Finally got my motor up on a stand after getting it from the machine shop about 2 months ago and the motor has been wrapped up so its nice and pretty...except for a tiny crack about 13/4in long right behind the rear cylinder push rods on the passenger side...it looks to be about the width of a piece of hair literally, so do yall think its in the casting or do i have an issue before i finish putting the motor together? Its a L69 305 from an 87 Monte Carlo, .030 over, mild cam, flat tops, ect. Nothing fancy, but i want to know everyone's opinion before i move along...

 

Yes it's an issue.

That's the most common damage that results from freezing.

It shows BEYOND ANY SHADOW OF DOUBT that the engine froze.

The block is garbage. (even more so than on account of being a 305 in the first place, as if that wasn't already cause to throw it in the trash)

 

So you think it would pass through the machine shops process completely? I took them the block and heads completely dissassembled and they did all of the machining and assembly with a warranty...and it was supposed to be magnafluxed

 

As well...the motor was low mileage and running like a champ when i bought it. Car only had about 70,000 original miles and i saw it run with my own eyes. I just did the full rebuild because it was out and cheap.

 

Ive heard a lot of the newer blocks are prone to lifter valley cracks. The one you mention sounds kind of large, though. Most of the ones they're prone to are small enough to need a magnafluxing to see.

http://www.hotrodders.com/forum/crac...ey-146706.html

There are many other examples, but these cracks are common and usually come from blocks that had no issues in their prior lives. Maybe they were frozen and just didnt get damaged enough to cause issues. Maybe it's something else. I dont know, but I'd say it's probably just going to be a gamble on your part as to whether or not to stick with it. Since it's a 305 I'd just go find another 305 block. An LG4 block isnt any different than an L69 block. I guess since it's an 87 you need an LB9 or L03 block, but still, those shouldn't be hard to find. But if you've already made the machien shop investment, I'd just run it and see what happens.

 

Im gonna call the machine shop tomm and talk to them. Its on the raised area that is the "sleeve" where the head bolt runs through and its just irking me so damn bad. Depending on what they say tomm will sway what i do.

 

False and false.
Such cracks are more common in the '87-up blocks, but Monte Carlo SS had the L69 into '88, so a cracked L69 is possible. And when the '87-up blocks do it, it is from stressing a thin casting.
I had such a crack in the 350 that pushed my '88 IROC to a 10.21 second 1/4-mile pass. Just took a bit of leftover block filler, poured with the block carefully angled so most of the filler was resting around the crack, in the water jacket.
That block is still in daily use without issue, in a friend's farm truck.

 

Wait..... what? Head bolts are nowhere near the lifter valley. Are you saying it starts up on the deck where the heads bolt on? If so, that thing is JUNK. A crack running down from a head bolt hole or the deck surface into the wall of the lifter valley is BAD juju.

Just make sure it's actually a crack, not some sort of casting imperfection. (Which should be ground flat, even if that's all it is, to prevent a stress-riser).

The REAL problem with cracks is that they GROW. Once they start, they don't stop. It may leak little or none right now, but it will. Just give it time.

 

If you are looking in the valley between the heads...it runs with the motor long ways, like in the direction of end to end, and it is located on what seems to be the area that the head bolt would run down into the block. You can only see it with the intake off...I'm trying to figure out how to upload a pic.

 

We've all seen it before; no need for a pic.

It's from FREEZING. Temp goes below zero, owner hasn't got enough foresight to put anti-freeze in it.

Super commonplace.

But of course; especially the part where they cash the check. I GUARANTEE it went through that part of the process smoothly.

"Magnaflux" my horse's a$$.

Throw it in the trash. Write it off as a hard-won learning experience. Maybe, a warning that you shouldn't have been messing around with a 305 block in the first place. Move on. What's done is done.

 

http://m1361.photobucket.com/albumvi...30400.jpg.html

 

Very true gents. I appreciate the advice. Ill be calling tommorow, maybe my one saving grace will be this warranty they gave me. Sometimes this camaro can be so dis-heartening. There's the pic i figured it out. Ill sleep on this, finish my beer first of course and figure it out tomm i suppose.