I know there have been a few threads on this, but I am curious about using it in a Chevy big block (Mk IV). This would be a NA, high compression, sorta high rpm (7500rpm max) strip motor, with straight four-stud mains.

I have heard of a bottom fill, 1" or 1 1/2" fill, half-fill, quarter-fill, up to the freeze plugs fill, and up to the water pump holes fill. How do I know how much is right, or if I should do it at all? If I do a small fill, can I fill more later? Seems like it would be best to do all the filling at once, and before any machine work is done. Anybody have brand preferences? What about coolant and oil temps? What if I suddenly wanted to drive it up and down the boulevard Friday night?


Just to clarify: I'm not worried I'll blow the block apart, but I wonder if it would be at all beneficial just to make the bottom end more stable and rigid.

 

So no one has anything to say about block filler???

 

Perhaps folks were waiting for you to do a search:

http://web.camaross.com/forums/showt...hreadid=139270

and from that thread:
http://web.camaross.com/forums/showt...threadid=23473

http://web.camaross.com/forums/showt...threadid=57959

My $.02

 

Yes, I did a search before I posted and I read all those. Most of it was about cutting into a water jacket and fixing it. (I wonder how that ended up working out.)

What about filling a little now and then more later? What about brand preferences and why you like what you like? What about people who drive their filled blocks on the street? What about filling just the thrust side? What about how much I can fill and still be able to drive it on the street twice a year? What about potential benefits from stability rather than the need for increased block strength?

 

That sounds like quite a challenge to accomplish. I suggest the thermal distortion of a cylinder bore with only 180 degrees filled might prove counterproductive.

 

That sounds like quite a challenge to accomplish. I suggest the thermal distortion of a cylinder bore with only 180 degrees filled might prove counterproductive.
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Thats for sure !!!

 

I don't think it would be needed for what you are describing. To my mind, it has the most utility on a motor that sees very high cylinder pressures. Positive displacement blowers and nitrous are the two setups that will produce the highest cylinder pressures (high torque at relatively low rpm). The benefit is reinforcing the thin cylinder walls found on production blocks, which are prone to splitting, especially when overbored.

I did a partial fill on my last block, partly for support and also to help with support the epoxy I used to seal where I'd gotten into the water jacket. That block was 40 over though. It never leaked or broke. This year, I am only 10 over, and I have decided not to use fill. The car still sees a lot of street time and it ran pretty hot with the fill. If it were a car used mostly on the strip I think I would have used some fill. OTOH, a big block is generally beefier. How much overbore are you running? That is a factor to consider. But in general, unless it's an all out race situation, I don't think I'd feel the need for fill on a big block.

I used the "Hard Block" stuff you see everywhere and yes, it's advised to fill before any machining. Once that stuff is in there, it will never come out! It doesn't seal well in and of itself becuase the water passages are inevitably surface rusted and the rust will seep unless some other sort of sealing is accomplished.

Rich Krause

 

I filled my lt1 after I had it machined with Hardblock and checked for bore distortion after it set, it seemed to change by less than .5 thou. I only filled to the bottom of the frost plugs. A short fill (1 inch) only took about .5 litre per side. To displace such a small amount of water shouldn't affect cooling ( I hope).

John Carpico

 

My block is filled to the bottom of the lowest frost plugs. To be able to drain the block I drilled and tapped drain plug holes on the sides near the front, level with the lowest frost plug.

My block(s) are both bored .070" over. A 454 block can easily go out to .125" over before sonic testing should be done.