Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: alexdecker on May 06, 2022, 04:51:15 PM

Title: Crank not rotating
Post by: alexdecker on May 06, 2022, 04:51:15 PM
Just connected to the halves of the bottom end. My crank seems to be stuck though. Checked the gears before installing and they were fine.

Is it supposed to be able to rotate free at this point?
Title: Re: Crank not rotating
Post by: Bryanj on May 06, 2022, 05:09:10 PM
Something is put togerher wrong, should turn easy
Title: Re: Crank not rotating
Post by: alexdecker on May 06, 2022, 05:24:58 PM
It happens when I torque the 10 main bolts down. 17 foot pound is my spec. Why is this??

Title: Re: Crank not rotating
Post by: alexdecker on May 06, 2022, 05:35:06 PM
Just went down to 14 foot pound. Still seizes when I tighten.
Title: Re: Crank not rotating
Post by: Oddjob on May 06, 2022, 05:46:18 PM
Wrong shell in wrong location?

Check nothing under the shell making it stand prouder.
Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 06, 2022, 05:48:12 PM
My thoughts.
1.Is it in neutral.
2.Is the cam chain free.
3.Did you Plastigauge the mains.
4.Are the conrods free.
Title: Re: Crank not rotating
Post by: alexdecker on May 06, 2022, 05:57:00 PM
Everything is free. I didn’t plastic gauge, as I marked the location of each bearing and put them back in the same place.

Title: Re: Crank not rotating
Post by: murdock on May 06, 2022, 06:19:27 PM
How big was the hammer you used to remove the rotor? ......
I'm scared of you. ;D
 
Title: Re: Crank not rotating
Post by: Bryanj on May 06, 2022, 06:21:05 PM
You did put the shells into the cases with cases and back of shells dry didnt you,mixing up shells would not normally lock it up, i have built with all tightest shells before now with no problem.
Primary shaft needs to be fitted and cam chain free but should turn by hand.
You havent tried to miss match cases?
Title: Re: Crank not rotating
Post by: Johnny4428 on May 06, 2022, 07:20:27 PM
Crank seal located correctly?
Title: Re: Crank not rotating
Post by: Oddjob on May 06, 2022, 07:23:37 PM
A black in a yellow location might lock it Bryan but I was more thinking of something behind the shell making it bind onto the crank.
Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 06, 2022, 07:33:34 PM
I assume the upper half case was upside down when you started assembly. Did the Crank rock freely when sat in the Crank mains with assembly lube applied? I am assuming it not significantly different to a 400/4. I
Can the Crank be fitted in the wrong way round.
Title: Re: Crank not rotating
Post by: alexdecker on May 06, 2022, 07:40:03 PM
How big was the hammer you used to remove the rotor? ......
I'm scared of you. ;D

Oh god, I hope I didn’t do what you are referring to!
Title: Re: Crank not rotating
Post by: alexdecker on May 06, 2022, 09:12:05 PM
I assume the upper half case was upside down when you started assembly. Did the Crank rock freely when sat in the Crank mains with assembly lube applied? I am assuming it not significantly different to a 400/4. I
Can the Crank be fitted in the wrong way round.

I did exactly that. Pretty sure I mounted it the right way. And yes, it moved freely.
Title: Re: Crank not rotating
Post by: alexdecker on May 06, 2022, 09:16:04 PM
You did put the shells into the cases with cases and back of shells dry didnt you,mixing up shells would not normally lock it up, i have built with all tightest shells before now with no problem.
Primary shaft needs to be fitted and cam chain free but should turn by hand.
You havent tried to miss match cases?

I only lubricated the crank contact side of the shells. I fear that the crank might have gotten bent when I put the hammer to the rotor puller to get the rotor off.

Still - I didn’t have the crank in a vice when I did that, so it could move freely, and the rotor puller and rotor contact point seems too small to be able to bent the crank like that. But it’s the only possible thing I can think of happened. Everything else is in its right place. When I torque it down with my drill, it still rotated freely. But with the torque wrench it seizes up 😕
Title: Re: Crank not rotating
Post by: Oddjob on May 06, 2022, 10:47:53 PM
Remove the gearbox, remove the camchain and primary chain and shaft. So just the crank is left in place. If it still won't rotate then maybe somehow you have bent the crank but I doubt it. As you tighten the bolts do each one a little, check the crank rotates after touching each bolt, keep doing that as you keep tightening the bolts, a little at a time. If the crank stops after tightening one specific bolt check the journals nearest to that bolt.

I'd also spin the crank with no bottom case on, see if you can spot anything wrong, like a bent end of the crankshaft.
Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 07, 2022, 07:02:01 AM
I think it very unlikely that you could have bent the Crank.
At the start of your strip down did it rotate freely?
If it did what is the range of the Crank case markings codes could you have confused number 1 cylinder with 4 it's easily done when stuff is upside down?
Plastigauge is where I would start now to identify the cause, Kens advice sounds a good starting point.
Title: Re: Crank not rotating
Post by: smoothoperator on May 07, 2022, 08:41:42 AM
+1 on plastigauge measuring. Will let you know what your clearances are. Take your time, walk away from it for a while. When the plastigauge turns up, give it another go.
Title: Re: Crank not rotating
Post by: alexdecker on May 07, 2022, 10:55:31 AM
Ok, did some extensive research this morning. I made several discoveries.

It turns out the crank seizes when I tighten down on a specific journal. My motor has the writing BCBCB on it. I am not sure about the color of the bearings though. But it seems to be one bearing in particular that makes the whole thing seize up.

Another thing I discovered is that the crank does not seem to rotate completely evenly throughout its motion. This is not visible to the naked eye, but when tightening down certain journals, I can feel the rotation taking more force throughout half the rotation. Not by a lot, but definitely noticeable. This could support a bent crank, but could maybe also just be the uneven tightening of the screws in this experiment?

Weird thing is that everything rotates freely and with no trouble before I took it apart. So something definitely happened along the way…

I am using allen head bolts with a washer, instead of the original bolts. Could that change anything in regards to the torque spec? When I torque the bolts down with my screwdriver, everything still rotates. But when torquing to spec, it seizes up on the on particular journal.

- Alex
Title: Re: Crank not rotating
Post by: Bryanj on May 07, 2022, 11:54:10 AM
From what you are saying it would suggest a bent crank, many decades ago i worked on an accident damaged 500 where the tapered end had been bent in the accident, we actually managed to straighten it with a specialy made bar and it did many years service BUT the crank rotated free all the time, it was not out of the cases ever.
I am negotiating with an ebay seller who tells me he has 2 nos cranks, i would like one to go with the nos cases i have, i could ask for a price for both if you wish.
Title: Re: Crank not rotating
Post by: alexdecker on May 07, 2022, 01:32:04 PM
Damn it.

Ok, assuming the crankshaft is bent and I need a new one. In that case, I don't need to measure anything, I can just pair the case markings with the crankshaft markings, and then get new bearings based off the result?

But what about the rod bearings? I assume I can't reuse the old ones, and would have to get new ones as well for the rods?
Title: Re: Crank not rotating
Post by: Oddjob on May 07, 2022, 01:42:01 PM
So long as the rods aren't bent as well you can transfer them over. However, like you say the shells will need to match, you have a chance of that happening but I wouldn't count on it.

Have you checked the crank bearings, sometimes you can still see the colour on the side edge of them. Worth having a look.

I'd remove all the shell bearings one at a time, inspect them closely. It's possible you may have damaged one very slightly and that's why it's grabbing the crank.

I don't think the crank is bent, never heard of one ever.

Which journal is the iffy one?
Title: Re: Crank not rotating
Post by: alexdecker on May 07, 2022, 02:21:10 PM
Ok, so gave it another go on the experimental part, and started moving bearings around a little more aggressively. I found it that not even did the problem follow a specific bearing, but it all came down the the specific screw on the specific bearing being tightened, and then the thing seized up (see picture).

[attach=3]


So I closely inspected it, and lo and behold, didn't even have to inspect it that closely. This is obviously a case of not being able to see the forest for the trees, but this bearing has a spot on it. Now, it's very small, and I can HARDLY see any bulge in the metal with my naked eye - but there is a tiny slight one. It seems much larger in the picture, but trust me, there is almost nothing. Basically nothing. It seems weird to me that such a minuscule spot can seize the entire crankshaft like that. But the problem followed wherever I put that bearing, and that is the only fault I can find in the bearings, so can't think it can be anything else.

What do you guys think?

Also - I can see the colours off most of the bearings, and they are green, brown or black. The offending bearing is green. What would be the best way to go about this issue? Plastigauge all of it, or just buy a new green bearing? Also, I find it really weird that it didn't lock the engine up before taking it apart. All bolts were pretty tight when taking it apart, so it was obviously torqued down alright. Wonder what that is about.

[attach=2]

Title: Re: Crank not rotating
Post by: Laverda Dave on May 07, 2022, 02:38:49 PM
Good that you have found the potential problem.  That shell is toast, no way would I try to use it again, you are talking microns of clearance on these bearings so not worth the potential problems of trying to rescue it.
If it were mine I would plastigauge all the bearings so at least you know what you have got to start with and especially now you have been swapping them around. I would use that as a starting point and buy new bearings to suit.
I still can't see how the bolt caused the bearing to spot in the way it has though, did you inspect every bearing shell during the engine strip and was the spot there before? To my eye it appears as though there was something on the crank journel when you initially torqued the cases and this caused the bearing damage and prevented the crank from turning. I would inspect the case very carefully in case there is a bit of grit floating around in there, same with the crank, give them both a good clean. A piece of grit may have become dislodged when you were hammering the rotor to remove it?
At least you have a way forward now and not a bent crank!
And best to check the crank journel of the damaged bearing for a score mark in the same location as the bearing spot.
Title: Re: Crank not rotating
Post by: Oddjob on May 07, 2022, 02:50:02 PM
Looks to me to be a rust spot. When the bearing was removed it allowed the rusted area to expand (which it couldn't do before due to the crank stopping it) this then bloomed out to look like it is now.

Check all the others for similar damage, you're probably lucky as it's extremely rare for this to happen in my experience. You could just replace this bearing with another green but I'd strongly advise buying a pair of green bearings to replace those on that journal. Don't order new ones until you've checked the others very carefully.

Your lucky, green is about the only colours it's still easy to find. Yellows and blacks are rare and browns are starting to go the same way.

If your stuck finding new bearings contact me as I have quite a few NOS ones. I started to collect them many years ago and it's coming to the point where I'll sell them all and cash in. As soon as I've finished building the engine on my last restoration I'll be selling a lot of stuff.
Title: Re: Crank not rotating
Post by: murdock on May 07, 2022, 03:03:25 PM
bingo ! I scared you!
change that , the 2 , apart from that strange crater has marks ,think in microns !!!! check them very well with a magnifying glass, the best thing would be a plastigauge test .

Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 07, 2022, 03:11:14 PM
It's surprising how easy a binding can happen, on my assembly a con rod had a high spot from burnt oil residue on the back holding the shell proud.
Pleased you appear to have found the reason.
Title: Re: Crank not rotating
Post by: alexdecker on May 07, 2022, 03:34:54 PM
Looks to me to be a rust spot. When the bearing was removed it allowed the rusted area to expand (which it couldn't do before due to the crank stopping it) this then bloomed out to look like it is now.

Check all the others for similar damage, you're probably lucky as it's extremely rare for this to happen in my experience. You could just replace this bearing with another green but I'd strongly advise buying a pair of green bearings to replace those on that journal. Don't order new ones until you've checked the others very carefully.

Your lucky, green is about the only colours it's still easy to find. Yellows and blacks are rare and browns are starting to go the same way.

If your stuck finding new bearings contact me as I have quite a few NOS ones. I started to collect them many years ago and it's coming to the point where I'll sell them all and cash in. As soon as I've finished building the engine on my last restoration I'll be selling a lot of stuff.

Thanks all for the encouragement! This had me feeling rather hopeless for a minute there. I will be so much more equipped for a second restoration, now knowing how many things to be aware of all the time.

I like the explanation with the rust spot having expanded - mostly because I expected them carefully taking them off, and am sure it wasn't there. But didn't expect them going in, other than making sure they came into the same place where they left.

I inspected them all again now. I have a few questions.

1. I have one black one with a tiny speck of a dot, that may actually have been how the other bearing looked like before that rust spot expanded. Nonetheless - is this usable? I have checked the journals on the cam, and they are all silky smooth with literally nothing in terms of spots, scratches etc. See photo below.

[attachimg=1]

2. I have to other bearings, both brown, with wear like this (the top part of the bearing. Easier to see when zooming in). It feels smooth when I run fingers or nails over it, but it still looks… weird. Don't know if this is usable? Again, the journals have no damage whatsoever. See picture below.

[attachimg=2]

What do you guys think?

Incidentally, I found a guy over here, who sells a brand new crankshaft and a brand new cylinder block for what amounts to 230£, which I thought was fairly cheap. Still glad I don't need it though (hopefully).

I ordered some plastigauge, and am going through all of them next week.
Title: Re: Crank not rotating
Post by: Oddjob on May 07, 2022, 05:57:13 PM
The black one I'd replace, both of them, it's not really a good idea to mix a new and a worn one on the same journal. Left in I think it will end up scoring the journal surface.  The black shell can only have come from either number 2 or number 4 journal, as the ONLY combination to use a black shell is a C2.

As I said though, finding black shells is difficult, 13315-323-000 is the part number, CMS did have some months ago but they've gone now and they weren't cheap when they were available, they are showing them as selling for £11.25 or so but I can guarantee that when they were available they were a LOT dearer, I think they reduce the price of the part when it sells out so that they can buy someone else's stock and claim they aren't worth as much. Sure they were close to £28 a shell when they did have them, plus P&P of course.

I'm not keen on the state of the rest of the shells TBH, that scoring on the upper edge is worrying, not sure how long this engine may have been stood but to me the surfaces of the shells look contaminated and that's why they are starting to break up. I'd replace all the crankshaft ones if it were mine, I'd also check the rods shells just in case.

£230 for both or each?
Title: Re: Crank not rotating
Post by: Bryanj on May 07, 2022, 06:12:58 PM
That looks like physical damage and/or badly contaminated oil to me, BUT i would far sooner have them in front of me and not in a pic.
Title: Re: Crank not rotating
Post by: alexdecker on May 07, 2022, 07:29:44 PM
The black one I'd replace, both of them, it's not really a good idea to mix a new and a worn one on the same journal. Left in I think it will end up scoring the journal surface.  The black shell can only have come from either number 2 or number 4 journal, as the ONLY combination to use a black shell is a C2.

As I said though, finding black shells is difficult, 13315-323-000 is the part number, CMS did have some months ago but they've gone now and they weren't cheap when they were available, they are showing them as selling for £11.25 or so but I can guarantee that when they were available they were a LOT dearer, I think they reduce the price of the part when it sells out so that they can buy someone else's stock and claim they aren't worth as much. Sure they were close to £28 a shell when they did have them, plus P&P of course.

I'm not keen on the state of the rest of the shells TBH, that scoring on the upper edge is worrying, not sure how long this engine may have been stood but to me the surfaces of the shells look contaminated and that's why they are starting to break up. I'd replace all the crankshaft ones if it were mine, I'd also check the rods shells just in case.

£230 for both or each?

Ah, the black shell was actually from the number 5. I don't know what the signs of a previously opened bottom end is, but somebody must have opened it before me. I marked the positions of the bearings when taking it apart, and that black one can not have been anywhere else than there.

I will use a micrometer on the crank and try and figure out what the correct bearing sizes should be, and source some new ones. What are the options of I can't source a particular color? I will also open up the rod and see how they look like in there. Man, was hoping I could avoid all this. But hey, might as well now, as long as Im in here. This turned out to be quite a lot more expensive than I thought it would be.

And yes, £230 as a collected price for both :)

PS: Are the rod bearings just as rare as the crank bearings?
Title: Re: Crank not rotating
Post by: Bryanj on May 07, 2022, 07:51:31 PM
If you cant get a particular size go for the next thickest shell, i have in the past fitted all black shells and done some carefull running in, which you dont have to do if you get the Honda spec clearance right
Title: Re: Crank not rotating
Post by: Oddjob on May 07, 2022, 08:14:10 PM
Look for markings on the crank

Rod shells are getting rare, especially the black and yellow ones.
Title: Re: Crank not rotating
Post by: alexdecker on May 07, 2022, 08:19:01 PM
Look for markings on the crank

Rod shells are getting rare, especially the black and yellow ones.

The markings on the crank seems to have disappeared completely. But it’s just a matter of measuring and matching up, like with the crank journals, right?
Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 07, 2022, 10:32:10 PM
The markings are not in plain sight it took me ages to find mine as I was either looking in the wrong place or not seeing them. Eventually I found most of the. After cleaning the Crank with petrol using a paint brush.
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:09:42 PM
Took of the rods today. Can you guys help me with the condition of the bearings? I feel like there is a big difference in how they look like, and how they feel like. In the pictures, number 1, 2 and number 4 feels silky smooth, with number 3 having some trouble. But just looking at them, they all look a bit weathered. I don't know how to judge it. Any tips is really appreciated.

They had the following colors and the journals the measurements (in mm):
1. Brown 34,97
2. Brown 34,97
3. Brown 34,98
4. Green 33,02

All the journals are smooth with no marks whatsoever. I have yet to wash the crank down with petrol, so still can't see the numbers and letters on the crank.
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:10:06 PM
Rod bearing 1:
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:10:32 PM
Rod bearings 2:
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:10:52 PM
Rod bearings 3:
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:11:13 PM
Rod bearings 4:
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:26:31 PM
Also, I measured the crank journals for the main bearings. My case is BCBCB. I got these measurements in mm:

1. 32,96
2. 33
3. 32,95
4. 33
5. 32,95

Does these numbers make sense? The shop manual only shows this in inches - does an official source with metric measurements exists, that I can use to determine what color bearings? The colors I pulled out, from 1 to 5, was: Brown, Green, Brown, Green, Black
Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 08, 2022, 04:27:54 PM
Make sure the conrod surface where the shells sit is nice & clean - then I would Plastigauge all the bearings this gives you an accurate clearance measurement for the journals that you can check against the manual tollerances charts.
Title: Re: Crank not rotating
Post by: alexdecker on May 08, 2022, 04:30:44 PM
Make sure the conrod surface where the shells sit is nice & clean - then I would Plastigauge all the bearings this gives you an accurate clearance measurement for the journals that you can check against the manual tollerances charts.

But can I still use plastigauge as an accurate measurement when both the bearing and the journal is worn? Then the numbers might not correspond to the correct size when buying new shells? Or am I misunderstanding something?
Title: Re: Crank not rotating
Post by: Bryanj on May 08, 2022, 05:07:57 PM
If the clearance is still inside tollerance then they are safe to reuse
Title: Re: Crank not rotating
Post by: Seabeowner on May 08, 2022, 07:08:34 PM
Also, I measured the crank journals for the main bearings. My case is BCBCB. I got these measurements in mm:

1. 32,96
2. 33
3. 32,95
4. 33
5. 32,95

Does these numbers make sense? The shop manual only shows this in inches - does an official source with metric measurements exists, that I can use to determine what color bearings? The colors I pulled out, from 1 to 5, was: Brown, Green, Brown, Green, Black
The crank journals when new go from 32.98 - 33.00mm.   Class 1 is 32.99 - 33.00.   Class 2 is 32.98 - 32.99.  Presume this stayed consistent through all 500/550s.
Only way to get accurate clearance on a used motor  for the DIYer is with plastiguage really.
Title: Re: Crank not rotating
Post by: Oddjob on May 08, 2022, 08:40:19 PM
Looks like Brown, Brown, Brown, Green to me. You can still see the colour on the side of the shell. Looking at them I suspect something wrong with the oil, loads of really small score marks like the oil had little bits in suspension. Probably not changed for ages.

Still useable though.
Title: Re: Crank not rotating
Post by: K2-K6 on May 08, 2022, 08:56:09 PM
Looks like Brown, Brown, Brown, Green to me. You can still see the colour on the side of the shell. Looking at them I suspect something wrong with the oil, loads of really small score marks like the oil had little bits in suspension. Probably not changed for ages.

Still useable though.

Yes Ken, I'd agree with your oil observations and Bryan also pointed out earlier in thread. To split it down further though, it looks like oil film breaking down and causing small parts of the shell material to stick to the crankshaft, suppose you could call that "micro seizure" with the waste going round to give score lines.
Stray particle from elsewhere in the engine or more abrasive in nature usually would get stuck in the soft shell material and cause the crankshaft itself to be scored.
So, oil film (shearing quality/consistency) below a level that can support competent bearing spacing to crankshaft.  Doesn't look too drastic as you note, but a good warning to ensure oil condition/quality is high enough not to let further deterioration happen.
Title: Re: Crank not rotating
Post by: alexdecker on May 10, 2022, 05:59:35 PM
Hey all

Alright, I have plastigauged both the crank journals and the connecting rod journals. My mind is getting slightly confused with all the numbers in relation to used bearings shells, and I was hoping to get your guidance as to how to proceed from here.

All measurements are in inches. For the crank journals, I got this (color of the existing bearing + plastigauge measurement):

1 (brown): .0019
2 (green): .0019
3 (grown): .0017
4 (green): .0019
5 (black): .0017

For the connecting rods, I got this:

1 (brown): .001
2 (brown): .0013
3: (brown): .0015
4: (green): .0013

As you can see, some of them fell in between sizes on the included measuring tape of the plastigauge, but I did my best to estimate where in between it fell.

Can anyone make sense of this math?
Title: Re: Crank not rotating
Post by: Seabeowner on May 10, 2022, 06:56:20 PM
According to the manual, fine, but I expect someone will be along later to say they are not keen on the Honda specs.

Crank and big ends:       New 0.00079 - 0.00181     Service limits 0.0031  (in inches)
Title: Re: Crank not rotating
Post by: Bryanj on May 10, 2022, 08:01:16 PM
Sizes are just about within spec but markings on shells wory me.
I suspect fitting new of same colour would give tighter tolerance
Title: Re: Crank not rotating
Post by: alexdecker on May 10, 2022, 08:08:22 PM
Sizes are just about within spec but markings on shells wory me.
I suspect fitting new of same colour would give tighter tolerance

Yes, definitely. I was hoping they would be within spec, because then I could replace them with new ones of same color (if I can get them), and all should be well. But is that the best course of action? Does some of them need to be replaced with tighter tolerances?
Title: Re: Crank not rotating
Post by: murdock on May 10, 2022, 09:19:45 PM
alex , what you need is a plastigauge test to see if they are all within tolerance.
Title: Re: Crank not rotating
Post by: Oddjob on May 11, 2022, 12:18:17 AM
Those are done using plastigauge Murdock.

I'm not a fan of plastigauging old shells, sure you get an indication of the clearance but it doesn't tell you what's worn, just that something is. However if you fit a new set of shells and the plastigauge them, the results will show you just how worn the crank is, if it is at all. So for instance, you fit new shells and the clearance is still over spec, you then know that fitting the next size shell up is the potential answer. One good reason for keeping a new set of yellow shells around, you fit them, get the clearance they give and then calculate the colour required to get the clearance back into spec.
Title: Re: Crank not rotating
Post by: alexdecker on May 11, 2022, 05:12:12 AM
Those are done using plastigauge Murdock.

I'm not a fan of plastigauging old shells, sure you get an indication of the clearance but it doesn't tell you what's worn, just that something is. However if you fit a new set of shells and the plastigauge them, the results will show you just how worn the crank is, if it is at all. So for instance, you fit new shells and the clearance is still over spec, you then know that fitting the next size shell up is the potential answer. One good reason for keeping a new set of yellow shells around, you fit them, get the clearance they give and then calculate the colour required to get the clearance back into spec.

I totally see the reason in that. But getting an entire set of yellow new shells for that purpose and then an entire set of something else possibly sounds very expensive and not that feasible. I could understand from earlier answers, that measuring the crank is not an accurate enough option. So if measuring the crank is not an option, and going by plastigauging old shells is also not recommended, what can I do then?
Title: Re: Crank not rotating
Post by: alexdecker on May 11, 2022, 05:13:03 AM
alex , what you need is a plastigauge test to see if they are all within tolerance.

Those posted numbers were the plastigauge measurements :)
Title: Re: Crank not rotating
Post by: Oddjob on May 11, 2022, 02:55:55 PM
You only need 1 set Alex, you just do 1 at a time.
Title: Re: Crank not rotating
Post by: alexdecker on May 11, 2022, 03:47:25 PM
You only need 1 set Alex, you just do 1 at a time.

Of course. Sometimes the most simple answers are the hardest to see. I can try and source a pair of yellow shells. Can't seem to find them anywhere, neither CMS or David Silver. Any other good resources for that kind of stuff in Europe?

Can I maybe use a green pair for the same usage?
Title: Re: Crank not rotating
Post by: McCabe-Thiele (Ted) on May 11, 2022, 04:10:58 PM
My starting point was to buy one pair of shells for the most common colour - in your case it looks like brown for the con rods - try them for the brown fitting places using Plastigauge for each one in turn starting with the largest clearance position first. Tricky for your mains as there are no more than two the same.

I understand some folk fit the next thickest shell or even all black shells then take longer to run them in but that sounds wrong to me. I suspect that is why black shells can sometimes be hard to source.

There is a range of acceptable clearances in the tables so I would not stress myself over small differences as long as they are within acceptable range.

Title: Re: Crank not rotating
Post by: Oddjob on May 11, 2022, 08:09:32 PM
Yellow are hard to find. Green would be ok to use, especially as you'd need a set of green shells anyway if you were fitting new ones. So check them all with the new greens then see what clearances that gives you for each one and work out the correct shell colour for each one.

Using blacks is ok Ted BUT I'd normally only recommend it when all the crank markings are not visible and you can't work out the correct shell.  Last time I counted them I had 58 or 59 black main shells and 30 or so conrod ones. Plus a load of yellows and some greens and some browns.
Title: Re: Crank not rotating
Post by: alexdecker on May 11, 2022, 08:26:15 PM
Yellow are hard to find. Green would be ok to use, especially as you'd need a set of green shells anyway if you were fitting new ones. So check them all with the new greens then see what clearances that gives you for each one and work out the correct shell colour for each one.

Using blacks is ok Ted BUT I'd normally only recommend it when all the crank markings are not visible and you can't work out the correct shell.  Last time I counted them I had 58 or 59 black main shells and 30 or so conrod ones. Plus a load of yellows and some greens and some browns.

So I should basically buy black shells of you and not CMS? 😉

On a serious note though, thank you for the advice. My big end shells are mostly brown, and then one pair of green. Should I buy a pair of brown shells for testing the big ends, or also a green? Do one always go for the biggest size possible for testing?
Title: Re: Crank not rotating
Post by: Oddjob on May 11, 2022, 09:33:46 PM
Go for the smallest size you expect to use, as you don’t have any yellows use green.

CMS don’t have any black shells left, they had some a year ago but they’ve clearly sold them all now
Title: Re: Crank not rotating
Post by: alexdecker on June 04, 2022, 01:51:42 PM
Ok, finally got the measurements of this thing. I ended up buying a set of new green bearings to test the crank wearing with.

My crank case is BCBCB, and these are the measurements I got with plastigauge:
1: .0016
2: .0015
3: .0013
4: .0016
5: .0015

Did the same with my rod bearings (fresh pair of green shells). Got these measurements:
1: .0014
2: .0014
3: .0017
4: .0015

Now - the math is getting a bit lost on me. Can anybody help me figure out, what size shells would be the best for my particular crank case, based of above measurements?

- Alex
Title: Re: Crank not rotating
Post by: Oddjob on June 04, 2022, 02:31:14 PM
Alex the standard measurements are between 0.00079 and 0.00181 for both crank and rods.

A couple are close to the max 0.0018 but are still within range, just.

According to my calculations the difference between each shell colour is roughly 0.0004.

So crank 1 is .0016, if you fitted a brown in there it would be .0012 and with a black .0008. So black would be right on the edge of giving a minimum clearance so I'd go with brown in that journal although black would probably mean within range much longer.

No2, brown again

No3, I'd leave green.

No4, brown, again you could consider black

No5, brown.

Rods.

No 1, Green are ok.

No2, green

No3, Brown or even black. Black would give 0.0009 which is tightish but acceptable.

No4, Brown.
Title: Re: Crank not rotating
Post by: alexdecker on June 04, 2022, 03:22:43 PM
Alex the standard measurements are between 0.00079 and 0.00181 for both crank and rods.

A couple are close to the max 0.0018 but are still within range, just.

According to my calculations the difference between each shell colour is roughly 0.0004.

So crank 1 is .0016, if you fitted a brown in there it would be .0012 and with a black .0008. So black would be right on the edge of giving a minimum clearance so I'd go with brown in that journal although black would probably mean within range much longer.

No2, brown again

No3, I'd leave green.

No4, brown, again you could consider black

No5, brown.

Rods.

No 1, Green are ok.

No2, green

No3, Brown or even black. Black would give 0.0009 which is tightish but acceptable.

No4, Brown.

What an absolutely magnificant explanation and answer, thank you!

Had to tighten and untighten the screws quite a few times to make this measurements. I stayed within the torque spec of the crank case though. Can threads "tire" if you do that and loosen up, or should I stop trying to see problems where there are none?
Title: Re: Crank not rotating
Post by: Oddjob on June 04, 2022, 06:25:38 PM
As long as you trust you measuring skills I'd just accept that result.

The threads should be ok, they are designed to be undone etc as they are not stretch bolts.
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