'73 tii engine rebuild

[Summit321 123]

Hi all,

I am rebuilding my engine and ran into some trouble with torquing down my connecting rods (40 ftlbs). I had my crank shaft polished and it is original size. I am using new stock conn rod bearings. Crank becomes very difficult to rotate with one rod torqued and it is impossible with 2. I am using two flywheel bolts and a long screwdriver to rotate it. I checked bearing clearance and it is about .0025 which I think is normal. After torque and one rotation the bearing on the rod cap side had coating loss and scoring, mostly on one side. The other had a bit also. Side clearance is .005-.007. What am I doing wrong? Rods backwards? I'm using 50/50 assy fluid/oil. Not sure if I uploaded the pic properly.

Thanks,

Summit

[bergie33]

I had the same problem with my 74 tii engine when I rebuilt it. I loosened up the rod and main bolts and torqued them back down and all was good with the world. It's easy, might be worth a try. 

[jgerock]

Look at the back of both rod and main bearings before installing them. Don’t trust the packaging they come in.

[Son of Marty]

Are the rod and cap numbers on the same side? With the rod pin oil hole facing the front of the engine and the arrow on the piston facing forward.

[jimk]

Make sure the tangs on the bearing caps are oriented per the book.  As I recall the rod caps are not oriented like a many other engine designs.

[TobyB]

You did keep the caps with their respective rods, right?  

 

t

made that mistake once.

[Summit321 123]

On 9/24/2023 at 6:59 PM, Son of Marty said:

Are the rod and cap numbers on the same side? With the rod pin oil hole facing the front of the engine and the arrow on the piston facing forward.

I will double check the caps. There was no direction indicator on the pistons they are from ross, but they I think I have them the right way from the picture. Can I still see the rod pin oil hole?

[Summit321 123]

19 hours ago, TobyB said:

You did keep the caps with their respective rods, right?  

 

t

made that mistake once.

Almost positive...

[Summit321 123]

On 9/24/2023 at 6:59 PM, jgerock said:

Look at the back of both rod and main bearings before installing them. Don’t trust the packaging they come in.

Packaging was a bit weird and not really labeled but they looked good.

[jimk]

Plastigage is your friend.

[tech71]

You used some sort of assembly grease ? What was it exactly and how much did you apply?

Excessive amounts of assembly paste/grease can lock things up tight.

Edited September 26, 2023 by tech71

[Summit321 123]

22 minutes ago, tech71 said:

You used some sort of assembly grease ? What was it exactly and how much did you apply?

Excessive amounts of assembly paste/grease can lock things up tight.

I'm just using tacky assy fluid thinned out with some oil. I flipped two of the end caps and it spun much better. Is there any way to make sure the rods are facing the right way?

[Son of Marty]

Yes the rod numbers are on the same side and the piston pin oil hole facing the front of the engine. Also the bearing shells need to go together tang to tang.

Edited September 26, 2023 by Son of Marty

[kbmb02]

2 hours ago, tech71 said:

Excessive amounts of assembly paste/grease can lock things up tight.

I am having a difficult time imagining that. Wow?!

[tech71]

20 minutes ago, kbmb02 said:

I am having a difficult time imagining that. Wow?!

I over did it using redline assembly paste, might have been on the mains but same deal.

Buttered stuff up pretty good and…No spin no turn

Guess a little dab really will do ya

Edited September 26, 2023 by tech71