What say you more experienced guys about doing a partial fill to stabilize walls of a street/strip mill that's been together for several years? I'm going to lean on my small block mopar a lot harder later on and would like the walls supported better with a fill to the bottom of core plugs. I've been told by some that you only fill a block before final machining? Will this be wasted effort if I happen to have the heads off for some reason and I drop in some hard block? -rick EDIT: YES, the engine would be out of the car and prepped to have clean dry water jackets.-rick
I have filled them on assembly or after. Filling shouldn't shift the cylinders around its cast iron for cry sake. Someone will tell you different but they are full of it. We have filled the bottoms of street strip motor and not had any problems with them. probably not going to be a get in it and drive it to the coast motor but what street strip car is?
Will this be wasted effort if I happen to have the heads off for some reason and I drop in some hard block? -rick Probably. But not because of the supposed cylinder movement or cooling issues. The block has to be CLEAN on the inside.. I use muriatic acid in the water passages of the blocks that I h-blok. Any anti-freeze, rust etc. Will screw up the bond.. Also a thin, pourable slurry mixture is not good. The stuff is hydraulic cement. I usually trowel it in. Then use a common air hammer, with a large bit, and vibrate the block untill the mixture settles/levels off.
Yep good advice here. Most often hard block happens when the mill is in pre assembly stage but it can still be done on a used engine if you follow this advice. I didn't think to mention clean I just figured it was a given. Anyway if the block needs to be stabilized it needs to be stabilized.
We did a half fill on our 331ci 283. Hasn't seen much street use but every time we've run it it's always run cool. Engine was bored .155 from stock to yield a 4.030" bore with a 3.250" stroke. -Dean
My 392 hemi block is a 1/2 fill and it never goes over 180F at the strip. Running gas at 11.7:1 compression. I was worried it would get hot but it doesn't. One thing I would wonder about filling a block in a car - how will you rotate the block to be level? Or maybe you meant with the engine out of the car?
We built a car on a driveway ( actually 3 or 4 in 7 years) that you would have had to jack the front of the car up to make the engine set level. LOL
What good do you think it will do? Have you ever seen a small block Mopar where the block scattered because it wasn't filled? I can't imagine what you are doing to put that much stress on the block. Mopar blocks are strong, I can't see why you need to do this???
I had a 455 +.060 Pontiac in my Bonneville car. It developed cracks at the bottom of the bores. The next block got Hard Block. How you would fill the water jackets to the freeze plugs with out having the engine out I have no idea. Rotating the block 45 degrees each way seems to require it be out. Anyway, with the concrete filling it was heavy, but bored very round and did not crack again.
Rusty with it bored a ton and huffed on alchy I guess it could scatter but I am like you it will probably toss a rod before it breaks the block and a stud girdle and good rod bolts goes a long way to help the lower end.
Despite the experts, it depends on many things IF the iron decides to move as the HardBlock starts to cure. It's a crap-shoot actually. I don't know too much about the bottom end of a small Chrysler block, but I wouldn't do it to a block with previously bored cylinders. But that's just me..! Mike P.s. - Have you called the makers of the stuff..? I'd guess that they'd provide the BEST answer to your question..!
Concrete shrinks when it sets. Core shift happens at the factory not 20 years after the fact. Oh not an expert here just an old wrench who has tried a lot of shit screwed up a lot of shit and been pretty lucky most of the time even when shit gets screwed up. Here is a pic of the bottom of the block in question (or one like it) which is why Rusty questioned the reasoning for filling it. The pan rails don't hang down really low on these blocks but filler won't help that where a stud girdle might.
The reason for my question is this. Stock Mopar parts are generally stronger than Brand C or Brand F and do not require reinforcing, or being replaced with heavy duty parts. Even in the cheap brands filling the block is usually reserved for all out race motors producing more than 2X the maximum factory rated HP. I was wondering what kind of motor the OP was running? Or if it was another one of those cases where someone hears about some "trick" part and wants it even though they don't need it?
Well I just did this on an already bored and honed block. Let me see if I can borrow Johnny's bore mic and we shall see if it distorted I worried about this for a week also, but in the end decided to fill it and re-hone if it moved.
Don't know what you mean by "lean on it harder" but I should think if you are really going to increase the HP that much you should tear the engine down for inspection and replacement of rings, bearings, timing chain etc. before going for 1000 HP.
I am mildly familiar with MOPAR blocks and as a rule you got to be trying pretty hard to break one. LOL If you look the bottom of the 360 block where the cylinders are set is pretty substantial. I did see an old super stock racer scatter a small block in a Cuda once though, but it was all from the crank centerline down. Adding nitric acid to your methanol will go a long ways toward breaking one though.
I thought the reason for filling the cooling passages was to reinforce the cylinder walls if they were bored paper thin or you were using nitro fuel or supercharging to more than 2 atmospheres?
And to those that "think...." that Hard Block shrinks...maybe either mix it better and or "read the manual"..! That's one of the benefits of this particular material, if done correctly, it doesn't shrink. Mike
I'm running a 5/8" stroker crank at 15:1 compression. That's why I did it. Probably the only way to know if it was needed would be to blow up an engine and say "it needed hard blok " .
lol, lots of great responses- Yes the engine is in or out of the car frequently as I slowly build the car-so I would definitely prep it right before filling. The reason I was considering a partial fill is that the mill made 480hp and 520lb/ft on gas and I've got a nitrous kit that will definitely be use as well as the possibility of a really big VR4 Paxton that was only made for a few years. If I hit the bottle hard, or switched to the blower/alchy, then I was thinking about stabilizing those long cylinder walls from flexing. (SBMopars have a taller deck than Ford/Chevys and it seemed like cheap insurance). But maybe it's money better spend elsewhere-rick
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