Hardblock fill question

[Joe-JDC]

I am in the process of cleaning two blocks for doing a half-fill or to the bottom of the water pump holes, and just wondering if you use a water additive, or just plain water to mix the grout.  Also, for those of you who have done this in the past, does the grout actually keep water from seeping around the cylinders and rusting them?  I am planning to use Moroso Hardblock.  They say that you can actually do a fill without having to re-hone the cylinders, too.  True or false?  Joe-JDC

[SSdynosaur]

I did several OEM 427 blocks in the distant past. Although the material used was called a "machine grout" and was very similar to the Moroso product, mine actually contained particles of cast iron. I used tap water and did the mixing (50% of dry product/side) in a five gallon bucket and poured only one side of the block while permitting it to harden for 12 hours before proceeding with the remaining side. It seems critical to get the block deck level in both planes and it certainly helps to have some method of "vibrating" the side of the block you are working on to assure there are no air pockets. I used a automotive pneumatic hammer by fabricating an aluminum slug, approximately 3"dia x 2"thick center-drilled 1"deep, to receive a cut-down chisel shaft that fit the hammer receiver. I don't have an answer to your question re.cylinder rust: if you mean external to the cast cylinder, I don't know as I have never removed the grout from any block I've filled. I DO NOT agree that you can fill a block and be confident that everything will be round and true. The method I employed involved pouring one side, hammering out the air followed by immediately installing a head gasket plus torque plate and torque to spec.. I always allowed at least five days curing time before honing to desired finish and size; obviously, this method is best if you have access to two honing plates. You will need to have everything organized so that, once you begin the mixing process, you can proceed as expeditiously as possible; curing begins rather quickly, depending on ambient conditions. Good luck.

[BattlestarGalactic]

When my old 428 block was done 20 yrs ago, the shop did one side at a time since they only have one deck plate.  Install caps and torque.  Tilt the block so deck is horizontal, fill that side, used air chisel hammer to settle the material into the corners.  Install deck plate and torque.  Let set and then repeat for other side.  Hone cylinders.  I would guess as long as the cylinders were still fresh before filling it really shouldn't need honed after.   All depends on the sequence of what you are building.

[blykins]

Joe, I prefer Hard-Blok to Moroso.  I've always had trouble with Moroso taking a very long time to solidify, with water pooling on the top. 

You will need to mix it with just water, per specifications on the jug. 

You will need to hone the cylinders after you do it.  It can change it quite a bit and I would wait 3-4 weeks before you hone.

[jayb]

I hard-blocked my Shelby block in my race car up to the water pump holes.  This is the block where I spread the bore spacing and broke into the water jacket towards the bottom on three of the cylinders during the boring operation.  I ran for a couple years without hard block, relying on sealer against the press-in steel sleeves to seal the engine, but it never lasted all that long.  Eventually I hard-blocked it, and it hasn't leaked since.  So, I would say that based on my experience anyway, the hard block will provide a seal.

In terms of honing, I would say that again based on my own experience, you may have to hone the engine, run it for a while, hone it again on the next tear down, run it again for a while, and hone it one more time to get a truly stable cylinder wall.  That may be due to the nature of the aluminum block, but I have heard that from others running cast iron blocks as well.