I have a 305 chevy I"m rebuilding. The block is bored .040 over. Re-man crank, new pistons, rings, main and rod bearings. How hard should the short block be to turn over( just the crank and pistons). This is my first rebuild and I"m not sure how tight it should be, and I'm not sure if mine is too tight or not. I can't turn it by hand, instead I have an old broken harmonic balancer on the crank, and I"m turning it with a pipe wrench. It's pretty stiff to turn. Any advice/comments?

 

It's going in an 88 Camaro. I don't plan on hot rodding it, but I do want the motor to be done right. Unfortunately, I'm lacking a lot of what most would consider experience, so any feedback or help would be greatly appreciated.

 

To tell you the truth mine is bored .60 over with everything new and mine is so hard to turn. but hey it runs good when i start it. i do need a large cranking amps batery though.

 

Well that eases my mind a little bit. Was yours hard to turn as a short block? Or only after you put heads, etc on it?

 

You're not likely going to be able to turn a new engine over without a lever, even a shortblock. Allot of it is the adhesive-force/surface-tension of the oil and other lubricants along with the piston rings. All those sleeve bearings amount to allot of surface area dragging on the crank/rods/cam. However, oil pressure floats all that stuff up and away from the metal surface once the engine is running. When you turn it, it should feel like it's stuck and then break free and move until it kind of sticks again. It takes over 1000 watts of power for the starter motor to spin the assembled engine. That's more than 1 horsepower. You'd have to be pretty strong to spin that by hand without some leverage.

 

 

If you're concerned because it takes significantly more force than a modern engine (that's also been run for a while), don't be. Almost all modern engines use light tension rings where older motors like yours use "standard" tension rings (rebuild kits almost always come with standard tension rings, too). Plus, an engine that's been run will always be looser than a fresh build.

If the force required to spin it is even throughout the rotation, you're probably fine. What you want to watch out for are any "tight spots" in the rotation. If you find one, you need to take it apart again and figure out why.

 

Thanks guys. It was taking 75 lbs foot-torque to spin it over. I remember that when I put the number four piston in the force requited to spin it almost doubled, so I pull it out and checked the rod bearings. The coating on it was rubbed away in a few places. Since there were no spurs on the crank, I figured it was the bearing itself. I took a piece of 2000 sand paper-super super fine, and wiped away some of the rod coating. Now my torque spin over is about 45 lbs.

 

You got the cap on the right way around on the rod? They're not reversible. Both bearing tabs on the same side, not on opposite sides

 

Have you used plenty of assembly lube on this rebuild??

 

Yeah their all on straight. The motor is pretty tight, but I think that's just the friction from the new bore and rings. Well I hope so anyways. I'm really hoping I don't get this motor running and it throws a rod or something a few miles down the road.

 

Yeah, between the main bearings and rod bearings there's enough lube to drown in. I was fairly generous with it.

 

Mine was the same. i just finished doing a huge burnout in mine with no problem. just that my brake booster when out right after -_-

 

Haha that sucks man. I'm trying to do this correctly, right down to the tee. I don't want a spun bearing in two months lol.

 

Well yeah. break it in first. mine was done about 4 months ago lol.

 

i just got it running again cuz my rochester cracked on me about last week so i slapped on a new distributor and carb

 

Well, I did make one mistake, which was totallty preventable. I actually feel pretty p#ssed at myself for not doing this. Since I bought a new crank, with new bearngs, I skipped the plastigauge. Could this have anything to do with the tightness of the motor? And if anyone wants to lecture me on how much of a amateur mistake that is, go ahead, I deserve it haha. Also, can I plastigauge the main bearings without removing the pistons? Or will that mess with my crankshaft end play when I retorque the crank?

 

i would go safe route and remove the pistons and rods.
Plastigauge the crank first then check for endplay then move on to the rods and of course you already checked rod clearance

 

Should take around 30-40 ft-lbs to turn a completely assembled "new" motor.

If you're trying to turn it with the damper bolt, you're asking for trouble. Get a crank turning tool.

If it's taking much more than that, check to make sure the rods are facing the right direction. The side with the bearing tangs on all of them should be facing downward, away from the cam. The pistons should have a notch or other mark that faces toward the front. If any of the rods are backwards, the edge of the rod bearing that's supposed to be next to the other rod (they're not symmetrical) will be riding up on the radius at the end of the rod journal pin. This forces the rods together HARD on each journal. Each rod should be free to slide easily a few .001"s on the journal; should be around .010" - .015" of "side clearance". You should be able to just grab every rod and move it along the journal.

Make a point of checking the accuracy of your timing mark before putting the heads on; make a new one on the damper, if it's off.

 

I've been using the damper bolt, what trouble will I have caused? I'm not doubting you, I'm just curious. The 3 4 5 and 6 piston rods don't slide easily. The rods are on the same way, with the notches facing each other like they should. What would cause this? Its a re-man crank with new bearngs. I guess it's possible that who-ever re-manned the crank messed up.

 

He's saying that the assembled rod only goes on the crank journal one way (with the rod bearing tabs pointed OUT/DOWN/TOWARD THE OIL PAN RAIL/AWAY FROM THE CAMSHAFT. However you want to describe it. You can't flip it over 180* and bolt it on the crank. It might fit, but it won't rotate correctly.

And since we're on the subject of getting everything on the right way, might as well throw in the last critical orientation- the main bearing caps also have to go back in their original locations, no mixie-matchie. AND THEY ALSO MUST BE ORIENTED WITH THE CORRECT SIDE TOWARDS THE FRONT OF THE MOTOR (there is an arrow cast into it that should point front).

I think we've now covered the entire universe of critial parts orientation in the bottom end of a small block Chevy!!

 

You can break the damper bolt or strip the threads. If you haven't done so yet, then just don't use it to turn the engine over any more and it will be fine. Don't install the damper and try to turn the engine by turning it with the outer ring or it will slip. I didn't have any fancy tools to turn mine over last time I needed, so I put the damper on and put puller bolts into the three pulley holes letting them stick out about an inch. I then used a long screwdriver as a lever between two bolts to move it. The longer lever you use, the easier it is to finely position it.

 

Just checked the bearings. There is a slight discoloration along the inside of some of tje rod bearings. And with 15 lbs of torgue, i cant slide the rods along the journal. The rods are oriented correctly. The main caps are in The right direction also. Maybe i have a misplaced main bearing or rod cap? How would i tell?

 

Whew! I think i figures it out. Before i dissasembled the block i took pictures of bottem end. The numbers are kinda hard to read on The main bearing caps but im about 75% i mixed the number 3 and 4 main caps. Can i take them off and retorque all the caps without removing all the pistons.

 

Yes; as long as the rods are in the right place.

 

Agreed.

But that would only affect the crank being able to turn freely. Should have no effect on the rods being able to rotate/slide on their journals. If you swapped a main cap, it's possible you swapped a rod cap too. Keep digging. Hope and guesswork is not the same as knowing.

 

Hmm. Well im at a loss. Any way to tell which rod goes where?

 

Tangs away from the cam, piston notch to the front

Other than how they're assembled, they're all the same

You should have seen the crank spin more freely as the main bearings were torqued; and been able to grab the crank snout with your hand and spin it, and it rotate at least one more full revolution on its own inertia.

When you put the 1st piston in, the crank should still have been very easy to turn for a certain distance around TDC and BDC, when it wasn't moving that piston. The rod should have been able to freely slide along the crank pin.

When you put the 2nd piston on the same rod journal, both pistons should still have been able to freely slide along the crank journal; you should be able to move them to any of 3 positions (both to the front, both to the rear, the front one to the front and the rear one to the rear) and insert a .010" feeler gauge in the resulting gap.

How about it? Is that what it was like as you were building it? How freely do the rods slide along the crank pin?

 

My suggestion was not that you got the wrong rod in the wrong hole, but rather that you might have gotten the wrong cap on the wrong rod. Like accidentially putting #6 rod cap on #8 rod (and vice versa). The rods can be installed in any hole, but the cap and it's rod rod are a matched set.

 

Sorry guys i meant rod caps. The rods are on correct. The number 1 and 2 piston went on easy and slide along the journals. So do 5 7 and 8. The problem is 3 4 and 6. Any way to check rod caps besides guess and check? 3 4 and 6 wont slide along the rod journals.

 

Did you stamp both the rods and their caps when you disassembled? That's sorta important.

Anyway, if you get the wrong cap on the wrong rod you will always have TWO rods that are paired with the wrong cap. Which means if you have problems with three of them you actually have a problem with 4 of them (at least). Two rods per mistake.

No way I know of to figure it out except trial and error (or a trip to a good machine shop).

Regarding trial and error.... I've found that assembling the rod onto it's journal while it hangs down out the bottom of the motor gives you more room to move it around and see how it "feels" on the rod journal.

 

Not really; cap 3 could be on rod 4, cap 4 on rod 6, and cap 6 on rod 3.

Nothing wrong with "guess and check". Take those 3 apart, and try each cap on each rod, and see if it gets better.

It's not rocket science you know, just a car.

 

Good point. True.

 

There are bad things all over this thread. First you used 2000 grit sandpaper on a rod bearing. Well you just ruined that rod bearing and you better buy a new set.

Second is you didn't check any clearances. The best method is with a dial bore gauge. Most use plastigage which isn't the most accurate but I'm 100% positive it would have shown serious issues in your case before you went and ruined the bearings.

I suggest two things:
Figure out the rod/cap mix up and then plastigage everything after you bought new rod bearings.

Second is take it to someone who knows what they are doing.

EDIT: Sorry to sound like a dick here but I was once in your spot too. But I stopped when I wasn't 100% sure about something and went and got the help I needed. The mistakes here are basic engine assembly 101 and should have been researched before you even started.

 

No offense taken. Yeah, I know I should have plasti-gauged, but since it was a new crank I figured I could get past it. I guessed wrong. My biggest mistake was buying this motor, it was in a crate when I bought it. the only bring put together was the crank, all the rods were in a basket. I assumed that who-ever put the rod caps on the rods, did so in the correct order. Thats where I really messed up. And no worries, I ordered a new set of bearings.

 

Sorry guys, I haven't been on here a few days. College has kept me pretty busy, plus my internet has been down( of all things, a ground hog chewed our cable up ). I appreciate the advice. I took the rod caps I thought were mixed up, and the respective pistons out also.Cap #4 fits rod #6 perfectly, I can run my finger along where they meet and not feel the connecting point. Cap 6 does not fit rod six though, in fact, non of the caps fit rod four correctly. I was told I may have warped it by torquing down the wrong cap on it. I'm dropping them off at the machine shop tomorrow to get them checked out, hopefully I won't have to have the rods re-sized.