PKR, Thanks, is there an easy way to check the valve guides?
I bought a tool to do it when I did a rebuild last year. It would probably have been cheaper to get an engineering shop to do it, but I like buying tools and wanted to at least try it myself.
This is what I bought :
There are other ( cheaper ) types like these
but 8mm is the very lowest limit with those and the valve guides are speced at 7mm ish so no good.
If you do want to do it yourself, that isn't the end of it!. The gauges don't measure the holes. You then need a micrometer to take the reading off the gauge( 25mm in this case ).
Also, if you want to measure the cylinder bores you'd need a gauge capable of measuring 84mm as well. Like this -
and that needs a 100mm micrometer!
These videos will give you an idea of how it's done
Blueprinting Pontiac 455; 1 (Measuring Bores Pt 1 of 2) - YouTube
Blueprinting Pontiac 455; 2 (Measuring Bores Pt 2 of 2) - YouTube
I measured in two axes ( front/back and left/right) at the top, middle and bottom of each guide/cylinder.
I didn't find anything wrong with my engine in respect to wear except some ovality. I have read ( and this is pure hearsay! ) that they could come out of the factory with ovality to the cylinder bores.
In the year following my rebuild, I did not even have to top up the oil at all
. It went about 5,000 miles without consuming more than about 0.5 litre of oil!
Be careful where you get replacement valve stem oil seals. I got some off eBay and they failed immediately ( they came off the valve guides
) which necessitated another head removal
. I then got some genuine ones and they've been fine.