Harmonic Damper

[Tailwheel]

So I went and drove my truck and noticed a weird feel/noise on shutdown. Fired it back up and the crank pulley started wobbling. I’ve removed the damper and am doing front/rear seals, timing cover seal, HF water pump, HO oil pump, etc.. I purchased a new GM damper.

I used the proper puller and had one hell of a time getting the damper off the crank. Once off, the crank was overall clean, straight, but it had some gouges. The keyway is in excellent shape.

Looks like someone has pried on the crank with a sharp edge and put gouges and burrs on the snout. I was able to file down the burrs and the majority of the surface is fine but how concerned should I be? I don’t have pictures on hand.

Should I be concerned about crack propagation? If it’s time to replace this engine I’m selling the truck. I have too much money and sweat equity into it at this point and I’m not getting any form of return.

 

[Tailwheel]

Also, found it near impossible to remove the front seal. Took nearly an hour and I ended up hacking it to pieces before it finally came out. Can’t get the new one in even while tapping it with a perfectly fitting socket.

 

[cucvrus]

May I suggest that you remove the front timing cover and replace the gaskets. As far as the crank I would not worry unless it is still wobbling with the new balancer. I never had a bad balancer on a CUCV. Never. I hear of guys adding expensive ones. My friends and I have had vehicles from the early 60's and 70's with the same engines and balancers. Never had any issues. If it wobbles I would be concerned. But they make the gaskets and the seal in glued in place and I am sure it was a treat to remove in place. Good Luck. Report back. Happy New Year.

 

[Tailwheel]

May I suggest that you remove the front timing cover and replace the gaskets. As far as the crank I would not worry unless it is still wobbling with the new balancer. I never had a bad balancer on a CUCV. Never. I hear of guys adding expensive ones. My friends and I have had vehicles from the early 60's and 70's with the same engines and balancers. Never had any issues. If it wobbles I would be concerned. But they make the gaskets and the seal in glued in place and I am sure it was a treat to remove in place. Good Luck. Report back. Happy New Year.

Interesting, everyone tells me these balancers are real cause for concern. I don’t think the Fluidampr is necessary, nor does our local 6.2/6.5 builder, in fact he advises against them. He does a lot of HMMWV builds and said they generally have to replace the GM dampers every 40,000 miles or so in that application.

The timing cover is coming off. I decided to replace those seals and do a water pump since I have it all apart. I picked up a Melling oil pump yesterday at our local Detroit Diesel shop, and I ordered the FlowKooler HF water pump. The Melling oil pump appears to have 30% or so longer gears, he said it’s worth about a 30% flow increase and 20 psi pressure increase.

 

[Sharecropper]

Also, found it near impossible to remove the front seal. Took nearly an hour and I ended up hacking it to pieces before it finally came out. Can’t get the new one in even while tapping it with a perfectly fitting socket.

I hope you remembered to order the clockwise rotation water pump for V-belt operation.

 

[Tailwheel]

I hope you remembered to order the clockwise rotation water pump for V-belt operation.

Yes, it is a CW rotation pump for the V-belts. They are very specific when ordering.

 

[Sharecropper]

I used the proper puller and had one hell of a time getting the damper off the crank. Once off, the crank was overall clean, straight, but it had some gouges. The keyway is in excellent shape.

Looks like someone has pried on the crank with a sharp edge and put gouges and burrs on the snout. I was able to file down the burrs and the majority of the surface is fine but how concerned should I be? I don’t have pictures on hand.

Should I be concerned about crack propagation? If it’s time to replace this engine I’m selling the truck. I have too much money and sweat equity into it at this point and I’m not getting any form of return.

I wouldn't be too concerned about a few gouges on the crank snout. If you filed those off and polished the snout with fine emery paper, you should be fine. Installing the new damper will require a longer M16-1.5x70mm bolt because the 50mm OEM bolt is not long enough to safely engage the threads to pull the new balancer on. Once the 70mm bolt gets the balancer half-way on, you can remove it and reinstall the OEM 50mm bolt. The bolt is metric fine thread and I can assure you that Tractor Supply will not have such a bolt. You can buy one at McMaster-Carr for $3.40, part #91180A822, and it will save you a lot of headaches. You will also need ingenuity to torque the bolt to 200 foot-pounds. I demonstrated my method in my rebuild thread at post #284 - https://www.steelsoldiers.com/threads/kinda-got-carried-away-m1028-rebuild.54469/post-2175994

Regarding crack propagation, if you do not plan on turboing the engine, you should be fine. The J-code 6.2 engine was never designed to be turboed. I would run the engine until it gave out before tearing it down to rebuild, With proper fuel (additives), lubrication, and safe operation (under 3000 rpm), the engine will probably outlast all of us.

Hope this helps.

Say, I would like to take a ride in that Curtiss-Wright C-46.

 

[Tailwheel]

I wouldn't be too concerned about a few gouges on the crank snout. If you filed those off and polished the snout with fine emery paper, you should be fine. Installing the new damper will require a longer M16-1.5x70mm bolt because the 50mm OEM bolt is not long enough to safely engage the threads to pull the new balancer on. Once the 70mm bolt gets the balancer half-way on, you can remove it and reinstall the OEM 50mm bolt. The bolt is metric fine thread and I can assure you that Tractor Supply will not have such a bolt. You can buy one at McMaster-Carr for $3.40, part #91180A822, and it will save you a lot of headaches. You will also need ingenuity to torque the bolt to 200 foot-pounds. I demonstrated my method in my rebuild thread at post #284 - https://www.steelsoldiers.com/threads/kinda-got-carried-away-m1028-rebuild.54469/post-2175994

Regarding crack propagation, if you do not plan on turboing the engine, you should be fine. The J-code 6.2 engine was never designed to be turboed. I would run the engine until it gave out before tearing it down to rebuild, With proper fuel (additives), lubrication, and safe operation (under 3000 rpm), the engine will probably outlast all of us.

Hope this helps.

Say, I would like to take a ride in that Curtiss-Wright C-46.

I baby this engine with no intent to turbo at this time. I regularly change fluids on either time/mileage. I’m definitely going to clean/change the CDR before cranking it up next time. I use the Diesel Power additive in every tank. Overall it runs well, if underpowered.

The truck now has a 4L80E with 37” MTR’s and it drives so much better.

 

[Tailwheel]

Sorry, can’t do rides in the C-46. Not after the Collins Foundation crash last year. That accident ruined it for everyone.

 

[cucvrus]

Just up front you do know that oil pumps do NOT increase oil pressure. A high-volume pump will increase the flow to the engine, which will provide an increase in pressure. The amount of the improvement depends on the amount of wear in the engine or the size of the leak,”. But, you still have the leak or worn condition. High-volume pumps are designed to be used when increased demands on the oil system — such as high RPM usage, racing, remote filters, and/or coolers Just keep that in mind. Good Luck. If I were going to pull the front cover I would pull the oil pan and maybe the entire engine and change all the seals and gaskets along with motor mounts and oil cooler hoses. It never stops on these old trucks. Replace it all up front and drive on for years. I have taken my harmonic balancers to the shop that rebuilt heads for me and he says run it. Or like he said spend money where it don't need spent. Overhaul the transmission or transfer case. They are weak links in the old CUCV. Take Care and Happy New Year.

 

[Sharecropper]

Sorry, can’t do rides in the C-46. Not after the Collins Foundation crash last year. That accident ruined it for everyone.

Yeah I hated to see that crash. But to be honest, If I had been a passenger on that flight, I would have demanded to get off after one of the engines would not start, and then the now-deceased pilot, who I will not name out of respect to his family, attempted to "blow-out" the stalled engine with a can of nitrogen. I am a student of the Eighth Army Air Force 1942-1945 in England and know that if one B-17 engine will not start, you do not attempt to take off anyway. I can only imagine how many of the deceased and injured in the Collins crash had the same thoughts that fateful day.

 

[Tailwheel]

Just up front you do know that oil pumps do NOT increase oil pressure. A high-volume pump will increase the flow to the engine, which will provide an increase in pressure. The amount of the improvement depends on the amount of wear in the engine or the size of the leak,”. But, you still have the leak or worn condition. High-volume pumps are designed to be used when increased demands on the oil system — such as high RPM usage, racing, remote filters, and/or coolers Just keep that in mind. Good Luck. If I were going to pull the front cover I would pull the oil pan and maybe the entire engine and change all the seals and gaskets along with motor mounts and oil cooler hoses. It never stops on these old trucks. Replace it all up front and drive on for years. I have taken my harmonic balancers to the shop that rebuilt heads for me and he says run it. Or like he said spend money where it don't need spent. Overhaul the transmission or transfer case. They are weak links in the old CUCV. Take Care and Happy New Year.

Yes I understand that. Hence the reason I stated approximately a 30% increase in flow. I was replacing the pump anyway and a local place had the Melling in stock and I’ve had great luck with them in the past.

I’ve got the pan off and everything cleaned. The inside of the engine looks great, no excessive rod play and I’m replacing the rear main, front main, pulling the front cover, damper, water pump, etc. I can see some slight cam wear but it may be normal for 50,000 miles.

Unfortunately I had catastrophic oil line failures just a couple weeks after I purchased the truck. I was unaware of the recall. I got an oil pressure light and a spray of oil up the windshield and at the same time the return line let go and covered my left brake in oil. When I hit the brakes the truck veered right pretty damn hard. I shut the engine down and coasted to the side of the road, all happened in a few seconds, I don’t think it did any measurable damage. I made custom AN lines, did a couple of oil/filter changes in rapid succession and screened the oil. When I pulled the oil pan it was pristine inside.

I’m now running all custom oil and power steering lines. I’ve replaced the entire power steering system and have all new brakes, from the master, hardlines, etc., sitting in a box

 

[frank8003]

If there is any doubt at all then replace the harmonic balancer with NEW. Its effect when turning is to stop the engine from destroying itself. Search "moment of unbalance" for your engine.

 

[Tailwheel]

If there is any doubt at all then replace the harmonic balancer with NEW. Its effect when turning is to stop the engine from destroying itself. Search "moment of unbalance" for your engine.

Already done, new GM part is sitting on the crank snout. My concern was the small gouges, I assume from a previous repair, that were revealed when removed the old (although it doesn’t look old” crank damper

From the replies it sounds like I should be good so long as it doesn’t wobble. The crank seems to run true with no other indications of issues.

 

[royalflush55]

The rubber in harmonic balancers deteriorates with age whether they run or not. Just like the rubber in motor mounts and transmission and transfer case mounts. Running down the highway at full throttle and never changing a harmonic balancer do not go together on any vehicle the age of these cucvs. The rubber can and will separate from the inner and outer ring on a balancer. When it does all kinds of problems develop quickly.

If you suspect a problem with a balancer replace it with a new one before driving anymore!

 

[Sharecropper]

Yes I understand that. Hence the reason I stated approximately a 30% increase in flow. I was replacing the pump anyway and a local place had the Melling in stock and I’ve had great luck with them in the past.

I’ve got the pan off and everything cleaned. The inside of the engine looks great, no excessive rod play and I’m replacing the rear main, front main, pulling the front cover, damper, water pump, etc. I can see some slight cam wear but it may be normal for 50,000 miles.

Unfortunately I had catastrophic oil line failures just a couple weeks after I purchased the truck. I was unaware of the recall. I got an oil pressure light and a spray of oil up the windshield and at the same time the return line let go and covered my left brake in oil. When I hit the brakes the truck veered right pretty damn hard. I shut the engine down and coasted to the side of the road, all happened in a few seconds, I don’t think it did any measurable damage. I made custom AN lines, did a couple of oil/filter changes in rapid succession and screened the oil. When I pulled the oil pan it was pristine inside.

I’m now running all custom oil and power steering lines. I’ve replaced the entire power steering system and have all new brakes, from the master, hardlines, etc., sitting in a box

It would certainly be helpful to everyone on SS to see details of your custom oil lines. As you probably know the OEM lines were discontinued years ago and rubber deteriorates constantly. I believe you were fortunate to get your engine shut down quickly before serious damage was done. Think about this - what if your idiot light had burned out and a line had simply sprung a leak instead of experiencing a sudden catastrophic failure? In all likelihood the loss of oil would have caused severe damage before your were even aware that there was a problem. In my view new oil lines rank right up there with the Doghead starter fix as an essential modification. I also am a firm believer in indicator redundancy, that is, to keep the idiot light operable and adding a mechanical oil pressure gauge in a direct line of sight from the driver’s seat.
Back to the oil lines (didn’t mean to ramble). One of the great things about Steel Soldiers is the sharing of information. Please share photos and how you produced your custom oil lines.
Thanks in advance for your contribution.

 

[Valor]

Yes, it is a CW rotation pump for the V-belts. They are very specific when ordering.

I am looking to order one for my v-belt 6.5. What part number did you order? I didn't see any CW rotation pump for the GM 6.5. All were CCW. Thank you.

 

[Tailwheel]

It would certainly be helpful to everyone on SS to see details of your custom oil lines. As you probably know the OEM lines were discontinued years ago and rubber deteriorates constantly. I believe you were fortunate to get your engine shut down quickly before serious damage was done. Think about this - what if your idiot light had burned out and a line had simply sprung a leak instead of experiencing a sudden catastrophic failure? In all likelihood the loss of oil would have caused severe damage before your were even aware that there was a problem. In my view new oil lines rank right up there with the Doghead starter fix as an essential modification. I also am a firm believer in indicator redundancy, that is, to keep the idiot light operable and adding a mechanical oil pressure gauge in a direct line of sight from the driver’s seat.
Back to the oil lines (didn’t mean to ramble). One of the great things about Steel Soldiers is the sharing of information. Please share photos and how you produced your custom oil lines.
Thanks in advance for your contribution.

Sure, I can do that. I won’t be home for several days but I’ll try to remember to grab some photos. The inner fenders and pan are still off so you can clearly see the lines.

It’s just SS braided AN line. I used the brass fittings from the block to adapt to the oil cooler flare fittings. No issues so far, no leaks, works great.

So, to clarify, I removed the broken OEM lines, removed the brass adapters from the block, then replaced the O-rings on the inverted flare fittings coming off the oil cooler. I then adapted the brass fittings into the inverted flare fittings on the oil cooler, used NPT/AN adapters to adapt the brass fittings to SS AN lines, then used another set of NPT/AN adapters and installed them in the block with a touch of Permatex sealant. I’ve had no issues for several thousand miles and nearly 2 years of driving this way.

 

[Tailwheel]

I am looking to order one for my v-belt 6.5. What part number did you order? I didn't see any CW rotation pump for the GM 6.5. All were CCW. Thank you.

1895 1982-1993 Chevy GMC 6.2L Diesel CW water pump

Flowkooler's hi flow water pump 1895 is design to stop overheating in the 6.2L Diesel. Its has a CNC machined billet impeller designed with an increased vane count and a reduced plate-to-impeller clearance to achieve greater flow rates, higher head pressure and a more efficient flow than other...

flowkoolerwaterpumps.com

This should be the one you need. Didn’t have a part # so I shared the link, hope that’s okay.

You would need to run the 6.2L Water Pump backing plate with the V-belt setup, but I assume you are already doing so based on your post. Should work fine on both 6.2’s and 6.5’s.

 

[Valor]

1895 1982-1993 Chevy GMC 6.2L Diesel CW water pump

Flowkooler's hi flow water pump 1895 is design to stop overheating in the 6.2L Diesel. Its has a CNC machined billet impeller designed with an increased vane count and a reduced plate-to-impeller clearance to achieve greater flow rates, higher head pressure and a more efficient flow than other...

flowkoolerwaterpumps.com

This should be the one you need. Didn’t have a part # so I shared the link, hope that’s okay.

You would need to run the 6.2L Water Pump backing plate with the V-belt setup, but I assume you are already doing so based on your post. Should work fine on both 6.2’s and 6.5’s.

Looks like it is a part number #1895. I'll order one shortly. Thank you Tailwheel.