The Chrysler Minivan Fan Club Forums banner

41 - 53 of 53 Posts

·
3rd gen > all others
Joined
·
2,763 Posts
You don't need to worry about balance that close to the center of the crankshaft. You're replacing steel with steel anyway (and I surely hope a SOLID pin). I hope the threads are better in person than those pictures, where they look nonexistent!

That is still a loose fit. When I replaced the balancer on my 3rd gen, it would hardly go on! I had to use some sandpaper in the balancer bore to make some clearance so it would go all the way onto the crank. The first time I tried it (with WD40) it would only go on halfway, even with a puller/pusher tool. It was starting to mar the threads, which I greased with moly grease. After sanding/fitting, it went on 3/4 of the way before any real resistance with the tool. It turned out fine and ran true, and had no further problems even thousands of miles later. My original balancer had developed a slight wobble and made the belt chirp in rhythm of the wobble.
 

·
Registered
Joined
·
2,164 Posts
Great pictures and explanation of your proposed procedure.

I can see where it may had been slipping for a little while and then suddenly "came off the rails proper". Luckily the ole girl rolled into your driveway under her own steam.

Surprised that the design is not such that a slip would tighten the bolt. Like my lawnmower, if the blade slips it will tighten the reverse thread nut...

When drilling, high pressure, low speed, and plenty of lubricant. The machinist know what to 'listen' for. When I have the right combination of speed and pressure I can 'hear' every tooth taking a full mouthful.

Consider three pins minimum. two and it can wobble either way. Three or more and you are on solid footing. A bipod vs a tripod. I'd not hang my dutch oven over a fire on a bipod unless I had additional support/

updates, updates... don't sign this off in the log book just yet...
cheers!
 

·
Registered
2013 Dodge Grand Caravan
Joined
·
771 Posts
I withdraw my idea that a shim would work. That is WAY too much slack to take out with a shim. Any shim big enough would be too solid to bend. I'm not sure how that wasn't making a horrid noise for many months.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #48
You don't need to worry about balance that close to the center of the crankshaft. You're replacing steel with steel anyway (and I surely hope a SOLID pin). I hope the threads are better in person than those pictures, where they look nonexistent!

That is still a loose fit. When I replaced the balancer on my 3rd gen, it would hardly go on! I had to use some sandpaper in the balancer bore to make some clearance so it would go all the way onto the crank. The first time I tried it (with WD40) it would only go on halfway, even with a puller/pusher tool. It was starting to mar the threads, which I greased with moly grease. After sanding/fitting, it went on 3/4 of the way before any real resistance with the tool. It turned out fine and ran true, and had no further problems even thousands of miles later. My original balancer had developed a slight wobble and made the belt chirp in rhythm of the wobble.
I believe the nose is only tapered toward the end, to facilitate ease in getting the balancer started on the crank prior to pressing it up to the shoulder. Having said that, I will attempt to use some shim stock, at the direction of my neighbor the machine builder, up toward the shoulder on the crank, at a minimum. The pinning will take care of any possible movement toward the outer end.

The old bolt's threads show no signs of wear and it threads back into the crank without any play. The pic of end of crank nose is deceiving, making it look like the threads have been worn smooth. The crank nose, from shoulder to end, is 1.167" in length. The machining of the threads in the crank do not start until a depth of 1.300", which makes sense since you'd want the balancer to be secured to the mass of the crank journal and not only in the nose.

I will definitely be using solid pins! I've seen some pics where roll pins were used and that immediately did not look right in my eyes. I love the suggestion of using 3 pins for added stability, and will be going that route.

Will provide all of the detail and pics that I can once the jigg has been made and I've got everything in place.
20200629_140019.jpg
 

·
Registered
Joined
·
2,164 Posts
58732


How about a thick washer with some grinder nibbles (sorry my graphics abilities are not up to par with Levy) that should give you room to run a drill and be easy to make....
 

·
Registered
Joined
·
365 Posts
Is the diameter of the crank shaft worn down where the back side of the HB butts up to the crank or is it a tight fit on the new balancer? This must have been loose for a long time?

I thought this was a case where the rubber isolator was damaged and the outer metal ring had separated.

Dan
 

·
Registered
Joined
·
39 Posts
Discussion Starter #51
I'm going to try to be as precise as I can to get the proper fix the first time around. The thick washer nibbled out to provide drill point access is pretty simplistic and easy to make DIY, but here are my thoughts for not going that route. I'm thinking that the crank and balancer consist of different metallurgy, and if that is the case, the difference in hardness will cause the drill bit to wander into the softer of the two materials. With a jigg, the bit will be guided precisely with no wander, and remain in parallel with the crank nose.

I've included a pic of a rough drawing of the jigg that my neighbor will make at his machine shop. The pics can be a little deceiving, but I've measured everything precisely to get as exact a tight and square fit up against the crank nose shoulder as possible. With the new balancer held tightly against the shoulder, there is no radial movement. Any movement is noticed at the outer end of the balancer, when not held tightly against the shoulder, because the old balancer wore the end of the nose down slightly when it spun off and got cocked due to the belt tension. Because there is a good square fit at the shoulder, I believe the jigg will hold everything in place correctly once tightened down against the new balancer so that the holes for the pins can be drilled precisely. I have not included a dimension for the diameter of the pins I'll be using as I am not familiar with pin stock. My neighbor will clue me in on what's available and we'll go from there.

Please continue to provide all the input that you care to. This is an extremely rare occurence and equally rare repair procedure. BTW, my machine building neighbor is making this jigg free of charge at his shop for me so it's not like it's going to be an expensive job. Besides, it's really quite easy to make, the toughest part of it being drilling the holes for the pins 120 degrees apart, but that's not rocket science either.
20200630_150700.jpg
20200630_150243.jpg
20200630_150149.jpg
20200630_145953.jpg
 

·
--UNKNOWN MEMBER--
Joined
·
11,886 Posts
Get the pins before you start drilling.

Drill a piece of metal and test your pins before you drill on the actual crankshaft-pulley.

Pins must fit tight or....


Good luck.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #53
Pins HAVE to be very tight or this will be a waste of time. Hope I don't need luck cuz I don't believe in it LOL.

Off topic, but just noticed you've averaged 6 posts per day for 5.5 yrs. You are quite dedicated!
 
41 - 53 of 53 Posts
Top