The "ZL-1" is Done!

[Joe L.]

Re: The "ZL-1" is Done!

lyndon-----

I could have used original style heads. However, these heads are so superior to those that it would not have made any sense, at all. Functionality is always the number one priority as far as I'm concerned. If functionality is close, I go with original configuration; if the newer part is significantly better, I go with the newer part. This is not meant, at all, to be a 100% original configuration. There are many reasons that I wouldn't want that and, if I had to do that, I wouldn't have built the engine, at all.

[Joe L.]

Re: The "ZL-1" is Done!

clem-----

Oh yes! That was one of the "curves" (but, a minor one). I had to grind the tops of the studs so that they were flush with the top of the nut. Since I ground the studs off the engine, it was a bit tedious to get it "just right" ( I wanted full thread engagement in the nut but nothing "left over"). I also had to grind a bit off the exhaust manifolds at several "contact points".

Of course, I could have used bolts and eliminated all these problems. Even though GM did this originally, it was a dumb thing to do. With bolts, there's no practical way to get 100% thread engagement. With an aluminum block, of course, you want 100% thread engagement. Plus, you want as little "frictional wear-and-tear" on the block threads as possible. Studs are the only way to go. I thought long-and-hard about this one, trying to justify the use of bolts (I could have used ARP bolts trimmed to the exact same length as the originals, compensated for the difference in head bolt hole length). In the end, though, I just could not justify it or feel comfortable with it from the perspective of the best functional installation I could achieve.

[Joe L.]

Re: The "ZL-1" is Done!

Duke-----

I thought long-and-hard about this one, too. I ended up using the GM #12366543, although I strongly considered going with the GM #24502611. The fact was that I already had the 12366543, plus I had read reports of folks being very pleased with this one in engines otherwise similar to mine (albeit cast iron). So, I went with it. Final compression ratio is right at 9.0:1.

[Joe L.]

Re: The "ZL-1" is Done!

Michael------

No, I don't mind, at all. The fact is that's the way I was hoping that it would have appeared when I posted it.

[Joe L.]

Re: The "ZL-1" is Done!

Brian----

The balancer bolt is an ARP piece. It's ARP #135-2503. This piece is just way too functional to pass up for an original bolt. It's quite expensive as balancer bolts go but it would be cheap at twice the price.

[Joe L.]

Addendum

By the way, in case any of you are wondering why the oil pan and timing cover are black, that's because original ZL-1 engines had black-painted oil pans and timing covers; they were NOT Chevrolet orange, as some folks think. In fact, the ZL-1 was the first Chevrolet engine to use black-painted "tin". It came back, for good, with the advent of "corporate black" in the early 80s for all GM engines (since "color-coded" engines were no longer something that GM wanted in an era where there was engine commonality across all GM car lines).

I deliberated quite a bit with myself over this, though. I really wanted to paint the timing cover and pan Chevrolet orange as a "testimonial" to the Chevrolet heritage of the engine. However, since there was no functional advantage to the paint, I decided to leave them black, as original.

[Joe L.]

Re: BTW,,,what's the "hangydown" thing between

tc-----

I think that it's a "photographic artifact". I don't recognize the guy taking the picture. The image is just too distorted in the reflection on the chrome. It would have been even more distorted if I had used an NOS GM valve cover from the collection. The quality of the stamping and chrome on those would distort any image beyond any sort of recognition.

[Duke W.]

Re: Addendum

Painting the oil pan a dull black increases surface emissivity and helps transfer heat from the oil via radiant heat transfer.

Duke

[Craig S.]

Re: Addendum

Great job Joe - of course I knew it would be immactulate when done! Now you need a run in stand....but I bet you have one of those too.....Craig

[Patrick H.]

Re: The "ZL-1" is Done!

Congrats, Joe!!!

Only 2 months until I show up in person....I hope it's installed by then.

Patrick