crankshaft help

[jlw35]

Situation:

'75 spider (1.8l)
Timing belt off, cams properly aligned, aux shaft at proper position, crank set at TDC.

When I rotate the crank using my socket, it moves freely from the approx. 1 o'clock position to approx. the 7 o'clock position (going clockwise), and when going counter-clockwise it will move freely to the approx. 8 o'clock position.
In either case, I cannot move it past those positions (hits up against what I would term a "soft bump" rather than hearing a loud clank).

I've moved the aux. shaft to different positions and this has no effect. In addition, when I hit this stop, I have kept pressure on the crank nut and freely moved the aux shaft at the same time to see if this would matter, and it has not.

As a matter of full disclosure, I had previously replaced the timing belt, started the engine ( which produced a loud clatter) but shut it off immediately. Prior to that start,I had rotated the motor several times by hand to be sure of no problems and it moved freely.

Thanks in advance for any and all advice.
Jeff

[ScotcH]

You can't rotate the crank all the way without the belt on ... you're hitting valves.

[jlw35]

Scotch,

Great. Just what I am looking for. I'll put the belt on and see what's next.
Thank You.

Jeff

[jlw35]

OK belt is on, same scenario as above, cannot get the crank to rotate past the numbers as listed above.

Any ideas?

Thanks
Jeff

[RoyBatty]

Your intake and exhaust pulleys may be reversed.

[jlw35]

Yeah, but I did not have those off.

[redcars]

When you started it before and had noise you could have bent valves and now the do not close. One you hear noise it is already to late to prevent damage.

[RoyBatty]

They may have been wrong when you got it.

[RoyBatty]

Remove both cam covers.
Carefully try to turn the engine so that one of the cylinders is at top dead center compression.
Look at the position of the cam lobes for that cylinder.
Are the high points of the lobes pointing away from the shim buckets?
Check this for all cylinders that you can.
Report back here with images if you can.

[jlw35]

Thanks RoyBatty

I'll get to that this weekend.

Jeff

[RoyBatty]

Also, take note of whether or not you have any valves hanging up in the open position as you turn the engine thru.

[jlw35]

RoyBatty

Cambox covers are off, no deformity on the tappet covers (look smooth and no gouges).
All move smoothly.
Crank still only moves to the same relative clock positions mention in the first post.

Next step, I suppose, will be to remove the head and check for any foreign matter in the cylinders, connecting rods deformity etc.

Sound reasonable?

Thank You
Jeff

[RoyBatty]

Based on the problem you describe,I think that's the direction I'd be going.
Not at all hard to do

[jlw35]

RoyBatty,

Going for it this evening, really doesn't look too intimidating as you say.

Thanks
Jeff

[jlw35]

So I pulled the head, about a 2 hour job for me. Mostly, taking pictures and making notes of where all the lines, etc. go.
I left the intake manifold (with carb attached) and the exhaust header on the head.
After lifting it off, I was , thankfully, able to rotate the crankshaft without interference. Pistons moved freely. The #2 had what looks like a small indentation in the shape of an "o" (like a small washer) on it. Haven't had a chance to clean anything yet, done for the night, maybe get to it tomorrow.

Have not looked at the underside of the head yet, just set it on the table for now.

Feeling better about the motor now as it seems that the problem will be valve related.