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Discussion Starter #21
I got the crank out! Encouragement helps! So, now I’m finally able to carefully inspect what I have.

General observation is that overall everything looks better than expected. To my novice eyes anyway.

The cam lobes have almost sharp peaks with even edges and no scoring or uneven wear apparent. The valves cleaned up nicer than I thought possible. Still some factory grind on seat face, don’t appear bent, maybe a polish regrind can save them.

Block looks like Dr. Frankenstein made it, but the cracks don’t show on any machined surfaces or pass through. One cylinder looks ok, doesn’t appear to need to be reamed. The other one has a gouge at way bottom. That piston and rod are toast.

The crank. Well, that may be the show stopper. Everything is nicely polished, round, little wear. Except where the bearing failed. Tha journal has a gouge in it. I,m doubtful it can be salvaged, but I’ll leave youse guys (old Southern term) to tell me the verdict.
CA56A08C-8A22-461F-A714-BB7C30589101.jpeg
 

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That's a pretty ugly rod journal alright. Nothing to lose by trying to clean it up...other than a little time.

Mine did not look as bad, just covered with aluminum from the rod. Would wash it up, and if it looks like aluminum, try the lye bath. Otherwise, looks as though you most likely need a crank...check with Boomer.

Al

20200714_081123.jpg
 

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Discussion Starter #23
I’ve been digging some on crankshafts. Many tick over little nicks And scratches not gouges like mine. I think it’s going to be beyond tolerance but I really don’t know. If I’m buying valves, springs, piston, rod, pin and crank I might be out of the practical for this. I’ll check with Boomer. I’ll get back after I find out. Maybe take the block, crank, and other parts to a machine shop for inspection?
 

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Would not be the worst idea to take them in to be measured...so long as the cost is reasonable and you get your parts back either way.

Al
 

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Discussion Starter #25
Took it in to one of local machine shops that had several decent reviews and liked their webpage. Called teachinist said he’d inspect for free. That clinched it, plus supportive attitude. So he thinks maybe can work with the crank, depending on what bearings are available, bore the cylinders, keep intake valves but not exhaust. So I’m calling Boomer see what he says. Still in game so far. Experience was a bit disheartening though... asked me if I’d thought of repowering instead. Reminded me of a time I asked a barber for a shave and he brought out a Bic razor. I said I thought I’d get a straight razor shave. He laughed said nobody does that anymore the new razors are much better.
 

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What I'll advise is to get a REALLY good idea of what it's really going to cost to get it running before spending a dime on it. And then add 30% for all the incidental stuff you will inevitably forget to put on the list. If you're still within a workable budget, then you make the yay or nay call.

I made the mistake of just diving in/ordering parts willy-nilly on a rebuild ('88 Yamaha FZR1000...4 cylinder, 5 valves per cylinder) a long time ago...it was a harsh, and expensive lesson.

Al
 

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Discussion Starter #27
Roger that. I abandoned my first rebuild attempt on a Ford 351m-400 for just that reason. I was hoping this would work out.
 

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Discussion Starter #28
Boomer thinks my block is toast because one of the main bearings spun. Apparently someone got into the engine before and didn’t put the pegs back in that hold the bearing in place.

I’m holding off buying parts for now, but my little bucket list project isn’t completely dead yet. I’m going to catalog my parts, develop a price list of needed parts, as you suggested, and basically do measurements to determine whether parts are within tolerance.

If I can do that much at least I’ve learned something I didn’t know before. I put my 2 HF calipers in the trash... bit of advice, don’t leave batteries in them and don’t bang them. After downloading a document on small engine tools, I’m going to get them out and see if I can manually measure with them. Might need a magnifying glass and study up on reading scales. Been more decades than I like to admit since drafting classes!
 

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Discussion Starter #29
The replacement bearing is single piece aluminum. I’m trying to work out why this spells the death of the rebuild.
 

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Kish JD 318/420/430
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You did not show the bearing that goes with the crank that shows wear where it was turning most likely with out oil lubrication. That original bearing was with out the inner spacing race (spacers for adjusting end play) which had notches to keep it in place and not spin. So as long as the inner block opening for the bearing has not changed (measurement) and clean the new bearing be okay as long as the crank is okay in that place as well.
 

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Discussion Starter #31
Oh sorry. Sent a bunch of pictures to Boomer but didn’t post any here. Thanks for asking me to post them, it would’ve helped me to have them so maybe someone else will find them useful. Did my best to capture the flaws I observed so I can get good feedback.

Starting with the crank: a picture of the gouged journal when the rod broke free. The rust will clean up. Machinist says he can work with it but I need to find out if I can get bearings.

If you look closely at the piston heads you can make out “STD”. That shows the pistons are original and the cylinders have never been bored. If they had, you’d expect .010 or .020, or .030 for the bore done. Plus, the type of pistons and rods are later model “improved” solid forged rods apparently (based on number inside piston)

One cylinder is farely clean. The other cylinder not so much. Probably have to be bored, but maybe not. There is no wear ring on the cylinder wall... according to Boomer these occur about 1/3 below where the forces are most pronounced from the thrust of the piston. I drug my fingernail up the wall and there is no “step” in the metal. The second one shows a nick at the bottom of the cylinder. The machinist says that is not something to worry about because it is way low. The rust might clean up with ball honing but there is some surface irregularity that may be or not scale.

It’s because of the bearing that Boomer declared the block a lost cause. The type of bearing, a single piece aluminum one that incorporates the thrust washer and not steel like an original means it was replaced. The pegs in the block that keep the bearing from spinning are missing. Boomer says more likely than not a backyard er sanded the block down to make it easier to install instead of having a shop press it in. This is another reason it spun and it came out when I pulled the crank. The pictures show grooving when it spun.
 

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Kish JD 318/420/430
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Without those pins to hold the bearing in the correct orientation, the block would be a lost cause. Can the engine machine shop replace them? If yes and that is a big yes then the other damage/issues in the block might be overcome. The wear spot in the 5th picture is the next big issue, because it looks like it started a crack in the block in a casting imperfection, from the constant beating and broke some the cylinder wall lip away. Those should be checked by the engine machine shop, that would be your second opinion (like doing major surgery, the are the actual engine doctors who have to do the work), remember your wallet when asking these question of the shop also.
 

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Discussion Starter #33
I pointed out the damaged areas from parts crashing around and machinist didn’t seem worried. He was more concerned about the availability of journal bearings and main bearings. He was curious about the main coming off with the crank.

I went to Onanparts.com and saw those same bearings in different sizes, so I don’t know why the block was ruled unsalvageable. Seems one could simply bore oversized and press in new. Cost is a of course a different consideration.

I bought a digital caliper and set of micrometers today so I can check specs. I also picked up a binder track my project better. With me teleworking I’m spending more hours at home so I can do this.
 

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With the bearings, the od is always the same...it's the id that's oversized...to fit the crank after it's been ground undersized.

Al
 

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Discussion Starter #35
How did you know I drew a blank on that? I was struggling with how to talk about the bearings. So, after grinding the journal, I’ll need oversized bearings with a larger ID? That can’t be right. I need oversized bearings with a smaller ID. o_O

Based on my closer looks at parts it appears they bearings are referenced as standard or undersized and pistons as standard or oversized.
 

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Discussion Starter #37
I was thinking oversized in my earlier post but couldn’t visualize it. I was trying to wrap my head around it but I think I spun a bearing in my neck instead!
 

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Discussion Starter #38
If one main bearing is bad does it mean I have to replace both? Did you notice the prices? A compete gasket kit priced out at $1200+! I’ll be working on a tally but don’t like where this is going.

Today and the upcoming free time this week I hope to get some measuring done. I dug my 2 HF digital micrometers out of the trash. I thought maybe they could still be some use since they have a scale that can be read manually.
 

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Not sure where you're looking for parts but....


If you end up doing an overhaul (replacing one rod/piston), and one main bearing looks/measures good, I would only replace the one bad one. I consider an overhaul to be a "half time" engine at best...because that's what it is. But sometimes, that's all you need.

If going to the expense of boring/honing and replacing both pistons, you're doing a rebuild and should be aiming for as near a "zero time" engine as possible. JMHO, but it does not make sense to drop $1K + on parts/machining and then not replace a single $120 bearing.

As ever...opinions and thoughts on the issue will vary.

Al
 
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