The Stovebolt Site Forums The Shop Area Engine Shop 216 re-assembly

Hello;
I am currently re-assembling my 216 motor out of my 52 one ton GMC 9430. I have torn it down and cleaned all of the parts and block and now trying to get it back together. I currently have the crank in place with all original bearing and shims. I have started putting the pistons back in with new rings from Jim Carter http://www.oldchevytrucks.com/cart/product.asp?prodid=ME368S&i=|piston%20ring||||
I have 5 of the pistons in and have noticed that it has become extremely difficult to turn the crank to position for the next piston. I have used motor oil on all crank faces and piston bore. The piston rods move side to side on the crank and before the pistons were installed the crank moved fine. Is this drag due to the new rings? I have not done anything to the bore other then a light honing stone to cross hatch the face for oil.
Any advice would be greatly appreciated, thanks.
Mark

I would ask if you have checked the gap on the rings. Also the rings themselves should have been covered in oil. Did you oil the ring up well?

I applied a fair bit around the bore and the piston but didn't put directly on the rings deliberately. I have poured some oil on the piston heads to soak down through over night. when you say the gap which would you be referring to?

Mark

Define "extremely difficult", please. Are you using the flywheel to turn the engine, or some type of pry bar, etc.? It's not uncommon for new rings to make a crankshaft noticeably harder to turn as the drag of more cylinders accumulate. Have you checked the clearance of the rods as you assembled things? I'd suggest backing all the rod bolts off a turn or so after installing the final piston, and checking the oil clearance on each rod as you torque them up. There should be little or no difference in the effort required to turn the crankshaft as the rods are torqued. The ideal oil clearance should be .0015"-.002", with .003" as an absolute maximum. Good luck!
Jerry

I didn't due any clearance checks but did put new rod shims in. The rod moves freely on the crank with hand pressure side to side with the nuts torqued to spec. As far as force to turn it I have it in an engine stand with the back end holding it to the stand so I have been turning it with a pipe wrench on the balancer shoulder with a rag to try to protect it from getting chewed up, I'm 6'-4" 250 lbs and had to put my all into it. I think the oil issue or lack of on the rings may be the main issue. we will see once it sits over night. One question to add is that I assumed #1 piston is at the front or water pump end…correct?
I have positioned the piston rods with the cylinder number stamp facing the cam as per the book.

First, a suggestion, based on close to 60 years' experience building engines, including a lot of 216's. Put 3 flywheel bolts into the rear flange of the crankshaft, and use a 3-foot long piece of 1 1/2 inch flat bar as a lever to turn the crankshaft. You'll be a lot less likely to damage anything that way.

Second, you've got WAY too much drag on the engine, so disassemble it and start over. This time, check the gap on every piston ring before you assemble them over the pistons by pushing each ring a couple of inches down into the cylinder with an inverted piston and using a feeler gauge to measure the gap. It should be a minimum of 12-15 thousandths near the bottom of the ring travel. Check every ring! If a ring doesn't have enough gap, file the ends until it's right. If you manage to force a too-tight ring into the engine when it's cold, you'll lock up the engine and score the cylinder(s) as soon as it warms up a little and the rings expand.

Next- - - -USE PLASTIGAUGE ON EVERY ROD AS YOU ASSEMBLE IT! Do- - - -not- - - -assume- - - -anything is right until you measure it, unless you're fond of building the engine up 3 or 4 times before you get it right.

Yes, the cylinders are numbered 1-6, starting at the water pump end. Have fun!
Jerry

this is an aside, but I have been hearing stirrings about the NEW method of installing rings is dry, But I googled it and there seems to be a conflict of opinions. I didn't pursue it in depth, but it seems like it may be legitimate...

I believe you'll find that method deals with assembly of low-tension rings in cylinders diamond-honed to almost a mirror finish. It's completely inappropriate for a stovebolt engine.
Jerry

Thanks Jerry; Its that kind of experience and advice I was looking for. I will let you know what I find once I check this out.

Mark

When I rebuilt my 216, I was unable to turn the engine by hand with all pistons installed and new rope seal. I too was worried, but all seems fine. The starter has no trouble, engine runs great.

I used plasti-gauge and ensure all bearing clearances were right on .002" That rope seal is the likely culprit. In order to turn the crank, I temporarily installed the vibration dampener and used a pry bar in the "ears" to turn the engine.

One more suggestion, and I had to learn this lesson the hard way- - - - -a smooth layer of carbon builds up behind piston rings as they wear. Unless all the carbon is cleaned away before installing new rings, the rings squeeze down on the carbon layer and dramatically increase the drag. Take an old, dull hacksaw blade and carefully scrape all the carbon away down to bare metal at the bottom of all the ring grooves. A broken-off old compression ring filed to a chisel shape also makes a good carbon scraper.
Jerry

I had the same problem last week with a 235 I am putting together I read the manual and make sure the number on the piston is facing the cam once I turned all my pistons the right way it turns without to much difficulty.

Recently I dropped the pan and plasti-gauged my 49 216 but didn't change anything w/any of the bearings. I did one at a time and put everything back together as they came apart.
With the plugs removed I was able to grab hold of the flywheel and somewhat easily turn the crank but after I replaced the bottom rope seal in the rear bearing cap I couldn't budge it by hand. I had to use a large screw driver on the flywheel teeth to turn it.
I agree w/the consensus it's probably the rope seal. Course new rings coupled w/tight bearings will tighten it up too.
Dave

Thanks for all the advice. I will see if I can get the Plastigage around here and check the oil clearance which I found a video on
I will also check the ring gap first. I did scrape the carbon out of the piston ring groove with an old ring section which was no easy task…Im glad I asked about this, as I said I assumed everything would fit like a big puzzle. Im in no hurry to get this done as I figure Im on a two year schedule

Mark

What is the acceptable clearance of the connecting rod to crank clearance? My manual only says it is selective fit and needs to be movable by hand. I want to make sure I get the right plasti-guage.

Mark

I like to use the green PG. The clearance I've always tried to get is .0015", which is in about the midrange of the green stuff. Red is slightly thicker, and the blue is WAY too thick to be used for bearing clearance. Rod bearing clearances larger than .002" have a tendency to rattle a little on startup until a good film of oil gets established between the rod and the crankshaft. Main bearings work best somewhere between .0015" and .002" also.

There's a procedure involving Prussian Blue indicator paste and scrape-fitting Babbit rods to establish a perfect fit between the rod and the crankshaft before shimming for clearance, but it's usually used when fitting new or reconditioned rods to a used or reground crankshaft. If the rods in your engine have been run against the crank for some time, that's probably not necessary.
Jerry

Thanks again Jerry!
I plan to pick some up tomorrow.

Mark

I have found what the major issue was for making it so hard to roll over. When I cleaned the pistons up it was winter and my lighting wasn't good enough for these old pair of eyes I have. I missed a couple of sizeable peaces of carbon in the ring grooves on a couple of the pistons. I was working in the daylight and could see much better today. Thanks for the tip on the hacksaw blade Jerry, worked great.
Now I have found that a couple of my connecting rod bolts have stretched and will not torque properly. Any idea where a guy can get a few of these or possibly 12 to replace them all.

Mark

I see NOS stovebolt rod bolts on Ebay occasionally, but the powers that be on the forum don't like to see ebay links posted for some reason. Try searching the "antique engine parts" category (or maybe "vintage"?)
Jerry

I have emailed ARP to see if they have a kit and I see Chevs of the 40's have them used. I think I will replace all. The first time I assembled and torqued them they all seamed fine but the second time a couple failed. I did lube the threads and torqued to 45 FT. LBS.

Mark