Archive for December, 2012

Decking

Posted: December 5, 2012 in Block
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I have test fitted a piston tonight into cylinder no 2 of the block just to check the piston decking at TDC. Fitment is as good as it gets on the new pistons.

Setting up the DTI and zero’d on the block face shows that with the piston raised to TDI the crown now sits perfectly decked to the block face. Prior to machining i had around 020″ of block material above the top of the piston crown.

Pistons are AE slipper type 21253 +060″ with an 8.3cc central dish.

 

Mini spares ltd sell these units using part number P21253-60 for around £50 each inclusive of rings.

DTI showing block to piston crown measurement

DTI showing block to piston crown measurement

Next jobs are to get the conversion kit on order from SC. Order a lightened road spec steel flywheel, clutch back-plate, orange pressure plate, performance clutch plate and a suitable crank pulley and dampener to work with the SC ignition system.

The whole lot then needs to go for balancing.

The pistons need to go away to SC and have the valve pockets cut.

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Block back

Posted: December 5, 2012 in Block
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Its back…

I picked up the block last week from the machine shop and i’m pleased to say that the work that has been carried out is perfect – Very happy!!!

The bores are perfectly honed and matched to the pistons type that i chose (sticking with following the SC 8V engine build). The cam bearings have been replaced and the centre cap has been milled flat for the centre strap fitment. The modifications to the block face have been completed to a great standard.

The machine shop were a little concerned about how the drillings for the new head studs would turn out if they hit a flaw in the casting or how the intersection drillings would even drill straight. The only issue i can complain about is the fact the block has been through the either acid bath or high temp cleaner and its taken some of the blue paint off. Repainting can be done again though when the bottom end and pistons are away being balanced and machined for valve relief pockets.

Incase anyone is planning to have a go at the conversion Sam from theminiforum did highlight some good advice. Measurements for the new head stud should be drilled on a mill, clocking off the 3 original retained head studs. 76mm to the side and 86mm back. Thank you Sam.

block face prepped

Centre main strap