Here is a little history leading up to today. Complete rebuild of my 8BA. .080 over, all new parts, line bored, 20-20 crank and all new valves and cam. Assembled engine and installed in frame. No body on frame so working on engine is easy. Engine turned over kinda tight. Using a torque wrench in pulley bolt requires 80 foot pounds to rotate the works.

Installed original 6 volt starter and apply 12 volts. Just sits there and growls. Not surprised as this machine sat under water for some time before I got it and the starter was probably junk.

New 12 volt starter got here day before thanksgiving and I installed it today. Well, guess what. I does the same thing. It won't turn the engine either. I am using jumper cables (00 size welding cable, plenty big) attached to my F350 Diesel batteries AND a 250 amp battery charger. Finally removed the spark plugs and now it turns with the starter but sounds like crap and doesn't rotate very fast. I am able to build oil pressure up to 60 psig though.

I guess my next step is to remove the starter and take it to a repair shop and have them check it.

What do you guys think? I wouldn't think 80 foot pounds to rotate a new engine is very high. And I would also think a decent starter would crank at least 100 foot pounds of torque. Plus when you take in the mechanical advantage gained by the drive reduction between the starter drive and ring gear, which is probably 50:1, I don't see a problem with the engine.

What do you guys think? Has anyone ever found out how much torque is required to rotate a new V8 engine?

 

They can be very tight. How long since you oiled the cylinders? Light oil or 30 wt.?
What did you use on the mains and con rods? If it's that thick goopy assembly lube, it will be very hard to turn until fresh oil gets in there.

You might want to put light oil in the cylinders (MMO) and give the engine oil system an enema -- hang a quart bottle of 10w30 with a line that connects to the oil port on the bellhousing, to gravity feed lighter oil into the system.

Then crank the engine with the starter with all the plugs out.

 

I can't say I've ever measured the torque needed to turn a new engine, but I don't think 80 pounds would be unusual. I tighten my lug nuts more than that with ease. There's a lot of drag inside there with new rings, and especially with rope crank seals, they put a lot more pressure/drag on things than the rubber lip type. It also doesn't seem likely you'd have 2 bad starters in a row, but stranger things have happened.
Sorry I don't have more words of wisdom, except don't give up. Good luck.

 

pull it back down ..15 pounds spins my flatty with no plugs when I rebuilt my 428 it was only 28 ft lbs to turn it over..something is very wrong !!!rings not gaped right ..a rod bearing slipped ..don't force it !!a gasket set is cheep ..how hard were the pistons to install ?? did you spin the motor with the crank without the rods and pistons connected ??start again ..better then wrecking so much work

 

Did the honing grit and swarf get cleaned out prior to assembly? I bought a long block years back, went to check it and found grit. Had to clean it out and reassemble it. Somebody was in a freaking hurry.

 

I agree with ALBUQ-1, newly re-done cylinders/rings can be tight, and do loosen up.

so what is too tight?

I would remove plugs and leave out, so your not fighting compression. put some light oil in holes on top of pistions and rotate with your breaker bar quite a few times. i'd then try to crank with plugs out with your new starter and 12v battery. it will loosen up or not.

I made an engine turn over after "new rings" that was hard to turn once. i eventually got started. it drove with low power for about 3 minutes and then just stopped, i check and it got tighter. I pulled apart re-honed cylinders and installed new rings, worked perfect. my guess is rings weren't properly installed.

edit; i just remembered another time that the main bearing caps were installed wrong. i figured out by loosing cap bolts 2 turns and eventually motor turned easy. it ended up one cap was on backwards. (it required new rings to fix)

 

After I rebuilt mine (040 w/new pistons) it turned over fairly easy and fired right up on the 6 volt battery. If it were mine I would pull the pan and take a look..... maybe a main cap or rod cap in the wrong position.

 

When I assemble an engine, I turn it over after every part is added. Install the crank, turn it over. Tighten main caps, turn it over. Install one piston, turn it over, and so on. This way if it suddenly changes the effort to spin it, you know what part made the difference. I had a main cap that would let the crank spin when it was tightened to 20 ft/lbs, but would lock the crank at full torque. Turns out the machine shop had apparently dropped that main cap and put a small ding in it. I was able to isolate which cap and fix it before it caused problems.

 

[QUOTE=rhopper;12518842]When I assemble an engine, I turn it over after every part is added. Install the crank, turn it over. Tighten main caps, turn it over. Install one piston, turn it over, and so on. This way if it suddenly changes the effort to spin it, you know what part made the difference.
/QUOTE]

Exactly what he said. The only way to assemble one. If it won't turn with the starter something is wrong.

 

Did you/they plastiguage the crank/rod bearings for clearance? 80lbs sounds a little much to me.

 

perfect advice.... my exact method also.

 

Lots of great tips guys! Thanks ever so much. Here is more info on the assembly.
Prior to assembly I measured every piston, bore, bearing journal and ring gap and they all fell within spec. I even put each piston in its bore with the minimum and maximum feeler gauge to make sure it was right. Also used a bore gauge to check main bearing bores with the inserts installed.As I assembled the engine I would rotate the crank looking for any significant difference and I did not notice any. Each assembly caused it to turn a little harder. I have worked on cars all my life and I remember way back when occasionally you had to tow a car around in gear to break it in enough so the starter could turn it over. This is what I may be looking at. I think it is because of the rope seals. I will also squirt a little hydraulic oil in the cylinders & crank it over some more. I have installed a 0-100 psig gauge in the system and am able to register 60 psig while cranking. Monday I am going to take the starter to a shop and have them take a look at it.

I will followup on this as I learn more.

Thanks
Steve Bark

 

The way you did everything sounds good. Since it was more then likely line honed not line bored did you plastigage the mains? Then the next thing that comes to mind is are you sure you have the main caps and rod caps in the correct position and location?

 

hook a chain to it and tow it down the road, one of two things will happen.

1 it will turn over and start.

2 it turns over and locks up.

 

Well, BigBlock, When I put the crank in, using oil as a lube I could spin it with one finger. It spun real easy.
And bigwin, I don't have any sheetmetal or seats on this truck. I am doing a frame off rebuild. I would look real funny sitting on a kitchen chair being towed around the neighborhood. I guess I could tie a toilet down behind the steering wheel. My neighbors would get a good laugh.