Well I think I maybe able to finally put this thread to rest now.
So working on the engine vibration problem, pulled the trans off, pulled the clutch off and bolted up an empty trans case to keep the engine level. Started it up and vibration still there (figures...) ok so let’s try the flexplate that I have, pull trans case, pull flywheel, bolt up flexplate and bolt up trans case again. Start it up and.... vibration still there, that’s my luck on this engine so far haha
So just to clarify, machine shop 1 did the rebuild, they are in very good standings in my books, machine shop 2 did the balancing and are not in my good books. Ok with that out of the way, I talked to machine shop 1 and he was nice enough again to let me use his shop space and tools to tear down the engine and try swapping cranks, he also gave me a free 7.3 standard size polish crank to swap in! I can’t thank machine shop 1 enough at this point!
Ok so the idea here is machine shop 2 balanced the crank by putting super expensive Mallory weight into the crank throws (or pork chops) and they didn’t touch the ends (flywheel/balancer)
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(You can see where they welded in weight on the crank)so we figured the easiest way was to swap the crank out and see if that solves the balancing issue.
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It is possible to pull the crank with all the rods left in.
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Some weird wear on rod 1 lower bearing (top pic) almost like the bearing was delaminating in that one spot, probably from the unbalance.
Second pic shows weird wear on main #1 block side, found that the block had been hit just enough by the bolt hole to push a bit of metal out and cause that part of the bearing to wear, filed the high spot off and it feels smooth now.
Ordered new bearing for the mains and rods, didn’t feel comfortable reusing those old bearing with weird wear on them. Parts house was nice enough to send me powerstroke bearings which I didn’t notice were the wrong ones till we tried to drop the crank in and the thrust bearing was way too big, out come all the bearing and rod bearings to be cleaned up and sent back and then wait a week for the correct bearings to show up. Got the crank dropped in, everything bolted up and back together with no new surprises.
Got the engine back into the truck and hooked up just enough to start it, put the flexplate on and trans case for testing and fired it up, the rpm must of shot up to 2k or so on start up (no tach hooked up) and it blew out a few ounces of oil out of the turbo all over the firewall, trans case and engine ( not too surprised about this as the engine was upside down for a week).
The vibration seems to be gone now, with just the flexplate there is a tiny amount of loping at idle (650rpm) which I believe is because I don’t have the torque converter on to add mass and smooth out the engine firing pulses at low rpm, at 1200rpm it seemed smooth. I then swapped out the flexplate for the flywheel and fired it back up and it is definitely factory smooth again so whatever weight machine shop 2 added was wrong.
A little about machine shop 2, (this is back in November) I showed them the truck and they said there is definitely a balance issue and told me to try pulling the clutch and swapping to the flexplate which I did and it didn’t change anything. Before I did the tear down ( about 3 weeks ago) I went back and talked to machine shop 2 about the balancing problem and what I have tried to narrow it down to and the first thing the guy says is he has never had a problem with an engine he balanced( we can see where this is going already....).
He keeps insisting that it’s something external to the engine, well I have no trans, no clutch, pulled off the belt for the front end accessories and the shake is still there, going down a hill and turning the engine off when it was at 1200 rpm made no difference so that rules out the fuel system. I tell him that there’s nothing left for me to try, it has to be the balance. Now I’m going out on limb here and trying not to be completely thrown under the buss and say I will eat the cost of R&R the engine, and the gasket cost if they would double check the balance, he never did give me a straight answer but he said if they spun it up it would be perfectly in balance( ya ok I was definitely born yesterday
) so I ask what if it doesn’t balance out, he says that they would balance it but it wouldn’t be out and if it was I would have to get it rebalanced at my cost.... ok so no help from them.
So a few hours later machine shop 2 calls me and says he’s been talking with some of the guys and my problem just doesn’t make sense, he had called another customer that had a few NA 7.3 balanced there and they never added weight to those, then he goes on to say he can’t find my balance card (figures...) and he doesn’t know why they added weight to the crank. That’s pretty much where I got with machine shop 2 and decided to say f it and just swap cranks and see how that turns out.
Now machine shop 2 did manage to balance my NA flexplate to the turbo flywheel at least so I did get something out of this besides an $800 bill and a garbage crank with $3-400 worth of Mallory stuck in it.
Just to recap quickly
Tear down 1, initial engine rebuild
Tear down 2, upside down head gasket
Tear down 3, cavitation in cylinder 8
Tear down 4, improperly balanced crank
Hopefully I can now finally enjoy this engine for once instead of working on it every day and hoping this was causing my poor fuel mileage.
Story/rant over thanks for reading
