runpasthefence

iTrader: (2)

L92 swap in a B-body Chevy. Was pretty much finished a month or so ago, but I've had an oil leak from the oil pan since first start up.

First startup: oil streaming out oil pan near starter
- dropped pan, re-sealed the pan corners with RTV

Leak still present, but much slower
- dropped pan again, resealed with Hondabond

Leak still present, even slower, but still too much to live with

Previously, I had only dropped the pan low enough to clean, apply RTV, and re-torque the pan in the hopes that I wouldn't have to drop the transmission or bull the engine. But I bit the bullet after wasting way too much timing farting around with RTV and I pulled the engine today with a plan to check tolerances and replace the gasket.

I was worried the rear cover was misaligned, but both sides are nearly identical, and the "drop" from the rear cover to the block's oil pan mating surface is somewhere around 0.004" (I've read that less than 0.020" is within spec).



I started getting a suspicious about the block to pan mating surface. I had the block gone through by a local machine shop, so I didn't pay too much attention to surfaces when assembling the engine. I checked around with a straight edge and don't see any low spots, but I did find this on the block to pan mating surface near where I found the leak.



I'm just looking for some feedback - what's the likelihood that this scratch is my culprit? If it is, what's my best next course of action? Some light sanding to take the edge off? A filler of some sort?

MuhThugga

Did you put RTV on the heads of the side bolts that go into main caps?

runpasthefence

iTrader: (2)

Short block was assembled at the machine shop, so I can’t say for sure. Probably not a bad idea to check while the engine is out.

I think I was able to visualize the leak from the pan mating surface while the car was running, but I could be mistaken.
I’d think the leak rate wouldn’t have changed (from streaming to dripping) with each re-mounting of the oil pan if it was one of the side bolts.

LS1 TJ

So I will be a super debby downer.
A friend of mine bought a salvage yard iron block 6.0. Super low miles like 6K.
But it had a busted oil pan. He put it in 72 Nova with a 2002 Camaro oil pan. Started it up and had an oil leak from the back of the engine. Ok out the engine comes and new real seal. Engine goes back in. He fires it up and it still has the oil leak from the back of the engine.
Engine comes out again. Further investigation reveals the back of the block is cracked right behind the two long small diameter bolts in the back of the pan. Those bolts are right next to the block oil galleries. The hit to the oil pan cracked the block.
Hope that isn't the case.

runpasthefence

iTrader: (2)

Same. I've been concerned about this too bc the initial purchase of this block was with a less than honest forum member. I've looked, but I don't see any indication of block damage other than that scratch on the mating surface.

I've also had the pan on and off 3 times now, and each time the leak got better with more/better sealant? I would think a crack would leak the same regardless of how much RTV I use on the mating surface.

IDK; I'm going to spend some time with it tomorrow and see what I find. If anyone has any thought on that scratch, I'd love to hear them. Sent my machinist a message and nothing back yet.
I'll probably do some very light work with a file on that scratch then skim it with epoxy this weekend

runpasthefence

iTrader: (2)

I'm an idiot; well, my engine builder is one, but I'm stupid for not noticing sooner.

There were no main cap bolts installed.

Pretty obvious from one of the pics I posted, but in my dark garage (and under the car) it kind of looked like there were hex socket bolts in there, and I just didn't think about it tbh.

Needless to say I'm both livid to have received an unfinished short block but relieved that the problem is isolated. Can't believe I've wasted so much time on this.

Thanks bringing this up.

LS1 TJ

Wow no main cap bolts? All of them? Lucky you didn't wreck the crank and bearings.
I suspect you are going to have a conversation with the engine builder. Hopefully you can keep it civil.

G Atsma

I think he meant the side bolts going thru the block into the caps, not the bolts going thru the caps into the block.

MuhThugga

Wow. I had assumed that you removed the bolt in the one picture while investigating things. Leaving them out entirely will certainly create opportunities for oil leaks.

I once had a machine shop incorrectly clock the reluctor ring on the crankshaft, and that was only discovered when trying to get the motor to start. That was a fun weekend taking the motor back out and tearing down to install a new reluctor on the crank. So, at least you don't have that going on.

Old Buzzard

"Needless to say I'm both livid to have received an unfinished short block but relieved that the problem is isolated. Can't believe I've wasted so much time on this".
Machine shop??? More like a group of morons playing with puzzles.
Given the mess you have, I'd take it down to the last nut/bolt and start over.
Other note: Did the morons paint that block, or was it done after you got it back?
If it was painted when you sent it there, there was never a bolt in that hole to begin with.
This further supports my suggestion to start over.

runpasthefence

iTrader: (2)

Yeah, it's funny how tunnel vision works. I was convinced that my rear cover was misaligned, and I took that picture mostly to show the rear cover to oil pan transition. As the saying goes - if it was a snake...

Yeah that sounds like a nightmare. As much as I try to support local shops, this is just another example in a long list of major reasons why I don't trust others to work on my stuff.

The shop painted the block, but I'm with you. Missing main cap bolts really kills the trust in the shop and drops my confidence in this build to zero. No reply from the guy either; no apology etc.
Since it's already out of the car and I've missed my time slot for my exhaust build, I'm going to pull it apart and see what else he missed or said he did but didn't.

Old Buzzard

I'd be all over his *** like stink on ****...
Your cross bolts are most likely in the trash at his place...

LS1Formulation

iTrader: (13)

This is why I assemble my own engines, regardless of who machines them. If something is screwed up, I'm the only one to blame.