The "closed deck" h23a1 block

[92cb7pnw]

So while doing some research I had learned about the h22a1 and h23a1 and that they were "closed deck". I ended up picking up a h23a1 for 100$ and after looking at it I would have to lean towards calling it more so of a stock block guard. Still useful but I had my hopes up but still have a build planned because i was given a h22 head .

[deevergote]

Why do you say "block guard"?

[92cb7pnw]

Because isn't the block guard installed at the top of the sleeves? I may have been misinformed on what an actual closed deck block is, but to what I have learned it's suppose to be closed all the way down the sleeve with smaller coolant passages.
When I saw a block guard that's what this "closed deck" on this h23a1 looked like it just appears to serve the same purpose. I mean the block is still a little stronger when compared to open deck no?

[Jarrett]

It is stronger. Not much, but some. Calling a closed-deck design similar to a block guard is like appreciating Edison's accomplishments over Tesla's, though. The closed deck concept came first and the block guard was a means to imitate that.

So anyway, what's your question?

[92cb7pnw]

I didn't have a question before but I do now, but I can do some research to figure it out. I was just thinking I had a major come up for a high boost build, but that's not the case after looking at the block lol. I knew it sounded too good to be true.

[GhostAccord]

Closed deck is when deck is closed. It's not the entire block that is filled in.

A block guard and a closed deck H22/H23 look nothing alike.

Open deck;


Closed deck;


Block guard;


the closed deck doesn't make the sleeves any stronger. It keeps the cylinders from moving under high RPM or high boost. Open deck engines have a tendency to have the actual cylinder walls move.

[92cb7pnw]

I was more so saying that the block guard and the closed deck shared similarities, not that they looked identical. They serve the the same purpose though, do they not?
I do believe I have been misguided as to what a closed deck truly is but I'm about to reeducate myself on some things.

[GhostAccord]

Yes the block guard works in the same way as a closed deck. When installed properly

[deevergote]

Block guards have a tendency to shift, whereas a closed deck block will not.

Block guards are also known to warp cylinders.

[Stoner51]

Thanks for the post ghost. I never really knew what the difference was. I had an idea what it was but that pic makes it easy to understand.

steve

[GhostAccord]

Block guards have a tendency to shift, whereas a closed deck block will not.

Block guards are also known to warp cylinders.

If a block guard is stitch welded into place and then the cylinders are measured, bored and honed to correct any shift. There shouldn't be any issues afterwards. It's these steps that some people don't bother with. They just pound the block guard into place and figure all is good. This is where the shifting and warping comes from.

[92cb7pnw]

Thank you guys this is all really useful information.

[Joey GT-R]

Moving as I see fit....