Community Forums

Piker · 07-21-2019, 03:17 PM

Dennis, the only issue is that the OEM attachment is no longer OEM... the center post on the crankshaft was damaged because the old damper was flopping around on it, thus the addition of dowel pins to provide alignment. Since one of the dowel holes ended up being a little looser than the .0005” press I was shooting for, I thought a washer big enough to encompass the entire bolt circle and the dowel pins would provide positive retention on the dowels... there would be no way they could work out unless the bolts and washer holding the damper were removed.

After talking with Fluidampr, and the crew here on the forum, I feel pretty confident I’ll have a solid connection of the damper to the crankshaft with the two dowels and stock bolts.

Yes, I’m all too aware that I should have replaced the damper when I rebuilt the engine... but I just didn’t know.

Cheers

dennis45 · 07-21-2019, 03:38 PM

Quote:

Originally Posted by Piker

Dennis, the only issue is that the OEM attachment is no longer OEM... the center post on the crankshaft was damaged because the old damper was flopping around on it, thus the addition of dowel pins to provide alignment. Since one of the dowel holes ended up being a little looser than the .0005” press I was shooting for, I thought a washer big enough to encompass the entire bolt circle and the dowel pins would provide positive retention on the dowels... there would be no way they could work out unless the bolts and washer holding the damper were removed.

After talking with Fluidampr, and the crew here on the forum, I feel pretty confident I’ll have a solid connection of the damper to the crankshaft with the two dowels and stock bolts.

Yes, I’m all too aware that I should have replaced the damper when I rebuilt the engine... but I just didn’t know.

Cheers

IMHO, you are correct. Your repair, with a new damper will go for another 25 years. Live and learn. Next.......

OldToolmaker · 07-22-2019, 06:23 AM

Quote:

Originally Posted by Piker

Here's another question for the group... Fluidampr sells what they call a "Full Power Kit" - basically its a 1/2" thick washer with longer bolts that goes over top of the damper to help distribute clamping force. Here is a link: Full Power Kit

I''m going to back the RV out of the garage and pressure wash the CAC and Radiator while the fan is removed... then I'll replace the pump and thermostat and put the fan and pulleys back on all at one shot.

I can really see the allure of a side radiator in one of these now...

-cheers

I'd go ahead and make the clamping plate, if only to retain the dowel pins. It will also give you peace of mind. And use a removable Loctite on the bolts. Belt and suspenders.

Our new ride is a rear engine pusher, with a rear radiator and charge air cooler. I need to replace the belts before our next trip. There will be beer involved after the job is done.

Piker · 07-22-2019, 08:51 AM

Quote:

Originally Posted by OldToolmaker

I'd go ahead and make the clamping plate, if only to retain the dowel pins. It will also give you peace of mind. And use a removable Loctite on the bolts. Belt and suspenders.

Soooo... I don't have as much thread engagement as I thought I did. There are two holes in the crankshaft that have the original threads, and the top of these holes actually have the threads relieved down at least 1/4". On top of that, the threads in these holes are not very good. Remember that I pulled a galled up hunk of thread out with the bolt that I was able to turn out, and the other hole lost a bolt which must have rattled around in the hole for a good long time, so these threads are kind of loose. I think I am going to go ahead and helicoil these two holes as well. This will allow me to sink the thread inserts down to a depth where I have good threads for the whole length of the insert, which is almost 1" long...

The other two holes that currently have the helicoils... the thread inserts were screwed down to a depth that made sure I didn't bottom out the screw on the tang on the insert - (When we were in wyoming, I did not have a tool to break the tang off). This leaves an even larger section of thread that is relieved above the threads, and when I add the spacer I will end up with somewhere between 1/2" and 5/8" of threads engaged. This is probably enough, but If I could remove these inserts, I could just put new inserts in to the correct depth.

QUESTION: I have never removed a helicoil insert... and was wondering if it might just be easier to screw the existing inserts down further, and place another shorter insert on top of it, and then break out the tang. Has anyone ever done this? Does it work? The bolt would engage across both inserts.

cheers

Piker · 07-22-2019, 06:16 PM

I was getting ready to drill the other two bolt holes out and realized that the original thread relief is about .030” bigger than the tap drill for the helicoil. I truly cannot add the clamp plate and get the thread engagement I would like unless I use longer bolts. I have thus far not been able to find longer flange bolts of the correct size and grade. These are class 12.9 metric, which apparently is the strongest bolt you can get... stronger than grade 8.

I take that back... fluid damper sells new bolts with their $165 “full power kit” ... as much screwing around as this is going to be, $165 doesn’t seem like a bad price.

The other option is that now the dowel pins are .020 below the face of the damper, I could just peen the edge of the hole over top the pin. Heck, this is how the stake pins in my king pins are held in place....

I just want it right so I don’t have to worry about it. Am I being too fussy about this? I dunno... given my track record, I’d say probably not.

Cheers

Piker · 07-22-2019, 07:44 PM

I ended up helicoiling just one more hole... the one that I turned the stuck bolt out of and damaged the threads. When you looked at the threads closely, you could see that a lot of the threads that were in the hole were just relocated steel that wasn’t really attached to anything. I’m really glad I drilled this one out and fixed it. The last hole, the one that the bolt fell out of, actually had really good looking threads in it. They fit the bolt a bit looser than the helicoiled holes, but I think they are just fine.

I just need to think about the clamp plate idea. I could make a very thin clamp plate out of .030” thick hardened shin stock (spring steel), that way I’d only lose less than 1 thread worth of engagement, and I’d still have retention on the dowels. I could also order the kit from Fluidampr $$$... or, peen the edge of the holes over top the dowel pins (not my favorite).

I think I’ll sleep on it.

Cheers

Unplanned Tourist · 07-22-2019, 10:48 PM

Center punch around the dowels if they are below the surface. "Machinist Weld" as my brother (tool and die maker and machinist for many years) used to call it.
As you likely know, clean the mating surface well, and a thin layer of Loctight will help keep everything in place.
Happy Glamping.

Piker · 07-23-2019, 04:51 AM

The dowels are not as far below the surface as i would like them to be for a good peening... but I don't want really them any shorter... so I'm moving forward with the .030" hardened shim stock washer.

It looks like i have the helicoils turned in about 3 threads too far... plus there's a .010 friction washer behind the damper, and there will be a .030 retainer washer in front of the damper which amounts to one more thread. 4 threads at 1.25mm pitch is about .200" less thread engagement than the original configuration, with a total of about .625 vs .825.

This is probably good enough... but if I thought i could get another helicoil in above the existing ones, I would do it. I'd still like to hear from someone who has tried this... Granted, there is almost never a reason to put more than one helicoil in a row because they are sized to length to give you 1.5 x's the Ø thread... unless of course you screw them in too far.

-cheers

Piker · 07-23-2019, 07:02 PM

I screwed the existing helicoils all the way to the bottom of the holes... and then inserted another helicoil in front of them... easy peasy... the bolts thread in perfectly, and I’ve got way more than enough thread engagement now.

The .030 hardened plate/washer is in place over the dowels and under the bolt heads... so the dowels aren’t going anywhere. There is blue loctite on the bolts, and red loctite on the dowels. Hopefully the damper won’t ever come off again.

I’m going to drain some antifreeze out tomorrow, replace the thermostat and the water pump... and call it good... Until the next RV debacle... and I’m sure there will be a next.

Cheers

WILDEBILL308 · 07-23-2019, 09:01 PM

Piker, yes you may be over thinking it but that is much better than half a**ing it and breaking down again.
For future reference. If you want it to really stay find some loctite pramoter to use before the final installation. The bad / down side is you need to do the install quickly and no stopping. Once it sets you mostly need lots of heat or a drill to get things apart. (using loctite red)
They make longer incerts but are hard to find, using 2 will work just fine.
Bill

Piker · 07-25-2019, 09:03 PM

When I opened up the box to the new cummins thermostat and saw “made in China...” I was at first kind of disappointed. But then when I removed the old thermostat from the housing and found casting sand from my China made cylinder head jamming it in the open position, I figured that irony had come full circle and all was well.

The bus is back together and roadworthy once more. Going to take a break from fixing and repairing and worrying, and just enjoy it for the rest of the season. Thanks for everyone’s input and advice on this fiasco with the damper...

Oh, and I found another oil leak... the bottom bolt on the hydraulic pump that mounts to the back of the gear housing was looooooose. This one was a doozy... After pressure washing the engine bay when I cleaned the radiator and CAC, I was able to watch oil drip out of it with the engine at an idle. Tightening the bolt stopped the drip immediately.

All for now... cheers

WILDEBILL308 · 07-25-2019, 09:31 PM

Glad things are going your way. Go enjoy!!!

Bill

ronspradley · 07-26-2019, 05:17 AM

Good work Piker. Now time to enjoy what you have been able to accomplish.

ronspradley

OldToolmaker · 07-27-2019, 06:24 AM

Quote:

Originally Posted by Piker

When I opened up the box to the new cummins thermostat and saw “made in China...” I was at first kind of disappointed. But then when I removed the old thermostat from the housing and found casting sand from my China made cylinder head jamming it in the open position, I figured that irony had come full circle and all was well.

Oh, and I found another oil leak... the bottom bolt on the hydraulic pump that mounts to the back of the gear housing was looooooose. This one was a doozy... After pressure washing the engine bay when I cleaned the radiator and CAC, I was able to watch oil drip out of it with the engine at an idle. Tightening the bolt stopped the drip immediately.

All for now... cheers

Irony? In my day we were taught Noun verb subject. Capitalize the first letter and use a period at the end. What are you some English Lit major?

And regarding the loose bolt. Do we need to sign you up to the Loctite of the Month Club?

Glad to see you made it to the end, Piker. I too have been in the valley of despair. The walls are steep and all you can do is keep putting one foot in front of the other. What else can you do? Trust the work to someone else? Someone with questionable qualifications?