FE Block Filler

[jayb]

So, my grenaded 577" Shelby block is slowly being repaired; the shop is moving slowly and deliberately on this project to make sure we cover all the bases.  The plan at this point is to hard-block the block after all the repairs are made, to add some strength to the bottom end and support to the bottom of the cylinder sleeves. 

On three of the back cylinders in this block, when the block was originally offset bored in 2008,  the boring broke through the aluminum casting, making the three press-in sleeves for these bore wet sleeves.  To fix that during the last go-around on this block I used sleeves with an O-ring at the bottom, to keep water from leaking between the sleeve and the aluminum of the block casting, down into the crankcase.  Assuming we proceed with the hard block option, my machinist points out that the hard block will cover these holes, and could potentially seal them up, if the hard block material had the same heat expansion rate as the aluminum block.

I have never used hard block before; does anybody know if there is a hard block material available that has the same expansion rate as aluminum?

[blykins]

I have only filled cast iron blocks.  Moroso and Hard-Blok  both say that their expansion rate is similar to cast iron...

I did find this for you though:

http://www.speedtalk.com/forum/viewtopic.php?f=1&t=1887

[Qikbbstang]

Interesting to see all the different product claims by the different Hard Block Co's and home-brewed concoctions on forums.  Your motor I'd believe needs to retain as much of it's roots as possible in being an endurance motor rather then a drag only motor since supposedly a large part of piston cooling is through the cyl walls.  I'd think that thermal transfer ability of the hard block could play an important role, in that the last thing you'd want is the hard block to act as an insulator that could create hot-sections in the sleeves and also encourage greater thermal expansion amounts in the highly heated areas of the sleeve/filler that have difficultly shedding their heat.

Oddly Hard Block includes in their product features: "graded iron" which you'd think would be great for thermal transfer yet they only state "for strength and vibration dampening".  I've spent time with customers with glass melting furnaces and boilers that use "cement"  firebrick as an insulator.  To me the terms cement and good heat transfer are opposed. I sure hope the "graded iron" in the hard-bloc never corrodes as that could make for dimensional changes - we've all seen steel reinforced concrete crack to hell for rusting steel reinforcing  within.
    For years I've been amused following hard block users statements that they saw little to no change in their coolant temp and thus they believed their motors were running just as cool with & without filler.  Taken to an extreme and running coolant only in the heads and not the block how hot would the pistons & walls get?

[blykins]

Gotta watch the oil temp a little closer, not so much the water temp.

[CaptCobrajet]

The Moroso stuff sucks..............it will move around badly.  It takes about two hone jobs to stabilize the Hardblok, but it is better.  Niether will hold back water.

[jayb]

Doing a little searching I found an outfit in CA called Riolo Racing Engines, who supposedly developed their own block fill specifically for aluminum blocks.  Hard-Blok also says their product is tested and proven with aluminum blocks, but I've also seen some comments where the bores became hourglass shaped (narrower in the middle by .001" or so) when using Hard-Blok in an aluminum block.  Hard to know what to use.  I'm going to call Riolo and see what they have to say...

[Joe-JDC]

I would think you will be dooming the block to not being able to replace any sleeves in the future by pouring in a block sealer.  If you have new sleeves, then you will only be able to bore them until they are used up.  Then the block will be a display item.  Is that your plan?  Joe-JDC

[jayb]

That is a concern, but I think I'll be able to bore out the sleeves if necessary, and then replace them.  If that doesn't work, then the block really would be done.  Given its condition now, and the difficulties of doing the repair, I'll be happy just to get it running one more time.

[fe66comet]

Saw a lot of filled blocks when I worked at the machine shop. I asked the Top Fuel guys about that same thing. Old Smokey explained to me that with either aluminum or iron there were two factors that made it irrelevant. First the engine does not run long enough to make a difference and second the fill actually stabilizes temperatures in the block as it has a composition to absorb heat. He at the time was running Keith Black aluminum Hemi engines above the 2500 HP mark with  no block  failures and super thin iron sleeves so I would say you would be safe. As far as leaks go once filled the compression has a tendency to blow the head off before a block failure occurs. I would worry more about cylinder head retention, crank and rod integrity more than block failure after filling as the block ceases to have any give  and places more stress on other components.

[Barry_R]

Maybe a gallon or so of this stuff?

http://www.easy-strike.com/prod_liquid.html

[66Bird]

Jay,
I have little experience with filling a block except for once. I was told by a well known Chevy race engine builder to put metal shavings in to the mix. He equated it to rebar in concrete. He also told me that it would prevent shrinking and expanding and keep the hardblok up against the cylinder walls for added strength. He poured my hardblok for me. He first went over to his Bridgeport and grabbed several handfuls of shavings and mixed them into the hardblok. Most shavings were around .75-1.25". He tilted one bank up and poured 3/4 up the cylinder wall and waited for 15 minutes. Then tilted the other bank up and poured the hardblok. This was on an iron block, and not aluminum. In my younger days, I poured many sidewalks, and his analogy to rebar struck home with me. Good Luck, and hope to see that engine running strong again one day.
Dan

[Kirk Morgan]

A couple of things we would do on our stock eliminator blocks. We used Embeco 885 to fill them. We would pour on side at a time with torque plates on and let it set 24 hours before pouring the other side. Also made a shaking device to vibrate the block to help get the air pockets out.

Kirk

[cammerfe]

For what it's worth, my ECTA engine is a four litre Jaguar V-8. It's an all aluminium engine with cast-in steel liners in the cylinders. The water jackets in the block only extend down about two inches below the deck surface with the block solid below that point. You might say it has hard blok from the factory. There is no problem with temperature control. The original engine in the car, at 3.9 litres, made at the Lima plant instead of the British location ran well for more than 150K miles.

Excellent oil control is part of the basic design with a fairly elaborate windage tray standard. My engine has a wet sump with an oil cooler but the Aston Martin versions are of dry sump design.

How about using Dev-Con as a block filler?

KS

[jayb]

I'm really not too concerned about overheating issues, and your Jaguar engine is a pretty good example of what may really be required, Ken.  The block fillers seem to be grouped into two categories, the cement based stuff and epoxy based stuff. I called Riolo Racing engines this week to ask about theirs, and they told me they'd been using it for 30 years on both iron and aluminum blocks, and that it is an epoxy based filler.  Seems like a lot of people are using that stuff, and it may be similar to Dev-Con, but it is not aluminum block specific, which is kind of what I was hoping for.  Finding a block filler that has the same thermal expansion characteristics as aluminum seems to be a dead end.  The reason I was interested in that is because when I offset bored my Shelby block I broke through the aluminum casting and into the water jacket on three of the bores.  The openings are all below the water pump holes, so I was hoping to find a block filler that would cover those openings and seal the potential leaks, so that I didn't have to use O-rings at the bottom of the cylinder sleeves.  But the guy from Riolo didn't think that it would be a good idea for me to rely on their sealer to do that. 

Also, I'm learning that adding metal particles into any block filler mix is a hit or miss proposition.  Hard-Blok says something about this on their web site, mentioning that the size of the particles is critical to making the expansion rate of the filler the same as the particle material.  Hard-Blok says that they have iron particles in their mix to make the expansion rate the same as iron, and that the size of the particles is optimized for this purpose, but then they also say that their product works great with aluminum blocks.  Go figure. 

In light of all this I'm kind of leaning towards the regular Hard-Blok stuff.  A lot of people have had good luck with that, and it looks like in any case I'm going to have to run O-rings at the bottom of the sleeves in this engine again, to keep any water seepage from leaking past the outside of the sleeves.  That is, unless I want to fill the block ALL the way up, which I'm trying to stay away from...

[Jim Comet]

To bad you can't leave it at the place that is casting your intake adapters and have them do a short pour of aluminum in place of hard block when they are doing thier next castings. Jim