Cortina (non-uprated) Engine Rules

[Dave Harmison]

I have a 1969 Titan Mk5 that I want to get put together. I also have a bunch of Cortina engine parts (not uprated) so I figure to use them on the Titan. Is there a website I can get the current rules for Cortina engine building? I have an old GCR and a VERY old copy of "The Formula Ford Scrutineers Manual" but I have no idea what the current rules are.

Biggest questions are piston weight, crank weight, flywheel weight, con ropd weight and can I machine the top of the piston to get the compression ratio right?

[JHaydon]

The current GCR still acknowledges the original engine:

Pistons: minimum wgt: 525g (as for the uprated)
Rods: 630g for both
Crank: 23.5 lb for the original engine only
Flywheel: 15.5lbs for both

A minimum bowl volume (31.50cc) is listed for the original pistons. There is no mention of allowing machining the pistons for compression ratio.

[Roux]

I think you end up having to deck the block to get to 10:1 compression. Any machining of the pistons will only lower the compression, unless you take even more off of the deck. My 10:1 cortina had the pistons ever so slightly above the block deck at TDC to get to 10:1. The pistons miss the head thanks to the thickness of the gasket as I recall

[John Merriman]

Cortina piston weight is 525 gr. but note the weight for Uprated piston was reduced to 515 gr. when the new Uprated forged piston was approved. See February 05 FasTrack, Page F44.

[Goldie]

You can find these at www.monoposto.com and they cover the Cortina engine as well as the uprated. Piston weight for the Cortina shows as 573 and 555 for the uprated. Living in Michigan and owning a Monoposto eligible car, it's worth looking at working to these specs as most vintage events you will want to enter will be run to these rules.

Dave

[Dave Harmison]

Thanks for the feedback. I was afraid there would be at least two sets of rules, GCR and Monoposto. I measured the deck height of one of my blocks and it has been decked .050 so I am concerned about maybe having to get the compression ratio down, not up. I think the first step is to order a crank and cc everything and then determine where I am.

Thanks again. I'll be asking more later I'm sure.

[Wooly]

I looked at building a Cortina motor 2 years ago and couldn't find a set of legal pistons, that would be the first thing I'd look for!

Wooly

[Mark Blythe]

Dave:

I've got a prepped Cortina crank if you are interested!!

Mark Blythe
marbly@spiff.net