MkIndy7
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| posted on 31/3/07 at 05:01 PM |
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Low compresion Pinto to High
After dismantling a recently recoditioned Pinto we happened upon at the Scrapyard it would appear its the Low compresion version! 
The Pistons are +1.0mm oversize.. but the 2.0L HC on the crown has been Crossed out with a punch and LC stamped on as well.
As listed on here very helpfully by dave blissett ages ago
high comp (9.2) 41.65mm
low comp (8.2) 40.35mm
Is the distance between the piston crown and the Gudgeon pin center.. and ours appears to be the Low comp.
Would it be possible? or there be any point considering its 1.0mm oversize and re-bored etc in trying to reclaim the lost compression ratio by
skimming the top of the engine block?
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ecosse
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| posted on 31/3/07 at 05:05 PM |
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Just a thought, but 8.2:1 would be a nice compression ratio for a turbo 
Cheers
Alex
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MkIndy7
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| posted on 31/3/07 at 05:08 PM |
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Hmm we thought that as well but we were aiming for the 1mm oversize High compression with Throttle Bodies 
Might have to put the TB's on our existing 2L pinto and keep this for a later date.
Would the standard pistons stand up to Turbo or Supercharging tho? or would they need to be forged ones?
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BenB
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| posted on 31/3/07 at 05:32 PM |
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Good point! That CR would allow pretty high boost levels on pump gas... The pistons might not handle it too well....
(just looked it up in my tuned induction book)
With a 50% efficiency intercooler that CR would allow around 12-13PSI on RON98....
[Edited on 31/3/07 by BenB]
[Edited on 31/3/07 by BenB]
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snapper
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| posted on 1/4/07 at 03:02 AM |
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Cosworth rods are 1.5mm longer, pin retention is different and your standard ford piston ring lands will fail at high rpm.
V6 pistons (Kolbienschmit) are 1.5mm shorter 93mm wide and cosworth rods 1,5mm longer = 2.1 L and 8,000 rpm.
I do have a set of Fiesta diesel con rods in the spares box 3.2mm longer, these are wider and need machining as does the crank and pistons, but for
£100 will take 8,000 rpm all day
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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MkIndy7
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| posted on 2/4/07 at 04:57 PM |
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Its probably not worth trying to make it a 2.1L as its only a 200 Block and not a 205
The main point of the question was...
Would there be any point in skimming the 1.3mm differance in piston height from the top of the engine block height to regain the compression ratio?
Or are there other unforseeable problems with this such as the low compression pistons being weaker as there's 1.3mm of material missing from
the thickness of the crown, or the loss of capacity from skimming the top of the block.. (althought that should be negligable with the 1mm overbore)
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mcerd1
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| posted on 3/4/07 at 02:01 PM |
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quote:
Originally posted by MkIndy7
Its probably not worth trying to make it a 2.1L as its only a 200 Block and not a 205
you mean its a 20 block not a 205
a 200 block is the cossie 4x4 one - its the strongest type you get
[Edited on 3/4/07 by mcerd1]
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matt_claydon
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| posted on 3/4/07 at 02:36 PM |
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quote:
Originally posted by MkIndy7
or the loss of capacity from skimming the top of the block..
You won't lose capacity. Capacity is the swept volume and is therefore dictated by the throw of the crankshaft and the diameter of the bore.
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smart51
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| posted on 3/4/07 at 03:17 PM |
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If you skim the block (or head) is there a risk of the valves hitting the piston?
Which would be cheaper, skimming the block or finding some HC pistons and selling the LC ones?
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david walker
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| posted on 3/4/07 at 05:51 PM |
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200 Block is also Transit, which as he's got low compression that's what it is. 200 block lacks rear core plug otherwise same as 205, ie
good block
Don't skim by a mm otherwise other issues, ie cam timing, unless you are using vernier. Pistons will never hit valves no matter what you do with
the block.
Ignore all the crap about Fiesta diesel rods.
Sierra pistons will stand all the revs that V6 pistons will so don't worry about that.
Just buy some Sierra HC pistons and fit them. They are not that expensive in the scale of things.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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MkIndy7
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| posted on 3/4/07 at 06:08 PM |
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Good the hear the 200 block isin't all bad then, just seems a shame to have buy new HC pistons when the LC ones that are in are brand new.
If we were to invest the money in new pistons we might be as well going for the V6 ones and having it re-boared again to 2.1, then we've got the
best out of a bad job!
If we skimmed the block down with the LC pistons and got the timing back with the vernier pulley which were already running, I get the feeling that
being 1.3mm thinner the piston crowns won't last long running at the higher compression if at all 
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david walker
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| posted on 3/4/07 at 07:12 PM |
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I don't know that the LC pistons have a thinner crown, because they are a lower deck height doesn't follow that they are.
That said, when you build a 2.2 with V6 pistons, offset crank and matey's Fiesta diesel rods, you have to skim 2.0mm off the top of the pistons
and they never have a problem with holing through.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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