Oil consumption

[peterg]

Geoff,
Working on a now very limited budget I'm throwing out worries, possibilities and options to gain opinions before throwing cash at them.

I couldn't work out how the wear occurred where it has. Opinion is, rather than engine block problems, that it was poor machining when the liners were originally installed.

On the options front I can replace the liners and reuse the split skirt pistons my specialist doesn't like, use JP pistons, 9.0:1 Hepolite or 9.5:1 Cosworth pistons at ascending cost; or rebore to plus 10 thou and install JP pistons or Cosworth (presumably). At a higher cost I can even get new pistons made. There may be other options but I haven't discovered them yet.

I have no idea why he doesn't like them. Possibly because they are not recommended for racing?

We have 95 & 98 octane here and I have no problems running my Gold Star (9.5:1) on 95, hence the consideration as the pistons are available.

If other pistons are available in the UK I would like to know and whether it is safe to rebore the liners as Bristol's didn't recommend it.

[Geoff Dowdle]

peterg,

BCL as far as I know only ever supplied STD or 0.010 oversize pistons .

In Australia we have been using 0.020 JP Pistons for about 20 years .
I have a set of 0.030 JP Pistons in one of my 400's and have only done about 15,000 miles but no problems yet and don't expect any.

What is the cost of Hepolite 9.0 pistons ?? The flat top split skirt pistons that I assume are with your engine are probably Hepolite

Geoff

[peterg]

The Hepolites are £828 inc VAT for the set plus delivery (I assume).

Bottom line is the car is apart at my specialist, so I am over a barrow. Final decision is to rebore and fit Cosworths (because that is what he does & is comfortable with), at a great cost. The crown of the pistons will be shaved to get as low a compression as possible (down to 9.75 as std and 9.5 if possible).

To fit new liners would have increased the costs even more.

At least I know it wasn't his fault when the engine was rebuilt. I wouldn't have expected him to measure the cylinders mid length when there wasn't any sign of wear top or bottom.