Crankshaft won't turn over 360 for valve adjustment

[Sean M Rooks]

Boy I hope this is something simple - I haven't fully troubleshot this yet, but when I just tried to make a full rotation of the crankshaft to check valve clearances, it hangs up just before TDC. Plugs are out. Feels like it's binding on something and I am hesitant to force it. I could use advice from the 356 engine experts.

I got to the point of nearly buttoning everything up on my (cosmetic) engine refresh (see here: https://www.instagram.com/p/BZHLhhzlfXe ... =seanrooks). I did nothing deeper than the rocker assemblies. Here are some of the things I did in this process:

crank pulley seal
flywheel oil seal
gland nut
cylinder head o-ring seals (removed the rocker assemblies to do this obv)
oil sump plate gaskets
plugs
removed distributor (was going to paint body, changed my mind and just put a new condensor on and reinserted)

That's pretty much it I think. Everything was torqued to spec including the gland nut to between 350 and 400 ft lb. Followed the workshop manual for pretty much all of it including rocker removal and reinstall.

Intakes and such were covered during all the work. It's possible something went in there but I kind of doubt it.

The crank will spin both directions, clockwise and counter-clockwise and it stops maybe 5 or 10 degrees before the OT gets to the mark on the 3rd piece coming from either way.

Did I mess something up when I put the rockers back on? I was well on my way toward finishing things up for Helen next week.

Engine is still out of the car.

[David Jones]

First guess is that you have one pushrod that is not seated properly. It is hanging up on the edge of a lifter. Problem is the engine should rotate almost two revs for that to happen. For it to happen when you cannot go a full revolution it is not camshaft so look at crank. As you removed the distributor if you turned the engine while it was out you could have displaced the drive shaft but again no likely as the fuel pump pushrod would stop it raising up.
Just check all clearances and look closely at the valve train. worst case pull the rockers and see if it turns over then carefully re-install everything if it does.

[Sean M Rooks]

David,

Thanks for the quick reply. I'll start there at the valves.

It's possible the crank was turned while the distributor was out. The fuel pump was not installed at the time (there was a block off plate there). Does that make a difference?

[Sean M Rooks]

Shoot David I misspoke. I can make a full 360, just not twice as you said.

OT can pass the mark on the third piece once, but not twice. Second time around is where it binds near TDC.

[Charles H Jacobus]

Good one Dave!

ChuckJ

[David Jones]

Yes it makes a difference. There is nothing to stop the distributor drive gear from raising up in it's bore when you rotate the engine if the fuel pump is not in place. You can damage the brass drive gear on the crank so that is a possibility. If you remove the fuel pump you can then remove the distributor drive gear and see if the engine will rotate. Usually the gear can be fixed with a fine file.
If you can go almost twice around it sounds as though it is a hung pushrod as the valve is trying to open from both directions and cannot as it is always hung up. Look at which valve is trying to open as you turn the engine and you will likely have the culprit.

[Sean M Rooks]

Dave: just pulled the rockers and she rotated just fine past the bind. Going to carefully reinstall now and cross my fingers!

[Sean M Rooks]

That was it!!

She rotates beautifully through the full two revs. Thanks a ton, David! My mind went all kinds of scary places wondering what was wrong!

[David Jones]

Excellent result Sean. Congratulate yourself for stopping before you bent the pushrod. Hope it runs well down to Helen. I just wish I could be there. I really enjoyed the last get together. A bunch of really nice people turned up and some really nice cars as well.
Here is a shot of the parking lot at the winery lunch.