The Stovebolt Site Forums The Shop Area Engine Shop Harmonic balancer install gone bad.

Greetings to all Stovebolt members!
I have goofed up my harmonic balancer install on my 54 GMC 248 and need some advise on how to proceed.
It started out about a year ago as a simple timing cover leaky seal sleeve repair that went well and I thought the balancer install did also. Situations change so I had to sideline my restoration until a few months ago and I had decided to replace the old signaw 4 speed with a T5 S10 manual speedo tranny I had found with open drive shaft on a Colorado rear end. Hello freeway! Anyway, since it was all apart I wanted to check out the clutch assy...That hasn't happened because when trying to turn the flywheel to remove the pressure plate bolts the crankshaft now binds after about a third revolution. I have pulled the oil pan and timing cover and pulled the crank timing gear to eliminate valve Trane problems...still no go. So I think I have narrowed it down to a crankshaft related problem. I'm now thinking I may have beat on the balancer a bit too hard and possibly bent the crankshaft? Any thoughts would be appreciated. Please don't chastise me too much as I am hearing impaired and couldn't here the balancer bottom out...my bad!

Welcome Jim J!
I have several issues with your story. As to the valve train; Pulling the crank gear has nothing to do with releasing pressure on the valves. IOW What ever position your cam was in when you pulled the crank gear, the cam is still in that position, meaning; the same valves are still open.
You've got the oil pan off. Can you see anything out of place, or inconsistent on the crank? Loose rod cap, missing rod cap bolts, bent rods?
As to the valve cover being off; how do the valve stems look? Any bent, or rusty stems?
In the end; just a guess. But I'm inclined to think the timing gears weren't positioned correctly. They may have even been the wrong ones. Ultimately; it seems like a valve colliding with the top of a piston. So (likely) valve timing. This doesn't rule out things like rust in the cylinder(s) causing a ring to seize part way through travel. But you'll at least want to be aware that because the timing gear is off your crank, you haven't released all the valves to their closed position(s).

HTH

Chris

He removed timing gear to disconnect valve train from crank to see if crank still will not turn. Which eliminates valve train as the issue or gear put on wrong. The crank shaft turns the valve train thru gears/chain.

What I read is a simple cover seal that needed balancer taken off. He "hammered" it back on, which I believe is what the manual says to do. My first thought is you can't bend the crank. You can possibly drive crank backward into something. I can't even believe that.

Put it back together and rotate motor, with plugs out, using bolts in balancer and a bar. It may free up. If it does, use starter for a short while. There may not be enough leverage at flywheel. If you have screwed up the motor real bad, throw it away and buy a runner 248 for $300. Leave the truck alone and it will leave you alone. Adding a bunch of tricky transmissions and such to an old farm truck, meant to go 45 MPH, is angering the Gods.

Hearing impaired has nothing to do with measuring depth of balancer and installing back to same dimension.

Yes Bartamos you are correct that was my intent. Plugs are out so will give your suggestion a try to try loosen it up. The engine ran great a year ago before I pulled her all apart to restore and the engine has been well looked after (covered) so no need to worry about rust anywhere inside as all looks good and clean and in the right places. Also I see your point Detroit Iron about valve timing but it hasn't been changed since it was running. I had given thought to a sticky valve (it had two bent push rods when I bought it) and will check that out. I suppose using a bar to turn it might push a sticky valve back? Lol
But I will keep my fingers crossed and hope it works...anything but a messed up crank!
Thanks for the insight .. I'll get back.
Oh and Bartamos I can't hear you when it comes to restoing
Guess my hearing aid batteries died..

Did not know you rebuilt motor. Thought is was running and you decided to fix a leak. If it was not running since rebuild, All bets are off.

For clarification, I didn't rebuild the motor, as I said it was running great when I took the truck apart to start my total restoration. Did the balancer sleeve fix and put it back on. I haven't tried to start it since the start of the build.
As said above I will try your idea and report any progress. One thing I will say is there are no problems with the valve train (no sticky valves).
As always I appreciate any and all advise...regardless if bets are on or off. Personally I like to keep my bets on the table. :-)

If you get it to rotate, and you have the pan off, consider getting rid of those two bolts that install into the timing cover from the oil pan side by tapping the two holes in the cap and drilling out the two threaded holes on the timing cover and installing bolts from the balanced side of the cover. Also, since you have it apart this far, drill and tap the crank snout for a bolt and get an harmonic balancer install tool.

https://sdparts.com/i-24132641-proform-66515-harmonic-balancer-installation-tool-fits-small-and-big-block-chevy-crankshafts.html?msclkid=a79bfb1c7a11158e0918a66dbc3eb3af&utm_source=bing&utm_medium=cpc&utm_campaign=PLAs%20-%20%2425%20-%20%2450&utm_term=4582695748898622&utm_content=Brand


https://mrhotrod6.myshopify.com/pro...-tap-fixture-tool-kit?variant=1142530609

I inherited a rebuilt engine with the same problem where the owner gave up on it. He also removed the timing gear which allows the cam to hold valves open causing the piston to hit the valve. I would remove the rocker shafts before trying to turn it with a big pry bar. His original problem was that it was way out of time.

Piston will not push valves shut, they only bend them! Get valve train in time or completely loose ( pull the rocker arms ) before proceeding with any rotating.

If this has sat for a summer or longer, its really not hard to believe it has rusted a bit, and pretty sure it's humid where you live.

Really no chance of harming the crank while beating the balancer back on. You didn't use a 10 lb sledgehammer did you?

Thanks Dragsix for the pointers to get those pesky cover bolt heads out where they can be accessed easily. It is a small easy project before it goes back together...if and when.
I'm trying to think of when it could of jumped time, when I did the balancer sleeve I didn't remove the gear. It certainly is perplexing...but what you suggest is an easy way to eliminate that possibility and I will definitely give it a try and no I used a 2lb hammer lol. If that doesn't work I guess the next step would be to remove the head to get a gander at the cylinders and valves.

Here's another thought...has anybody used a lighted phone endoscope/ borescope to inspect the cylinders and valves through the spark plug holes with any success?

It would work to check the cylinder walls, but to get it to look upward toward the valves would be a challenge. I have a $25 borescope that works on my cell phone or laptop, but the light in it it pretty weak. It's also real nearsighted, so you have to be close. Might be hard to maneuver it to get good coverage of the cylinder walls.

Unless you're planning on changing the timing gears every few days, why bother to drill and tap the main cap for access to those bolts? Timing gears last about three days past forever, and I can't think of any other reason to remove the timing cover. Even the front seal can be changed by simply pulling the harmonic balancer and leaving the timing cover installed.

My borescope works with a laptop, has a bright light, and comes with a 90 degree mirror for looking sideways. It also fits through any hole larger than .22 caliber (5.56 MM)
Jerry

Well fellows looks like I won't need the borescope for now but thanks for the great info. The problem has reared it's ugly head...as in removing the head and discovering water had indeed creeped into the #6 (most common) cylinder and did it's dirty deed. Seems it had somehow gotten past the tarp I had covering the engine and found it's way through the carb and intake to take the route of least resistance and end up in the rear most cylinder. I took a piece of 400 sandpaper to it and looks like it might clean up with a good honing. The piston was about 2/3rds the way up so being able to bottom it out I might have some room to clean it up enough to get the piston out then really go at it. Otherwise off to the machine shop.

One of the reasons for doing the timing cover conversion is to be able to replace the timing cover gasket without having to remove the pan. I had one go bad on me last year. Way easier to replace the gasket with out having to drop the pan.

Some photos

I've always believed in "Do it right the first time!"
Jerry

I am sure you do. However, for those of us who are less perfect, this old tried and true modification is a good one.

Thank you to all the Stovebolters for taking time out of your busy schedules to give your input thus far... The diversity of ideas, thinking out side the box! We may not always agree but one thing I know we can all agree on is this IS the best site for member participation BAR NONE!
Now that I am passed the balancer thing perhaps some knowledgeable bolter can advise on the best way to attack the slightly rusty cylinder walls. I was thinking honing may be a solution but hoping there may be other methods out there barring boring or even best way to hone...I am all ears, and again...THANK YOU!

Rust is hard, so make sure you cover the crank and other innards, then clean well if crank is in.

Ed

If you're planning on honing the cylinders with the pistons installed, be aware that you'll need to get ALL the hone grit out of the cylinders afterwards. I once wore out a set of new piston rings on a cross-country trip from California to Tennessee to the point that after 2500 miles on a fresh "in the frame" rebuild, the engine was using 3 quarts of oil to a tank of gas. When we opened up the engine in Nashville, the oil ring expanders were rubbing the cylinder walls, and all the compression rings were half their original thickness. I had scrubbed the cylinders down after honing with clean rags and gasoline, followed by Lacquer thinner on clean paper towels until no stains were on the paper. Clean? I thought so! Now every cylinder I hone gets scrubbed down with hot soapy water and a stiff-bristle brush, and rinsed repeatedly with HOT water.

Use a button hone the proper size for your cylinders, powered by a 3/8" or 1/2" drill motor, lubricated liberally with 30 weight motor oil, and hone until the cylinder is smooth. You won't get rid of all the rust pits, but the surface where the rings ride will get smooth. If you can hang a fingernail in very many rust pits, it's time for a teardown and a rebore job.
Jerry

Thanks to both of you for your insights. I needed to get enough of the rust out to pull the Piston so I went to a deglazing hone. The engine now turns freely so the next step is to remove the Piston. There's not much of a ridge so I am hoping the Piston rings will clear. It's unbelievable how clean and fresh looking it is inside. How many times have you heard (like I have) "it was rebuilt not too long ago" well I actually believe it this time to be true!
Anyways after that I will take a ball hone to it as you suggest keeping all parts covered under from debris, AND keep my fingernails crossed. ;-)

When you get to cam installation bear in mind that on Chevrolet 216s and 235s if the cam stops turning the crank will turn about a third to half a turn before a counterweight on the crank hits a cam lobe. I don't know if 248 GMCs are like that but I'd sure check before I used either the starter or a bar to turn it over if there's any doubt about cam timing.

On drilling the main cap to screw the timing cover bolts in from the outside, it's a handy shortcut, and a previous owner did this to mine, but that means that you have to tighten all the bolts before you put the balancer on so there's no way to center the cover and seal on the crank. The factory way you can put the balancer on then tighten the two bottom bolts from the inside insuring that it's all centered. Maybe this shortcut was done because fiber gears wear out quickly. When they strip you can kiss the cam goodbye. I had this happen to me far from home. It was stressful.