"Turn Like Butter"?, Engine Assembly Options

[Highland]

I'm sure none of you remember but I posted a few months ago an engine that I rebuilt where apparently I did not align the pin correctly to the main bearing. Engine seized after a bit over 500 miles. Fortunately after a visit to the machine shop the damage was minimal.

I'm at the stage where I have the case torqued together today. Internals are all in with rods hanging out. With the flywheel the engine turns pretty loosely compared to my first build. My main concern is when I get to about #1 TDC I feel a loose spot where there's noticeably less drag.

I've read the term "it should turn like butter" over and over, but that means nothing to me.

Should the resistance I feel be even throughout the entire rotation?

If I can feel any hint of difference should I open it back up.

I don't want to open it up for no cause since there is a risk I'll screw something up upon reassembly if everything is okay now.

Thanks for any advice.

[colingreene]

What did you assemble it with, oil or assembly grease, is the oil pump in the motor, are the lifters in the motor.
If you still have problems with it you can bring it to me and i can go though it.
But yes, i remember you not aligning the pin.
It should spin free the entire way through the revolution, I suspend the rods with rubber bands when i go to test how it turns so they cant drag on anything.

[porschetub]

I'm sure none of you remember but I posted a few months ago an engine that I rebuilt where apparently I did not align the pin correctly to the main bearing. Engine seized after a bit over 500 miles. Fortunately after a visit to the machine shop the damage was minimal.

I'm at the stage where I have the case torqued together today. Internals are all in with rods hanging out. With the flywheel the engine turns pretty loosely compared to my first build. My main concern is when I get to about #1 TDC I feel a loose spot where there's noticeably less drag.

I've read the term "it should turn like butter" over and over, but that means nothing to me.

Should the resistance I feel be even throughout the entire rotation?

If I can feel any hint of difference should I open it back up.

I don't want to open it up for no cause since there is a risk I'll screw something up upon reassembly if everything is okay now.

Thanks for any advice.

It should turn with even resistance right through fully 360 degree rotation,what was done to put your original mistake right?.
Remember you have only one chance to get this right as you have unfortunately found out...not worth it again,did you test fit the one piece bearings in the case for example to make sure they were true to case centre line?,as in fully down and located on the dowels.

[tomrev]

Near TDC when rotating the crank, it always seems to turn easy, as the pistons are slowing to a stop, and starting back down; this takes a chunk of rotating degrees, while having minimal ring drag, and feels like no resistance till the piston begins moving again. This may be what you are feeling.

[tomrev]

Near TDC when rotating the crank, it always seems to turn easy, as the pistons are slowing to a stop, and starting back down; this takes a chunk of rotating degrees, while having minimal ring drag, and feels like no resistance till the piston begins moving again. This may be what you are feeling.

Beg pardon; didn't read the part about no pistons!

[Highland]

Thanks for all the replies.

The machinest smoothed out the saddle area and replaced all the bearings. He returned the crank torqued in the case so I'd know what it felt like. He said that once the cam was installed it might feel different because of the meshing of the gears.

Like before the case halves came together pretty easily and like before I verified the bearing were completed seated in their case saddles. The last time I took the case apart multiple times cause I thought there might be a problem cause it was so tight but found everything seated every time.

Is there anyone near Carlsbad I can bring my partial assembly to so they can tell me if it rotates properly? Otherwise I guess I'll just bring it to my machinest on Monday.

[colingreene]

Im in South Orange county, thats not far, I can come by if you would like.

[r_towle]

I'm sure none of you remember but I posted a few months ago an engine that I rebuilt where apparently I did not align the pin correctly to the main bearing. Engine seized after a bit over 500 miles. Fortunately after a visit to the machine shop the damage was minimal.

I'm at the stage where I have the case torqued together today. Internals are all in with rods hanging out. With the flywheel the engine turns pretty loosely compared to my first build. My main concern is when I get to about #1 TDC I feel a loose spot where there's noticeably less drag.

I've read the term "it should turn like butter" over and over, but that means nothing to me.

Should the resistance I feel be even throughout the entire rotation?

If I can feel any hint of difference should I open it back up.

I don't want to open it up for no cause since there is a risk I'll screw something up upon reassembly if everything is okay now.

Thanks for any advice.

Did the machinist check to see if th crank is straight?
In the condition of your motor, with no oil pump, no Pistons, and really no other potential resistance except the crank and camshaft......something may no be straight.

[r_towle]

My wife's cousin used to work for a few famous vw race shops as the engine builder, he lives in poway, and he is a vw nut....

He may be available to take a look if you want me to reach out.

Rich

[porschetub]

I'm sure none of you remember but I posted a few months ago an engine that I rebuilt where apparently I did not align the pin correctly to the main bearing. Engine seized after a bit over 500 miles. Fortunately after a visit to the machine shop the damage was minimal.

I'm at the stage where I have the case torqued together today. Internals are all in with rods hanging out. With the flywheel the engine turns pretty loosely compared to my first build. My main concern is when I get to about #1 TDC I feel a loose spot where there's noticeably less drag.

I've read the term "it should turn like butter" over and over, but that means nothing to me.

Should the resistance I feel be even throughout the entire rotation?

If I can feel any hint of difference should I open it back up.

I don't want to open it up for no cause since there is a risk I'll screw something up upon reassembly if everything is okay now.

Thanks for any advice.

Did the machinist check to see if th crank is straight?
In the condition of your motor, with no oil pump, no Pistons, and really no other potential resistance except the crank and camshaft......something may no be straight.

(IMG:style_emoticons/default/agree.gif) but not really normal to see these bent but good point ,OP never answered what the crank was like on the main bearing that seized,hope he has the crank polished on that journal......

[Highland]

Thanks again. I'll just take it to the machine shop and see what he thinks. Was hoping there might be someone "street" local.

Yes, the crank was polished and visibly no damage. I can ask about straightness. When he returned the parts to me the crank was torque in the case so I think he was gauging straightness by the way crank rotated in the case.

Forgot to mention I've got both assembly grease and Lucas assembly lube in there. Although that probably doesn't make a difference.

[craig downs]

Was the clearance for the cam ever checked? You need .002 end play.

[Highland]

No. I didn't know about that specifications. Would that cause this symptom?

[craig downs]

The thrust bearing. You need .002 back and forth clearance.