benefits of 1/2 filling block

i searched hard block and block fill for the article that was on here a while back looking at the benefits,if any, of only half filling block. did not find that article. does anyone remember the heading? tgis would be for a street motor if there are any real benefits. thanks in advance.

I'm sure it makes the block stronger and everything but I recommend running an oil cooler. Several years ago I had a '69 Dart with a 500" low deck 1/2 filled and it would cook the oil on the street. I'd start out at 60# of oil pressure and after a 15-20 minute cruise it would be at 20# at a traffic light.

It's obviously stronger...and I have racing friends who swear it aids in consistency likely due to less temperature swings between rounds.

Capacity is king in a street car. No reason for it.

Well Im driving around with a 528 that runs 10.1 and will go 9.9's in my street car, thought the half fill may save it ??
Yes I run a large oil cooler plus larger radiator and twin fans

Years ago back in the early 1990s I built two SB motors for a NHRA 340 SB stock car 1971 Challenger racing family in SO CA. One short block was a freshen, new pistons and rings, new cam shaft and lifters and freshen the X heads, that motor had been built by Greg Luneack originally and it was around half filled with what looked like cement. The other motor was all new parts starting with a new R1 block(legal for NHRA) and a different set of J heads that they had. We put in all new valves, springs keepers and retainers on both sets of heads.
We dyno both motors and found that the filled motor on the dyno had two different distinct heat zones on the block, above the fill the water temps. measured with a infra red gun, was 120 F, below the fill was 180 F I haven't filled or advise any one since to use block filler, never, no more :tsk
Cast iron expansion will follow the heat , hotter expands and cooler contracts more, not what you want on a cylinder in a running motor, especially a race motor
The non filled block ran faster at the race track with the same heads and camshaft as the filled motor did with both motors having the same brand pistons, bob weight, C.I. and compression ratio
Cement based fillers shrink away from the cylinder walls after curing, the other type plastic based filler maker says it doesn't do that, maybe it does and maybe it doesn't
EDITED: Some people swear on using block filler, I swear against using it
AKA aside, I won't use it again, no matter the circumstances

If you are going to 1/2 fill your block, use Embeco Metallic 885, as it will expand and contract with your Cast Iron Block. This was used by a lot of the Alcohol racers in the past when they could not afford the KB blocks...

Mark

Hardblock is specifically designed to NOT shrink and pull away from the block.

What's the comparison vs a non filled block? You're checking temperature on the engine directly against water cooling passages...why wouldn't it show a cooling difference?




We're the two runs on the same day? What were the weather changes between the two? Unless it was a controlled apples to apples, I wouldn't put much into an ET change aside from the additional weight.




Any pictures or proof it pulls away? Only reason I ask is because I've heard this for years, and it's always word of mouth and never hard experience. If not, it could have originated from some shade tree mechanic using actual cement and having issues.

For the most part weakest point in a block
is in the center of the cyl.. I have cracked
3 blocks(all SB) and they tend to crack near
mid way down the bores.. that is generally
the weakest area in the block... if you do a
1/2 fill you strengthen the block to the middle
of the bores.. in a stock block the thinnest
part of a block is the cyl walls(its about .200
thick if its a decent block) so with a 1/2 fill
you strengthen to that point(about 1/2 way down)
then you have the top of the deck.. they are
thick so if you didnt fill you would have the
total cyl area that can be weaker.. if you fill
you are reducing the weak area and shortening
the area above the fill.. it can add rigidity
to the whole block(depends on design) but most
blocks are fairly solid in the bottom end.. IMO
it wont help correct cracking the bottom
end.. to me that is another issue... this is
just my opinion... I have both filled and not
filled.. if a street car use a oil cooler.. as
said your taking away the heat transfer when
you fill