The Stovebolt Site Forums The Shop Area Engine Shop engine wont turn over any more

ok, so im rebuilding a 62'-63' 327. i kept the stock pistons because they were in good shape, but i replaced the piston rings. the pistons are 4.001 and the rings that i got are 4.01. with all the pistons in i could bump the starter and it would turn over a little slow, but not bad. but when i torqued the rod caps it just stopped working. by that time the battery voltage was at 12.2v. at first i torqued the front 4 cylinders and bumped it over and noticed that it was a little slow, then i torqued the rear 4 and it just was not turning over at all. i torqued them to 32ft lbs, but when that did not work i re torqued them all to 30, then to 28, all the way down to 20 ft lbs. and it will not turn over. my battery puts out 690 cca @ 0 deg (its a good battery.) i brought it home and put it in my olds and it started right up. all that was connected at the time was the starter and a remote switch. i pulled the starter and inspected it down to the last detail- nothing was wrong with it. yes i used assembly lube, i honed the cylinders very carefully, and oiled them and the pistons and the rod bearings before i installed them. has any one had this problem? would a hi-torque or ultra hi torque starter be the solution or am i going to have to take everything apart again? if a starter is the solution can any one suggest one (id like to keep it under $200)? the truck is a 66 c-30. it has the stock 4 on the floor and stock flywheel.

did you check ring end clearance,rod bearing clearance, main bearing clearance,crank end play. I would stop where you are and back check.a spun bearing is a bad way to end,a over haul.

Are you cranking it with the heads off? If so, it should spin easily. I agree with 49floyd, you need to check your clearances on all the bearings you replaced. Were the old bearing shells marked as oversized or standard, etc? Sounds like a definite mismatch on the clearances. Now is the time for double checking. Good luck.

SimS

Check the end gap on the rings first. If you're trying to force a set of .010" oversize rings down a standard-size bore, the ends of the rings are going to be butting together as soon as the piston gets into the unworn part of the cylinder, probably about one inch or so from the top. There's also a possibility you've put undersize rod bearings on a standard-size crankshaft, and as soon as you start tightening them to the proper torque the bearing is locking up the crank.

People who don't own micrometers, and know how to read them shouldn't be rebuilding engines! At least let a professional engine machinist do some measuring and advise you on what parts to buy before you screw up a good engine!

Jerry

Could be putting the rod caps on wrong. Or on the wrong rod.

If it quit turning over as you were tightening the rod caps, start there.

I talked with my local shop about your engine and piston situation. There was no problem with the four pistons facing back wards as long as all sixteen valve reliefs were on the top side (lifter side of the bore). If you installed them with the reliefs on the exhaust side, then you have all eight rods in the wrong hole. I gave wrong information on where the valve reliefs went and apologize for the incorrect information.

The crankshaft has a radius in one corner of each rod bearing. Each rod has the bearing off set to one side for clearance of this radius. If you get the rods facing the wrong way, you are torquing the bearing down against the radius thus locking up the crank.

Pull one pair of rod caps back off and check them, if there is a sizable gap between the bearings, then you have them installed wrong. Also, when torqued down, you should be able wiggle the rods side to side slightly, if you can't, they are installed wrong.

Torquing rod bolts has no effect on rings or main bearings.
Joe

I agree that your problem is with the rods, somehow. You should not use a starter to turn an engine that is binding like that. Torquing the rod bolts should not make any difference.

I dont understand what a radius is. i pulled a cap and mic checked it against the old ones, not even 0.001' difference. and i did look at the piston ring end clearance- i did not check it with a mic, but with them compleatly compressed around the piston there is still a gap. the cylinders were well worn; thats why i went with bigger piston rings. so if the valve reliefs are supposed to be twards the intake manifold, then i have all of them in backwards. . . .damnit!

Brian,here is how to check the ring gap. Take a compression ring, insert it into the cylinder and use the head of the piston (upside down), to push it down into the cylinder to near the end of the ring travel. Next take your feeler gauges and measure the gap. Your ring instructions will tell you what the gap should be but I think it is around .003" per inch of bore diameter. If you don't have a wide enough gap you will end up with a failed engine.

There is simply no way that .010" oversize rings will work in a standard bore, without some serious file-fitting. Every ring needs to be checked, at the bottom of its travel. For a 4" bore, you need about .012" minimum ring gap, at the bottom of the ring travel. As the rings heat up and expand, the gap gets smaller, so with a cold engine, you definitely need some extra room for expansion. If the cylinder has more than about .005" of taper wear, the rings won't last over about 10,000 miles anyway.
Jerry

Brian, the radius is where the bearing surface meets the cast part of the crank. Grinding wheels don't have sharp edges so there is a radius on each end, also the radius keeps cracks from forming.

Since you have one rod cap off, look close at the bearing and how it sets in the cap. You should see its offset to one side, and the cap has a bigger opening that goes over the radius of the crank. You should also see where the bearing was rubbing on one side if this is your problem.

Joe

What size rod and main bearing did you put back in? Did you regrind the crank and refinish the rods? Try using some plastiguage to find the clearance of the rod bearings and let us know what you have.

Brian, Also you must have cleaned the ring grooves of carbon or the new rings cannot go deep enough in the groove and the pi stons would be difficult or impossible to install in the bore.
Note what Jerry said about checking end gap in the unworn (below the ring travel)part of the bore.
A change of ring OD or bore diameter of .001 causes a change in end gap of .0031416.
If you have to increase the end gap, don't put the ring in the vise and apply the file but put the fine file in the vise and apply the ring.To do otherwise will probably result in a broken ring.
After filing to the fit you want, use a small sharpening stone to eliminate the burr or sharp edge turned up where the filed area will contact the bore--don't stone much just a touch or two will do.
good luck

ok, the pistons were in upside down, and the rods were on opposite sides because of that. pulled them out flipped them around- valve reliefs twards the center of the motor, and the bigger chamfer twards the radius- double checked the piston rings, everything should work fine. torqued the rod caps and the rockers and it still cranks! thanks for the tips!