3L to 4.5L ?

Steve Welton · Joined: 17 Oct 2013 Posts: 105

Does anyone know what is involved in increasing the capacity of a 3L to a 4.5 L. Is there a learned article somewhere that I could read. What is the reputation of the different blocks? I believe there are ones in the UK and others manufactured in NZ.............

John Murch · Posted: Sun Jun 14, 2015 5:40 pm Post subject:

Steve, if you already have a Phoenix crankshaft and rods, there is the possibility of fitting a 'big bore' 3ltr block. Which can give you 4.5ltr capacity with a long stroke. See
http://www.arie-jean.com/en/reverse-engineering?id=1
I'm not sure if an original crank with the big bore would be a sound idea.
But if you have a good crank, with this route there could be cost savings as there are other parts that can be reused.
Also it still looks like a 3ltr engine. The downside is that these 3ltr style blocks are more expensive than most of the 4.5ltr ones.....
John

Robin Gurdon · Joined: 28 Apr 2015 Posts: 5

Also see Classic & Sportscar June '15, p215 – interview with Ewen Getley of Kingsbury Racing. From the article this seems to be his thing.

John Murch · Posted: Sun Aug 21, 2016 8:43 pm Post subject:

A few months ago Ewen Getley transformed my 3ltr by fitting a 4.5 block onto my crankcase, utilising my existing 3ltr phoenix crankshaft. (Overdrive fitted as well, 3.54 diff. 33mph/1000rpm)
Not quite as simple as it sounds, a lot of other bits had to be replaced as well, but things can be put back to standard if one wanted to.
But I can't imagine one ever wanting to! The performance is now amazing, overtaking is simple, I've done about 1000 miles on it now, cross country trips utilising the performance has resulted in an increase in fuel consumption from 17mpg to 16mpg, but a 250mile trip up and down the M1 this weekend using the o/d and cruising at 70 + resulted in over 20mpg.
I know some people will disapprove, but for a well used car in all sorts of conditions and roads it's great!