Engine Seized? - Page 11 - Alfa Romeo Bulletin Board & Forums
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post #151 of 572 (permalink) Old 10-18-2017, 05:16 PM
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There are at least three different flavors of crankshaft nut and at least one of them is unique. Depending upon which one you have, it may be harder to source than you might imagine.

Ed Prytherch
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A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #152 of 572 (permalink) Old 10-18-2017, 05:56 PM
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#4 main bearing is trying to kill your crankshaft

Hi

Someone said:

"...Put the number 4 main cap back on and if it locks the crank down you can then use a long breaker bar and a jack handle over it to make it longer and get the nut free. Have someone stand on the leg of the engine stand on the opposite side to keep it from flipping over. .."

I wouldn't do that. I think you run the risk of scratching the crankshaft, which as I understand it; is currently okay? You've spun the crank over 360 degrees and it's shiny and unscratched everywhere yes??

Whatever made the motor seize is in the area of the #4 main bearing. Since you've taken off the lower cap of the #4 bearing, and there's nothing there so horrible as to seize a motor, the horribleness must be in the top half of the #4 main bearing. The part you can't see yet and won't be able to see until you get the crankshaft out.

Or maybe taken together the upper and lower parts of the #4 main bearing are so horrible that they can seize a crank in place.

In any event if you clamp the crankshaft between the two halves of the #4 main bearing, and then twist on it, you're subjecting the crankshaft to the horribleness that made the motor seize in the first place. Don't think that's a good way to proceed.

You've stripped the motor down to a bare block and a front cover and crank, right?

That's not super heavy, load it it into the trunk of your car or something and go seek somebody with an impact gun.

Hope this helps
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post #153 of 572 (permalink) Old 10-18-2017, 06:02 PM
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Shakey,

I should have mentioned this in my post about moving the pistons. With the main bearing caps off you can, if you are patient, move the upper bearing insert. I've been through this. I used a small block of wood and some light tapping to dislodge the insert. Tap on the flat side so the bearing can slip out of the retention recess. The bearing will slide around the main journal until it is free enough to work with your fingers. Also, once out of the recess a slight turn of the crank may start the insert sliding around the journal. Sorry, this is not well written but I have done it myself.
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post #154 of 572 (permalink) Old 10-18-2017, 07:24 PM
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I also watched a professional mechanic replace the upper main bearings by tapping them around the crank journal with a small screwdriver enough to get them up to remove them by hand. New ones were put in the same way.

However, you need to get the crankshaft out to see what caused the seizure, if that is even possible. You need to get an impact tool.
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post #155 of 572 (permalink) Old 10-18-2017, 07:48 PM
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Well, I'd do it a bit differently. Put the crank bearing caps back on - they don't need to be so tight the crank locks, in fact better if it does not; Stick a 2 by 4 ( or something smaller that will fit) in the first piston journal so that the crank can't rotate.

I found a Craftsman 1-7/16 socket fit my crank nut (early Duetto with the bent lock tabs); it's 3/4 inch drive so I just got the 30 inch long 3/4 inch drive breaker bar. And a 4 foot length of heavy iron 1 inch (to fit over the breaker bar) water pipe (the thin wall conduit will fold nicely, so skip it). With the crank jammed right up front by the pulley and the block locked in place, I put the socket on the nut, the pipe on the breaker, and stood on the pipe. First time I tried this, I didn't know about the lock tab. I just bent it open and unscrewed the nut. 30 inch breaker, 4 foot pipe, crank jammed, and the block locked down, and stood on the pipe. I put at least 1500 ft lbs on the nut. Everything will unscrew with that.

Three or four guys on the pipe and we might unscrew the earth's spin....

As one of my engineering Prof's said - "Brute Force and Perseverance".

BTW - after I found out about the bent lock washer, it was really easy to unscrew the pulley nut.



Robert

BTW - Still have the 3/4 drive breaker. Only use is that one nut...

Last edited by 60sRacer; 10-18-2017 at 07:52 PM.
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post #156 of 572 (permalink) Old 10-18-2017, 11:25 PM
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Quote:
Originally Posted by 60sRacer View Post
Well, I'd do it a bit differently. Put the crank bearing caps back on - they don't need to be so tight the crank locks ...
I don't get the concept that putting the main bearings caps on will cause the crank to not turn. I get the want to put the main bearing caps on, with the bearings so the crank does not mark the alloy block, and the lump of wood to stop the crank turning but without the lump of wood the bearing caps won't stop the crank turning ... ????

BTW I didn't have any issues undoing the crank nut, but my engine was seized ... so the first thing you should have done was undo that nut
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Last edited by PSk; 10-19-2017 at 12:04 AM.
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post #157 of 572 (permalink) Old 10-19-2017, 12:41 AM
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There are at least three different flavors of crankshaft nut and at least one of them is unique. Depending upon which one you have, it may be harder to source than you might imagine.
Ha, really ?
I stand corrected.. Now I want to know all about the nuts and which one the OP has

'66 1600 Duetto | '73 1600 GTJunior | '03 156 1.9JTD Sportwagon | '11 Giulietta QV (wow, revelation) | I really don't need this many Alfa's...
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post #158 of 572 (permalink) Old 10-19-2017, 04:54 AM
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Robert, I have a similar breaker bar for use on my AC VW engine. It is a 4 foot piece of 1 1/2" angle iron with the 36mm socket welded to one end permanently. The torque needed is from 250-350 ft. pounds. A simple flywheel lock keeps anything from moving.
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post #159 of 572 (permalink) Old 10-19-2017, 05:50 AM
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Quote:
Ha, really ?
I stand corrected.. Now I want to know all about the nuts and which one the OP has

A simple search on crankshaft nut reveals this. It took about 20 seconds to find.

http://www.alfabb.com/bb/forums/engi...shaft-nut.html

Ed Prytherch
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A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #160 of 572 (permalink) Old 10-19-2017, 06:20 AM
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A simple search on crankshaft nut reveals this. It took about 20 seconds to find.

http://www.alfabb.com/bb/forums/engi...shaft-nut.html
Are you seriously telling me off for not searching and finding your thread on crankshaft nuts?

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post #161 of 572 (permalink) Old 10-19-2017, 06:46 AM
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Why should you search when you can get someone else to do it for you.

Ed Prytherch
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A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #162 of 572 (permalink) Old 10-19-2017, 09:40 AM
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Now, now boys. Don't be snippy.

As to the OP question above: I'd not want the bearing caps to actually stop the crank from turning. They're installed to hold the crankshaft in place gently. In fact, the crank should turn easily so the torque load will be taken by the wood block. The block of wood will jam the crank from turning without marring anything, and allow you to put a lot of torque on the nut. A flywheel lock does the same thing, but he has already removed the flywheel. Besides, the block of wood should be in the #1 crank throw position, so there is less torque along the length of the crank.

I have a 350ft lb Dewalt impact gun, but I prefer to use gentle (??) force rather than the hammering of the impact wrench. Also, a socket (needed for an impact tool anyway) and a long breaker bar is cheaper than an air or electric tool. Both pieces cost me about $45 at the local Sears Store (if any of them are left in your area).

Remember that you should NEVER use an impact gun to INSTALL any nut. Spin it on close with the tool if you want, but use a torque wrench to tighten it. NO nut has a 300 ft lb torque spec for tightening! Even wheel lugs are 30 to 80 ft lb and over tightening will warp the discs.

If you go to HF, get a large internal AND external micrometer (not a digital caliper - not accurate enough) so you can measure your bearings and journals. [Get a top-of-the-line Starrett set if you can afford it]. Also get some Plasti-guage to measure your installed clearances. You don't want to have this problem again. Don't order new bearings until you get some good measurements - you may end up grinding or polishing your crank journals because of the seizure, and will then need oversize bearings.

BTW - if you get a new micrometer, spend a few hours spinning it open and closed repeatedly. The threads will gently wear in and average any errors across the entire range of the tool. It makes them more accurate (used is better than new!). I have my Dad's shop class Starrett micrometer set from 1938 that will has been calibrated to better than half-a-ten thou. This is a case where the better tool you can afford, the better you will be.

You might also take your block, crank, and journals (con rods too) to a good machine shop and have them measure everything. You'll need them if you need to grind or polish a surface anyway.

I just prefer to spent the same money on a good tool and learn to do it myself.

Enough yammering. Sorry for the blathering everyone.

Robert

OK, more blather. Be sure to check the oil passages in your block and crank to be sure something isn't blocking oil flow somewhere. That would be the most obvious cause of your original problems.
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post #163 of 572 (permalink) Old 10-19-2017, 09:57 AM
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If you use a long breaker bar how do you prevent the engine stand from toppling over?

Ed Prytherch
79 Spider
76 Suzuki GT500
2011 Jaguar XKR

A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #164 of 572 (permalink) Old 10-19-2017, 09:58 AM
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A few sandbags worked for me. You could wedge it in a door way?

Adapt, innovate, overcome......

Robert

Last edited by 60sRacer; 10-19-2017 at 10:01 AM.
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post #165 of 572 (permalink) Old 10-19-2017, 11:05 AM
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Quote:
Originally Posted by 60sRacer View Post
Be sure to check the oil passages in your block and crank....
+1

@Shakey
was there a particular symptom that made you add STP in the first place to the oil?

Oh, and a good chance to get rid of the alumaseal in the water...a good working coolant system doesn't need any hocus pocus...antifreeze and distilled water is all it needs.
Nows the time to have the rad flushed and checked thru

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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