you should really have some kind of service wagon for work, in case the Astro is down for an extended period while you sort this issue;)

what did you use to clean it? I am assuming anything marginally abrasive might erase the witness mark if I even have one, especially if its that faint!

Im looking around for another interim van actually, a wagon is a bit too small.

(I know what wagons you think :D)

that sounds suspiciously like a one sided deal to me, plus your 84 617 may have a biased flywheel balance too. (though at least its bolted up still and can be marked)

All the engines are in balance once all done up otherwise they would quickly destroy themselves, this engine is a 300k engine that funola especially can verify as a great running smooth engine.

There is just a totally untraceable number of 617 motors that the crank balance was not fully worked out on the crank itself, and some have biased flywheel balancing to make up for it. By the time everything is together, its a fully balanced unit. (I have read of some accounts where the harmonic balancer on the front of the motor may have biased balance too, but have never seen that)

The engine in my 74 240 is an early 80s 617 with biased flywheel balance as well, though on that project I wasn't so careless about the potential issues, and did it properly. It was a couple grams off on one side if I recall.

Not at all - I don't think "taking it to bits" is always the answer


The problem is (as you said) =>

...if the witness marks aren't there then you are left having to either guess or getting a professional job done aren't you?

yeah, exactly. Ill start with the guessing, then move to professional job probably if the guessing doesn't yield fruit.

Im hoping that I may have missed some kind of witness mark on the crank, there is decent surface rust it could be hidden under

Fingers crossed

Have you spun the flywheel you've removed on a pencil or rod to see if it favours a certain position?

haven't pulled it apart yet, going over there in a few minutes though

That's good because it wasn't a serious offer :). The serious question is at the bottom of the post, though... can you tell if the FW is off balance without driving the car, i.e., at idle? If nothing else, could you at least nail down which one of, say, three orientations is the right one and then fine-tune it further with driving? That way you could play with the FW without installing and reinstalling the transmission so many times.

Also, no-one's mentioned it and that's probably because it seems obvious or because I'm not catching something, but I would think that if your first mounting location vibrates, you would want to rotate it [EDIT -- Ignore the rest of this -- see my next post -- you would want to rotate 120] 180, see if it vibrates more or less, and then further fine-tune the desired mounting position using a similar process of elimination, hopefully making the maximum amount of fittings required less than 12.

Basically, I mean something like this, where A, B, and C are three different mounting orientations and I, II, and III represent different levels of vibration (III = the most). The bracket should not extend to the bolt two away from A, please ignore that...

http://img.tapatalk.com/d/14/01/31/be5ame2a.jpg

I would assume that the ideal mounting point would be right beside A between A and B. If this works this way -- if the shaking gets worse as you move further away from the balanced point -- then you should be able to find the correct mounting point for the FW in four test-fits. If, say, A and B are the same, then you could assume that the sweet spot is right in between them.

Going this way, you would have a 25% of getting it right one of the first three times and a pretty high likelihood of getting it right the fourth time.

Pretty much what I described in post #427.....Rich

Again, pretty much the same thing I suggested in post #427...Rich

Missed that.

I think triangulating it would probably result in much less work, though.

the stats are in-

I timed myself this time, and It takes me 33 minutes, 20 seconds to completely remove the T5 and driveshaft, and an additional 12 minutes 15 seconds to remove the clutch and flywheel.

I have performed the spin test on the aluminum flywheel, and that too has a definite heavy spot, though not as pronounced as the cast iron stock flywheel.

Since installing the 617, ive driven maybe 12 miles in test drives, and I have more bad news. The imbalanced flywheel fiasco has caused what looks like a rear main seal leak around the crank that has clearly presented itself since the last time the transmission was down (2 days ago). That will have to be fixed now as well, I hope I didn't wipe any bearings also.

Im uploading the spin video on the custom aluminum flywheel which Ill add to the post soon

OK, so that stinks. Were you going to test the bearings now or just replace the seal and hope all is well?

With that set up for the rough balance of the flywheels I reckon you should be able to adapt it to work for the method of correcting the balance in the FSM. I think that'll be a first on this forum!

I think you need to do that test at least three times (but don't spin so hard and for so long) to make sure the wheel does stop at the same heavy point. In your modified flywheel video I got the impression there was a bit of bearing interference with the motion but it is hard to track that spin on the wheel when the surface looks so samey (and of course just at the wrong moment the camera man seemed to loose all hope and wandered off to look at the clutch)...

...the rear seal leak might seem like bad news but to put a positive spin on it (groan) you have hopefully caught this in time - check those bearings

Start with crank end float

Next time I'm in your area wanna swap the clutch on my truck while I order pizza?

here is the custom aluminum flywheel spin-

Mercedes 617 turbo diesel to GM transmission custom flyhweel crude balance test - YouTube

Ill probably do what stretch suggests, and measure crank end float and whatnot to know, but at least its going to be fairly convenient to replace the seals in this van. Way easier than doing it in a stock mercedes, for sure. I can easily remove the upper and lower pans with it mounted in the engine compartment

lol, I was actually trying to turn the camera off, these damn contraptions!

The modified flywheel was a little harder to jig up, the weight is very off center between the face and back, so I used a little electrical tape to keep the bearing sort of half in on the front side, which is why it looks a bit lumpy.

Ive been thinking that a really good test jig would be the input shaft from a transmission, with the exact ID for the inner race of the bearing

Unfortunately Ive already run the flywheels down the street to have them marked and matched by the machinist, so ill have to play with this after I get them back (could be a few weeks)

Is your ford truck also using a T5?
we can bang that sucker out before you stop gagging on the anchovies :D

where were the marks on yours you were able to find (so im looking in the same place)?

the crank itself has a "z" stamped into it, anyone know what this indicates?

http://i1217.photobucket.com/albums/...ps3245292d.jpg


and in addition to the oil leak in the above pic, heres what the rear main seal leak is getting onto the flywheel also, definitely gotta fix this

http://i1217.photobucket.com/albums/...psd06b263d.jpg

The last time I removed a flywheel, there was a distinct mark on the crank inside the hole where the pilot bearing would be, and a corresponding mark inside the hole in the flywheel. I actually saw the marks after removing the flywheel (marked before removing).

I wonder if the gouges created by bolt rubbing made the imbalance.

Definitely possible, not much material was removed though

So since I wiped out the rear crank seal, it pretty much looks like the crankshaft nearly has to come all the way out for that anyway. If that's the case, I might as well remove it fully and balance the flywheel with the crank. I may go grab the flywheel in the morning

If this is an inherent flywheel thing - and not the mounting onto the bearings - THIS IS YOUR PROBLEM! This is absolutely the worst thing to have; a front to back wobble will enhance / improve / exaggerate any out of balance force that you've seen with the "spinning it on a stick" trick.

If this is the case you have a serious problem that I don't think you can solve as a DIY mechanic

I agree using the parts on which they are meant to fit is probably the way to go.

I'm glad the machinist is looking at the flywheels - inform him of this back to front wobble problem if it is relevant (see above).

I think this is the best long term solution.

I know it seems like a lot of extra work but leaving the crank dangling on the big end bearings whilst trying to fix the rope seal in the block strikes me as a right pain in the arse; when you consider the additional out of balance / vibration problem it makes no sense (to my mind) to be trying to cut corners / save time / do less. In my experience these short cuts have always turned round and bitten me on the arse...

...whatever you decide - measure that crank end float!

long overdue update-

pulled the 83 motor and installed an 85 motor.
83 motor is on a stand for future repair and use in some other project.
85 motor out of a 300CD was installed.

Very busy summer work season is drawing to a close, so hopefully I can get this SOB up and running. Unfortunately I replaced the van with a bigger van a while back, and dont really have a use for this anymore. (once you can lay a 4x8 sheet of drywall or plywood flat in a van, its hard to go back to the smaller version)
Dont want to let it sit and rot, so probably will get it running reliably and sell it.

some new pics. For a little spicy variety, I decided id try and install the new motor through the front of the van. This is technically possible, but I wouldn't do it again. Thought it would be a time saver, but it took almost 4 total hours to get the engine lined up with the motor mounts. and even then I may have cross thread one of them, will resolve later. Some pics of the install process-

83 engine removed-

http://i1217.photobucket.com/albums/...pscbb54be9.jpg

85 engine ready for teardown-

http://i1217.photobucket.com/albums/...ps45b66f85.jpg

cramming that sucker in there-

http://i1217.photobucket.com/albums/...ps2910a8f3.jpg
http://i1217.photobucket.com/albums/...ps2825ec84.jpg
http://i1217.photobucket.com/albums/...ps13edf227.jpg

It can only be done at an angle, and just barely at that. Flywheel is off getting matched balanced and this time I MARKED the position of crank to flywheel. :D

I may make a modification to the front lower bracket here along the red line, if that dropped a few inches, you could fire a motor in and out of this van very fast.

http://i1217.photobucket.com/albums/...ps99b0e0c0.jpg