1981 sc 3.0 project / Seized engine investigation

[Mixed76]

Remove all other rods from the crank, rotate crank till it doesn't bind, lift out.

Sent from my Nokia 7.1 using Tapatalk

[reclino]

Get everything out of the way, turn crank to extend rod. Cut rod small end off with destructive tool of your choice.

[911 tweaks]

Use an air powered wiz wheel so u r not shaking everything all over the place
Anything but a recepricating sawzall cus them shake all over and what they cutting

[Mixed76]

If the bent part extends to the big end of#5 rod you may need to cut the other #5 rod bolt off, or split the nut with a chisel. You're going to throw it away anyway. That's assuming you can reach it.

Sent from my Nokia 7.1 using Tapatalk

[gs_subsea]

Thank you all for the very helpful suggestions!

I ended up attaching the pulley and used it to rotate the crank to get a little more clearance for the #5 rod , I managed to jam a socket into the nut and it came off.

The crank seemed to have loosened up after the rotation and as I was trying to pull the #5 rod clear.

I ended up having to hammer the rod bolts out and the rod came off. The bearing and crank surface for the rod, looked surprisingly smooth and intact. I thought it would have looked pretty bad considering how much force was put into it with the piston & cylinder mayhem.

I checked all the bearings and journals with my fingers and they all feel smooth apart from a scratch at the crank journal next to the #5 rod towards the flywheel side, the bearing on the right side of the case had a corresponding scratch but the other side of the bearing on the left case was smooth.....

I saw copper on the intermediate shaft left case side of the second bearing, right side bearing looked ok

Oil pump spins smoothly, will take it apart to clean it soon.

Here are a few pictures, would appreciate any insight observations

Thanks in advance

[reclino]

When you take the oil pump apart be sure to mark the gear location, and mesh relative to it's corresponding gear. They prefer to go back exactly the same as they have run. Otherwise it might bind up.

[gs_subsea]

Thank you so much reclino! very timely advice, I will make sure to do so

With respect to next steps, I am thinking about doing the following:

- Look for used case / thought I had one secured but unfortunately I got some bad news and it didnt work out...
- Email pics to Ollie's to get a quote and opinion on whether my case can be saved
- find local Houston machine shop to send crank and other items to be measured

If anyone knows any good Houston TX machine shops for case / crank / head work, I would very much appreciate your suggestions

[Flat6pac]

Buying a complete core will be less costly
Make sure the crank isn’t bent and be careful of the case repair hang time
Intermediate shaft bearings always show wear from the tensioner pressure
Bruce.

[gs_subsea]

Thank you Bruce. I did have a deal for a long block that unfortunately did not work. I am on the lookout right now for other options.

What do you mean by case repair hang time? Taking too long at the shop doing the repair?

Thanks again

[Jim2]

Whenever I look at the pictures in this thread I wonder how long the person kept driving the car with the engine rattling away, don't get that shot peened appearance after an instant shutdown.

edit: sorry for the pointless post.

[gs_subsea]

Jim,

I think you are right, someone must have kept going after a bang and some smoke....
I am actually very curious myself to piece together what happened, unfortunately I don't have a lead to the story as this happened in 2009 and it looks like 2 owners before me picked up the car and did not start the project.

Now that I have everything taken apart and aside from the obvious # 5 piston - cylinder - bent rod and case damage, I saw the following:

- #5 head while beat up still has both valves attached
- all other heads and pistons look fine with no sign of valve to piston collision / this somehow makes me doubt that it was an over rev from a money shift. Wouldn't all the valves have kissed the pistons in that case?
- Everything on the motor came apart real easy, the stud barrel nuts were nice and shiny, the exhaust stud nuts came off very easy and the rest of the pistons / cylinders looks relatively unmolested. I am thinking this engine died very shortly after it was rebuilt...
- Rocker arms on intake side driver side 1/2/3 were all broken, the rocker arm foot on #1 was missing and it actually punched a hole in the valve cover!!
- The other intake side only had the #5 rocker arm broken
- Exhaust side rocker arms all intact apart from # 5 which was broken
- Both camshafts lobe surfaces look great

When I opened the chain covers, I found on both sides the chains were tensioned and the hydraulic tensioners were ok.

When I took the cam nuts off, the inner cam timing sprocket gear had two teeth missing, same on both sides...

I am leaning to what Fred said earlier that the #5 piston somehow failed and the failure wasnt enough to keep the engine from going

Any theories?

Thanking you in advance

[Walt Fricke]

deleted - answered

[Mixed76]

Why would #5 piston failure lead to all those broken rockers?

Sent from my Nokia 7.1 using Tapatalk

[Flat6pac]

Broken rockers because the cam setting pin wiped two lobes off the cam gear backing plate.
Bruce

[eastbay]

Maybe I missed it, but where were the missing piston pieces?