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wil_h

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Betwix Harrogate and York

11th Nov, 2009 at 09:11:54pm

Just building up an engine and because I've had the block decled to remove some damage the pistons stick out of the top 15 thou.

I measured a used head gasket and it was 40 thou thick. doing the maths that's 25 thou clearance piston to head cold. Is this too tight?

Cheers

Fastest 998 mini in the world? 13.05 1/4 mile 106mph



On 2nd Jan, 2013 fastcarl said:
the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


Joe C

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Carlos Fandango

Burnham-on-Crouch, Essex

11th Nov, 2009 at 09:25:12pm

I think that is a bit tight... but might be ok

i think Vizard reckoned that crank flex and rod stretch can be more than 10 thou at high rpm, dunno how true that is though. so you'll be ok there


apart from that though from what i have read going too tight on the squish will rob power, and by too tight I think tighter than about 30-35 thou.

what gasket are you using? are you still on a 1275 gasket? if so i noticed Vmax have started doing some thick solid copper plate gaskets, for about 25quid one of those could be worth a go.

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



theoneeyedlizard

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The Boom Boom speaker Police!

Essex

11th Nov, 2009 at 09:39:03pm

Or perhaps 2 gaskets eh Joe? *wink*

In the 13's at last!.. Just

wil_h

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Betwix Harrogate and York

11th Nov, 2009 at 09:43:09pm

Maybe get the file out then!!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph



On 2nd Jan, 2013 fastcarl said:
the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


theoneeyedlizard

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The Boom Boom speaker Police!

Essex

11th Nov, 2009 at 09:45:05pm

Don't bodge it with a file Will!....

use an angle grinder.

In the 13's at last!.. Just

Vegard

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I pick holes in everything..

Chief ancient post excavator

Norway

11th Nov, 2009 at 09:47:02pm

Why not turn the pistons down 15thou?
However, I'd say that 15thou positive deck is OK.

On 13th Jul, 2012 Ben H said:
Mine gets in the way a bit, but only when it is up. If it is down it does not cause a problem.

Joe C

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Carlos Fandango

Burnham-on-Crouch, Essex

11th Nov, 2009 at 09:51:10pm

LOL

worked a treat for me!


On 11th Nov, 2009 theoneeyedlizard said:
Or perhaps 2 gaskets eh Joe? *wink*

On 28th Aug, 2011 Kean said:
At the risk of being sigged...

Joe, do you have a photo of your tool?



http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1

https://joe1977.imgbb.com/



wil_h

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9258 Posts
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Betwix Harrogate and York

11th Nov, 2009 at 10:02:18pm


On 11th Nov, 2009 Vegard said:
Why not turn the pistons down 15thou?
However, I'd say that 15thou positive deck is OK.


I guess I'm being lazy as I've built the engine all up now. They're dished so it's no big job.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph



On 2nd Jan, 2013 fastcarl said:
the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


Sprocket

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Preston On The Brook

12th Nov, 2009 at 12:32:13am

15thou posative deck hight, 3thou main bearing clearance, 3thou big end clearance, and for arguments sake 4 thou flex/ stretch leaves 15thou clearance.

Just be sure the gasket is 40thou compressed.

I managed to get the pistons to touch the head when the center main failed, and that was a whole 35thou crank flex at less than 3krpm

Edited by Sprocket on 12th Nov, 2009.

On 26th Oct, 2004 TurboDave16v said:
 Is it A-Series only? I think it should be...
So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'...


On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........

PaulH

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Dublin Ireland

12th Nov, 2009 at 12:43:44am

the most I have ever run with is .010" like sprocket wile the motor was new there was no problems but in the later life of the motor when wear set in there was a faint outline of the combustion chamber in the top of the piston :)

On 17th Feb, 2009 Rob H said:
I find the easiest way is to super glue the bolt to the end of one of my fingers.

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gr4h4m

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Chester

12th Nov, 2009 at 09:57:31pm

V Max Scart solid cooper gasket help?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!


BENROSS

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Resident Cylinder Head Modifier

Mitsi Evo 7, 911, Cossie. & all the chavs ...... won no problem

12th Nov, 2009 at 11:17:42pm

on your high reving motor wil i would make them flush!

Edited by BENROSS on 12th Nov, 2009.





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