Up against the main bearings.

Nevada1906

Registered User
Sorry about the length of this post, but it's necessary.

Well, I can't avoid this any longer. The main bearings in my '93 auto have to be replaced, and I don't mean maybe. But as usual, there's good news and bad news, and I need some advice. Thanks in advance.

First, while I have bits of crud in the oil, some of it is glittery metal and some is black, crumbly gunk. I think what's going on here is that because I've been doing oil changes every two thousand miles in an effort to keep the mains alive, I've been loosening up gunk that was the result of the previous owner's lack of maintenance. But the glitter, that's bearing. Ouch!

Now, I haven't had bearing-to-journal contact yet because, frankly, I've been driving like an old lady in order to keep the engine alive. I mean barely goosing the throttle, 2000 rpm shifts and so forth. There's enough torque that I don't have to get on the gas too hard, and besides, I have to practically ride the brakes to stay off peoples' bumpers anyway! That's why I love this car!

As I said, the good news is that my low-stress driving technique, and the resulting lack of metal-to-metal contact, means that I probably can just replace the bearings without having to get into any machine work.

I think.

However, the bad news is that I've only got enough cash to cover new main and rod bearings, a new set of gaskets, and the engine hoist rental. And that's it.

And this is my only car.

And it's my daily driver.

And no, the above variables are not negotiable.

And failure is not an option.

So, with all that being said, Here are my questions:

1: Can someone remind me what the problem with the stock balancer is? Like, why can't it be reused? Is it a matter of becoming damaged by just a single removal/reinstallation cycle, or is it more along the lines of, "I can't repeatedly shift at six grand with a reinstalled stocker?"

2: Would it be possible to stick an NA 3.8 longblock under the blower? No, this question is not as stupid as it sounds. As I mentioned, I'm not that hard on this car, and I have no plans to lean on it until I get my Project 3.8 built. So if I'm gentle, I think it should be okay, as long as there aren't any sensor compatibility issues.

I mean just physically swap an NA longblock into the SC longblock's place and bolt all the other parts back into the car.

The crank sensor being the big one in this case.

See, I need transportation here. If the car has to exist in a "reduced" state for a while in order to stay alive and functional and get me around town, then so be it. I'd rather just swap longblocks and be on my way.

Just for right now.

Thanks for any advice.
 
Since you're already in hyper-miler mode...

Change the oil, pull the SC belt, cross your fingers and drive.
 
Sorry, but metal filings means that there has been bearing contact. That's also a "non-negotiable". :( If the motor is knocking anything more than very slightly under only just exactly the right conditions means the crank is toast. The knocking sound that you hear is the piston hitting the head. Since the motor is built with a flush deck and the gasket it .040" thick, that generally means that you have a pretty much nothing left for a bearing before it starts knocking. If it knocks continually then pretty much forget about replacing any bearings. If it's not knocking at all then you stand a good chance of extending its life.

All you can do is pull it apart and see what you find.

Having said all that, it is quite possible to swap main bearings without removing the balancer. A properly shaped nail or cotter pin stuck into the crankshaft oiling hole will allow you to roll out the main bearings and roll new ones in.

As for the NA block, that isn't going to work very well because of the crank sensor. The NA blocks up to 1999 are external balance and do not have the correct attachment for the 89-93 crank sensor. You could install your SC balancer on a 1999+ 3.8L motor but then the problem is attaching your 93 crank sensor to the block since it doesn't have the proper provisions for it. On the older na blocks, it may be possible to attach our crank sensor but I don't think so.
 
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