Hard block???

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JBurch

JBurch

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Have a block, all machine work is done, BUT, is not hard blocked..........I KNOW that it is preferable to fill BEFORE machine work is done.......just want to know what if any down sides to filling after machine work.

Thanks
 
I don't think it's the machining as much as it is the torque plate installation immediately after filling and leaving the torque plate on overnight while it sets up. It should be okay if you torque the main caps to spec and have a torque plate tightened up to what your machinist set them to on each side of the block while letting the filler set up overnight. Your goal is to try to duplicate the distortion of the block from having the mains torqued and the torque plates on while it was being machined so that when the filler sets everything will be held straight, round, true, square, etc.... It's the same procedure before machining one so as to "pre-stress" the filled block to its normally assembled condition, so that the drawing forces of torquing everything down aren't pulling against the filler.
 
The problem my buddy had was the block stayed cold and the pistons got hot and kept scuffing and actually stuck the first time,
He kept opening up the bore till he had about .012 clearance before it stopped scuffing the pistons
 
Thanks again Brian6pac! Yes, I definitely could see cold seizure becoming an issue, I had forgotten about you mentioning that on the last posting... my concern was having cylinders set out of round but I would torque the mains and torque on a set of compressed head gaskets in with whatever heads I used while filling the block. Then (this part hurt$) have whatever your piston manufacturer (Call Them!) recommends for block filler (I.e. JE recommends .00166 for every inch of piston diameter for filled blocks and usually more ring end gap as well) torque plate honed out of the cylinders. I guess cost for honing cylinders twice could answer the question of why it’s better to do fill block beforehand...
 
.00166 x 4.32 = .0717, I know the newer pistons don't swell as much as the old stuff so that would probably be fine like you said call the manufacturer
 
brian6pac said:
.00166 x 4.32 = .0717, I know the newer pistons don't swell as much as the old stuff so that would probably be fine like you said call the manufacturer
Click to expand...
Almost the same clearance as air cooling...
 
brian6pac said:
Looks like I missed a 0, should be .00717
Click to expand...
Reminds me of helping overbore Harley Evo cylinders, during final honing we would take ten inch long feeler gauges with motor oil to stick them together in a stack .0062 thick for a 3.515 inch bore (forged S&S pistons) and push bare pistons through lightly oiled bore to confirm clearance and would go to an .007 stack for a go- no go gauge. It was right when a slow steady push would push it across the .0062 and it would still slide through on a .007 but it would wipe all the oil off one side of bore with thicker gauge.. it still amazes me at how well that technique works, being it is actual clearance measurement when done properly.
 
My 470 stroker was hard blocked 20 years ago. No issues yet. A guy at the track had a piece come loose and stop the water pump causing it to overheat. I’ve seen that when u add hard lock to a bored block that u need to bore to the next oversized cause it distorts the bores. Kim
 
JBurch said:
Such as??? Just trying to learn something here.
Click to expand...


Busy day so I’ll keep it short. Two of my friends overfilled their block and had to scrap them, high oil temps, flaking like mentioned above, less water cooling ability to keep cylinder temps even. Just to mention a few
 
You have to remember that a BB doesn't have freeze plugs in the front or rear of the block so there is no going back once you fill them, another friend of mine got a block that was filled SB and took a air chisel and busted up the filler going through the freeze plug holes and from the top. He said he got it all out but I'm not so sure, I know he got a lot of it busted up.
 
My buddy half filled his Pontiac 455 to the freeze plugs. It was the coolest running street car I have ever been in. We believe it filled any hot pockets that coolant would get trapped into creating heat. He drove it like this for many years.
 
brian6pac said:
.00166 x 4.32 = .0717, I know the newer pistons don't swell as much as the old stuff so that would probably be fine like you said call the manufacturer
Click to expand...
I don't think I'd wanna run over a 1/16 piston to wall.
.007 might be more like it.



(Sorry, I just had to.)
 
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