Fixin my rod knock..

[Una]

So my GLHS has developed a light rod knock lately. I've got maybe 600 miles on the engine since I installed it. Whole lotta history on this block, long story.. Short summary, I bought a "55k mile T2 motor" from some guy on the SDML, and it arrived with like 55k worth of grease on the oil filter.. Absolutely shot, I spent about an hour grinding the carbonized oil off the tops of the pistons at one point.. (He said it had a bad turbo.. He was right, they had driven it with that bad turbo blowing oil into the intake for AGES, till finally the shaft in the turbo had snapped.) Anyways, I figured if I fire it up and the rods don't knock, I'm golden.. I was wrong.. They didn't, but it seemed like at just the right RPM range I'd get something that almost sounded like knock. I noticed that if I cornered real hard, the engine was VERY apt to suck air and lose all oil pressure and start rattling real bad till I finished the corner and it regained oil pressure. Needless to say, I think that may have been the death blow for the poor thing.
So I dropped the pan today to change the rod bearings and put in a baffled oil pan I had laying around. What do I see in the oil pickup? RTV.. Few minutes diggin around in there with my 45degree pick tool and I have myself a handfull of RTV! It was almost completely plugged up with RTV. Well after I finished that, I realized that was the least of my problems, the oil pickup was awefully high, in fact, the back of the tube had been hit by the crankshaft at one point?! and the front of the round pickup had a nice dent in it like the pan had been run into something big time.. By my measurements, it was about 2" above the bottom of the oil pan!! I reefed on it and pulled it back down to where it needs to be. That should solve that problem. CRAZY... All of my rod bearings were down to the copper/brass or whatever that is that you're not supposed to be able to see. The crankshaft looked fairly good still. I've got it all back together now, waiting for the RTV on the oil pan to cure. In the morning I'll add oil and fire it up to see if it's fixed.

[Tony Hanna]

I think people ought to have to pass a test before they can buy rtv. It seems like every redneck wannabe mechanic will use 3 tubes of the stuff on an oil pan and then by the time it makes it to a new owner, it's all ended up in the pickup screen. I've given up on using rtv completely in favor of the oil resistant supertack (yellow) stuff.
At least your crank wasn't hurt.

[turbovanman²]

I love to see that RTV on customer cars, makes me money but yeah, backyarders should be shot or have an RTV usage license, lol!

Good luck!

[Dave]

So when should one use RTV? I use it on the valve cover itself then place the gasket over top and that's it. I also used it on the oil pan itself, again with the gasket over top.

Rob told me to always do it that way. Blame him.

[Una]

One or the other.. Gasket and no RTV, or RTV and no gasket. Also keep your bead very small. Wash the surfaces down with alcohol or brake cleaner before applying the RTV. An oily surface will just squirt out the RTV in no time.
I drove the car home this morning. Seems much improved, oil pressure is much higher (on the stock gauge, haven't found a good place to mount my aftermarket one yet). Give the car another 500 miles and we'll see where it's at then.. I have a newer healthier engine coming next weekend I believe.. I'd just like the car to continue to be driveable till I get a chance to swap motors again.

[turbovanman²]

So when should one use RTV? I use it on the valve cover itself then place the gasket over top and that's it. I also used it on the oil pan itself, again with the gasket over top.

Rob told me to always do it that way. Blame him.

As Una said, one or the other but its ok to place gaskets using RTV as long as you use small amounts and let it dry or get tacky otherwise the gasket will just squish out. There is no need for both, and no need to use a whole tube on one item,

[Tony Hanna]

As I see it, there are 2 big problems with RTV and they both work together to cause problems. The first problem is over use. When you put a monster bead of the stuff around a valve cover gasket or oil pan and then tighten the part down, the RTV squishes out from between the parts. The big problem with this is that it also squishes out inside the parts, so there's a big bead of the stuff overhanging the sealing surface on the inside.
The second problem is that RTV is not oil proof. It will resist oil for a time, but eventually it will break down and come apart.
Now, here's where the two problems combine. When you've got a big bead hanging inside the engine, and the oil begins to break it down, chunks start falling off of it. These chunks usually find there way into the oil pump pickup screen eventually blocking it off and causing oil starvation. You can guess the rest.
The solution to this is not to use RTV unless you absolutely have to, and then only in the smallest ammount you can get by with.
Another solution is to avoid RTV alltogether and use the the oil resistant stuff like the yellow supertack I mentioned earlier. When looking at sealers, check the package to see if it's compatable with gasoline. If gasoline won't hurt it, it's a safe bet that oil won't either.

[Una]

I use the dark grey/black stuff from Mopar.. Good stuff..

[turbovanman²]

Another solution is to avoid RTV alltogether and use the the oil resistant stuff like the yellow supertack I mentioned earlier. When looking at sealers, check the package to see if it's compatable with gasoline. If gasoline won't hurt it, it's a safe bet that oil won't either.

Yes and no, as you state, you need to find right one, I use Wynn's Extend RTV and its not oil soluble,

[Una]

"The Right Stuff" is some AWESOME stuff too, alot like the mopar stuff, except that after it sets up, you could remove all the bolts from the valve cover and never notice.. It's a PITA to get the valve cover back off the engine..

[Tony Hanna]

Yes and no, as you state, you need to find right one, I use Wynn's Extend RTV and its not oil soluble,

I wonder if you can get that in the states? The usual fare in the parts stores around here consists of the normal blue, black and the orange high temp (yeah right ) all of which will break down in constant contact with oil.

[Tony Hanna]

"The Right Stuff" is some AWESOME stuff too, alot like the mopar stuff, except that after it sets up, you could remove all the bolts from the valve cover and never notice.. It's a PITA to get the valve cover back off the engine..

I think I have seen that around here somewhere, but I haven't tried it yet. I started using the supertack stuff for everything, and have been happy enough with the results that I haven't tried anything else in awhile.

[turbovanman²]

I wonder if you can get that in the states? The usual fare in the parts stores around here consists of the normal blue, black and the orange high temp (yeah right ) all of which will break down in constant contact with oil.

Just go to a dealer or auto shop, they could get you some, its around $30 a tube but you can do 10 engines with it. BG Products is the same too. I have never tried The Right STuff but it sounds good too.

[Tony Hanna]

Cool, Thanks!