Rebuilding a 304

[jauringer]

Well, I got a new project I wanted to share with you folks. I was lucky enough to score an entire drive train on Friday....304/727/d20. I had been looking for an engine as I've really wanted to dig inside an SV and rebuild one from the ground up, but getting a Torqueflite and a Dana 20 with it was even better.

I've never been all the way inside an SV engine. I'm pretty familiar with them but the only engine work I've done are things that can be performed while the engine is in the truck, rocker assemblies, springs, lifters, mains, rods, Oil pump...stuff like that.

I look forward to getting a little more familiar with these engines and hopefully when I'm done, I'll have one bad SV!

My goal here is to go ahead and beef this engine up a little. I'm not going to go crazy but I would like to put as much performance for my dollar that I can. I'm not familiar with how to do that so I'm hoping those of you that are can lend a hand. I am not in dire need for this engine to go into the Scout as my current 304 is perfectly fine. It's a typical good running 40 year old SV. Probably would benifit from a set of rings and cam bearing but it runs good and has good compression so I'll be taking my time with this one as well as pushing it aside for other more important projects that pop up. (rebuild my front axle)

So here she is. One dirty mofo!


First thing I did was separate everything and get the engine on a stand. The harbor freight 1000lb stand is a little scary with a fully loaded SV on it so I added a little support to the front end. It's amazing how much a little 2x4 helps support the load. Here's a peak under the valve cover as well, pretty nasty in there. We'll see why next.



Here's a mod I haven't heard of before!! When I spoke to Davis about it, he was betting that the PO was using a truck pump on a double hump pan.



Well, Davis was right. Not only did they use a truck pump with a double hump pan, but they rigged the Scout II pickup on it as well. When I pulled the pan, I could have sworn it was melted duct tape holding the pickup together! The further I dug into that crap, it turns out that the pick up tubes were welded together and then coverd in some type of silicone to keep it from leaking. Now that's a PO virus!



A little sludge along with a some RTV to go with it! I was preparing myself to find 13 spun bearing to go along with all this.


So I removed the pump, flipped it over, removed the manifold, heads, valley pan, dampener, timing cover...everything on the top end. Ironical as bad as the rockers looked the oiler hole was not blocked. Next I moved back to the bottom end and started pulling main and rod bearing caps. To my surprise, the bearings weren't as bad as I had figured. A couple where showing copper, but none were spun and none were totally destroyed. These were original IH bearings manufactured in 1970 BTW.



Here are the worst two main and rod bearings.




Even the crank looked half way decent. I guess that hack job at least provided some oil. Of course he had a zillion qts of oil in there so maybe it was all splash lubrication


Now can you see anything wrong with this picture? It's not a great picture, sorry.


The #3 main bearing oil gallery was plugged! One thing I can't explain is why the thrust bearings had ZERO abnormal wear. As a matter of fact there was no copper showing on either bearings. Even after a pulled they glob out I still couldn't see through to the cam.




Speaking of cam, at this point everything was out of the engine except for the cam. I saved the best for last. I've never seen a bad cam bearing before so I was expecting today to be my first.
The only bolts on this entire engine that were not loose where the manifold bolts, and the two phillips bolts that attach to the front cam plate. Luckily Home Depot had an impact driver in stock with a giant phillips head attachment that made quick work of those two.



Next, I got my flash light out and started inspecting the cam bearings. At first glance I was surprised to find that they were all in tact....Then I pulled out my mirror to take a closer look at the underside and this is what I found at the #2 bearing.



I finlay get to see a delaminated cam bearing. This is not at all what I had imagined it to look like. In my green pee opinion, this looks like a manufacturing defect. Half the bearing just flaked off. Very interesting.

So with the cam out I called it quits for the day. Tearing this sucker down when a lot smoother that I figured it would and went by pretty fast. Tomorrow I'm going to knock out all the expansion plugs and oil gallery plugs. Then I'll call around to a few machine shops and find out prices on getting all this stuff cleaned and the crank inspected. I have taken zero measurements on the crank but most likely I will tomorrow. Overall, I was very surprised at the internal condition considering the oil pump and the sludge build up. These are certainly tough engines.





Jason