302 cubes for Suburbia

[1project2many]

Well... after another week of crazy late nights and a marathon session at the shop yesterday I got to hear the 302 run. For about 10 seconds. Turns out I've got something wrong inside the engine. I've built quite a few engines over the years and except for the first one I ever tried to build back when I cashed my paychecks at the liquor store I've never had a major problem. But this thing's turning pushrods into modern art in just two or three crank revolutions. My guess right now is that either the pistons were installed on the rods incorrectly and I didn't catch it, or they were installed correctly but I flipped the rods 180 degrees. Either scenario would put the valve reliefs on the wrong half of the piston. Very frustrating. I just ordered a cheapie reman crankshaft for the 5.7 that came out and I'll be putting in more late nights putting that back together and back into the 'burb so we can use it for Christmas. Then I'll dig back into that 302 and see what the $%^ I messed up.

[EagleMark]

Well that sucks! Especailly when you know better. I went through a bunch of pushrods with a big cam on my first motor build in high school. Didn't know anything about releifs back then...

[dave w]

Well, I have a similar not good engine rebuild experience to share. See pics below. SBC 406, 6.0" rods.

dave w

[JeepsAndGuns]

Dang dave, what happened to that thing?

[1project2many]

Thanks for sharing. 406 parts aren't cheap especially with those long rods.

What's the pink stuff?? Obviously something hard enough to do damage. Piece of a bolt or screw that got sucked in?? Is that groove too deep to run?

[dave w]

The engine was fresh from the machine shop, which also assembled the engine. It appears to me, something foreign was in the ring compressor when the piston was installed into the engine. I'm requesting the machine shop sleeve the damage cylinder, at their expense.The machine shop insists the cylinder only needs a hone. Drama, Drama, Drama, I can't say I want to do business with a machine shop that is reluctant to fix the problem the way I think the problem should be fixed.

Anyway the first picture shows how the piston valve reliefs should be installed.

I'm not sure what the pink stuff is, paint from the rings or maybe assembly lube?

dave w

[1project2many]

Dave... Are you saying it's part of a ring compressor?? For 4" bore engines I have a nice, adjustable tapered aluminum compressor that I use. I'll be using it tomorrow if all goes well.

Pulled heads and pan but left the block in the truck. Pistons are installed backward. Rods, however, are installed correctly. So the machine shop assembled pistons to rods incorrectly but I'm still a bonehead for assembling it this way. I built the engine between the time I injured my back and the time I had surgery and all I can figure is the pain killers I was taking had something to do with it. It's no excuse but I can't see any other way I'd let something so obvious go. So tomorrow am I arrive at work early and knock the pistons out. During the day I'll either send the rods/pistons to another shop or try my hand at disassembly / reassembly using a torch to loosen the pressed pins. Hopefully the local GM dealer will have the head gaskets I used in stock so I don't have to wait for those. Part no 10105117 .028" compressed thickness.

Now I have a 45 minute drive ahead of me to get home so I can catch a few hours sleep and be back up at 4:30 to head back to the shop.

List of things to bring in from home tomorrow:
Tapered Ring Compressor,
Coppercoat
Toaster oven for heating rods
Patience, patience, patience.