My seized up new rebuild

TNford

Member
So I was finally able to get around to taking my engine apart
again. No blown head gasket, no water in the cylinders, oil
pump worked, main bearings and journals looked fine, but 3 of
the 4 rod bearings/journals were all messed up. I did order the
right bearings after all as they are 1 over and that?s what the
machine shop has written on the crank. Going to take the
crank back in today to have them redo the rod journals. I
doubt they did it wrong the first time, but I guess it could
happen. Is there anything else that may have caused just the
rod bearings to be too tight? I did torque everything to spec
and did use assembly lube.
 
What do you mean? 1 over! 1 what. .001, .010 Have the machine shop furnish bearings for the crankshaft they just done for you!!!
 
TNFord,

Many, many years ago when I was a teen-aged "know-it-all", I rebuilt a six cylinder Chevrolet engine. I installed a reground crankshaft and matching rod and main bearings. The engine was seized when I was done. After much messing around and guidance from someone who knew what he was doing, it turned out that I had installed a couple of rod caps backwards from how they should have been installed.

You're probably smarter than I was, so you probably installed the rod caps properly, but it might be something to check.

Good luck with your rebuild.

Tom in TN
 
Bearings are undersized according to Ford, but they are in reality oversized to make up for the undersized crank. I think some vendors sell .001 bearings. Ford sells .003, or they did. I always use plastigauge to check, 1 step forward, 2 steps back if you dont check the work.
 
I hardly doubt I?m smarter than you at all, and while I don?t think I had the caps flipped I guess it?s possible. I kept everything in order, the same way with the same piston as I disassembled.
 
(quoted from post at 10:11:09 06/21/18) They ground the crank to one under, meaning I needed one over bearings.
ummmm.....I have a hole for a 1/2" bolt, but all I have is a 7/16" bolt, so I need to drill the hole a 1/16" larger. Make perfectly good sense.........to someone, I guess? :roll:
 
(quoted from post at 10:04:56 06/21/18) Bearings are undersized according to Ford, but they are in reality oversized to make up for the undersized crank. I think some vendors sell .001 bearings. Ford sells .003, or they did. I always use plastigauge to check, 1 step forward, 2 steps back if you dont check the work.

[b:696fa56cc3]NO, NO, NO[/b:696fa56cc3]. The crankshaft journal [b:696fa56cc3]OD[/b:696fa56cc3] is ground to an UNDERSIZE - e.g smaller diameter. That requires the [b:696fa56cc3]ID[/b:696fa56cc3] of the bearings to be a matching UNDERSIZE - e.g. smaller inner diameter. For example the ID of stock main bearings is 2.250. When the crankshaft is ground .010 undersize the ID of the matching .010 undersize bearings is 2.240 - .010 smaller than stock bearings. This is industry standard bore and shaft nomenclature that every machinist understands - trying to describe it otherwise is a recipe for confusion and potentially disastrous problems

TOH
 

I've never seen a crank ground .001 under, normally a good polishing will get you .001 under.
Most machine shops in this area will ether polish the crank or grind it .010 at a time depending on what needs done to make the journals smooth again.

I'm not sure what caused the issue but take the rods with you, if the bearings turned in the rods they'll need to be reconditioned for the bearings to fit properly.

Hope your machine shop knows how to grind the proper radius on the sides of the journals, mine doesn't grind cranks anymore and shipped it off to be ground, that shop ground the required .120-.140 radius down to a .040 radius which resulted in a broken crank that I just got done replacing.
 
One or more caps installed backwards would be my guess. Did you line the numbers up? Make sure you plastiguage the bearings on the next go around.
 
When you do your reassembly, do one rod at a time turning crank over several revolutions after each one. You then may be able to spot which is your problem. Were your rods checked for twist, bend, or out of round?
 
(quoted from post at 15:47:07 06/21/18)
(quoted from post at 10:04:56 06/21/18) Bearings are undersized according to Ford, but they are in reality oversized to make up for the undersized crank. I think some vendors sell .001 bearings. Ford sells .003, or they did. I always use plastigauge to check, 1 step forward, 2 steps back if you dont check the work.

[b:bcdd68712b]NO, NO, NO[/b:bcdd68712b]. The crankshaft journal [b:bcdd68712b]OD[/b:bcdd68712b] is ground to an UNDERSIZE - e.g smaller diameter. That requires the [b:bcdd68712b]ID[/b:bcdd68712b] of the bearings to be a matching UNDERSIZE - e.g. smaller inner diameter. For example the ID of stock main bearings is 2.250. When the crankshaft is ground .010 undersize the ID of the matching .010 undersize bearings is 2.240 - .010 smaller than stock bearings. This is industry standard bore and shaft nomenclature that every machinist understands - trying to describe it otherwise is a recipe for confusion and potentially disastrous problems
Wouldnt that be 2.260 Hokie ? If you cut something out you have to replace it with something thicker.
TOH
 
(quoted from post at 11:47:51 06/21/18)
(quoted from post at 15:47:07 06/21/18)
(quoted from post at 10:04:56 06/21/18) Bearings are undersized according to Ford, but they are in reality oversized to make up for the undersized crank. I think some vendors sell .001 bearings. Ford sells .003, or they did. I always use plastigauge to check, 1 step forward, 2 steps back if you dont check the work.

[b:d3ed9d0ad3]NO, NO, NO[/b:d3ed9d0ad3]. The crankshaft journal [b:d3ed9d0ad3]OD[/b:d3ed9d0ad3] is ground to an UNDERSIZE - e.g smaller diameter. That requires the [b:d3ed9d0ad3]ID[/b:d3ed9d0ad3] of the bearings to be a matching UNDERSIZE - e.g. smaller inner diameter. For example the ID of stock main bearings is 2.250. When the crankshaft is ground .010 undersize the ID of the matching .010 undersize bearings is 2.240 - .010 smaller than stock bearings. This is industry standard bore and shaft nomenclature that every machinist understands - trying to describe it otherwise is a recipe for confusion and potentially disastrous problems
Wouldnt that be 2.260 Hokie ? If you cut something out you have to replace it with something thicker.
TOH
/quote]RR, Sometimes you just have to wonder, "who ties your shoe laces?"
 
I?m not home, but this is the most logical conclusion. I will check them when I get home since I put them back on the rod same way I took them off. I fear I may have put them on backwards when installing. I know it was a very stupid thing to do.
 
(quoted from post at 11:47:51 06/21/18)
(quoted from post at 15:47:07 06/21/18)
(quoted from post at 10:04:56 06/21/18) Bearings are undersized according to Ford, but they are in reality oversized to make up for the undersized crank. I think some vendors sell .001 bearings. Ford sells .003, or they did. I always use plastigauge to check, 1 step forward, 2 steps back if you dont check the work.

[b:052db2e7b1]NO, NO, NO[/b:052db2e7b1]. The crankshaft journal [b:052db2e7b1]OD[/b:052db2e7b1] is ground to an UNDERSIZE - e.g smaller diameter. That requires the [b:052db2e7b1]ID[/b:052db2e7b1] of the bearings to be a matching UNDERSIZE - e.g. smaller inner diameter. For example the ID of stock main bearings is 2.250. When the crankshaft is ground .010 undersize the ID of the matching .010 undersize bearings is 2.240 - .010 smaller than stock bearings. This is industry standard bore and shaft nomenclature that every machinist understands - trying to describe it otherwise is a recipe for confusion and potentially disastrous problems

TOH
Wouldnt that be 2.260 Hokie ? If you cut something out you have to replace it with something thicker.

Your 2.260 measurement is incorrect. The OD of the crankshaft journal is being reduced by .010 and the bearing insert gets thicker by .005 per side to compensate for the material removed from the journal. That added thickness is applied to the inner radius of the bearing which reduces the ID to .010 under the stock dimension. So if a stock bearing is 2.250 on the ID then a .010 undersize bearing has an ID of 2.240. This is the sort of geometry/measurement problem that all budding machinists have to master.

TOH
 

Regardless of who does what, how and how much, the guy reading the plasti-gage is still in charge.
 
Well, I do get confused at times. Much learning is grievous. I went through my own engine redo and took some work to a machine shop. I think next time I'll take the whole engine to a shop and tell them I want everything to spec per the manual. I dont mind paying good money for good work. I prefer not to see something Ive labored over to come back to me while Im still kicking. I put engine shutoff controls on anything that I'm done with. Good luck with that engine, you might want to have the rods resized. Check your camshaft up and down movement at the hydraulic pump gear, I have only seen one where I could actually see it move up and down by prying on the gear with a screwdriver. I dont know if its the cam or the block thats worn. Theres always something learned by a mistake and you keep that with you, until you dont remember it.
 
(quoted from post at 11:11:14 06/21/18) I?m not home, but this is the most logical conclusion. I will check them when I get home since I put them back on the rod same way I took them off. I fear I may have put them on backwards when installing. I know it was a very stupid thing to do.


BE CAREFUL what you ask for, rr, in some situations, ordering a 0.001" OVERSIZE bearing would get you a bearing with a standard bore and the outside diameter 0.001" larger than standard to accommodate an "oversize" connecting rod bore!
 
(quoted from post at 14:34:16 06/21/18)
(quoted from post at 11:11:14 06/21/18) I?m not home, but this is the most logical conclusion. I will check them when I get home since I put them back on the rod same way I took them off. I fear I may have put them on backwards when installing. I know it was a very stupid thing to do.


BE CAREFUL what you ask for, rr, in some situations, ordering a 0.001" OVERSIZE bearing would get you a bearing with a standard bore and the outside diameter 0.001" larger than standard to accommodate an "oversize" connecting rod bore!

There should Never be a over size bore in a connecting rod! To resize/recondition a rod, it is cut at the parting line to make the bore smaller. So that reboring will clean a bad bore, from a bearing spinning, or for just making them exactly right. Then it set up on a fixture that holds it to get the bores in the exact right place. It is then bored to the correct bore size. If not, change your engine machine shop!

Pat
 
(quoted from post at 14:30:11 06/21/18)
(quoted from post at 14:34:16 06/21/18)
(quoted from post at 11:11:14 06/21/18) I?m not home, but this is the most logical conclusion. I will check them when I get home since I put them back on the rod same way I took them off. I fear I may have put them on backwards when installing. I know it was a very stupid thing to do.


BE CAREFUL what you ask for, rr, in some situations, ordering a 0.001" OVERSIZE bearing would get you a bearing with a standard bore and the outside diameter 0.001" larger than standard to accommodate an "oversize" connecting rod bore!

There should Never be a over size bore in a connecting rod! To resize/recondition a rod, it is cut at the parting line to make the bore smaller. So that reboring will clean a bad bore, from a bearing spinning, or for just making them exactly right. Then it set up on a fixture that holds it to get the bores in the exact right place. It is then bored to the correct bore size. If not, change your engine machine shop!

Pat

Agreed and I am 100% sure Bob knows that and more. But "oversize" bearings are not un-common fixes for spun camshaft and balance shaft bearings where the resizing operation creates a larger block bore.

TOH
 
Make sure when you get the crank back you clean the oil passages in the crank more than once I have found them full of grinder grit from the machine shop.
 
TNford, I hope you have good luck with the second attempt. Let us know how it turned out. Remember, Good judgement comes from experience, but a lot of that comes from bad judgement.
 
Thank you and that is so true! This is the second diesel rebuild I have done, and the first went ?perfectly? no problems at all. This time I made some critical errors (I?m sure no one else has done that) and am paying for it. At the same time, I?m NOT sure that I flipped the caps, but it is the most probable cause.
 
(quoted from post at 15:52:28 06/21/18) Thank you and that is so true! This is the second diesel rebuild I have done, and the first went ?perfectly? no problems at all. This time I made some critical errors (I?m sure no one else has done that) and am paying for it. At the same time, I?m NOT sure that I flipped the caps, but it is the most probable cause.

Nobody learns anything of significant complexity without making some mistakes. My very first engine overhaul (other than lawn mowers) was on an engine that had factory stamped main bearing caps and the OEM workshop manual had a very clear picture of how those stampings should be position during reassembly. Unfortunately the assembly line worker that stamped this particular engine decided to stamp half from the opposite side so the numbers were upside down wrt to block and cap. As a consequence I reversed ALL of the the caps and proceeded to torque the bolts. At mid torque the crankshaft would not turn and being a novice I theorized the caps were not yet squarely seated and I cranked up a bit more torque only to hear an ominous "crack" :oops: Disassembly revealed a crushed corner on the center main bearing and a crack through the web in the block. Fortunately I had a spare block so that particular "learning experience" wasn't as expensive as it could have been....

TOH
 
I am glad Roger in Iowa said what he said. When I started reading this thread, I too had never heard of any car or tractor part being ground .001" under, nor have I ever come across any new rod or main bearing advertised new as + ".001 to match it. My $.02 (grin).
 
(quoted from post at 19:08:22 06/21/18) I am glad Roger in Iowa said what he said. When I started reading this thread, I too had never heard of any car or tractor part being ground .001" under, nor have I ever come across any new rod or main bearing advertised new as + ".001 to match it. My $.02 (grin).

You don't have to look far to find .001 undersize rod bearings. Rod bearings for Ford 120, 134, and 172 CID tractor engines are readily available here on YT in both .001 and .002 undersizes. I didn't look at any other engines but I would not be surprised to find them.

The same is true for a lot of automotive applications. Commonly used by high performance engine builders between full builds and/or after polishing a crankshaft. You will also find .001 and .002 oversize bearings used to obtain additional oil clearance on a stock crankshaft.

Clevite/Mahle (and probably others) even manufacture bearings with .001 under upper and .001 over lower shells for use in SBC high performance engine applications that can benefit from the altered oil film characteristics they produce.

The Rodger Ramjets of the world do some crazy things with journal bearings.....

TOH
 
When I was a teenager a man brought in a 1959 Biscayne Chevy with 235 cid six to my dad's garage. He wanted a ring and valve job and we usually did a job like that in one day. When we got it back together that evening it sounded like a pea thrasher. We dug the old bearings out of the scrap bucket and the bearings were genuine GM bearings and they were stamped .009. We surmised the .009 bearings were used so a .010 bearing could be used when rebuilt allowing .001 wear.
I also pulled a Ford diesel apart that had .002 main bearings and it had never been apart since assembled at the factory. When I re-assembled it I put .002 mains back in it and bearing clearance was perfect.
Jim
 
(quoted from post at 22:08:48 06/21/18) That is true for machined split rods, but not fracture split.
Now that is a comment that I would expect from the guy who posts as "master of the obvious"! :)
 
Some where I have heard that Ford did not recommend turning the crank on the tractor engines. Also there is a fillet radius on each side of the crank journal that may not be right.
 

Ford offered bearing for these cranks ground to as much as .040 undersize.
If they didn't consider the cranks to be safe when ground that much I don't think they would have offered bearings in .010, .020, .030 and .040 undersizes.
The 65-up cranks have a .120-.140 fillet radius that must be keep, the machines shops can maintain this radius simply by dressing it into the sides of the grinding wheel before grinding the cranks journals.
The average car crank will only have a fillet radius of .040-.080 depending on the journal size.
If a machine shop mistakenly grinds one of these Ford tractors cranks with a smaller radius than .120-.140 the end result can be seen in the photo below.

18781.jpg


This crank was ground .010 under on the rod journals with the correct radius and ran for several years.
It was later reground .010 mains and .020 rods but with less than a .060 fillet radius, something I failed to notice while assembling the engine.
The broken crank was discovered at 340 engine hrs when the oil pan was removed to investigate a confirmed low oil pressure issue, the first indication of a possible problem was at less than 50 hrs but was thought to be sending unit issue at that time.

Grinding these cranks undersized will not cause a problem.
Grinding them incorrectly will.
 

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