Finished dismantling my second 3.2

Dadofour · Dadofour's Garage

I bought an engine in pieces last year. I got the engine into my car this past summer and now have over 1500 miles on from track use as well as breakin.

I felt confident enough to take my original 3.2 and start to break it down for rebuilding, so this is the first engine I have seen broken down and not cleaned and machined.

I was surprised at how little wear was visibly apparent.

This is the bearing for the timing chain sprocket. Is this wear because the timing chain is pulled against this side of the bearing where the timing chain wraps around the crank?

This wear is the last bearing on the crank at the flywheel. It's the only crank bearing to show any wear at all. I am leaving the bearings in place for the machinist to see if these mean anything.

Is this normal because the greatest force is here because there is no other bearing beyond this point?

These are the crank bearings and you can see they are nice

I know there is a lot of debate on whether we should use o-rings and oil or o-rings and silicone. I used o-rings and oil on my rebuild.

I have to say this looks a lot like the factory uses a sealant other than oil and o-rings.

Thoughts?

Boxer 6 · 12-02-2006, 06:35 PM

Hey Than,

Looks like you have been very busy. How many miles did this motor have?

Dadofour · Dadofour's Garage

142k Mark. Amazing how clean the engine is even after 142K.

The engine was running great, but the oil cooler had a nagging leak so I figured I would use it to stretch the next rebuild past a stock configuration. I think you and I are heading in very similar directions

88-diamondblue · 12-02-2006, 07:57 PM

The blue around the case through bolts are the remnants of smashed blue silicone o-rings. My intermediate shaft bearings looked the same with 86000 miles. Another thread commented that most intermediate shaft bearing look like this. Not the greatest picture.

Dadofour · Dadofour's Garage

Michael,

I considered that, but I had a hard time imagining the o-ring being crushed so badly that it was under the washer and not in the recess it is designed to float in.

Most of the o-rings were a mess, so are probably right.

Than

88-diamondblue · 12-03-2006, 07:19 AM

Than,

I used the green viton o-rings with my rebuild because of seeing how many times these blue ones get smashed during installation. There are some other threads that show them coming out of the washer as they were being installed. Consider using the viton seals on the engine rebuild, they are much tougher and only cost a little more. Lots of fun ahead.

Dadofour · Dadofour's Garage

Viton o-rings. Git it! If the normal o-rings be smashed like that, then they will never funtion as designed.

I appreciate the tip.

cstreit · cstreit's Garage

Dadofour,

Pretty typical... The ble ones are super soft and do get crushed easily, hence the use of the viton ones...

Determined · Determined's Garage

I'm using the viton green o-rings in my 3.2L rebuild as well, in addition I believe Wayne's book recommends putting some Black high temperature silicone (Loctite) around the o-rings as well. Don't forget that the surface must be very clean to properly seal and if your case thru bolts use the beveled washers you can reuse them after a good cleaning. Good luck, I'm nearly completed with my complete engine rebuild.

Regards,

Alex

boxermania · 12-05-2006, 08:29 AM

Dadofour.....

That engine and the bearings look great, the cam bearing, is past the babbitt but not bad and the last main is not bad at all, just a little polished.

Let me see if I can explain the bearing "wear" that you see:

On the cam bearing - If you draw a force vector in the direction of the force exerted by the wrap of the timing chain on the sprocket you should find that it is in the direction of the "wear"
Yes, it is due to the force of the chain on the sprocket. This is not to be considered a failed bearing, but one approaching the end of it's design life. What you see is the oil film being pushed to it's limit (over 146K miles) a little more surface area on the bearing would have added to the wear capacity.

On the last main - Think about the flywheel and its weight hanging off the crank and then the last two opposing rods/pistons "yanking" on the crankshaft back and forth in the direction, I will bet if you can visualize this, you will see that the "wear" is in the direction of the piston pull. Now I need you to visualize an ever so slight movement of the shaft at that end caused by opposing forces of the pistons pulling on the loose end of the crank. Another possible explanation would be a slight out of round condition on that saddle, but the "wear" is so slight that it doesn't support that theory.

Basically there is nothing wrong with that assembly. Micro polish the crank, throw in some new bearings and close that engine., assuming that the rod bearings are OK and the big ends are not out of round.

Now you peaked my interest, how do the cylinders look, can you see the cross hatch still? How is the wear at the top of the cylinder?

Dadofour · Dadofour's Garage

Al,

That is a great explanation. Thanks for taking the time to map it all out. After I removed the first cylinder and piston I checked the cylinder and was suprised to see cross hatching.

I did not check the top of the cylinder, but now you have peaked my interst so I will pull out the crate and check them before I head to the machinist in a couple of weeks to go over everything and figure out what can be reused and what excuses I have to upgrade

boxermania · 12-06-2006, 04:39 AM

Dadofour

If you saw the cross hatch you will also be surprised, after you measure, to find little wear. That being the case there is no need to change anything.

Let me caution you, not to mix cylinders and pistons and even barrel locations on the engine. Even though the wear might be well within the specs, do realize that each piston/cylinder will wear in differently as each cylinder will experience different heat/cool cycles.

Last but not least make sure that when you assemble the engine position the oil ring gaps preferably at the top of the cylinder, never at the bottom.....do you know why?

Good luck and keep us posted

Dadofour · Dadofour's Garage

I marked the cylinders and pistons prior to removal, so there will be no mixup. I am hoping to have an excuse to upgrade pistons to increase compression. My first rebuild was a stock rebuild, but I want to experiment with this one a little.

I setup my first engine with Oil ring gap up and two other rings to opposite sides.

I can't remember Wayne's explanation, but I assume it is to seal the oil out of the combustion chamber that pools at the bottom of the cylinder.

????

boxermania · 12-07-2006, 02:56 AM

Yep....being a flat or pancake engine there is a potential for oil to get into the cylinder, unlike V engines whose cylinders are on the vertical and have gravity working against it, once in the cylinder the oil will be "scrapped" by the oil ring.

If the oil ring gaps are at the bottom, some of that oil will find it's way past the ring gaps, eventually finding it's way to the combustion chamber........