Spun Rod bearing 3.8

[Jeffrv]

Still waiting for more info from machine shop, but in meantime looking for some input from those very familiar with the 3800 engine.
I have been searching online at various forums, and most seem to generally agree the 3800 is a demanding engine to rebuild. I can see how it is exacting, but it has been repeatedly mentioned the engines seem to have a high failure rate after a rebuild. I am not exactly sure where the main problem is, but I sense it is the lower end. Has there been any post mortems done indicating where and why they failed?
So far it seems I have 3 options for the crankshaft on my engine:
1) get a refurbished crankshaft kit, is there something I should be looking for specifically
2) get my crank welded and ground, is there something the shop should be aware of? Cost of these 2 options are comparable.
3) there are NOS cranks listed on the web. While of course these would be the most ideal, they do come at about a 40% premium over the first 2 options.
In the meantime still beating the bushes for a good used crank
Thanks for any input
Jeff

[Jeffrv]

Ok, progressing on the build, got the rods in and torqued. Elected to go with the used crank, .010 under both rods and main.
GM specs show a side bearing clearance of .003 to .015.
2 rods fit that nicely
2 rods are about .017
2 rods are about .020.
I did find one NOS rod to replace the one damaged by the spun bearing, but haven't come across any more. Any used ones I find I fear will be as worn as the ones I currently have.
Is there any trick to bring the clearance back to spec? Any possible ramifications to letting it go as is?
Thanks
Jeff

[maxwedge]

No way to cjange rod side clearance short of trying to mix and match loose and tight ones.

[Jeffrv]

maxwedge, that is correct, the new rod I bought is well within specs. Haven't been able to find any more, nor do I wish to sink that kind of money into a grocery getter.
searched a bit online, and got as usual varying opinions. They were mostly dealing with v-8,s in racing applications, that use 2 rod per throw as opposed to a single rod per throw on the 3800. Some of the clearances people reported were quite large, over .150, so my .020 or so max is kinda paltry.
Basically, larger clearances might result in:
more noise-or not
slightly higher oil consumption-or not.
But both camps did agree on the thing that concerned me the most- the engine probably wont self destruct in a few months
Jeff

[Jeffrv]

Bit of an update. Have about 2500 Km on the rebuild, basic engine runs great but still have an oil leak like the old engine. it is showing up in the rear of the oil pan, around starter area, but I dont think it is the oil pan or gasket. Hard to tell if the oil is coming from above, but I suspect it is from the valve cover gaskets. When I did the rebuild, I put those special valve cover bolts in a very safe place-now cant find them! Just used regular 1/4 bolts and washers but I suspect they didnt seal the covers and are allowing oil to leak. Got 10 (need 12) from a 1995 Buick LeSabre that showed up at the local Kenny U Pull before Christmas ( where was it a year ago??) so hoping that will fix the leak.
Also had a coolant leak showing up under the throttle body. I had used a new gasket when I did the rebuild, so took throttle body off and ran a straight edge over the face of the upper intake, found it warped. Got a new Delco manifold and have installed it.
With any luck, winter going to be pretty much over in a month or so, get it out and drive it!

[Blue Bowtie]

Another possibility is the intake leaking.

[Jeffrv]

When I had the upper intake off, I did look close for leaks in the valley of the lower intake, didn't observe any. Thank being said, this took place a bit over 2 months since the engine had last been run, so hopefully the oil didn't drain away in the meantime. Will see what this season of driving will bring.

[Jeffrv]

Further update. Now have about 13,000KM on the rebuild, still have that annoying oil leak. Have put dye in the oil, most oil seems to be collecting at the bottom of the engine, between engine nd transaxle. cant really get to see from the top of engine where the oil is coming from, just cant seem to get in there. The back of the engine is damp, at least until you get to exhaust manifold, cant see above that. There is some oil dampness on the head just below valve cover, so seems to the pointing to the cover, although the amount there doesn't seem to fully jibe with the amount that is actually dripping off the engine. Going to remove the cover, and closely inspect it, have seen some posts online about the valve cover itself warping or cracking

[Jeffrv]

Removed the rear valve cover, there are several cracks in it. Looked at front, not much oil leaking, but it too looks like it has a crack, so both covers being replaced with Dorman aftermarket.
Some oil at the rear lower intake manifold. Rather frustrating as I thought I had cleaned everything throughly and put the dab of RTV at the corners, but leak has returned.
Has anyone used something like Permatex gasket maker in place of the RTV? Seems to be a oil leak at the rubber gasket, Any suggestions welcomed, thanks

[Blue Bowtie]

It seems that your diligence is paying off. All those small leaks and seepage accumulating at the rear (left?) of the engine have to drain off somewhere.

[Jeffrv]

Blue Bowtie:
Not so much diligence, as being fed up with a messy driveway from oil spots. Generally a trip across town results in one spot close to an inch in diameter under middle of engine ( possibly valve cover?) , and a second one much larger at rear of engine, presume from intake valley gasket. This gasket has been changed several times but the leak persists. Once off this time I will be closely examining it, including running a flat edge over head and manifold- think I did that last time but will recheck.
Each time have used the RTV at the corners, but leak comes back. This time I think I will use Permatex gasket maker instead. We used to use that on our GM locomotives built in the 50,s 60, and 70,s with success, but generally they used paper gaskets, not the rubber style.

[Blue Bowtie]

I get the sentiment. I have a '94 Impala that has about 60K on a rebuild, and it was tight as new for several years. Lately it's gone through oil cooler hoses (again), the oil filter/adapter gaskets/o-rings, and now it appears to have developed a timing cover seal drip, behind the Opti distributor. It looks like Round 3 is about to begin for me, sparring with drips. I don't really feel like pulling a good-running engine again just to resolve seals and gaskets, but it's almost that frustrating and would buy me another 10 years of peace of mind.

[Jeffrv]

It is apart now, nothing jumping out as to why the lower intake keeps leaking. I cant pass a ,002 feeler gauge anywhere along the intake, head and block surfaces, they all seem flat and smooth. I did get some info from AllData about a revised procedure for the Series 1 engine installed in the 1995 U bodies. basically, there is a minor change in the torquing sequence for the lower intake manifold, and both upper and lower manifold bolts torqued to 11 ft pounds,
I also came across some documentation indicating about 2006 or so GM consolidated all the various sealers and gasketing material spec,d over the years to just 2. I havent been able to find out what they are, and if one of those may be appropriate to use on the LIM.

[maxwedge]

My 2003 Lesabre leaked oil at the lim rear area, after doing the updated lim gaskets, took it apart second time and used "the right stuff ", grey sealer. That fixed it.

[Jeffrv]

Maxwedge, thanks for the info. It seems this area of the engine is extraordinarily sensitive to a particular sealant, and this trial and error approach really sucks.
Some U Tube vids show them laying a thin bead underneath and on top of the entire rubber gasket, as well as a thicker daub at the corners, any thoughts on that?