After other commitments, I finally got back on it pretty heavy by taking yesterday off and tearing into it. This is gonna be a quick update, then I'm heading back out because I took today off also.
I decided to tear it down to the short block before making a final decision. Even though the distributor turned easily, I found out that it was stuck and would not come out. I even used the engine hoist to lift the intake, but it didn't help with the distributor. After a half hour with a rubber mallet, it finally came out and I got the intake off. It looked pretty cruddy around the lifter valley pan. At this point, I wasn't expecting things to work out with this engine for Drag Week.
Still wasn't looking good, so I tore the heads off.
First thing I noticed was that it still had an original steel shim head gasket....and what appeared to be stock pistons. I wasn't expecting anything good when I saw that, but when I looked closer, it gave me some hope. There was very little ridge at the top and all the cylinders looked VERY good with no scoring or odd wear. There was a fair amount of dry carbon buildup on the tops of the pistons, but since I never noticed the engine smoke, I'm guessing that the carbon was just normal buildup from the 60k miles showing on the odometer. When I bought the car off of an old friend, there was a discrepancy about the mileage. He thought the car likely had 160k miles, but I wasn't so sure about that. The car just felt too tight and ran too good. More on that in a minute.
I went ahead and pulled the pan for the final look.
This is where my hopes shot up. The bottom end was not full of crud, although there was a fair amount of gunk in the bottom of the pan. The pump screen didn't look bad. I grabbed all the rods and could not get ANY play out of them! The bottom end seemed to be in very good shape. After a good look at the cylinders, the stock pistons and clean bores, the bottom end with no play and what appeared to be stock rod and main bearings, I was convinced that this was indeed an all stock, fairly low mileage engine, and that that 60k was indeed original. It seems that the only thing ever done to the engine was the double row timing chain, and I'm guessing that was only done for preventative measures.
I decided to mic the bores, and was very happy with what I found. I don't have a bore gauge, but I use a depth gauge set that I have. It's harder to use, but with a good touch and some patience, you can get solid readings. After some time measuring, I found that all bores measured right at 4.053, with very little, if any, taper or out of round. In fact I couldn't find anything more than 4.0535. I measured the ridges at the top and they were all at 4.05-4.051. This was indeed a stock bore block, and a very good one at that!
That's when I decided to try and get this thing back together and drive it for Drag Week. So I decided to clean the block the best I could, being extra careful NOT to get any gunk down in the bores or around the cam and oiling system. So I decided to turn the engine upside down and clean everything while it was down, allowing any and all crud to fall to the floor. I plugged all the lifter holes and drain holes and scraped and sprayed the lifter valley, using lots of brake cleaner.
I also did the same with the piston tops and decks. After I was done, well, mostly done, I still have one side of the lifter valley to do, I was pretty happy with how things were turning out. That gave me even more motivation to get this thing back together and give it an honest shot at making the event.
I'm still not sure what I'm going to do with the heads. Either I pop the springs off the original heads and put new umbrella seals on them, temporarily until I get a chance to rebuild them, or I'm thinking about throwing on the C4 heads that I had on the 390 in my old '68 Highboy, which have had hardened exhaust seats put in and are machined for positive type valve seals. They were done 25 years ago, and they have quite a few miles on them, but they are still in good shape.
The downside to switching heads is that the C4's off my Highboy had been milled, which means my pushrods might not be the proper length. Or I could switch to my adjustable rocker set that I used on my Highboy, but that means all new pushrods on the old lifters. At this point I'm leaning towards the old heads with new umbrella seals, just to keep the engine in a state where everything worked together. Still, a replacement head gasket will raise the head a bit over the factory steel shim gasket, so that could make its own issues. Ugh, I hate making decisions like this. I wouldn't have gave something like this a thought when I was a kid. I would have just thrown it together. Not I kinda hate to do stuff like that, but I don't have much choice in this one.
Question for you guys; do you think I should use some sort of sealer on the head gaskets? If so, what should I use?
I've done razor blade cleanups with new head gaskets plenty of times and never had issues, but this is the first time I've run across steel shim gaskets and not had the block remachined. Kinda concerned about a new gasket holding up. What do you guys think?
Also, what is a good thin head gasket to use? I don't want to open up the squish area any more than I have to, so I'd like to know what are some of the thinnest head gaskets that would match the steel shim gasket, which I think was something like .015 if I remember right?
