248 inline 8 Crank and Pistons wont move? is this normal for these

[Guest countrywill]

Well heres the story. The crank has been reground and all the main bearings are new and connecting rods are repoured and new piston rings have been installed. Prior to installing the connecting rods/pistons the crank and would turn but now that the connecting rods/pistons are in I cant get it to move at all. in fact I think i heard it laugh at me. Everything has been torqued down as it says in the book. I barrowed a freind torque wrench thinking mine wasnt right and rechecked everything.( things are good). The QUESTION.... Is this normal for these engines? oooorrrr is there somthing im missing. As Ive said in previus post this is my first engine rebuild, and i picked a doozy! I took the connecting rod caps off and the crank will spin but once i put the caps on even hand tight it wont move. I backed off 5 pounds of torque on the caps so its still with in the specs..has this happened to any one else? I asked a professional car builder that I work with and it stumped him....hahahaha.........any help would be great:confused:

[Pete Phillips]

I had a similar problem with a 1935 50-series engine. Turns out, some of the connecting rods had been installed backwards, and the flange or shoulders on the rods were rubbing against each other, until we turned them around.

Pete Phillips, BCA #7338

Leonard, Texas

[Guest countrywill]

When I first started to install them I got half way and realized I put them on backwards.

[Ben Bruce aka First Born]

countrywill, I am confused. Happens often. But if you have all the rods connected and torqued, you must have been able to turn it up to a point.What was that point? May only have one rod too tight.??

You say bearings have been repoured. What year is the engine. I must have missed that. What ever year, with poured bearings, there should be shims on the rod bolts between the rod and cap. If not, that is your first step. Get them. With all, correct amount, in place, check clearance with plastigauge. Not sure how? I well send a pm with my phone #. Feel free to call.

Ben

[Roadmaster75]

Ben's right, Countrywill ...

Although I have NOT done a straight 8, I've built quite a few V8s and on those, all new rings, bearings, and freshly machined surfaces

I find that the rotating assemblies will be considerably tighter than before they were torn down. For example, a big block 455 Buick

will be tight enough, that with the flex plate on the crank, it will be difficult to turn without some leverage on the teeth of the flywheel/flexplate

with a pry bar or large screw driver. (I'm guessing here now, but if I were to put a torque wrench on one of the flywheel bolts

and tried to spin a fresh rebuild on the stand it would take roughly 45-55 pounds of torque to begin to spin the rotating assembly within

the bores....)

Is yours actually LOCKED in place? Or, .... were you just not able to spin it by hand at the flywheel/crank end?

Keep in mind that Rings on freshly bored or honed cylinders

cling like mad! Once started and broken in a bit they free up. This is why newly re-built motors may tend to run

a bit "warmer" at first then settle in.

I suspect, Once you get the correct shims in hand AND a good supply of the correct size of Plastigage and check against

the recommended specs you'll be back in business

mike

[Guest countrywill]

roadmaster, i cant spin it by hand. First Born its a 1948. all the shims are there and i did use plastigauge by recommendation from other post her. But it did make me nervous using plastigauge. the plastic left little indentions in the babbit bearing.not real bad but just enough to notice. I had a freind come over with his proffessional grade torque wrench and we checked all nuts and bolts and torque. Everything has been done correctly and to spec per the book, so im thinking its just because it all fresh with new parts

[60FlatTop]

I haven't rebuilt engines many times. I always bought Buicks. Of course the cars weren't as old as I am either. I'm imagining an engine on a stand with oil dripping all over the place on the journals, out the bores, dripping into kitty litter on the floor. I'm hoping.

How many rods do you have to connect to the crank to get it to stop turning? If it is just one, is it any one? When the rod is disconnected how much force does it take to slide the piston up and down that oily bore?

Bernie

[Guest countrywill]

with every rod i put in it would get harder and harder and thats was with hand tight nuts. it got to about the 5th one were i counldnt turn it any more. with all rods torqued down to 40 pounds this time i still cant move it, but i know that everything is the way its supposed to be

[Roadmaster75]

Do you have the flywheel on the back of the crank, CountryWill?

If so, try putting a breaker bar or torque wrench on one of the flywheel/crank bolts and try to Gently

turn it .... With all the rods torqued down you will not be able to move it by hand. You need some external leverage to

turn it.

(you have plenty of engine assembly lube on the main and rod journal surfaces ...right?)

Keep the faith!

mike

[old-tank]

Did you:

Check the ring gaps in the cylinders?

Use very old NORS rings or some from recent manufacture?

Were the cylinder honed with the proper hone for the type of ring used?

Many years ago I did a 'ring job' on a 51 Ford six cylinder. The edges of the Hastings rings were like sandpaper and the engine could not be turned by the time I got the last piston in. The starter would not turn it, towing at first slid the rear tires, but it slowly started turning and was pretty loose after a mile of towing. The starter still would not turn it. I finished assembly and started by towing...it took and hour of running to finally settle down. Never had any trouble with later nailhead rebuilds.

Willie

[Guest countrywill]

ring gap???? the rings are nos.

[Ben Bruce aka First Born]

ring gap???? the rings are nos.

That makes no difference. Still could be too tight.

I rebuilt mine a couple years back, and though it was tight, I could still turn it. Back in the '50s and '60s, when working on these engines, using a ring to check the bore was a cheap way to do so. We always checked ring gap[clearance] before assembly.

Your engine should not be that tight!! You need to disassemble and determine cause. Period.

Ben

[Guest chevy_dude97]

ring gap???? the rings are nos.

Yes there should be a gap on each ring, also the gaps should be at different positions to not allow significant blow by(loss of compression). If they are too tight it can waller out the cylinder walls in short order.

[Guest countrywill]

Ive triple checked everything, the gap on the rings are opposite of each other. the clearences are on spot, torque is perfect. at this point Im going to put the motor in and hope for the best. I do need to know what a good practice would be for the first start? thanks for all the help

[Guest chevy_dude97]

Ive triple checked everything, the gap on the rings are opposite of each other. the clearences are on spot, torque is perfect. at this point Im going to put the motor in and hope for the best. I do need to know what a good practice would be for the first start? thanks for all the help

First start; I use non detergent oil, and plenty of assembly lube. Then lightly coat the cylinders via plug holes with oil or MMO. I then use a primer for the oil, in this case you can disconnect the ignition wire from the distributor and let her crank up untill you have oil pressure.(do not prime the fule by pumping gas) Warning on this however, if you do not see an immediate indication do not allow it to crank more than 5-7 seconds. If no indication try again allowing the starter to cool in between attempts. After oil is shown indicated then you can reconnect your ignition and fire her up. (lack of oil is the easiest way to wear down the life of the motor) If anything is assembled wrong you should know right away. My shop teacher always said if its going to break this is the time it will do it.

Good Luck!