Wow!
I Erbs
Sent from my iPod
On Dec 6, 2010, at 10:25 PM, "Chris Dimmock [Healey]" <austin.healey@gmail.com
> wrote:
> As I said Richard, my personal experience is:
>
> 1. A 1100cc sprite engine bored to take 68mm Hillman Imp pistons (~220
> thou overbore).
> That engine gave over 10 years of reliable service until a circlip
> broke,
> and scored the bore. I still have that engine in storage.
> I also had a 948 blocked bored to the same size.
>
> 2. My old 100/4 had Holden based pistons. That made it a ~3 litre
> 100/4 (~200 thou overbore).
> That car/ engine is now owned by another active member on this list,
> who has sleeved the block back to standard.
>
> 3. As I said, my BJ8 is 65 thou over.
>
> Here are some Australians who run 3.3 litre 3000 engines, (~3.5 in
> bore, which is ~ 220 thou oversize) - usually with Volvo based
> pistons:
>
> Cameron Sell; John Wakeling
> http://www.natsoft.com.au/cgi-bin/results.cgi?22/03/1998.ARDC.E13
>
> Neil Dunn (3.2 litre); Eric Rudd; Colin Rule; You'll also notice the 3
> litre 100/4 of Peter Ford
> http://www.natsoft.com.au/cgi-bin/results.cgi?25/07/1999.ORAN.R4
>
> Road going 3.3 litre 3000's - to many to list.....
>
> Typically, these kind of overbores require offsetting bores; and
> decking blocks; and getting compression heights right. And not every
> block can take that sort of oversize 50 years later, due to
> corrossion/ casting irregularities.
>
> However - you doubted it was possible. It clearly is....
>
> Overbore at your own risk - but 60 thou is more than pretty safe.....
>
> Chris Dimmock
> www.myaustinhealey.com
>
> On 04/12/2010, at 2:18 PM, richard mayor <mayorrichard@hotmail.com>
> wrote:
>
>> Ira, I'm a bit skeptical here. I know there's a lot of meat in those
>> Austin blocks, but I would like some confirmation from someone, or
>> two, down under that they have actually bored out their 3000 engine
>> 120 thousandths (.120 inches) without having any issues.
>>
>> Richard Mayor
>> BN7L-466 Vintage Racer
>> Portland, Oregon
>>
>>> On Thu, Dec 2, 2010 at 5:00 PM, Chris Dimmock <austin.healey@gmail.com
>>> wrote:
>>>
>>>> Ira,
>>>> I have the Denis Welch 85mm cosworth pistons in my BJ8. That's
>> approx 65
>>>> thou oversize
>>>> Many healeys in Australia have Volvo pistons to get 3.3 litres
>> ie well over
>>>> 120 thou oversize.
>>>> I used to have a Sprite with Hillman imp pistons - again well
>> over 120 thou
>>>> oversize.
>>>> BMC blocks have quite thick walls.
>>>> If your block is at 40 thou, don't worry, it has plenty of
>> birthdays
>>>> left...
>>>> ;-)
>>>>
>>>> On 03/12/2010, at 4:56 AM, I Erbs <eyera3@gmail.com> wrote:
>>>>
>>>> My BT7 engine is bored 40 over. I see on ahead4healeys' site
>> that they
>>>>> have
>>>>> .60 over piston and ring sets.
>>>>> I have always feared what would happen if I ever had to rebuild
>> my engine
>>>>> again?
>>>>> So the question is can I use .60 over pistons safely in my 29D
>> street
>>>>> engine, if need be?
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