Crank/Pistons Lock up.. Help- Im building

Notched

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Apr 1, 2004
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well im building my motor from scratch, have some knowledge and know most of what im doing
i put the crank in and torqued down the main caps.... put the pistons in, with the rod caps... and didn't torque them down untill they were all in


when last piston was in, it rotated fine with some effort....... now i torqued down the first 2 rod caps to 22 ft/lbs (NOT 24 LIKE I SHOULd, Im Stepping up the torque from smaller to the final amount)......

At 22 ft/lbs... it wont move. i can't get the crank and pistons to spin... with only the 1st 2 rods torqued down... i got brand new bearins, and oiled all the bearing that touch the crank..

help please!!!!!
 
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ok something like this happened to me when i built the motor in my sig. somebody told me that the main thrust bearing goes on the first main cap like a chevy, maybe the last. either one was wrong. anyway, that put the whole assembly out of allignment and i could not turn the motor over without a breakover bar. i called my machine shop and he said that the thrust bearing goes on #3 main cap. so i took every bearing back off and had to replace them as well as get my crank turned.
 
Notched said:
i got brand new bearins, and oiled all the bearing that touch the crank..

help please!!!!!

You did everything fine for the assembly, what are you using for lube? did you lube all the right areas? did you check you main cap tolerances? connecting rod to crank tolerances?
 
Make sure you didnt get your rod caps mixed up and put them on different rods. This will make a difference in most cases. Also, the deeper groove on the side of the rod goes against the crank counter weight....for better oil control.
 
CHECK ALL CLEARENCES!!!!!! Never skip that step, if you don't it will get you in the long run. Check what Mizark347 said as well. I know people that have put the rod cap on facing the wrong way and it causes binding and next to nothing for oil control. Never mix them up either.... both rod and main caps.
 
Definitly check all the tolerances,, main and rod bearings, rod side clearance, thrust, etc.... all are very important and should not be skipped. I'd use a good assembly lube on the bearings and surfaces to ensure good protection while you are assembling.

Are you use file to fit rings?
 
3rd vote for checking clearances. Especially (but not limited to) bearing clearances (main & rod journals) & connecting rod side clearances.

Did you have the block align honed? If not, it's possible that you've torqued the crank into a slight bind that doesn't show up until some of the rods are torqued at the outer radius of the crank. If it is in a bind it it might not be enough to affect it with no rods in. But the further away from the centerline you go, the more it'll show up.
 
Definately check your clearances. Measure everything. I just built up a brand new block and found that the mains were not equal from one side of the main to the other. Endedn up needing a line hone to stop it from siezing up with the coated bearings.

-Craig
 
well heres the thing. when i toko the motor apart, i kept everything in order so when i was putting them back, it shoulod all be right... now im a frosh in college, so ur gunna have to help me out with where to measure the cleareance, and how do i measdure the tolerance of them? im sorry, what u guys are suggesting is new to me, and i think i might need new rod bearings also since those might of been over torqued (bought a autozone torque wrench due to limited money)

thanks for the help, and if u could expalin what u are all talking about that would be even better

thanks ~ will
 
There are a few too many factors that we don't know to give you all the proper specs. We can give you general information, but you need specifics. Some of the things we don't know: What kind of machine work was done to the block in preparation for rebuild? What kind of parts are we building with- stock, cheap aftermarket or quality race parts? If stock rods, were they reconditioned? Was the factory crank ground & polished? What kind of bearings are you using? What application will this motor be used for: N/A, nitrous, boost, daily driver? How many rpms will this motor need to turn: 5500, 6250, 7500?

Some precision measuring tools that you will need: bore micrometer, outside micrometer, feeler guages & a rod vise.

I'd recommend investing in a few books. No matter what you read on internet forums, it's always nice to have it in print when you go to do the work.

I'd suggest these 2 for starters: How to Rebuild Small Block Fords & the Engine Builder's Handbook. both of these are published by HP Books.

I'll try to get you started. Clean the backside of all your bearings with some 2+2. Assemble the rod bearings in the rods w/caps fingertight. Hold the rods with the rod vise and torque the caps. Remove the rods from the vice and measure the inside diameter of the bearings using the bore mic. Take measurements at 3-4 different spots around the bearing. Do this at each edge and around the center to verify that the bearing is 'true'. Write down your measurement for each rod.
Now using your outside mic, measure the rod journals on the crankshaft. Again, measuring at each edge and the center, 3-4 different spots around the journal. Write down these measurements. It'll help if you keep your rod measurements in order and then you can put the journal measurements write down along side. The difference in the diameter of the rod bearings and the rod journals is your clearance. I don't know what the specs are for what you're building. Probably somewhere in the range of .003"-.006".

You can use the same process for clearancing the main bearings. And the specs for those should be about the same. They could be more, but the most likely will not be less than .003" unless you're building a serious performance motor.

I know you're on a tight budget, but those books I mentioned will be invaluable to you now & in the future. Both of these books are available from Summit: Book 1 & Book 2 or checkout your local bookstore.

BTW, where are you located?

Please forgive me for any technical inaccuracies, it's 4:00am and I still have 3 more hours to go.
 
Make sure on the big end of the connecting rod that the tapered side faces outward from crank journal (toward the counterweight). If the pistons are installed backwards on the rods the flat side will fall on the slightly raised portion at the outside of the journal and could lock it up.
 
well thanks guys, im going to get those 2 books, and borrow a few of the tools from some friends.

also about the locking up cause of the journals... i think that might be it.. i just took some caps off, and noticed that metal has beenshaved off in a line around the rod bearing.. so i need to replace those.


i looked at the rod cap... by taper, u mean, the side that is angled out (and has more room on the side of the bearing??)



Oh, and this motor will be used for daily driver untill i purchase a stroker kit... the bearings are federal morgul. new arp studs for the main rods.


I live in Greenwich C.T.
 
Go out and get some good assembly lube and use it liberally on the bearings, most auto parts sell it, Clevitte bearing guard, Holley, ARP, Redline, etc... this will keep the bearings from getting scratched. Also make sure everything is very clean before installation.
 
ok well with the taper facing out, there was a groove in the bearing.. should i have the taper facing in?

also i didn't know u could use assembly lube between the bearing and crank...thanks ill do that

anyone here think i should just save up, by the stroker kit so everything fits and matches, instead of guesing?

thanks
 
ok.. thanks soooo much guys... i look at the rods, and i got scratches on the bearings, and some of them had the taper facing in


tell me im an idiot, but also..... i think i may have made a grove on the rod, and rod cap.. cause i torqued some, and rotated (some were facing wrong way)

some of the caps, and rods have a grove on the wrong side becuase of my mistake.. do i need new rods or will it be ok if i just switch them, and get new bearings? thanks again.. so much.. if i could pay u all for ur help i would, cept i start my job in a week, and have no money right now


THANK YOU

~Will
 
Personally, I think you should stop where you are. Don't buy anymore parts or borrow any tools.

Then you should buy the 2 books, wait for them to arrive, read them cover to cover (at least once, more if necessary). And then go back to square one and restart your project with your improved knowledge, making educated decisions instead of using magazine guesswork. JMO.

I think you're only about 2-1/2 hrs from me. If I had more free time on my hands, I'd be willing to come up and lend a hand and probably some tools. But as it is, I've got my own ongoing project that I can't seem to keep up with.
 
Will if you didn't take the pistons off the rods then you alos had them facing the wrong way with the rod turned around.

Most local machine shoips would charge less then $300 to assemble that complete shortblock for you...