This past weekend I was prepping a Mexican 302 block for oil restrictors, and decided to take some measurements. The thickness of between adjoining (side by side) cylinders on the standard bore block was right around 3/8" (0.375"). I then measured the gap between cylinders. I did this with allen wrenches through the freeze plug holes in the side of the block. All I was able to get between them was 1/8".

So... Total distance between bores is 3/8", with 1/8" of that being air... so that leaves 2/8" (1/4") of metal between the two, half on one cylinder, half on the other. This comes out to 1/8" (0.125") thick cylinders.

Now, assuming there is no core shift, we've got a maximumcylinder thickness of 1/8" (0.125") to work with. How thin can these things go???

I can now see why Alex really likes to fill his overly bored blocks with that Hard Blok filler!

Good Luck!

The extra mass of the block filler makes the engine heat up and cool down slower, but it's not supposed to be that much more taxing on the cooling system. Oil temperature is supposed to go up a bit, but I'll be running synthetic oil, and not road racing... so it shouldn't be a problem.

Anyone have any first hand experience (especially street) with filler? I'm using Hard Blok, which is supposed to have the same modulus of expansion as steel. I'll also be cleaning out the water jackets with Muratic Acid to get rid of all the rust, and promote a good -bond-.

Thanks!

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Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

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Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

This is an area I am not real good with? I just take their advice.

My block was thicker on the inside, intake side, of the cylinder walls, as well as the outer side of the cylinder walls. But, between the cylinders was the thinnest. The thickest part of the cylinder was at the top and bottom and thinner in the center of the cylinder walls.

The range, between the cylinders, was between 125? to 220? The range on the intake & outer side was between 282? and 360?

I've been away from the computer for a quite a while, but have been working on the mustang.

I poured Muriatic acid into the water jackets to clean them out... THAT STUFF IS MEAN!!! It ate ALL the rust out. Then I dumped the rust colored liquid out onto the concrete driveway, it it made a big 'acid cloud'. I poured the drivers side water jacket right up to the bottom of the water pump hole, which leaves just under two inches of water jacket below deck. I poured the other side with the same amount of filler, and it filled up about a half inch taller. Hopefully it won't overheat.

I took it to the machine shop to have it checked out and bored. The dial bore gauge had all cylinders but one worn 0.010".... with the other worn 0.015". It's being bored square to the deck, each bank exactly 90 degrees to the other, etc.... and he said that if the block was very far off blueprint, it might not clean up at 0.030", especially the one cylinder, so he will bore that one first and get back with me. I do NOT look forward to prepping my only other Mexican block for oil restrictors, 1/2" head bolts, block filling, screw-in oil plugs, aligning drain back holes, etc. I HOPE it cleans up.

Oh well... as a side note, I looked at the recipt on the pistons. I bought them back when I figured the 'old' engine was about to 'retire', and it was dated April 4, 1996.

Good Luck!

Yep, in two places, between the cylinders AND in the lifter valley. I bought this one at a swap meet for $200... guess it's time to take the one purchased off a buddy for $100 a few years ago and set it up for oil restrictors, 1/2" head bolts, align the oil drainbacks, fill with Hardblok, etc... This, along with the fact that my good racing bud backed out of going to Norwalk, is rough on the motivation. I don't even know if I'll make it now.

It sure would be nice to be able to afford a new motorsport block...

Sorry for the rant...

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Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator