Hey, i have a 305 out of an el-camino im rebuilding.
I tore it down, cleaned it up, got new rod and main bearings, and new piston rings, all standard size.
I honed the cylander walls, didnt regrind crank *wasnt bad*

Ok, so i get half of the pistons installed, all on the one side.
I go to the other side, and start puttin stuff togather,
after the first 2 pistons, the crank got pretty tough to turn.
after i have all 8 installed and torqued down, the damn thing doesnt want to turn at all.

Im also building this on the hoist, because im too broke now to buy an engine stand, so its not the most rigid thing to try to turn this motor on.

Well, im thinkin i messed it up somehow, but dont know how. its a bare block except for crank pistons and rods. Im also thinking, that the motor was just as hard when i took it apart, that this could be normal, but since its not mounted in a car or a stand, it seems alot harder. And my final thought is that since everything is new, its just "tight".

Thanks for any info you guys can throw my way.

 

They will get tight after some of the pistons are in there. Good deal of friction from the rings.

A couple of things though, did you: check the ring end gap, protect the crank while inserting pistons/rods with some rubber hose over the rod bolts, wipe oil (I use ATF) onto the cylinder walls, check bearing sizes (didn't get a 10 under in a box of standards).

RBob.

 

i kinda checked ring gap, i just made sure rings fit into cylander before installing them.

I had a friend help me guide the rods over the crank

I also loaded up the pistons with oil, and the cylander walls with oil.

I loaded up the bearings with assembly lube, and plastigauged them (dont remember clearances, but i thought they were ok)

I just anchord the bottom of the block to the hoist, so it didnt turn, and used a big pipe on the flywheel to get the crank to spin. Its tight, but feels smooth.

Thanks.

 

since you "kinda" checked ring end gap i wonder want method you used to tell the crank didn't need turned. my guess is you didn't match rod caps to the rods and have one or more on backwards.

 

i did the poor boy check i guess, because all the money in the world i had was a penny, so i just rubbed the penny on the crank to see if it was badly scored. I figured as much as there was not a problem with the crank or bearings before i pulled the motor, so if there was something, it would probaly break in. Or so i hope...

Like i said, this is my first project, and i expect it not to be flawless.

As for the rod caps, i did match them to the rods, in the order i took them off. and the flat spon on the caps point to the crank rite? I could not find anything like that in my crappy book im using.

Thanks again.

 

i still think you have a rod cap backwards

 

how can i check

 

I agree... If someone here has a pic of how they should be oriented, you'll know right away if one is backwards just by looking.

 

Couple of things...
First since it sounds like you are going to be pulling this thing apart again wipe the cylinder walls down and don't lube them with oil, use ATF on a very clean rag (use oil and it'll probably smoke). Second it sounds like when you tore it apart you didn't mark everything, verify all rod caps are on the same rod and oriented in the correct position. Verify the main caps are on the correct journal and facing the right way. Check the thrust clearance, and bearing clearances. Did you buy file fit rings? Even if you didn't check the rings you have. Take the ring and insert it into the cylinder. Take the piston, turn it upside down and push down on the ring until it is level inside the bore. Then take a feeler guage and measure the amount of gap. If you triple check everything you may need to take the block, crank, and rods to a competent machine shop and make sure eveything is straight. Also make sure your rods and pistons are oriented in the right direction.
Good Luck
-Mike

 

One more thing...
Just so I get an idea of what "Tight" is take a torque wrench and use it to turn the crank. Adjust it till it clicks just as the crank starts to turn. Post the reading you get.
-Mike

 

Don't do that untill you know you have all the rod caps on the right way! You can really %$&@ up the rods and crank by doing that if the caps are on wrong.

 

Yeah it's true you can damage things by doing that but he has stated that he already tried spinning this thing over several times. Also after re-reading what I worte I probably should have indicated that i meant for him to try that after checking everything. But in any case any damage that may have occurred is most likely already done.
-Mike

 

The rod caps should be oriented such that the bearing tangs are "out", away from the cam. The rods themselves should also be facing that way.

Check your rod side clearance. Both rods on each journal should be able to slide easily (by hand) from side to side along the journal; there should be .010" - .020" of clearance. Check all 8 for free movement.

Expect 25-35 ft-lbs to turn the crank. If it's in that range, it's probably OK. More than 40 or so, something isn't right.

 

Hmm, something is definatly wrong, because i broke off the bolt in the front of the crank.
What is the torq specs on the rod bolts? That may help. My book shows 40, but when i loostend them all up, it spun better.
And also, what else did i mess up by turning the crank?
I did clean everything and lube everything up too.
The rings are not file fit.

I dont realy want to tear this engine down again, but if i gotta, what should i be looking for?

And by saying that the tangs should be pointing away from the cam, what does that mean? Any pictures? Thanks again.

 

i'd replace the bearings, but from the sounds of things going on it wouldn't make much differance. have you chacked the caps? are they or were thay al lon right or not? what you going to do with the broken crank bolt? i'd take the crank to a machine shop and let them get it out. take a cp off the rod take the bearing out and you'll see the tang or slot.

 

The cam is a long skinny thing that goes all the way through the block, above the crank. It's probably not in there yet, but if you imagine a shaft about 2-1/2" in diameter that runs from front to rear of the block in a hole of about that size, you'll find where it goes.

Once you locate that, look at the rods. One side of the rods will be next to it, "inside" the motor so to speak; and the other side of the rods will be facing "outwards", towards the oil pan. People often number-stamp that side (it being impossible to number-stamp the cam side while the motor is assembled). So if there's numbers stamped, they belong facing the oil pan.

The bearing tangs, and numbers if there are any, all belong pointing away from the cam and toward the oil pan.

If the crank loosened up from backing off the rod hardware, then either you have caps mixed up or backwards, or the wrong bearings.

 

i was about to say, I know what the heck a cam is... then i realized i needed it broken down to that level. lol.

Im gona try to get some pictures up. Thanks.

I do thinik i got caps mixed up, because when i only had 4 caps on, it was a lot easier, and when i put my 5th cap on it was a bitch to turn the motor.

 

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This is how tough it is. I have a house jack pullin down on the flywheel, and the motor is turning on the chains.

 

pull the rod caps and look there's no way to get around it