[Healeys] Forged pistons

[jvwojcik at comcast.net]

Hi Roger. Familiar problem. That porosity made me crazy and my first engine rebuild using several standard repair efforts made me weep. Then went to a hot rod engine builder who used Hard Blok, https://www.hardblok.com/
a product used by drag race engine builders. He dipped the block, poured this into the jacket, and rolled the block to make Hard Blok flow to the porosity area. It truly worked, and I had no further problems over the next 10 years of ownership.
 
As far as pistons, he installed Ross forged aluminum pistons that were about 50% lighter than stock, and had modern rings and a much shorter skirt. Again, never a problem. Engines have evolved and I think it isn’t necessary to keep using old tech to build a classic engine unless you have a 250 GTO or such. Happy to chat if desired. Jim
 
 
 
From: Healeys <healeys-bounces at autox.team.net> On Behalf Of Roger Grace
Sent: Wednesday, August 20, 2025 12:47 AM
To: Healeys <healeys at autox.team.net>
Subject: [Healeys] Forged pistons
 
Late model BJ8
In the process of changing out the block (because of a porosity coolant leak into the oil drain back).
Managed to find a Wolseley 110 saloon block of similar vintage. I do believe that it was original and had not been previously opened. Everything seemed the same and interchangeable with my original bock. Well almost ...
While the engine is in bits decided to do some upgrades - pots re bore, crank grind, balancing, new pistons etc. etc. Now discover that the pots are about 25 thou shorter than the original. Any thought as to reason ? I note that the Wolseley block had concave piston crowns. Maybe to reduce compression for a saloon car and the block decked to set the final compression ?
To add to this problem decided to spring for a set of AH Spares forged pistons. Surprise surprise the compression length is about 18 thou longer than standard BJ8 pistons. These variances might seem trivial but they are consequential. So now will likely have to machine the forged piston crowns or as a last resort consider a block shim. All rather painful !
Any thoughts or ideas appreciated.
rg
 
 

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