Sticky crankshaft

[christophe]

Hi folks,

I'm currently reassembling my OHV 6. My crankshaft has been redone (- 0.020) and, of course, I have new bearings. It's been plastigauged and all the clearances are OK.
Nevertheless, after tightening the main bearings caps to the prescribed torque, it's not easy to turn the crankshaft. It's very sticky, and I have to take a bar across the flywheel to make it turn. On the other hand, there is no stiff points.
I'm a bit confused. It's not by far the first engine I overhaul, but it's the first time I encounter this.
Sorry to bother you about this, but I'd prefer to get your advices before going on and making a possible mistake.

[Kdancy]

I am finishing up a flathead six that I had to rebuild a rebuilt engine due to very low oil pressure. When I started torquing the crankshaft down, I noticed the same thing -- the crankshaft would get hard to turn. I wound up having to have it (the bearing bores) align honed so the crank set in the main caps in a straight line. Here is a picture of one of the main cap bearings when I pulled them back out, notice the shiny areas where the crank was making contact like the bearing is cocked.

After the align hone, the clearances are fine and the crank turns as it should.

http://s294.photobucket.com/albums/mm97/studebaker2/1955%20Champion%20Sedan/Champion%206%20rebuild/

Tally George advised me that Champions had weak main bearing caps, also be sure to check your cap bolts to make sure they are straight.

[DEEPNHOCK]

Great pictures.
Nice work.
And a good treatise on the proper 'step by step' assembly routine.
When you do that one step that you see/feel/smell something wrong... Stop!
Easier to find out then, than run it and mangle it.
To add....
I was taught in my youth to always:
Run a small, fine flat file to dress all machined surfaces.
To de-burr all edges.
To chase all threads and de-burr all bolt holes.
I even chamfer (de-burr) the entry edge of the cam bearing bores.
(Scraped a cam bearing bad one time... It looked like it went in OK, but there was a curly metal shaving hanging off the edge of the bore)
Out the cam bearing came, and there was a line gouged out of it.
Had to buy a set to get one bearing (Grrr)
Chris.... Good advice Kdancy is giving here... Check now...
Thanks for sharing your experience.
It's a good one!
Hang in there...You'll get it!
Jeff

[jclary]

This reminds me of why I could never make a living doing mechanical work. Although I have done some extensive and very complicated work...I could never work fast enough to do it for a living. Have you ever watched a career mechanic tear into an engine, throwing all the parts into a solvent vat? Stripping a block, doing all the work, dumping all the parts on a table, and re-assemble the parts in short order?

I could never do that. I usually meticulously remove each bolt and part, lay them out in a manner that I can re-assemble them in exactly the same manner as they were removed. When I am done, I want every bearing cap, every rod cap, mated back to the same position it was in when removed. I even try to see that each bolt is in the same hole it came off of and each nut and washer is on the same bolt. I have a flat head six in the man cave I disassembled 22 years ago. The parts are in wooden boxes I built specifically to keep them organized in the way they were to be re-assembled. Then I found a complete new engine and never rebuilt the one resting in silent repose in a gazillion (but orderly) pieces.

I have always been leery of the guys that would fly into an engine with reckless abandon, but usually amazed when it worked out OK. You are wise to proceed with caution. If that crank is binding up with the mains torqued down and no rods attached...then I would definitely do some extensive checking and look into the "line" bore or honing as has been suggested.

[starliner62]

Excellent thread. It Is really amazing how a tiny variance will make such a big difference. I currently have a 289 torn apart and the crank looked like new. The same goes for a McKinnon 283 that belongs to Joe Roberts I have torn all to pieces. The crank looked perfect and measured nice and round. The tolerances were perfect on both crankshafts. I was really tickled with the condition of the cranks, knowing that they would polish nicely. Now for the weird stuff. The large end of the rods on the 283 were stretched, requiring reconditioning for all rods. The 289 Stude rods were perfect. I guess that's why Stude chose forged rods.
Last weekend while I was working on these engines, I stopped to help the owner of the shop assemble a couple of short blocks. One six cylinder ford which went well and a four cylinder Chevy S-10 engine that had spun a rod bearing. Its funny how excessive heat affects engine parts. We laid the crank in place on the block and started to install the caps. As we installed the third cap, I noticed that the crank "grabbed" my hand and locked up. After some measuring, we discovered the third rod cap had shrunk a little more than one thousandth of an inch. Now it's time to align bore the block. You wouldn't think that the heat from a spun rod bearing would transfer over to a crank journal that looked fine.
John, I'll tear an engine down and throw everything in a box in little time. I never get in a hurry when assembling one.

[christophe]

Thank you very much for your replies.
Kdancy, my bearings look exactly like yours. It's exactly the same problem. Presenting the caps on the block, I've noticed that one side of the cap was not relying on it till the tightening was applied. Retrospectively, this should have alert me. I've already phoned to my machine shop and will bring back the engine next week.
I'm still wondering about two points: Can I still use my bearings with the shiny areas or shall I order a new set ? To avoid overtightening the bolts, wouldn't it be better not to lubricate the head of the bolt and the washer as usually?
John, I know how you feel. I'm exactly the same. I couldn't make a living of that too. Nobody would pay a hundred hours for overhauling an engine and I don't tell about the gearboxes! Ultimately, I think that this OHV will be dismantled two or three times before I get it back in the car. That's the most important of the job anyway. A handyman cures the effects while a mechanic cures the causes. If possible, I intend to be a good mechanic.
Thanks again to all and have a nice day.

[PackardV8]

FWIW, we now line hone all our blocks. It is immediately apparent upon assembly. The crank always spins much easier in a line honed block.

Hint: If you haven't already done so, before line honing, run a thread-chasing tap down each of the bolt holes in your block - mains, heads and all the small holes.

I'm still wondering about two points: Can I still use my bearings with the shiny areas or shall I order a new set ?

Yes, you should be able to reuse those bearings.

To avoid overtightening the bolts, wouldn't it be better not to lubricate the head of the bolt and the washer as usually

Torque specs are for lubricated threads. The race hardware folks, ARP, provide a special lubricant so their threads will have exactly the right conditions for their torque specs. The rest of us just use engine oil on stock Stude engine.

jack vines

[Ron Dame]

Excellent thread. It Is really amazing how a tiny variance will make such a big difference. I currently have a 289 torn apart and the crank looked like new. The same goes for a McKinnon 283 that belongs to Joe Roberts I have torn all to pieces. The crank looked perfect and measured nice and round. The tolerances were perfect on both crankshafts. I was really tickled with the condition of the cranks, knowing that they would polish nicely. Now for the weird stuff. The large end of the rods on the 283 were stretched, requiring reconditioning for all rods. The 289 Stude rods were perfect. I guess that's why Stude chose forged rods.
Last weekend while I was working on these engines, I stopped to help the owner of the shop assemble a couple of short blocks. One six cylinder ford which went well and a four cylinder Chevy S-10 engine that had spun a rod bearing. Its funny how excessive heat affects engine parts. We laid the crank in place on the block and started to install the caps. As we installed the third cap, I noticed that the crank "grabbed" my hand and locked up. After some measuring, we discovered the third rod cap had shrunk a little more than one thousandth of an inch. Now it's time to align bore the block. You wouldn't think that the heat from a spun rod bearing would transfer over to a crank journal that looked fine.
John, I'll tear an engine down and throw everything in a box in little time. I never get in a hurry when assembling one.

N ew delay on installation of the 185 OHV? I thought all I had was 'sticktion". It was hard to start the crank turning, but once moving, it was fine, very little to keep it moving...is that the same problem or not?

[PlainBrownR2]

Speaking of which, you guys are using assembly lube or engine oil on those bearing surfaces aren't you? That might account for part of the sticking if its dry, because that's metal to metal contact that's happening there. When I put the heads back together, I was quite liberal with the engine oil(rockers, rocker arms, push rods, head bolts, etc), not only for the lubrication properties, but it also prevented corrosion of bare metal engine parts.

[christophe]

Hi all and thanks again for your input guys.

About the pre-lubing of the crankshaft, after reading old posts, I decided to use, for the first time, assembly lube. It's hard to believe, but I've been unable to find it easily in France, unless in whole sale. (Okay, I'll get the ten pounds one if your give me enough engines and life to use it!) So, I ordered in Britain a product called Graphogen. When I first noticed the stickyness, I wiped it off and tried with oil. The result was exactly the same. In fact, tightening the caps make the bearings so close to the crankshaft that the lubricant is ejected.
Ron, I think that if you want to be on the safe side, you ought to check your sticktion too. If there is no traces on the bearings, everything must be OK.
I've found a little diagnosis guide that I will study today. Here's the link: http://www.mahleclevite.com/publications/CEB-1-1208.pdf
Thanks Jack for your tips. All the threads were thoroughly cleaned and I always test bolts, nuts ans screws before assembly for undesirable hard points.
My machine shop asked me about the size of the bores. I can't see this figure in the shop manual. Do you think, this could be found elsewhere?

Have a nice day.

[starliner62]

Remember that if the front cover and hub is installed with the rope seal, it will keep the the crank from turning as easy. This is especially true for engines that use rope seal for a rear crank seal. Thanks goodness that Studebaker did not use a rear rope seal.

[Kdancy]

Remember that if the front cover and hub is installed with the rope seal, it will keep the the crank from turning as easy. This is especially true for engines that use rope seal for a rear crank seal. Thanks goodness that Studebaker did not use a rear rope seal.

Jamie, the rope seal was not the issue. It was very apparent when torquing the crank caps.
Yes, I prelubed, excess lube is pushed out as you torque down.
Yes, I re-used the bearings, no damage done.

[Dan Timberlake]

Was this a running engine when you took it apart?
Before I had the block line-bored/honed I'd check to make sure the crank is straight, the main caps are in the right location, and in the right orientation. The bearing tangs generally go toward the same side on the block and caps, except on BMWs and airplanes. Just one reversed cap locks up a crank 10 times out of ten.

Crank straightness check - First I'd put the front and rear upper main bearing shells in the cleaned block bores, oil the bearing ID face, and lower the crank into position. The crank should turn freely. Then I'd use a dial indicator to check each journal for runout while turning the crank still supported in the lubricated front and rear shells. It probably should have less than 0.001 inch runout, but up to 0.005 inch TIR would probably be OK. My shop manual is 40 miles away, so I can;t check it tonite for the factory's recommendation.
I'd remove the crank and 2 shells, clean everything, put all the caps on, torqued, with the crank and bearings out. Then I'd feel for a lip or offset at each parting face. Shouldn't be one. Then I'd use a bore gage to check each bore for roundness, size, and taper at 12, 10:30 (just above the parting line), 9:30 (just below the parting line, 8:30, and 7:30. 15 measurements per bore. Page 2 0f the mahle clevite pdf has good tolerances to work to, although you usually can get away with a bit more. If the bores are good size and roundness, a "straight" crank should turn pretty free. "Fresh ground" does not really guarantee very much when it comes to crank quality, unfortunately.

Just for fun ask the crank shop to show you how they polished the crank. Polishing it the "wrong" direction reduces the bearing capacity significantly, something like 30%. Not all engines have enough extra capacity to throw away much away. The Clevite link devotes 2 pages to correct polishing.

Dan T

[Kdancy]

Was this a running engine when you took it apart?
Before I had the block line-bored/honed I'd check to make sure the crank is straight, the main caps are in the right location, and in the right orientation. The bearing tangs generally go toward the same side on the block and caps, except on BMWs and airplanes. Just one reversed cap locks up a crank 10 times out of ten.

Crank straightness check - First I'd put the front and rear upper main bearing shells in the cleaned block bores, oil the bearing ID face, and lower the crank into position. The crank should turn freely. Then I'd use a dial indicator to check each journal for runout while turning the crank still supported in the lubricated front and rear shells. It probably should have less than 0.001 inch runout, but up to 0.005 inch TIR would probably be OK. My shop manual is 40 miles away, so I can;t check it tonite for the factory's recommendation.
I'd remove the crank and 2 shells, clean everything, put all the caps on, torqued, with the crank and bearings out. Then I'd feel for a lip or offset at each parting face. Shouldn't be one. Then I'd use a bore gage to check each bore for roundness, size, and taper at 12, 10:30 (just above the parting line), 9:30 (just below the parting line, 8:30, and 7:30. 15 measurements per bore. Page 2 0f the mahle clevite pdf has good tolerances to work to, although you usually can get away with a bit more. If the bores are good size and roundness, a "straight" crank should turn pretty free. "Fresh ground" does not really guarantee very much when it comes to crank quality, unfortunately.

Just for fun ask the crank shop to show you how they polished the crank. Polishing it the "wrong" direction reduces the bearing capacity significantly, something like 30%. Not all engines have enough extra capacity to throw away much away. The Clevite link devotes 2 pages to correct polishing.
Dan T

Yes, it was running and ratteling --
low oil pressure from the start- was told "don't worry, all champions have low oil pressure" ?????
Pulled the pan, bearings shot. Less than 60 miles on engine. yada yada --
Crank was ground and triple checked --- not the issue
Main caps were marked prier to disassimbly and re-installed as marked.
I sent the block and crankshaft back to the grinder who double checked both before the line bore. He is a top notch crankshaft guy.
The original builders quote to me-
"It's a 50 year old Studebaker, not a Rolls Royce, just put it together and run it"
Would this make you a little suspicious of his build?

[Dan Timberlake]

Line boring and even honing moves the crank closer to cam. Timing chains get looser, gears get tighter. Cloyes used to sell timing sets for line-bored engines for some applications.

Gear backlash at a few crank positions is another thing to check during engine assembly.
One of the Northeast's "best" crank grinders of 1977 succeeded in inducing over 0.005" TIR of timing gear/sprocket radial runout on an exotic foreign engine crank. The finished mains ran very true. Yes the mains and rods had to be welded for one reason or another, maybe because only standard bearings were available. The crank was also surprisingly out of balance since all the masses had been kicked out of position by welding.