (one for 92-93 and one for 94-02) and one is Sealed Power. The Sealed Power item says (Timing Set - 3 pc.)

What 3 pieces?

Chain and two gears, maybe?

Just curious, since I've never replaced either the HB (mine passes the visual tests) I had checked the '96 the day before it tossed the outer ring off the harmonic. I crawled under the motor and rocked the pulley and HB back and forth. It was solid. LOL

Don't say that! My truck is going on a 1000 mile round trip a couple weeks from now. That's the last thing I want to happen while toting 6 guys and pulling a trailer full of 4-wheelers and icefishing gear!

'92-3 does not require the Crank Position Sensor reluctor hub - '94-up EFI does.

And replace chain and BOTH sprockets - a worn crank sprocket will still give 3-4deg slack.

If you're gonna do the job, remove all the slack for best power - why start out with a 'new' timing set with 40kmi effective wear.

I have replaced several. Every engine the chain was tight. The bottom gear with the reluctor hub made on it, is what costs so much. The ones I did worked great. I got the Idea from a major engine rebuilder who told me about this insider trick. I also locktite the injection pump drive sproket onto the camshaft as the key system is very prone to shearing. It costs nothing to try as you can always take it back and tell them they gave you the wrong one, but you won't have to. They don't call me DieselPro for nothing.

OK MR PRO, I have seen this stated more than a few times to buy the older set and reuse the lower gear. I am wondering why everyone is suggesting this???

My harmonic came today. I found $91.79 for all three on rockauto and the same coyles PN# C3097 at O'reilley.com for 110.99 special order only to my local store.

I actually found out about this "trick" when I couldn't get a new lower gear to fit on the crank. The replacement gear was about .001" undersize. Couldn't find another set in town, so I called a local engine reman center where I knew the manger. He told me about the "trick" and now I do it on all 6.5's. If you don't won't to save a few bucks then don't do it. I'll keep my trade secrets to myself.

Saving a few bucks on critical engine components makes no sense to me....

I actually found out about this "trick" when I couldn't get a new lower gear to fit on the crank. The replacement gear was about .001" undersize. Couldn't find another set in town, so I called a local engine reman center where I knew the manger. He told me about the "trick" and now I do it on all 6.5's. If you don't won't to save a few bucks then don't do it. I'll keep my trade secrets to myself.Saving a few buck is a good thing as long as it is no harm saving. I thought it was done cause the 93 chain was better or something. Thanks for the tip I shall keep that one in mind

When building performance engines we use to try different brands and combos of gear sets to get the right chain tension. This was used a lot when the main bearings where align bored and the center line of the crank was just a hair closer to the cam center-line. Some manufacturers offered a special chain set combo for this also. Have had some sets to tight straight out of the box. When you think about it, when you use a good used gear your getting one that is polished and wear hardened to fit. The gear is already broken-in and you know it will hold up. One other side benefit in the 6.5 application is the timing will stay intact due to the reluctor staying the same.

Next Installment:

How to install an offset key in the crank sprocket to advance the reluctor timing and make more power.

Or: How to really screw up your valves in one easy step.

An offset key, heh. how offset would it have to be.

DSG gear drives are already set up with a bit more timing.

As for using a new chain on an old sprocket :rolleyes: I'd suggest NOT like GMCTD says. While not as dramatic, the same reasoning applies as does motrorcycle chain/sprocket setups...



If you REALLY want to be cheap, you could broach a new keyway in an old gear...

An offset key would be cheaper than having a new keyway made. They can be purchased at speed shops and are commonly sold by pulley and gear vendors. Kart enthusiasts use them in their little Briggs engines all the time. Where have ya'll been?

Before ya'll knock my suggestion why don't you try it?

Well Diesel-Pro some of us are listening and trying to learn why some people do as they do

Thanks Bowtie!
Go here for a sample picture;
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=92930&prmenbr=361

GM keys:
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3683&prmenbr=361

Of course if you advance the reluctor you might want to retard the cam back so the pump and cam will still function in the normal mode.

yes I have seen offsets before. I was referring to the reuse gear statement. Sounded like an idea that I wanted to know more about

How many degrees advance would be best on the cam, 2* or 4*?
Does timeset have to be done after changing the timing gears?

Yes, timeset has to be done when replacing the timing chain, and you will have to retard the pump as the timing gears will be restored to their factory location.

Tell me more about the offset. It advances the valving 2* or 4*, Does this work better if your running the pump 5.5* advanced? That is bring the valving up to the fuel timing? A new cam with increased duration(s) could have the valving advance ground in, right?

Depends on what you are trying to do. Retarding the cam tends to increase top end power and Advancing the cam tends to improve low end. Advancing the timing tends to perk up the motor and may lead to better fuel economy.