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Man of endless projects
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Discussion Starter #1
ok i worked on my 88 all the way till 3 am tonight teying to get a bearing job done. spend hours trying to figuer out why the crankshaft wont turn when new bearings installed. the motor is a 351w form a 80 Lincon Continential and the main bearings i got were these and the rod bearings were these. i can have all the mains and rods only finger tight and a breaker bar can still hardly tuen the crank. yes i did use the apporpriate lube and lots of it on al lthe bearings. the notches are all in correct spots. when the front main bearing is somewut tight, the crank wont turn but if its loose, the timing chain is as tight as it can get but it will still spin somewut. im at wits end and tried to get this simple job done for 5 hours no with no sucsess. cant tell if its the mains or rod bearings causing it. any help will be good. im gonna try the old bearings tomarow and see wut they do
 

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Chillin on the Gulf Coast
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The bearings that you posted a link to are undersized bearings. The kind you use on a crankshaft that has been resurfaced by a machine shop. You also posted a 0.020" undersized main bearings and 0.010" undersized rod bearings. Not sure why you would have two different sizes, most shops turn both down to the same undersize. Has this crank been taken to a machine shop for resurfacing?
 

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LS Swap Everything!
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The bearings that you posted a link to are undersized bearings. The kind you use on a crankshaft that has been resurfaced by a machine shop. You also posted a 0.020" undersized main bearings and 0.010" undersized rod bearings. Not sure why you would have two different sizes, most shops turn both down to the same undersize. Has this crank been taken to a machine shop for resurfacing?
What this guy said. There in lies your problem. You've probably burred and gouged the surface of the crank by turning it the way you have.

Remove bearings, take block & crank to machine shop, get proper bearings for correct tolerances.
 

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Man of endless projects
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Discussion Starter #4
awww crap. i thought undersize would mean that it would be similar to bearings being .20 worn out from factory. but now i see that that mean the crank has be cut .20 jsut like boring the block. no i didnt get the crank resurfaced. when i made a thread before and thats the size ppl told me to get. the bearings are stil fine cause i couldnt get it to turn with any pressure on them and theres lots of lube. where could i get the crank resuefaced, at any machine shop? about how much does this cost? or should i just ger some stock\oversized bearings or new crank?
 

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aka: kemicalburns
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take the block to the machine shop and have them assemble the bottom end. honestly this will benefit you in the long run and ensure its put together properly.
 

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take the block to the machine shop and have them assemble the bottom end. honestly this will benefit you in the long run and ensure its put together properly.
If you have never assembled a bottom end before then I agree with ^^.
If you want to do it, buy a manual and follow it step by step and make sure you do the Plastigauge part of the process.
 

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You could have bought bearings that were .001 oversized to make up for a used crank. Just watch for the decimal point it makes a big difference. At this point just go buy the correct bearings and cross your fingers.

WAIT, I just re-read your post. You said you cant tell if its the rod or mains but you have everthing finger tight. You need take it back apart and get some reference materials to build this engine. I cant see how you got to installing rod bearings and you haven't torqued the mains down and checked the end play of the crank? If it didn't spin then you know you have a problem. Rods and pistons should be over bench, not in the engine at this point.
 

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Man of endless projects
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Discussion Starter #8
i never pulled the pistions out. i left them in the engine while it was upside down, its definitly that both sets of bearings are for a ground down crank. the reason i couldnt tell is that after fidling with this problem for 3 hours, i had the mains caps off and jsut the rods connected and it still wouldnt spin. this all seams very easy to do if the bearings were the right ones. the main caps are numbered and have arrows, the rod caps have the notch to face it correctly, i got the haines manual for torque specs. all i was doing were the bearings, timing chain, and oil pump and now i have a big mess. the only machine shop around here wants 170$ to do my crank but i can jsut get a crankshaft kit for 165$ and it inclueds bearings. im starting to say ill jsut get another set of bearings and hope the crank is good enough cause it doesnt look like there any deep grouves

EDIT: i htink im jsut gonna go down to NAPA and order some cheap 0.001 bearings. id love to use the bearings i got but i guess ill save them. idk y im puring soo much money into an engine that could end up completly trashed on the 1st time mudding....
 

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Chillin on the Gulf Coast
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I just got a couple quotes on machine work and the shop I use wanted $65 to hot tank and repolish my crank, $65 to put on new pistons and recenter the rods, and $65 to hot tank my heads and install ARP rod bolts. So a bit over $200 with tax and that is for quite a bit more work. When they turned my last crank, hot tanked it, polished and camfured the oil holes it ran less than $200
 

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I have done what you are doing, to a 400 special that had low oil pressure. I used standard sized bearings and a high volume oil pump. It was successful, I guess, as it is still running after quite a few years, but the oil pressure was not as good as I expected. If I could have had a crank kit with bearings for $165, I would have grabbed it. I would suggest that you might want to do the same. That would give you an essentially new lower end. Once you have the engine out and rolled over, you might as well do the job right, in my opinion.
 

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dude with something like this its best to let the pros handle this, especially if u have no one with experience to help u. also there usually a stamped in # on the back side of the baering that will reference the bearing size u need in order to replace. This in my opinion is usually a band aid repair, cause if u go that far u might as well freshen up everything.
 

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Man of endless projects
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Discussion Starter #12
well im practiclyh broke right now. didnt even have a paycheck this week cause i had 0 hours of work. im sick of throwing money into this engine and truck and not see it useable yet. i got the NAPA bearings, 80$ for all of them and theyll be in tomarrow morning. but he engine has lots of power and compression even for an 79s motor (it sat for like 12 years). i originally got this motor as a get it running and drop in and tear it up motor with a 500$ totoal limit. now im on like 1000+ and i just want it together and to use it. why put soo much money into a motor thats gonna go underwater on a regualr basis, be mudding in the red limit, and jsut upwards beatin to a pulp. im jsut doing the bearings jsut so i can do this abit longer than my old motor. thats like buying a nice crate motor and taking a hammer to it jsut for the funn of it. all of the bearings i had were all the same anwyas minus the (middle mains). no numbers, all had same stampings and were identical. i jsut made the stupid mistake of not thinking of that i have to get the crank work done to make them fit cause i htought 'undersized' meant something different and someone told me to get those size bearings some reason. i just getting stock bearings now cause they didnt have any of the .001s and im jsut gonna put it together and hope for the best. if soemthing brakes, then o well idc and i learned something from it. even if these bearings are alittle loose still, i got a high flow oil pump to make up for it and i can always use 60w oil
 

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OK folks; ten years in an automotive machine shop allows me to say:
Those bearings that are advertised as "undersized" are incorrect. "Undersized" bearings would be for an "oversized" crankshaft. Huh? They dont make crankshafts "oversized". When crankshafts are "turned" they are turned to an "undersize" and the corresponding bearing is "oversized" the same amount to account for that.
So, what we have here is someone trying to stuff .010 and .020 (ten and twenty thousandths of an inch) OVERSIZED bearings into main and rod caps with a crankshaft that is still STANDARD size (minus a little wear). Never gonna work. Credit for trying though!!!!!!
To the OP: Please,please,please......I know you say you are out of money for this; but this is something that CANNOT be done incorrectly!!!!!! Please, save up some money and get this done right......or look up how to use plastigage or a micrometer and measure this crankshaft correctly before going any further.
"learning by doing" is a wonderful thing, but only when the right things are done.
If my post sounds like I am being a jerk, please accept my apology now. I do not mean it to sound that way. I just hate to see people spend money on the wrong stuff because they listened to the wrong info.
Please......do some more research before proceeding.
 

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x.2 were here to help u and the bottom end of a motor is something u just dont play around with also did u put the main caps/ rod caps back on there original one they came off of cause that also makes a difference. dude no one here is trying to bash on u or anything were here to help u, also if ur gonna do this urself still get plastigauge. Itll help u determine if ur tolerences are to tight or loose very simple to use and I use it on every engine build ive done (only one) but in school I built like 3-4.
 

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Man of endless projects
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Discussion Starter #16
ight ill get a set of them (or 2 jsut incase) and ill do some research. i dont blame any of u and ur not sounding like jerks, i jsut hate buying 120$ worth of bearings, spend 5+ hours trying to figuer this out and then still have to end up using another 80$ of cheap bearings. when i think under/oversized bearings for a crank, i think of bearings having that much extra clearence which in my mind would allows less wear and less friction. now i know. porject i know exactly what ur saying cause i was thinknig the bearings i was getting were gonna be .02 and .01 more clearence which goes with what i was saying before about leff wear and friction. the only bearings i can truely see called 'oversized' were some raceing bearings that were .001 bigger.
 

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So, this is all great advice. I just finished rebuilding the first motor I've ever done by my self. I know there are a few tricks I've left out (like the plasti-gauge, & using a micrometer on the crankshaft).
Mine also is meant to be a sort-of throwaway motor. Just practicing for building the motor I actually want to keep. So, just have fun with this one, learn a few lessons, and be glad it isn't a $5k plus race motor you're learning on.
 

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Man of endless projects
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Discussion Starter #18
didn't expect to see this thread to be revived. rereading all this makes me look like such a newb compared to now. I did end up getting that engine running great.....for about 30 minutes. it eventually threw a rod because the engine had soo much sludge in everything that there wasn't oil flow to the upper engine and to one of the rods. the engine apparently sat 12 years before I bought it I later found out and the oil turned to rock hard sludge

also its funny cause I just finished rebuilding another 351 for that truck tonight. gonna try and drop it in tomorrow. on this rebuild I decided to buy a reman crankshaft. its just a stock crank that's been machined already and includes matching set of main and rod bearings. 230$ and u have a perfect looking crank that's ground .010/.010 with bearings. soo much easier than going to a machine shop
 
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