northey

Experts and others.

What do you think of block grouting? I've only done it once on a Chev drag car and swore I wouldn't use it again.

Even though it was a methanol burner we couldn't get rid of heat. Water cooling wasn't really an option.
It was much easier using a good block and no grout.

What about shrinkage of the grout? I've seen an engine with small hairline cracking around the areas where the grout meets the block. The grout wasn't breaking up but had shrunk away from the block slightly. And that means it wasn't doing it's job.

How do you know the same thing doesn't happen with them all?

brenx

The trick with grout filling a block is knowing where you can/can not fill to. Each engine type will be different. My new engine has had a light grout fill. If I remember correctly it was to add support the mains and cylinders (lower part of the block).

I got a company that has done clevelands this way many times before. I'd also think grout manufacturing has changed not to allow for flex.

__________________
XB Fairmont (street car) 11.07@123.02mph.

davis

I've never had heat problems with methanol engines...were you running nitrous or a blower?

I usually grout fill my methanol engines to about even with the bottom of the waterpump inlet ports.

I don't know what kind of grout you use, but I use Hard Blok and we don't have any problems with it. You need to fill it per their instructions.

I usually find that my methanol engines run so cool that you can touch the inlet manifold with your hand after a hard pass...and it feels cool to the touch...if you touch them right after shutdown. If you wait about 10 minutes, they'll feel hot, but I usually run the electric waterpump drive and fans until the water temp is below 140*F. It doesn't get much over about 180*F in my experiences, except when using a blower and as much boost as it will take. Then, I see temperatures of about 220* in the water with about 22psi of boost.


:davis:

TD302

I've also found with friends grouted street engines (also level with bottom of waterpump inlets) a good engine oil cooler helps too.

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northey

Don't remember the grout brand. It was injected, naturally aspirated. Our manifolds used to run cool/cold as well (with carby also) but afterwards trying to get the engine cool enough for next round.
I realise that while the engine's running the methanol keeps it cool up to a point.
It was an altered and after learning painful lessons about running water we gave that a miss. Any problem at all during a run with water system means the driver and the rear tyres get a bath. It was dangerous in my opinion to have water in the car.

How about the shrinkage though? If the grout shrinks .003" (an insignificant amount) you have no extra rigidity in the block.

Cheers Northey

davis

Yes, water is always a problem when racing...but oil is worse! At least water won't catch on fire. <grin>

I've gotten my tires wet from popped radiator hoses. It isn't any fun. I run a small Sirocco radiator and a pair of 12" fans. No matter how small it is, it is still big enough to wet your tires and put you into the wall.

Regarding grout, have you ever seen a cake collapsed? Does it pull away from the sides of the pan or does the center just sink in?

The grout supposedly has the same thermal expansion characteristics as iron, and therefore would expand with the given heat during running the engine. Would it negate any shrinkage (if there is any)? Also, what of the metal around the grout? Doesn't it expand too? Won't it try to push against the grout as it gets warmer? The idea of using grout is to strengthen the bottom end by filling air space in the water passages in the block with a hard material. It seems to me that that is what happens. I don't think that it needs to be "perfect" to do the job as intended.


:davis:

northey

Yeah, I think you're right. I forgot about a few things there.

Racer

I agree. Even if it were only .0001 it would be useless in my opinion.

I personally know guys running 8's and 9's with Clevos and no grout. I would never consider it myself.

ps
Some people actually use concrete.

LTD351V2

Concrete has same thermal expansion as steel.

northey

Concrete in what form? There are so many types and uses. It's expansion/contraction rate varies as the mpa rating changes. And as different materials are used within concrete.

Apart from the excess heat grout worked ok in our engine but I'm not convinced it's as good as it's supposed to be.

If you fill the block to bottom of water pump holes as we did (exactly what we were told to do) are you not changing the expansion rates of the whole block?
The bottom of the block with grout can't expand at the same rate as the top (which has water or air in the passages).

Torque plates are used to get the best shaped cylinder one can get from the boring bar. So the pistons have a constant shape to work with.
Then we fill the bottom half with grout to stabilise and leave the top half untouched. And the top half has to deal with compression and ignition; where all the stress is.

I don't understand how it's best for the engine.

Cheers Northey