what does block filler do for your engine?

[BrazilianZ28Camaro]

Guys, and what about piston/ bore running clearances with a half filled block???

I believe the filled area won't expand much in diameter like it would normally, but the piston , contacting that hot area, may expand more at the squirt.

Thoughts?

[cjperformance]

Guys, and what about piston/ bore running clearances with a half filled block???

I believe the filled area won't expand much in diameter like it would normally, but the piston , contacting that hot area, may expand more at the squirt.

Thoughts?

Someone had to ask! Its a bit piston/application specific, but on say a 4" bore forged piston deal you want a half to 1 thou more clearance for a half fill running coolant. Unless its something thats going to get sustained beatings!, half a thou extra is fine.
Also,,Ask the piston maker, they are usually pretty helpfull if you give them lots of info.

[BrazilianZ28Camaro]

Someone had to ask!

lol

Once I'm the deal braker here, I have another question:

At engine operating temp, wouldn't a half filled block distort the cylinder unevenly across the bore lenght?

I do believe the distortion aways will be present with or with out block filler, but the water flow into a non filled block would act as a medium to stabilize the cylinder bore surface temperature and hopefully keep the bore with the best shape as possible, to reduce ring flutter at high rpm.

Hard to explain but I think you got the idea.

[cjperformance]

Someone had to ask!

lol

Once I'm the deal braker here, I have another question:

At engine operating temp, wouldn't a half filled block distort the cylinder unevenly across the bore lenght?

I do believe the distortion aways will be present with or with out block filler, but the water flow into a non filled block would act as a medium to stabilize the cylinder bore surface temperature and hopefully keep the bore with the best shape as possible, to reduce ring flutter at high rpm.

Hard to explain but I think you got the idea.

Yes I know what you are getting at. The general Idea is that the filler expands at around the same rate as cast iron so distortion due to heat is limited. But the support the bore gets from the filler stops/reduces the bore from flexing under cylinder pressure/piston loads which in turn helps ring seal, reduces flutter, reduces blow by and temp of the oil around the skirt area. All sounds great in theory! BUT when you look at a filled block and compare a used bore to a non filled (factory iron) block of the same hp level you see far nicer wear witness in the filled block.
Any distortion problems the filler may make seem to be cancelled out by the increase in bore support, the increase in bore support inturn has big benefits..

[RL]

When combustion finishes, no more heat supplied to the block. After half stroke there just isn't that much heat being produced.
The bottom 1/3 of the bore is just skit support.

[BrazilianZ28Camaro]

The general Idea is that the filler expands at around the same rate as cast iron so distortion due to heat is limited.

This is the "problem" I see.

The water cooled area on a filled block will get hotter than the lower cylinder area for sure, and will increase its size, wich is a good thing , so the piston won't seize there while expanding. LOL

The lower filled cylinder area will get less heat than the upper area, but I believe it will still be much hotter than the coolant , so this will expand the block and the "cement" a lil bit to all directions.

As that part of the bore is mechanically fixed in place and can't expand its outer diameter, the cement heating expansion should fix the bore size or even decrease the bore diameter, due all its mass expanding between the block walls.

I'm no expert at thermodynamics, so I may be off here. Maybe somebody can enlighten me.


And yes, I do agree the fill will increase substantially the bore/block strenght and make more power, but maybe only up to a short time period, before some parts heat soak .

[cjperformance]

The general Idea is that the filler expands at around the same rate as cast iron so distortion due to heat is limited.

This is the "problem" I see.

The water cooled area on a filled block will get hotter than the lower cylinder area for sure, and will increase its size, wich is a good thing , so the piston won't seize there while expanding. LOL

The lower filled cylinder area will get less heat than the upper area, but I believe it will still be much hotter than the coolant , so this will expand the block and the "cement" a lil bit to all directions.

As that part of the bore is mechanically fixed in place and can't expand its outer diameter, the cement heating expansion should fix the bore size or even decrease the bore diameter, due all its mass expanding between the block walls.

I'm no expert at thermodynamics, so I may be off here. Maybe somebody can enlighten me.


And yes, I do agree the fill will increase substantially the bore/block strenght and make more power, but maybe only up to a short time period, before some parts heat soak .

There would be absolutly no doubt that there are some differing expansion figures than in a non filled block during warmup and into a heat soaked condition, be they for better or worse.
The benefit is really down to the bore support. Even though the combustion still takes place in an unfilled area of the bore, the lower portion of the bore that is supported by the filler still has an effect on ridgidity/flex of the upper portion of the bore,,, when the plug fires, the bore simply cannot deform as much as it otherwise would, you get more of the combustion effort sealed in the chamber to push the piston down, and less gas leakage past the rings,, so, more power/tq + less blowby,-therefore heat getting further down the ring pack and into the skirt area which in turn will affect the oil film on the bore aswell.

Picture a factory Ford Cleveland bore, the portion of bore not supported by either the deck or the crankcase area (so surrounded by coolant) is aprox 5.5" high. A fill to just below the water pump holes which in turn gives plenty of room around the bottom of the head bolt bosses for coolant flow will end up giving you an unsuipported bore height of aprox 3". So just over half of the unsupported area is now fully supported. Now get a coke can, feel how flexy it is,,now wrap a heap of masking tape arount the outside starting just above half way down. Once done , feel how much stiffer the can is in the UNwrapped area. The support the tape provides low down simply allows a shorter area to flex, so less flex for a given pressure. Simple. The filler has the same effect on a bore.
Differing expansion in the filled block is going to happen BUT, The increases ring seal, bore flex and bore strength FAR outweigh and expansion issues. And this can be seen when inspecting a properly filled block V's a non filled block of equal power level and use. You see less sign of bore flex and blowby in the top of the filled block and a far more uniform wear pattern in this area. And in the lower portion you see less discolouration due to higher temp oil deposits and less wear. You also see less sign of gasses having gotten past the top ring in the form of combustion deposits between ring lands and less skirt wear due to less oil contamination and no doubt due to the reduced bore flex holding clearances at a correct level under full power.

[BrazilianZ28Camaro]

Ok Craig. Get it.

Do you have a idea how much weight the fill add to the block, say a SBC ?

[cjperformance]

Ok Craig. Get it.

Do you have a idea how much weight the fill add to the block, say a SBC ?

I've never filled a SBC block but I'll geuss at around 10-15lb , 4.5 - 6.8Kg for a half fill,, some chevy guys may be more accurate here, But its not a real big issue due to the coolant/water it displaces which drops some weight. All up it does come in heavier but not by a huge ammount.

[RL]

The general Idea is that the filler expands at around the same rate as cast iron so distortion due to heat is limited.

This is the "problem" I see.

The water cooled area on a filled block will get hotter than the lower cylinder area for sure, and will increase its size, wich is a good thing , so the piston won't seize there while expanding. LOL

The lower filled cylinder area will get less heat than the upper area, but I believe it will still be much hotter than the coolant , so this will expand the block and the "cement" a lil bit to all directions.

As that part of the bore is mechanically fixed in place and can't expand its outer diameter, the cement heating expansion should fix the bore size or even decrease the bore diameter, due all its mass expanding between the block walls.

I'm no expert at thermodynamics, so I may be off here. Maybe somebody can enlighten me.


And yes, I do agree the fill will increase substantially the bore/block strenght and make more power, but maybe only up to a short time period, before some parts heat soak .

You're over thinking the problem, because there is no problem. CI has a very low coeff of expansion, so even if the bottom of the bore got 50º more heat, it wouldn't make much difference - the heat would travel up the bore to the coolest point -

We started block filling in 1995 and have done hundreds of blocks, and never had a problem. In fact a 351C won't handle over 500hp without it. We have never given pistons any more clearance than recommended, and that is with 600hp 9000rpm 351C

[Leftcoaster]

Can anyone suggest a selection of "filler" brand names please?

[RL]

Can anyone suggest a selection of "filler" brand names please?

http://www.moroso.com/catalog/categoryd ... code=22008

http://www.hardblok.com/