How much is too much hard block

400 block 511. Whats the max amount you can have and keep it cool on the street?

The head bolt Casting boss will block your flow if you go to hi. I like at least a 1/2 inch below those boss' in the water jackets.

We fill to the bottom of the core plugs

But yes keeping it cool is a trick, I have a 528 on the street in a 71 Barracuda, it has a new large ali radiator with twin fans and I fitted a engine oil cooler but on a hot day on the highway it gets too hot.

I don't recommend using it
Especially if all the machine work is done

Ok, the shop that filled the block said it was above the soft plugs. They were not kidding, its way above the s plugs. I can stick my finger in the cooling jacket at the deck and touch the filler. 2 -3" below deck.

We have a high fill on the 440 block in the Barnyard Viper. Filled to the bottom of the water pump holes. We run an oil cooler, but still kills the oil on occasion. The water temp never gets over 200.

Looks like i will have to keep an eye on oil temp.

hard block fill is not the mod you really want to do to a street engine. i did it to an earlier build & even with a electric water pump the oil temp would soar when idling in the prestage queue. i ended up fitting an accessory oil cooler but once that motor went south i didn't bother repeating that mod. i use a girdle on my current stock block engine, that seems to be a better option imo.

I understand. My small block had a short fill and it was street driven often. Ran 195-200 water temp and oil temp was 230-240 in 75* weather.

Water temp will not be an issue..Oil temp will. Less water to cool so those temps will or should not get really high. Oil temps will be the issue

You need an 8 quart oil pan and a QUALITY oil.


That means an oil you probably can walk into a store and buy.


Not a fan of engine oil coolers.

Please explain.

Oil coolers are fine if the pump, and lines to the cooler, are sized appropriately. Lots of OEM applications have them, especially the heavier duty engines. Combustion heat has to go places, and with a filled block it heads to the oil.

The thing with the truck was, an old race engine got converted to street duty. Boone would complain about killing the oil on Drag Week, saying that when it ran over 240 oil temp for a period of time, it would start to burn it, and then oil pressure would drop fifteen to twenty lbs.

He always ran Valvoline VR-1 50wt. in it.

When I got the truck down here in Phoenix, I added a plate cooler that was 2 inches longer than the previous one, and switched to Lucas Classic 20-50wt.

Even though I have seen oil temps in the 240-250 range, I've never experienced pressure drop (solid 65lbs.) or burning, so I'm going to chalk it up to better oil choice.

It's not ideal, but sometimes you just use what you have.

I would find a different block and start over.

Yeah,
But I like driving them more than I like working on them, and as long as the old girl still slams me back in the seat, I'll keep beating on it!

It's a 440 source flat-top 4.25 stroke kit. topped with the old Edelbrock RPM heads/Isky ductile rockers that I've used since '99. Not once piece on that engine owes us a darn thing!

As said, water temp won't be the problem. Oil temp will. Personally, I wouldn't do it on a street application. If you decide to do it, I wouldn't go over a half fill - and count on using an oil cooler. On the plus side, todays lubes ( especially synthetics ) can handle ( and are designed to run at ) much higher temps than in the past. Running oil temps in the 250 range are not uncommon.

Its already done. No turning back on that block now.

I can only share my small block experience, but I bucked most of what is written in this thread.

1) I filled the block AFTER it was machined... checking the bore before and after it didn't move hardly SQUAT...

2) I never ran an oil cooler until I put a diaper on the car. Before that it never had any issue on the street. But once I put the diaper on it, the heat had no where to escape from the pan.

Mine is filled up pretty high (well above the freeze plugs in the side of the block... on a small block you almost have no choice but to do this because they are so low.) I can put my finger through the deck and touch the top of the fill, so it's up pretty high.

I feel like with everything, there is a lot of people perpetuating old wives tales from things they've heard.

Worst case it MIGHT need an oil cooler.... and at the absolute worst it MIGHT need to have the hone touched up. Hardly reason to throw the block away and start over...

Lots of opinions on this topic

Options:

1. Run it on the street with an oil cooler and HOPE for the best or SHOULD be ok.

2. Run it at the track only and not worry about oil temps.

3. Disassemble the block with all of your new un damaged parts, sell your filled and prepped
block on Craigslist, find a block with decent cylinders and remove the words HOPE and
SHOULD....

well, unless I find a box full of money and I mean a lot of money or hit the lottery, that's not happening. I will run it as is and be the guinea pig. now I did call brad penn and amsoil awhile back when I had high oil temps in the small block. brad penn told me their oil was good to 360* and amsoil was good to 400+. so, I will keep amsoil in it and we will see just happens. just not sure what to expect with the cam break in, its gonna get hot.

i'm with you. I will run it without a cooler if possible. Thanks guys

Been running ours for almost 10 years .. Lots of street and lots of track time. Oil cooler yes, never have I had a problem with oil or over heating the oil. Last year the wife and I decide to drive to New York .. It made it .. Changed the oil just because and drove it home .. I will admit it was not the best riding car to take but tons of thumbs up was worth it ..

My fill ( pics) on a 408 small block. Lost about 2 gallons of coolant. Water temp never sees over 180. Oil temp ( no cooler and 8 qt pan using 7 qts of oil - Royal Purple full synthetic race oil) seems to line out at around 220. That is about 3/4 hour driving on the street in 75 degree ambient temp. I believe that number would climb in hotter weather and for a longer period of driving time. Guess on that part, but rest not an old wives tale. Had my block machined after the fill. Have no idea how much the bores distort with heat and wasn't a high priority with the build anyway. It was a race only build and trying to get a stock block to live at 700HP range was the goal.

Cool! good to hear. Ill see how it goes without the cooler first summer. From the opinions looks like I have too much fill for comfortable street driving.

The thing with hard block is your trying to
stabilize the center area of the bores.. with
a short fill your really not doing anything
and IMO is a waste and just added weight.. so
if you fill high enough to do what its intended
to do then you run into the hot oil issue and IMO
a oil cooler is needed.. even then the oil still
gets fairly warm.. and as in any time the oil gets
heated up it gets thinner(viscosity) and pressure
gets lower... I have had a engine with it on the
streets and it did get the oil hot.. so I dont add
it to any street car engine... JMO.. but since its
already done use a good synthetic oil and a cooler

Two things I've heard from respected sources on oil temps, petroleum based oils will start to change molecure structure, go bad, close to 300F and be destroying itself at 325F.
Molil 1 synthetics oils are supoose to be good to 500F before being hurt
On the blocks with fill I have seen a filled 340 block prepared by Greg Lunatic ( ) on the engine dyno at Pettis performance have 180F on the outside of the block at or below the fill line and 130 F above the fill line using a hand held infra red temp gun I had freshen it for the owners and built them a complete new R1 block non filled spare motor, guess which one made the most power

ok Mike, looks like a oil cooler is in my future. not gonna use one right away as I would like to see where the oil temps are gonna go. can anyone suggest a good oil cooler?

I'm not a big E85 guy as I went straight to alcohol but if I had a high performance street strip car I would be running E85. That would probably help your cooling issues too.

Since option 1 is your choice then I hope the engine will be ok and the engine should run fine👍👍👍👍👍👍

FWIW our filled block has been together and in the car since 2001 and never had any issues. I run an oil cooler for insurance, never have seen oil temps over 230-240 and that is only after sustained highway jaunts. Car make 750+ HP fwiw as well and we never ran it without the cooler either. Saw no need wanted it just to make sure.

E85 might be an option. Ill know better what needs to be done once its up and running.

Cooling the water isnt a issue.. even with
E-85 the cyl and head temps will be the same
if your burning good and that transfers over
to the oil in the most part

Because most guys run a cooler that is too small, they use crap fittings and hose a mile long and, I'd bet very few here have ever checked the pressure drop across an oil cooler. I have. Unless it's very expensive, it's horrible.



8 quarts in the pan and a QUALITY oil and forget it.

We have a 12 qt pan, with diaper and I have a lot of money over 500 in the cooler and lines. It's not cheap to do it the right way.. I run two pressure gauges in the car one pre cooler one after .. Just to keep an eye on it. On 90 plus days I see maybe 15 lbs drop..

Doug my engine machinist forbid me to fill my 512 block even tho it was for strip only, told me the wall thickness is plenty suffiecent and that filling will change the temp at the lower end of the bore to cause piston scuffing and different wear charistics, now that said I did a half fill on my strip only 408 small block and have noticed that the oil pressure would drop quite a bit the more I ran it and had me concerned during round robin passes at the end of the class run's, is it because of the excess temp in the oil? don't know but that would make sense to me,,oh and by the way I ran Brad Penn 20W50 semi synthetic, proof will be in the teardown and freshen-up.

I ran a short fill in my 408 and the pistons were scuffed bad both times I tore it down. after a freeway ride the pressure would drop quite a bit.

one thing good about this issue is the thin cylinder shouldn't move around much, preventing any cracks. maybe I could add a power adder and put the boost right to it. with the aluminum caps I would think it should be a solid piece.

JMO... but the filler shrinks a bit so dont think you
wont crack a cyl.. I did it twice on the same cyl on
the same block.. but it wasnt a tall fill.. so I dont
think it was up where you need to help stiffen the cyl
walls
EDIT
Thats why some dont see any change in the bore
because it shrinks back a bit and doesnt PUSH
on the walls

I'm in the process of removing Hardblock from an overfilled 400. Total pain in the [censored]. I'd never fill a street motor... Absolutely no benefits and if you're cracking blocks on the street something else is wrong.

Good luck getting that out... major PITA

Spot on AL. This is exactly where I am with my street 528 Cuda, as you say sustained highway use get the temp up. I often wonder how many people are out there without a oil temp gauge ??

Dave If you don't run a cooler with all that fill your first 1/2 hour drive will see 300 on the oil temp.

Dizuster runs a generic small oil cooler on his turbo small block, half fill. Stays cool no issues since install. Plenty of street miles. Many factory Chevy high performance and truck motors run them from the factory. It's not rocket science.
Doug

Does the Hard Block indeed shrink and seperare from the cylinder walls after a few heat cycles as posted earlier? The manufacturers I looked at claim it does not?????

I have heard that both ways. It must depend on the brand of filler you use?

I have a few gauges in the car. oil and trans temp are just a couple. Once I get it on the road I will let ya know what the temps go to before I add the cooler. Can I use a B&M supercooler for oil cooler?

Look at a Hayden oil cooler... a trans cooler
wont flow enough... the diameter isnt big enough..
the one block I bought had a crack in a cyl.. I was
gonna just sleeve the one cyl but when I got around
to it I busted that cyl out to see it was a filled
block... the fill did shrink on it... dont know what
brand it was filled with.. it wasnt much but it sure
wasnt stopping a wall from cracking

Ya, they all claim there's doesn't shrink. I'd like to see proof. My machinist claims they don't shrink. True on the oil cooler thing "it aint rocket science". Many tow packages include them - most police package cars have them. Don't know how well these factory engineered packages would work under our type of racing conditions though. Pressure drop is definitely a consideration. FWIW, oil pressure on fire up @ idle with my 408 = 70psi. At 180 oil temp @ idle = 35psi. At 220 oil temp = 25psi.(10W30 synthetic).

All cements based fillers shrink I've used Moroso block filler once and it shrank away from one freeze plug after it pushed it out enough to need replacing
I've heard that "Hard Block" brand filler is a epoxy filler and doesn't need to cure 30 days and it doesn't shrink also I also heard it does expand and shrink I haven't used it so I don't know about it either way

Over my 40 plus years of racing I wonder how much I've saved by not buying concrete to fill my blocks. LOL

Hard Block is magnetic. It has a percentage of cast iron in it to help it expand and contract as the block warms and cools.

I have heard some crazy sounds the 1st few runs on a fresh fill. Never had a problem with a bore

Moroso is the brand I used . Your scaring me !!!!

Hard block is whats in my block. My machinest recommended it, said it wouldn't shrink. guess ill find out.

i have done this as well... on a tall deck big block, tall fill (bottom of the water pump holes). NO DIFFERENCE in the before and after measurements. at all. that engine lives on as we speak.

good to hear positive experiences. hope to have same

Any updates on street temps?

Not yet. Just installing 511 in the car now. Gonna run without a cooler to start. Will add cooler later.

FWIW, I talked to Jason Pettis who builds/tunes some of the baddest cars around and he said "Good luck keeping the oil cool on the street even w/a cooler"..........1/2 fill maybe but full in his experience is hard to do if not impossible........

I dont doubt that a bit. My sb was short filled and oil always ran hot. Good oil like amsoil is good to 380* before it starts to break down. Will need a oil cooler and may switch over to E85 if i need to.

I like dependable simplicity..........plus I drive mine more than most at this power level n/a and over heating weather oil or water is a no-no in my book..........

On a low deck block, filling to the bottom of the water pump hole can often result in water flow problems through the block, since at that height the fill can get to the bottom of the head bolt bosses....... Which can restrict/block the coolant from reaching certain areas of the block.

On an RB block, that same level of fill would have the bolt bosses 3/4" farther away from the filler.

its filled 3" below the deck. could have some issues.

I only repeated what I was told and personally would never add that weight to the ft. end of the car but that's me........stock 400 block here, 15 years of street/strip bashing, stock 413 off-set ground crank and stock caps. In the 9's for years and ZERO issues.............kinda like the 8 3/4 that went many years.......

I ran a filled 420 small block on drag week 6 times. Changed oil (Val 20W-50 racing) mid week and let it run. I have a oil cooler with -12 lines. Oil temp runs 205 to 210 with the oil temp sender in the oil pan. Interesting thing happened to me on one of the trips in the middle of the week I thought my valve springs were getting week so I changed them at the track to a new set, and the oil temp increased by 15 to 20 deg's. The old springs were a set of the polished ones, chrome looking springs. That block is now being used in the 468 in the Cuda drove it last weekend to KC 80+ deg air temp, and the oil temp ran 210 to 215, water temp was 185.

That's a great little tidbit of info about the polished springs.

Sterling Goins(owner of Air Flow Research) told me years ago that the valve springs make up a bunch of the heat in oil, especially on roundy round race motors
More pressure, more heat

what size oil cooler do ya think it would take to keep temps in check? fan?

after the cost of all that you could just put your current cooler in a water tank circulated with coolent from the heater tubes from the water pump,A tank 1" bigger than the cooler on all sides.

I have a 4 pass on mine.

10 row? 15 row? been looking at the coolers with fans on them.

i currently dont have any oil cooler.

To save a few bucks you could get 1 off a motorcycle but cooling with water can be better than in air.

Where do ya find the water to air oil coolers at. Iv never seen one.

Most stock radiators have them for the tranny to help warm them up

Think im gonna have a tough time cooling the coolant. Not sure i would want it to do double duty with both oil and coolant.

The engine has the same BTU you just use 2 ways to cool it.

yeah,but wouldnt it over tax the cooling system trying to cool the oil and coolant with the same radiator?