Okay – enough dinkin’ around.
Fordboy’s has a PLETHORA of flow bench numbers to share, so while he’s lubricating his slide rule, I’ll be the opening act.
I’ve been e-mailing back and forth with Kevin at Ishihara-Johnson Crank Scrapers. The BMC 1275 block is a pretty common application for a crank scraper, seeing as so many of them are used in vintage racing, so when I told him what I was doing, he sent me a pre-cut 1275 template for a stock crank to check against my short stroke billet piece.
And as I suspected, it didn’t even come close –
But you’ve got to start somewhere.
I sent him the above picture, and he sent out another template – this one with a lot more material, which I spent the afternoon carefully carving to clear the crank –
Key to doing this accurately was indexing the template with the screws – you can’t quite just hold it and cut. Everything clears, and there will be enough additional material vs. the stock style scraper that it’s likely they can construct this scraper two-piece, with a Teflon insert.
After searching the world – suppliers in the States, Australia, New Zealand, Great Britain, I finally sourced a set of Rimflow Valves for this beast. Exhausts only – seems Paul Ivey never made a Rimflow intake in a 1.480.
The upside is that I will be seeing better exhaust breathing – something St. Dema was concerned about when the cam was speced out. If we look back at reply # 3568, Graph #3, the Rimflow exhaust valve in my head gave about 8-12% more flow from .050 to .450 lift, and still betters the penny-on-a-stick valve up to .600 – and I’m not opening it that far. The anti-reversion design of the valve should help with the charge purity during overlap, AND, because the head actually protrudes into the combustion chamber farther than the non-anti-reversion valve, I should see a bump in compression.
Provided they fit – things get a little busy in this head at 9K.
Moroso electric drive for the water pump arrived today – Stainless’ recommendation – he goes faster than I do. Same pitch as the pulley Fordboy put together for me, so hopefully I can free up a pony there.
I’ll also be pulling the pistons, rehoning the cylinders with a deck plate, and going with gapless rings. Let’s see if we can get that leak-down better controlled.
It’s all the stupid little things – that’s about all I’ve got left to work with as far as wringing out the grenade.
Topic: Milwaukee Midget (Read 3277916 times)