Crawforj

Rebuilding my engine, and when i torque the rods done to spec the crank wont turn.

I put a kit into it, its a new crank with bearing to match it and Ive also put new moly piston rings on it. Its a 305. In order to torque ALL the rods down to spec, i have to turn the crank but after i torque a few past hand tight it doesnt turn? Is this normal or a problem?

Ward

iTrader: (1)

Have you checked the bearing clearances? I assume you're using assembly lube, right? Also, are you turning the crank with a wrench, or just with your hand?

Crawforj

Well, funny story... Using a wrench broke the harmonic balancer bolt, so now im using the flywheel.

But what am i looking to check with bearing clearances? And yes, a very liberal amount of assembly lube was used... I guess its bearing grease though, thats what the bottle says.

sofakingdom

iTrader: (1)

Does it turn with only ONE rod on each pin?

Try putting in ONE rod, say, #1. If it turns, put in #3. If it's still good, put in #5, then #7. THen go back and start on #2. Keep going until it locks up. If #2 locks it up, try #4. If #4 locks it up, then read on.

Make sure all the rods and pistons are assembled correctly; if you lay them on the table with the "front" mark on the pistons UP, there should be 4 of them with the bearing tangs to the right, and 4 with the bearing tangs to the left. The 4 with the tangs to the right should go in the odd-numbered cyls, and to the left the even ones.

Getting that wrong, will lock a motor up solid.

Buy yourself a crank turning tool. They're cheap, and worth every penny.

A complete, fully assembled short block, should take around 25-35 ft-lbs to turn. If it takes any more than that, STOP and see what's wrong.

You need a mic and a snap gauge, or a set of calipers, to check bearing clearances. If you bought this as a "kit", I'd look at other things first, before spending a bunch of time and effort on that. Especially if you can put ONE rod in and it still turns.

Crawforj

Thank you, thats exactly what i did. I mixed up the pistons when i was cleaning them! Haha... Thank you a ton!

Crawforj

Well, i have the pistons in right now, and they are torqued to 45lbs, in correctly the way you described and the caps are on right i believe... According to everything i can find its in right. But the crank once again wont turn, it turned fine the first four, then once i had 6 in it got harder and after all 8 were in and torqued it wouldnt move.

Im stumped, what could be the problem here? It was a kit from a reputable engine parts center, so i doubt anything is wrong with the bearings and crank. So what could it be??

sofakingdom

iTrader: (1)

Exactly what bearings are they, and exactly what machine work has been done to the crank?

Are all the rods and pistons oriented such that the bearing tangs face away from the cam?

Any possibility you have a couple of rod caps interchanged?

How much side clearance do the rods have? Do they slide freely from side to side on their journals, when there's 2 of them on a journal? They should be very very easy to move along the journal, should require no more than an ounce or 2 of force to slide them.

Cranks with a large radius fillet at the ends of the rod journals often require bearings with a chamfer. Many high-perf bearings are not symmetrical; that is, they have a chamfer on the side that's supposed to face the crank, but none (as wide as possible) on the side facing the other rod.

Crawforj

Facing away from the cam? Not sure what you mean...

But, the crank is a reconditioned crank, i think it was miced 10 over and the bearings come with it to match the machine work done to the crank. Clevite is the brand i believe. Its just stock style bearings.

Will the caps matter as long as they are on the correct way?

ALSO, i reinvestigated the situation and 4 of the bearings are scarred. So perhaps something got trapped under them and i didnt notice, or i couldve nicked the crank with the rod threads putting it in or taking it out, except the crank is smooth and looks fine. Then again turning the crank like i was doing mightve smoothed any small nicks out at the cost of the bearings.

I isolated the issue to two bearings. One simply made it difficult to turn and the other stopped it entirely(this bearing had the worst scarring.) But both were scarred. Will bearing scarring effect the crank turning even if the crank is fine?

jamon8

iTrader: (3)

Will the caps matter as long as they are on the correct way?

are you serious

I think that even the smartest person on earth should at least have to browse through a book before taking on any engine that is new to them

you could have saved yourself alot of time and effort if you would have sat down for about a half an hour to read

if you did not mark the caps 123......ect when removing the pistons and keep the caps with the rods then you are sol.

oh yeah 1000th post and I am still complaining

the way the cap is placed on the rod is very important but seeing that is basic common sense

if you have it on backwards it will not line up

sofakingdom

iTrader: (1)

Look at the rods once they're in the motor. One side of all 8 of them is "up", one side is "down". Facing the cam and the oil pan, respectively. The side of all 8 rods with the bearing tangs should be away from the cam, toward the oil pan.Yes of course they will. They are all DIFFERENT. They are machined together with their rod as a matched assembly. Make sure you get them all put back on their correct rods. You can usually tell pretty easily; putting the wrong cap on a rod will cause the 2 halves not to line up, and/or not to form a perfectly circular hole.

Crawforj

Wow I may be in trouble then, kept track of the caps but not the rods. But they seem to all match up flush around the crank, are you positive the caps cant switch rods?

sofakingdom

iTrader: (1)

Yup, pretty much... all it takes is a mismatch of .002" to lock it up solid....Whaddya think? See my signature for a helpful hint.

RBob

iTrader: (1)

Not putting something over the rod bolts will have the crank nicked. Check it carefully. The high spots can be gently removed with a fine needle file or fine stone.

Get a foot long or so piece of 3/8" fuel hose, the rubber stuff. Can even be an old used piece. Before sliding the rod & piston into the bore put the hose on the lower bolt and then slide the piston & rod into the bore. Now take the other end of the hose and loop it around the crank journal and onto the other bolt.

As the rings/piston are pushed into the bore the rubber hose aligns the rod to the crank. No nicks and it slides together easily.

RBob.

Crawforj

Well, i took a gamble and guessed.. Crank turns with 28-30lbs of torque. Or are we talking it locking up in the car?

sofakingdom

iTrader: (1)

Who knows...

All you can do, is put it in and find out. Might be fine, might blow up in 100 miles. No way for anybody to predict. It's a good sign that it turns, of course, and that the torque is in the range that passes the smell test; but as far as being able to guarantee anything, it's a long way from that.

A lesson learned for "next time". Hopefully "next time" won't come around too terribly soon.

onfire

Crawforj,


Also check your main caps are not mismatched. This too will cause your engine to seize. Next time, have your machine shop or when you tore down the engine, number punch your rods with your caps and your mains. Post what you found.


Rabi C.

Crawforj

Thanks guys for all your help and youre absolutely right, lesson learned

Engines in the car now and my books way of adjusting the valves was bogus so im doing that now, so hopefully i can tell you soon how the guessing worked out.

Red Devil

Wow.

...


Wow.

Didn't even use plastiguage?

Seriously, when you have to pull it out to freshen it up again, come on here and ask first then do. And get yourself a book or two, it'll save you a ton of headaches.

lukn4trbl

If this hasn't been solved yet, I'll bet my last cookie you have one or more
pistons with incorrect forward orientation.

Check that the rod end (big end) has the chamfer facing the crank fillet.

Crawforj

Engines in, but the starter wont spin the engine freely and theres a squeaking at the harmonic balancer. When the battery is fully charrged it turns it freely for a good 5-10 seconds then starts binding at a certain point and the battery drains quick.

Is this the result of my bearing cap foul up?
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Not that it WONT turn, it just turns slowly. Then spins fast again and slow again.

lukn4trbl

Were you able to determine whether the big end of the connecting rod
was facing the correct way against the crank fillet?

When the engine was out, were you able to turn the crank by hand after all
caps and mains were torqued down?

Do you recall the main and rod clearances?

sofakingdom

iTrader: (1)

Possibly.

Are you positive that you got all the rods and pistons oriented as I described in my first reply? Are all the bearing tang sides of the rods facing toward the oil pan and away from the cam?

Rod bearings are not symmetrical. They have a chamfer or bevel or sometimes even are just made narrower on one side, and extend amost all the way to the edge of the rod on the other. The chamfer is put there to clear the radiused fillet on the rod journal of the crank. When the engine is assembled correctly, the 2 chamfered edges are to the outside of the rod pair, and the other wider edges are toward the center, next to the other rod. If one is in backwards, then the non-chamfered side of the bearing will ride up onto the fillet, and bind.

If you have rod caps mismatched to rods, then the rods and caps won't align properly. Often the big hole in there won't be round. It might be oval, it might be half off to one side. The rod caps might not line up along the sides with the rods; the cap can sit kind of off to the side, and make the whole assembly thicker than it should be. Obviously if this happens there will be 2 of them that are off.

You said that it required 28-30 ft-lbs to turn the crank. Was that after ll 8 rods were in and torqued? Did it have the one tight place then, or was it smooth all the way around? What was the rod side clearance on all 4 journals?

I can't think of anything inside the engine near the crank damper that could possibly squeak. That's a weird one. Does the squeak seem correlated in any way with the place that it binds? Has the engine actually run yet? How much cranking has it done? (how many rotations approximately)

Losing track of which cap is which, as you now know, was a BIG mistake. There's no way to be sure, over the Internet, that you've got them back right. Hopefully you do. But at this point it isn't looking real good.

lukn4trbl

Here are a few pictures of what we're describing as a possible cause.

YOu can see the crank has fillets which must match up with the bearings
and rod ends:


The bearings have tabs on them, so it's pretty tough to install them backwards.
One thing you need to ensure is that the bearing with the hole goes
on the correct side to align the oiling passage (this is a picture of the
main, but you can see the tang that sticks out to the left):


Here's a picture of the rod chamfer. You can see the shiny, bevel
around the arc. This side must go against the crank fillet:

Crawforj

The thing about the rods is that they never left the pistons, so from the orientation mark on the top of the piston thats supposed to face the front of the engine and the earlier post about the tangs being on the left and right and that tells which cylinder it goes to. I was able to get the rods in fine.

Problem after that i isolated by torquing the rods and caps down one by one to find which one made it bind, i found 2, so i swapped caps and that allowed the engine to turn with the 28-30lbs of torque perfectly fine. it didnt have the binding when the engine was out of the car.

The sqeak seems to be from a seal, maybe my front oil seal is just dry since the engine hasnt actually FIRED yet. Because it squeaks at the slowest point of rotation which is probably just the rubber catching on the metal of the crank.

Also, i asked around a little and they told me a crank that is 10 under can require more torque to start so if my starter has gotten weak that could be the problem as well as timing. Timing however seems to be perfect... So today im getting my starter checked at advanced auto.

Judging from what happened outside the car i dont honestly believe its the bearings or rods causing it since it would turn and then sieze. And since i put enough torque on the harmonic balancer bolt to snap one i doubt the starter wouldve been able to turn the crank in that situation.

Im clueless right now, could be a mixture of things. My distributor coils in the distributor seem to go out if the distributor leaves the engine for more than a week. My only clues to it were when i first tried it it would bind, but it would shoot fire from the exhaust and backfired through the intake, so i assumed 180 degrees out. Fixed that and now theres nothing no even attempt at a fire.

As far as how many times its been rotated im not sure, ive turned it by hand and ive turned it by the starter im assuming maybe 50ish? Or less...
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AFTER that post im leaning toqards the starter, since it doesnt bind by hand. That didnt even occur to me til now...

Crawforj

But looking at your post about the bearings... Mine were all the same, no holes in them? Oil flows through my crank and oils them that way.

sofakingdom

iTrader: (1)

Lukn's pic showed bearings with grooves; most rod bearings these days don't have those. I suspect that's what he was referring to.

Yes the starter binding on the flywheel or flex plate is a possibility. Try adding one 1/16" (thick) shim, and see what happens.

If it's been turned 50 times by now, there should be no further surprises.Makes sense...That's not true. I wouldn't put too much faith in that as an explanation.Find #1 TDC by compression: take out the #1 plug and stick a piece of hose in it, bump the motor with the starter until you hear compression coming out of it. Set the motor slowly, by hand, rotating only in the direction it runs, never backwards, to a few degrees ahead of where you want the timing to be; say, if you want it to fire at 10° BTDC, then set the crank to a bit "earlier" than that, say, 15° BTDC. (I'm assuming you verified the accuracy of the timing mark while building it) Verify that the rotor is pointed at the cap terminal for the #1 plug wire (should be the one just to the driver's side of straight ahead). Turn the dist until the moving star wheel points line up with the stationary ones, paying attention to the #1 plug wire terminal. That should get it PLENTY close enough to fire right up. Put the #1 plug back in, check the plug wire order around the cap, make sure everything is ready to go. Reach in the window, turn the key, and crank it up.

Uglybronco

iTrader: (2)

WOW... Maybe you should just stick to oil changes from now on. Umm yea, sorry, that may be a bit harsh but sometimes the truth hurts. Go ahead and buy yourself another long or shortblock to have ready to drop in soon.

Crawforj

Starter tested out weak. And the timing is perfect I know that for a fact, the engine just isnt turning very quickly.

It tested about 10 amps shy, but that wasnt with a load on it. Its only about a year and a half old, so it shouldnt be testing shy at all. Ill test it with the load on it later on tonight. Maybe ill try the shims first though, sounds reasonable and wont take long. But regardless ill retime it again too.

Crawforj

I took the plugs out to remove the compression and its turning over fine now, the rebuild mustve added too much compression for the starter. Time for a higher torque starter i think.

Thanks for all your help guys, really appreciate it!

jamon8

iTrader: (3)

this is how you learn

if all the guys told you what you wanted to hear then you would never get it right

keep at it and the next one you do will go easier

take it from a guy who has made MANY mistakes

Crawforj

New issue guys... My rockers arent shooting oil the way they should. it trickles out, with my high flow pump it should be shooting out. Ive readjusted the rockers atleast 5 times. According to the information ive found from different people on this site.

I finally got one to shoot right, ive checked the pushrod orientation twice. Oil pressure is at 65lbs. It should be showering everything from all 8 on each side. Any ideas?

383blaze

new lifters?if you took them out,,did you put em in the same holes?

sofakingdom

iTrader: (1)

Not necessarily.

Yeah...

Nothing to worry about.

Probably just happens that the oil holes in these push rods doesn't happen to line up with the oil hole in the rocker.

Doesn't matter; as long as even a little bit of oil oozes out, that's all they need. Especially if they're roller rockers: those require only a fraction of the oil that ball-fulcrum ones do, since they don't generate near as much heat and don't need the cooling.