Does anyone have any tips suggestions on using this on a 400sbc? I may do this with the 400 block while it's apart. I'd like to go to a 3.875 stroke crank.

Also is it beneficial to smooth the oil galley under the intake manifold while it's apart?

Thanks :cheers:

 

i have done this on 400 blocks even for street machines to stiffen up the cylinder walls because they are weak at the bottom of the water jackets and crack there. if you do this it must be done before any machine work is done on the block. just deburr the oil return holes to remove the casting flash and make sure the oil return holes from the heads are not blocked by the block,if so just grind the block till the head return holes have no restrictions.:chevy


[Modified by clem zahrobsky, 12:18 PM 10/17/2002]

 

The machinist that put together my 383 shortblock put together a test mule to experiment with Hardblock on the street. He Hardblocked a ford 302 to an inch or so below the deck. Just high eneough to still get coolant flow to the heads. He used KB hyper pistons with .030" top ring gap.

The motor didn't run hot coolant wise. He didn't have an oil temp guage. That'll be on for the next time.

He did butt the top ring gap on 4 pistons, breaking the top land out of one of the pistons and breaking rings in the other 3.

The hardblock doesn't allow the cylinder walls to expand. I looks like there is some art in setting up ring gap when using a lot of Hardblock. I wouldn't do it unless you're only drag racing the car, or if you use a machinist that has actual experience Hardblocking a 400 for the street. Then leave it up to him on piston and ring gap selection.

 

you have to hot hone the blocks if you use the filler clear up to the bottom of water pump holes. i never use hypertech pistons only forged and i never had any problems. :chevy

 

Only do the lower 1/3 with epoxy. It's a smart idea even on 4 inch bore stroker motors. I'd also research some of the additional cooling tricks like external block lines and rear head crossovers. I haven't torn my motor down yet, But I'm a firm believer in thermal coated pistons. I had them three type coated at that place near your house for $235 or so. I just sent them my JE pistons. I also had the chambers and exhaust valves done.

 

I hard blocked my 400, and it runs as cool as my 350 ever did. I bolted the main bearing caps on to re-create running stresses, and leveled one deck to pour in the block filler. I filled it to the bottom of the forward side frost plug. The bell housing frost plug and the rear side frost plug were installed because they were lower than the front one (my 400 only had two side plugs). After filling the one side, I bolted on a head to pull the cylinders into running condition and than let it set up over night. Then I did the other side.
After doing both sides, I tapped the large deck holes for 3/4 npt and installed steel pipe plugs. These were machined flat when I had the block machined. Both of these mods make the block much stronger, and the cylinders are supported much better for better ring seal. On a street engine or drag engine you shouldn't have any trouble. For an endurance racer, I don't know.

You can also pick up a few more hp if you port your oil supply passages. Your rear main cap, oil filter passages, and the 90 degree passage just below the rear main cap are a couple of spots that benefit from a little porting.

 

you can fill it until the bottom of the freeze plugs. It won't have any affect on cooling (since the coolant is mostly used to cool the heads and upper half of the block, that's where the heat is)

 

It is questionable to do on any street engine, unless you stay below the frost plug holes. I just tore down a 355 that the guy had hardbloked to 1 1/2 inches down from the deck. He ran 12.8.1 compression, solid roller cam bowtie heads, and a single 850 holley. It was installed in a custom built jeep scrambler with a aluminum radiator and single 18" electric fan. It never showed a temp higher than 220*, yet started to use oil after 1000 miles. Upon teardown, the rings seemed very loose on the pistons. I sent 2 pistons and the rings back to Wiseco, they informed me the they had been over heated. The said that the hard block will not show a rise in coolant temp, because the coolant isn't getting hot where the hardblok is. They recomend not to hardblok any street engine unless you are going to run a oil temp gauge and they highly recomend running a digtal temp gauge that is installed into the side of block where the hardblock is. As they explained it to me, the area that is hardbloked will run slightly hotter than the areas with coolant but when you shut the engine off the hardblok areas will increase and hold the temps much worse/longer than the coolant areas. This heat is what can destroy your piston rings as they sit still in the bores when not running. I called hardblok directly and they said they have heard of a few "isolated" cases, but it should work! I have used it in racing applications, and it is great. The street applications that I've used it in have all had ring problems if the block is filled higher than the bottom of the frost plug holes. The 400 block is not a problem without hardblok, it will hold up to 12.-1 + comp, as long as it is built correctly. :cheers:

 

Thanks for the great info everyone.

74vetteman what is the hardblock like? Is it like a paste or a liquid? Did you go in thru the cylinder to fill the block? And lastly, does the Hard Blok come with instruction?

Thanks again to all, I want to make this block as strong as I can :) :cheers: !


[Modified by SmokedTires, 5:20 PM 10/17/2002]

 

I used a jug and a half of Moroso block filler. It comes in a powder that you mix with cool water (warm or hot water would make it set up too fast! Trust me, you want lots of time!!). I used the large holes in the top of the block (the ones later tapped for pipe plugs) to fill the block. Probably the hardest part is to get the right consistancy. You want it runny enough to flow around the cylinders (especially the rear cylinder) but not too runny. I used a welding rod to help push it around. You can download instructions from Moroso's web site (I think). Mine came with the filler. Good Luck!!

David Vizard claims that block filler is advantageous for performance. It supports the bores, strengthens the block, dampens unwanted harmonics, allows for hotter oil and cooler coolant (more hp). I've never heard of ring problems, but I am no expert..

 

block filler is expanding grout they use to set machinery. most products you mix with a liquid shrinks when it hardens,like concrete, so it would move away from the cylinders and do no good. if the block filler hurts performance the racers would not use it.:chevy


[Modified by clem zahrobsky, 9:50 PM 10/17/2002]

 

Couple of things I forgot to mention:

When filling the block with block filler, use a good size dead-blow hammer to help level the filler and remove any air pockets,

And after installing the pipe plugs in the large deck holes, and having the block decked, use your head gasket as a template to drill the proper sized coolant holes in the pipe plug. If I remember correctly, they are 3/16".

 

yes, a 3/16 hole in the plug is enough.

 

it depends on the head gasket you use but always check to make sure the water passage holes in the head gasket are not blocked by the plug you install. i have had to grind grooves in the plug to get it to line up with the holes in the head gasket :chevy

 

Thanks for the additional tips. Another dumb question, what is the purpose of tapping and plugging the holes (coolant holes I'm assuming) ? Does this hold the water up in the cylinder heads longer?

Thanks again, I'm getting there :crazy: !

 

I am not sure why those holes are so large in diameter, because the holes in the gasket are only 3/16", so the gasket limits the flow through the holes. It could be part of the casting process. By tapping the holes and installing pipe plugs, you really increase deck strength.

The flow of coolant is supposed to be from the front of the block, past all the cylinders, to the rear of the block, then into the heads and forward to the front of the heads, and back into the intake. The holes in the deck are mostly to let air pockets escape (although there is some coolant flow).


[Modified by 74vetteman, 5:20 PM 10/18/2002]

 

OK, that makes sense :yesnod: . I'll be picking up the engine today if it ever stops raining :) .

Thank you all for the useful info, I will be putting it to good use :yesnod: .

:cheers: