Hard blocking

Sorry! I didn't mean to immply that you were hard block crazy. I was inadvertantly thinking of some of some other posts (earlier thread?) on the hard block subject. Memory was telling me that the bulk of those posts were certainly pro-hard block and failed to mention any of the shortcomings of the stuff. Just wanted to make sure that readers know that everything isn't always "rosy" with hard block.

I agree that if it is a last resort, then by all means do whatever is necessary to salvage an engine (hard block and rebore)....

Regards,

Goldsburg
goldsburg@att.net

I would have to disagree with you on your point about not being able to run water and the sleeves needing support. Adding hard block for these (or any) reasons is only putting a band-aid on a problem, IMO. These problems can be solved with some creative engineering, which is what separates good engines from great engines.

My problem with hard block is that it deems the engine to a "limited" life. The expansion and contraction rate of the sleeves is not the same as the concrete (hard block), so after X number of thermo-cycles, the hard block will loosen its "grip" on the sleeve. At that time, you will most likely start seeing water in the oil and congruently the hard block will no longer be "supporting" the sleeves, without sleeve deflection. It is then time to break out the Water Glass!

The other problem that I have seen with hard block is when it is filled to within approximately an inch of the top of the block (just enough room to circulate water, it creates a stress concentration in a ring around the cylinder. I have witnessed sleeves cracking around their circumference at a height exactly coinciding where the hard block was stopped. That is why I do not use, nor believe in the value of "hard blocking" a tractor engine.

Race car engine blocks (ie: 350 Chevy) are parent metal bore, with considerably thinner sleeve walls which MIGHT need the support of hard block. But if the hard block pulls away from the "sleeve" of a drag motor, there isn't going to be water in the oil. In addition, a 350 Chevy blocks, for example, are "a dime a dozen." So if something goes wrong, you are only out $150.00.

This is not a flaming post! I am just merely presenting the other side of the hard block issue. Your use of hard block is a personal choice, but others need to know the "whole" story.

Regards,

Goldsburg

goldsburg@att.net

I would certainly think that this would be possible. I have never seen this done, nor would I do it, personally. I like the way that you are thinking of new solutions to existing problems though!

My guess as to why you don't see this done regularly is twofold: 1. I don't think the benefit of some small passages with a little coolant flow through them is going to yield much additional cooling benefit (the low thermal conductivity of hard block would also limit the benefit). 2. While it is possible to drill through the stuff (it has a consistency of mortar), drilling all the way through the block side to side OR front to back, is probably more work than most people are willing to tackle!

I would advise anyone who feels that they have to go so big on a bore that they need hard block, to back off of the bore size and go with the stronger sleeve (thicker wall cast, ductile, steel, etc). You could possibly find your power elsewhere. This might be in the form of some additional tweaking and testing on your induction system, different component technology (like Total Seal rings, ceramic coatings, etc), carburetion experimentation, or you might just even find the power you were desiring from a stouter sleeve wall that exhibits better ring sealing capability!

The point is to not accept status quo and keep those minds turning. Your tractor wheels will soon follow...

Regards,

Goldsburg

goldsburg@att.net