[weedy64]

I have assembled the short block on my SBC and was having thoughts about a half fill of Hard block/Moroso in anticipation of N2O. Can I fill and torque on some heads or does it have to be done prior to machining?

[speedfreak2]

Should be just fine. Keep in mind that Moroso block filler isn't compatible with anti freeze.

[k-star]

DO-NOT fill it after it has been assembled. The fill needs done before the machine work. When the filler cures it will distort the cylinders.


Keith

[weedy64]

I did not realize that Moroso's product is incompatible with antifreeze, not much good for a street vehicle.

Opinions please: 1 For, 1 Against.

Hard block's website indicates that it does not shrink and does not expand so hence that is why I am asking. And I didn't realize it existed prior to assembly...so I have learned something.

[engineczar]

x2 on the don't use after assembly. Too much cylinder distortion.

[speedfreak2]

I don't mean to argue especially with K-Star but Hard Blok is ok to use even after machining but you must either bolt on the head or use a torque plate. It has the same expansion rate as iron. To verify this, I called Hard Blok this morning to hear it straight from them. I've used this product for years in blocks before machining and blocks that were already machined with no ill effects. Also this product is recommended if you plan on using antifreeze where Moroso block fill isn't.
Again, not trying to argue with anyone.

[k-star]

Civilized discussion is good..I am always ready to learn new things.

I can say that I have never inspected and documented bores before and after a fill to confirm how much they move. Plus I have only used the Moroso fill so the Hard Block might be different. The Moroso instructions make it clear that the fill needs done before machining.

I was under the impression that they all used the Embeco machine installation grout. Maybe Hard Block has a different formula??


Keith