[Healeys] Forged pistons

[Roger Grace]

Thanks to all.
Relieved to hear that skimming the pistons is standard practice. The new
ones look soo pristine too !
Of course the supplier had never had this problem. The compression height
is definitely different to standard pistons.
A few response BTW's
The original porosity problem is not the usual oil (at 50 psi) into the
coolant (at say 3 psi) but coolant at atmospheric or slightly above, back
into atmosphere via a porous water gallery and draining back into sump.
Yes did all the usual measurements of block height from crank center line.
Now lightly assembling the crank with #1 and #6 without rings to check
clearances.
I may be wrong but feel that the Wolseley block had never been opened
before so still a bit of a mystery.
rg




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On Wed, Aug 20, 2025 at 6:23 PM <jvwojcik at comcast.net> wrote:

> 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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