Moroso Block Filler

Since winter is coming, and my car has been down the track four times since my last rebuild (last month), it's time to tear it down and start over. Yeah, there was damage, just don't know the extent yet.

One of the 1st items on the list after tear down is to fill the block. I'm looking at the Moroso grout. Looks pretty straight forward but I wanted to check and see if anyone has used this and if there are any 'gotchas' lurking.

This is going to be a pretty dramatic rebuild, lots of changes coming.

Watch this space.

so with block filler, your filling the water passages right? How much do you fill them? I never really understood what block filler does? Thanks for helping an idiot

Originally Posted by sharpshot71

so with block filler, your filling the water passages right? How much do you fill them? I never really understood what block filler does? Thanks for helping an idiot

Helps 'thicken' up the area around the cylinders and decks, allows cylinders to stay round and decks to stay flat longer. According to instructions, block gets filled to bottom of water pump passages in the block.

Takes about a month for this stuff to fully cure, at which point the block will head off to the machine shop for some 'touching up'.

Ain't no idiot about it. I'm still learning about this stuff, too.

so it still allows coolant flow through the block right? Its not good for the street cause of cooling issues correct?

I have run a bunch of blocks on the street with them filled to the bottom of the pump holes. The cooling system needs to be up to snuff, no shortcuts there. I have always had to bore the block after a fill, not just hone, thats just my experiences, if you have a 4.03-4.040 block now, depending on which year I would be hesitant personally. I would start with a 4.00 inch block, fill it, then bore and finish hone. It works but I only ever felt it necessary on the clevelands.

My street/strip 302 block is filled up to the bottom of the water pump holes.

I have not had any problems, but the extra mass of the Hardblok makes the engine heat up and cool down more slowly. The oil temperature can get hotter than one that is not filled, so good synthetic oil should be used, and if it gets very hot or gets a lot of sustained hard running, and oil cooler should be used. Make sure the cooling system is more than adequate.

As for the actual procedure...

Hardblok will help support the cylinders and keep them round under severe stess. It will drastically improve ring seal under severe conditions, and it's extra mass will help dampen major vibrations.

I would fill it to the bottom of the water pump holes (if that high) to allow for adequate cooling.

I filled mine with HardBlok, as this was the brand that was overwhelmingly recommended over any other... But, I haven't got to run it yet.

Fill the block BEFORE machine work is done. The Moroso brand is supposed to expand as it cures, and will make the cylinders tight. I have heard of people using the HardBlok product AFTER machine work was done without incident, but wouldn't recommend that if it can be avoided.

You do ONE bank at a time. It's a good idea to torque the mains and use a level to get the engine completely level front to back and side to side.

You then mix it up and pour it in. A mixer attached to a drill will make the mixing more effective and faster, and give you more 'pour' time before it starts to set up. An old alternator fan (or even a straight bar) welded to a rod works great for this.

Be aware that each bank will take DIFFERENT amounts of mix to fill.

When finished filling, I used an air hammer set on LOW to help with settling. I welded a fairly thick 1" square piece of steel to the end of one of the chisels to act as my 'blunt' tip. This makes the job go WAY easier. Settling takes place quickly and efficiently.

After it was all settled, I installed a head (and gasket) and let it cure for 24hrs before doing the other side. The head will simulate the loads on the bore when the engine is assembled. (same principle as 'torque plate' boring/honing)

The directions in the HardBlok containor are good, and fairly easy to follow.

If you have a GOOD scale (for reading low weights of less than 10lbs) the 'tall fill' containor is twice as big and will fill two blocks. (comes with two large bags) It's just important to weigh the filler out accurately to the 1/4 pound. The 'half fill' Hardblok is already pre-measured for half filling. (two small bags)

I also cleaned out the water jackets before beginning by filling them with muriatic acid. I let the un-diluted acid sit in there for a couple minutes in each bank before dumping it out and rinsing GOOD with water. It will eat ALL the rust out of the jackets and give a great surface for the Hardblok to bond to. Just be careful. When the acid hits a concrete driveway, it produces a nasty 'acid fog'. As a by product, the driveway will have one VERY clean spot. Wear gloves and eye protection, and try to avoid getting the acid on your clothes. Muriatic acid is found in hardware stores, and is normally used to lower the pH in swimming pools and clean bricks and masonry. (it's usually diluted for this)

Good Luck!

If you are running alcohol, it will take FOREVER for th engine to warm up. Plus, if you have a 351W based engine, I wouldn't fool with it unless you are in the 9's.

Murf, if I were you, I'd try shopping for a different machine shop! You're spending WAY more time turning wrenches than steering wheels.

N20mike hit all the points except one. The only thing I caution anyone to look out for is to watch the oil temps. Water temp can be "normal" but oil temps can climb fast and you will never know it. Last race day in the Mustang, in the final round, I staged at 140 water temp and 240 oil temp. Without the gauge I would never have known what the oil temp was. Good thing too because I dialed for it...and took the win.

four passes and you're pulling it down?whats goin on here mate?
i would be looking at whats goin on here before looking at filling the block.
no disrespect intended here murf,ive been following your progress with this falcon and i admire your ability and determination,but hell,the 351w is a reliable engine that does not need this much attention if machined and put together right,as mentioned above i too think another machine shop is in order

Originally Posted by steharz

four passes and you're pulling it down?whats goin on here mate?
i would be looking at whats goin on here before looking at filling the block.
no disrespect intended here murf,ive been following your progress with this falcon and i admire your ability and determination,but hell,the 351w is a reliable engine that does not need this much attention if machined and put together right,as mentioned above i too think another machine shop is in order

A bit of an explanation may be in order, I guess.

I set out to build a non-traditional litlle block Ford. i did not want another belly button engine, I wanted to do something a little different.

The difference I settled on was the mechanical fuel injection. The big difference within going with MFI was that I was injecting gas. If I had gone more traditional with an off the shelf carb or started out injecting alcohol I would have had fewer tuning issues for sure.

All of the mechanical issues I have experienced have been self inflicted, there is no machine shop or builder to blame or replace other than myself. And I will be replacing the builder on this go around.

The first time I built this mill it was exciting, the second time was a learning experience, the 3rd time was crap - I have to do this again? This build will be performed by the shop at my local speed shop, guys that have been very helpful to me all along, considering the low amount of dough actually spent there.

The events leading to this build are 2-fold. We have been discussing making the change to alcohol from the beginning and with the gas tuning issues I have had and the onset of the winter season make this an opportune time to make that change. The other reason is that the engine went lean on me last Friday night on my 2nd pass. Saturday it sounded like it was running on 6 or 7 cylinders and would not take a recurve of the fuel system to correct. My suspicion is that a piston has been damaged.

Since I need more compression for alky I am not too concerned at this point on the condition of the pistons as they would be getting replaced anyway.

Overall, the engine has performed better on this build than ever before. At Pacific Raceways 3 weeks ago the car went 11.67 with only about 3/4 throttle. At Renegade Raceway this past weekend the car went 11.93 off the trailer. RR is about 800 feet higher than PR and there was like 0 moisture in the air so a 3/10 difference is not unusual, but conditions may have contributed to the lean out.

This is a pretty long winded explanation to a simple question but I just wanted to point out that this is not a standard 351W build, and that the builder is me.

I'm just a duck in the fog trying to find my way to the pond.