Purple Bus Engine Rebuild

[jules]

Yet another engine rebuild thread. This one sure to have some thrills chills and surprises and hopefully a happy ending who's costs don't exceed that of the rent.

I bought this bus for pretty cheap with the intent of using it as a winter driver. Engine ran terribly. Compression tests reveal 120/120/70/120. Low on #3.

Also, temp sensor broken off in head.

Enough reasons to pull the engine and see whats going on and try to fix a few things.

I started the tear-down tonight.

The top of this engine is covered in layers of gunk everywhere, mouse nests, leaves, extra nuts and bolts, disintegrating pieces of old engine seals, all kinds of stuff.

Then we started getting into the fun stuff. 3/4 injectors came out and #3 injector is clearly damaged.

3/4 intake runner comes off and my jaw drops to the floor:


http://picasaweb.google.com/lh/photo/hR ... directlink

Yes folks that's a spark-plug sitting IN THE INTAKE!!

How the heck could this happen?? It seems like it would actually take a bit of work to get it there, I can't see it making it around the corner of the intake runner. It must have been accidentally left in there while the intake runner was off. Wow. just wow.


http://picasaweb.google.com/lh/photo/9b ... directlink

this might get interesting

jules
'75 "autumn" daily driver
'78 "purple boy" winter driver(currently running a 1600dp)
'78 spring project

[Sylvester]

As the old show used to say, "That's Incredible!"



Looks like something I would do.

[Amskeptic]

that's a spark-plug sitting IN THE INTAKE!!

How the heck could this happen??

Boggles the mind. Makes you paranoid about the condition of the mind of the engine rebuilder.

"Dude, where's the spark plug?"
"What's a spark plug?"
"Hey look, here's four new ones."
"Saved! This thing's gonna run so AWESOME!"

Colin
(note: keep a count of your parts and "checksum" along the way)

[jules]

Well, got the 3/4 head off.

It's not pretty. If you have a weak stomach when it comes to such things you might want to turn away.

Apparently it took a while for the other half of that sparkplug to smash itself to death, and it took its toll in the process:

The head:



And the piston:



The cylinder wall (not pictured) doesn't look too bad but one of its cooling fins is chipped off.

Not too surprised or upset, this is what you get with a $700 bus.

In the evaluation phase trying to figure what i'm going to do with this engine next. Some options:

* replace a single piston/cylinder/head try to get some more life out of this engine
* use the engine for parts, putting the working FI and hydraulic lifters on my '75 daily driver, currently 2.0 with solids and a single webber
* start a ground up rebuild of this engine as time and funding permits

In the meantime I'll finish the details on the 1600dp install into the purple bus from which this broken engine came.

jules

[hambone]

You are brave to take this on in NY, but with the new cyber world it's like remote surgery. Good luck! Ask lots of questions. I do continuously but the ducks and dogs (etc.) are starting to get annoyed.

[Amskeptic]

Clean it up, smooth the sharp edges where they may exist, and put it back together. That #3 combustion chamber and piston crown have merely been shot-peened stress-relieved (of course, it looks like someone used CV balls instead of buck shot, but hey). Number 3 looks no different than #4 as far as general oil consumption. Pull the valves and check the seats, maybe lap them a little, if the cylinder walls are good, just oil the hell out of them at reassembly. Then drive that engine as far as you can. Surprise yourself.
Colin

[jules]

While not the response I expected from you Colin I am encouraged by it.

Nothing to lose by giving it a shot.

Do you think the presence of the plug in the intake alone would have been enough to reduce compression to 70 on that cylinder?

Will report back as things progress.

Thanks
Jules