Piston & Ring Choice
Turbo Mini Forums

On 2nd of Dec, 2006 at 10:47am British Open Classic said:


Finally here's an AE piston I blew up earlier:

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Bad luck more than anything, the head came off one of the valves at about 5k rpm, the piston tried to compress it and the rest was history. To add insult to injury I'd only just ran the engine in and had it set-up on the rollers the day before. Although I had to laugh at the AA patrol who spent half an hour trying to get the Mini started by the side of the M5 before he gave in and towed me home. Here's a shot of the engine:

That's fucked mate...

sure is!

rob i dont know if this is connected to the type of gasket your using but this is what i found for the thickness of the 450 gasket ,
regards
robert.



14th of March, 2006 at 11:20:31amPM User | Quote | Manage Attachments | Edit
450 gasket ,
cyl 1 73.08 along the block73.89 across the block,
cyl 2,,72.16/73.64 ,,cyl 3 ,,72.14/73.66 ,,cyl 4 ,73.36/73.82//
therefore cyl 1 averages out to 73.485 //
cyl 2,,72.9avg/cyl 3 72.9avg//cyl 4 73.59.
overall avg 73.21mm
gasket thickness of fire ring next to bore on used gasket .94mm,therfore volume avg is 3.95cc.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Holes in all the pistons, and a dropped valve ???

Just who exactly set it up on the rollers ??? Im thinking the job wasnt quite finished lol.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Edited by Rob H on 19th Dec, 2006.

I was going to go for the 450, only one I've ever used, for some reason I though they were 3cc. Oh well that's another 1cc I need to deal with.

Ok, I'm confused now, just read this post:

http://www.turbominis.co.uk/forums/index.p...8264&lastpost=1

and Turbo Dave says they are 2.8 / 2.9 cc, which is what I thought they were in the first place.

Measure your old compressed one and work it out for your self.

Theres too much spurious information knocking about regards the cc of the BK450. The Minispares website isnt helping either as most take the information given as gospel.

IIRC I worked it out at roughly 3.8cc

a compressed one will give a rough idea but all gaskets relax after coming off.

Pain in the arse to measure the thickness properly really but possible with a bit of time.

2 bits of glass and some vasoline and a small syringe will do it.

always looking for them bigger bunches of bannanas

but then you wont get the compressed thickness. I was on about its tricky to measure compressed thickness.

One way would be to datum a point on the head with no gasket in, then fit a gasket and torque it then remeasure. Or do a similar thing to measure a new gasket then gasket compression.

Much better to use the dimensions to calculate it on something like this i'd say.

oh, and btw personally wouldnt worry about 1cc...

I guess though all the inaccuracies add up.

Then again i am a rough bugger! ha ha!

Dave has done just that, removed a part and measured between head and block. He came to the same conclusion as minispares...

If I get the chance before the new year, I'll bolt a bead and gasket up to the rest of that sectioned block and gauge the thickness when compresed, at the business end, the fire ring.

This should be as real a figure as your gonna get.