What is hardblocking?

[Towndrunk]

And is it okay for a boat application? TIA
TD

[slotracer]

my understanding of it is, you fill the block up with a filler that hardens once in the block. as far as for a boat. i guess that depends on what you plan to do with the boat or how much you fill the block.

[Moneypitt]

I think the majority, if not all the filled blocks are for 1/4 mile passes. I guess you could use one in a 1/4 mile boat. There are advantages and not so adavantages. Mainly those blocks are usually torn down after each run, and the melted parts are replaced.........I think?................MP

[bp]

nah, they can be used for river stuff but you have to plumb in a good oil cooler.

[revndave]

I ran a blown 477 with a filled block on the river.Ran a big oil cooler.Filled it to about 1 inch from the deck.My block was bored 100 over.Did it for stength.

[DelawareDave]

Filling the block (hardblock) is used to strengthen and stiffen the block. The water jackets are filled, usually 100%, thereby eliminating the coolant in the block. The intake has water outlets front and back, for cooling the heads, with a small radiator, and the coolant is changed every run. I don't think I would go this route for a boat engine for normal use.

[LakesOnly]

Hard-Bloc (http://www.hardblok.com/info.html) is a brand name of a water jacket filler. There are several manufacturer's of substances all of which are designed to do essntially the same thing.
http://www.hardblok.com/info_r07_c06.jpg
LO

[WannabeRacing]

Yup. The stuff is used to stiffen up the block and the cylinder walls. Especially stock blocks that are reaching their limit of bore. You need to understand that your rings will not last near as long. They bottom of the cylinder cannot cool, and the extra heat takes out rings. I have seen people do it, know people that do it, and I know people that love the stuff. I avoid it like the plague, but that is just me, and just my opinion.
And MP, it is a 1/4 mile deal. But in this day and age, there is no-one that uses hardblock type stuff and takes it apart every pass. Or even tears it apart every event. The guys that type of maintenance get good blocks. It is the guys that like the strength, but want to save the $$ of not getting an aluminum or Merlin block that use the stuff.

[Towndrunk]

Thanks for the advice guys. I think I'll pass on that motor.
TD

[jbone]

I must have a strong ass block then. Everytime I open it up, the back four cylinders are surrounded by sand.
Does that qualify for hard blocking?
J

[LakesOnly]

jbone,
I get the joke, but interestingly enough...in the old days (prior to specialized block filling concoctions), even sand was used to fill water jackets for supporting the backside of cylinder walls.
LO

[jbone]

jbone,
I get the joke, but interestingly enough...in the old days (prior to specialized block filling concoctions), even sand was used to fill water jackets for supporting the backside of cylinder walls.
LO
I do actually worry about it. I installed the rubber plugs and plan on flushing it at the end of each season.
Plus, I stopped reversing in shallow water. I found out that is the worst.
I read somewhere on hear that the sand might not be all that bad, because is still holds moisture and can only reach a certain temp. I don't want to take any chances though.
J