"But seriously folks" - deck cracks...

[Special Coupe Frank]

Okay, looking for perhaps a more rational / scientific discourse on the tendency for the A-block to crack around the exhaust seat area on cylinders # 2 & # 3, and ways to prevent it ( any modifications to the block / water jacket ) ?

The general consensus is that these cracks are a result of "overheating", perhaps repeatedly.

What are the shortcomings of the block design that contribute to the failure in this area, and are there any steps that can be taken to improve the block to prevent such failure, besides "don't let the engine overheat" ?

Thanks !

SC Frank

[PC/SR]

#2 and 3 exhaust ports are adjacent to each other and concentrates the heat. Fordgarage has the only practical answer. A friend of mine made a "4 port" A engine for Bonneville, using the 4 exhaust ports as intakes and the two intakes as exhaust. Should be interesting when he runs it.

[Special Coupe Frank]

Originally Posted by fordgarage

I think you already got it.
Don't overheat the engine, don't lug the engine, and don't overly retard the engine. Use the spark control properly.

Sounds like you want to 'improve' the block so it can't be damaged from overheating.

Yes, that would be nice...

Is there any water passage between the exhaust valve pockets and the cylinder bore on # 2 and # 3, or just solid iron ?

Why don't # 1 & # 4 crack ? # 4 is farthest from radiator ?


Does this problem also plague B & C blocks ? How about the flatty V-8's, with that long exhaust passage through the center of the block ?


SC Frank

[just plain bill]

Originally Posted by Special Coupe Frank

Yes, that would be nice...

Is there any water passage between the exhaust valve pockets and the cylinder bore on # 2 and # 3, or just solid iron ?

Why don't # 1 & # 4 crack ? # 4 is farthest from radiator ?


Does this problem also plague B & C blocks ? How about the flatty V-8's, with that long exhaust passage through the center of the block ?


SC Frank

The B C blocks are more prone to cracking because the deck is thinner

[Bill in Al]

I've posted this previously that when tightning the head down,(in proper sequence)I heard a slight pop. I knew something had broken so I took the head off and found a crack between the intake and exhaust valves of #3.One side of the crack was slightly higher than the other and the crack went under both the seats and down.The deck is very thin and I don't know for sure that it's factory or maybe rusted.It's a B block,sorry for not mentioning that earlier.This is an inserted, balanced crank with a 5.9 head and yes I was very careful torqueing the head. I didn't get past the 55 lb. point.I think that maybe some blocks that are cracked around the valve area may have been caused by the fact that there are so few head bolts on these blocks and that puts an unequal pull on that very thin area. I'm thinking that this may be a cause as common as heat causing cracks.

[BILL WILLIAMSON]

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Chief always thought that pouring cold water into a really HOT engine, WITHOUT the engine running, was a great contributor to CRACKING! Bill W.

[Milton]

Originally Posted by Special Coupe Frank

Why don't # 1 & # 4 crack ? # 4 is farthest from radiator ?
SC Frank

Proximity to the radiator doesn't matter as much as proximity to the water inlet. The inlet has a vane at the front side that tends to deflect the water to the rear. The deflection makes up for the water pump suction and ensures cooling for cylinders 3&4.

I wonder if the cracks that you are referring to aren't operator inflicted. The engine is overheated and has boiled out a considerable amount of water. The cap is removed and a hose is put in the radiator allowing cold water in and it enters between 2 & 3. Extremely hot cast iron and cold water, kind of like a "perfect storm" for cracks.

[Special Coupe Frank]

Originally Posted by Milton

Proximity to the radiator doesn't matter as much as proximity to the water inlet. The inlet has a vane at the front side that tends to deflect the water to the rear. The deflection makes up for the water pump suction and ensures cooling for cylinders 3&4.

I wonder if the cracks that you are referring to aren't operator inflicted. The engine is overheated and has boiled out a considerable amount of water. The cap is removed and a hose is put in the radiator allowing cold water in and it enters between 2 & 3. Extremely hot cast iron and cold water, kind of like a "perfect storm" for cracks.

Interesting point...

[dumb person]

Would it be dumb to reinforce the top of the block by brazing a steel plate cutout to the shape of the head gasket to the entire face? Or might this invite more problems unless the block had heaps more problems and the brazing was a last ditch effort?

[PC/SR]

No doubt that Milton's scenario of cold water on hot iron will make cracks. I worked in a service station in the 50's and "hot" cars were common. The routine was to spray the radiator, then use a long stick with a ratchet to remove the cap, keep the engine running, pour in water and watch it steam out. Lots or fun.
To answer Special Coupe Franks question, yes, there are water passages between and around #2 and #3. Just keep the cooling system working well. What I have seen and heard about cracked blocks are mostly historical, or racing. Anyone have a story about a recently cracked block in ordinary usage?

[Special Coupe Frank]

Originally Posted by PC/SR

What I have seen and heard about cracked blocks are mostly historical, or racing. Anyone have a story about a recently cracked block in ordinary usage?

For what it's worth, the two engines I have on-hand that have the same deck cracks ( single crack radiating towards cylinder bore from exhaust seat on # 2 and # 3), one is a 1928 Coupe, one from a '29 Tudor, As far as I know, neither engine was raced, both are stock in terms of bore, stroke, have original factory stock pistons, couple of replacement valves, perhaps had a re-ring & valve grinds in their lives. I know the engine in my Coupe overheated a couple of times during the the three years I've owned and driven it. Don't know about the other engine, except that the car it came out of ('29 Tudor) was in a barn for about 30 + years, and showed 62,000 miles on the OD.

I have no way of knowing how recent the cracks are in either block.

Neither engine was shipping water into the oil, but the '28 Coupe engine would seep water into # 3 exhaust port / exhaust manifold & pipe, and blow a spray of carbon-laden water / white vapor out the tail-pipe on a cold start after sitting overnight or a couple days...

I treated the '28 Coupe block a couple times with both K-seal and Bar's Leak Copper-Seal, and that seemed to stop the leakage... ( yes, I know it's only a band-aid ) and the Coupe motor ran w/o further overheating since installing a new BW radiator two years / 6,000 miles. Deck cracks on that mill were discovered when replacing a head gasket just after installing new radiator. Headgasket failed because a previous mechanic installed head & gasket w/o a cable clamp under #8 stud, nut bottomed on thread, but did not sufficiently clamp gasket between #3 and # 4 cylinders.


My question about addition of cold water to an overheated engine is this: if the block baffle at the inlet port, directs water towards the back of the block first, what IS the coolant path through the block & head ? Are there any good drawings / 3-D computer images ?

Thanks...

SC Frank