02GF74
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 posted on 14/1/09 at 10:06 AM |
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2.0 l zetec with 10.9 CR?
I did the sums last night and fitting a cylinder head from a 1.6 l zetec onto a 2.0 l zetec raised the CR from 10.0 to 10.9.
Is this too high?
i.e. too high for engine running with say twin 40s or bike carbs and spraking via EDIS with a megajolt like controller and regular pumnp 95 octane 4
start petrol.
Can the ignition map for a standard 2.0 l be used?
Presumably an ignition map can be set so that pre-ignition (pinking) does not occur but will it be so retarded that it is detrimental to bhp?
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AndyGT
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| posted on 14/1/09 at 10:09 AM |
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MAY be OK with 98 octane rated fuel. But not 95 octane rated fuel.
nothing is impossible
everything is possible
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tomgregory2000
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| posted on 14/1/09 at 10:24 AM |
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why do you want to put the head from a 1.6 on a 2L?
Tommy
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cd.thomson
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| posted on 14/1/09 at 10:26 AM |
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probably so he can raise the CR?
Craig
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tomgregory2000
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| posted on 14/1/09 at 10:30 AM |
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quote:
Originally posted by cd.thomson
probably so he can raise the CR?
But also reduce the amount of air the head will flow therefore reducing power.
Thats how i see it but i could be wrong, but surely the 1.6L head has smaller valves to fit with the smaller pistons.
But please correct me if im wrong
[Edited on 14/1/09 by tomgregory2000]
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AndyGT
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| posted on 14/1/09 at 10:34 AM |
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tomgregory, you are probably right but can the head be flowed and bigger valves be fitted to make it breathe (better flow) better and still have the
higher CR?
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tomgregory2000
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| posted on 14/1/09 at 10:41 AM |
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but a decompression plate and a supercharger would be better use of time me thinks
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Dusty
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| posted on 14/1/09 at 11:01 AM |
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1.6 ports are tiny compared to the 2.0L. I also suspect your sums are wonky. CR would be much higher. Simpler just to mod a spare 2L head.
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cd.thomson
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| posted on 14/1/09 at 11:10 AM |
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quote:
Originally posted by tomgregory2000
but a decompression plate and a supercharger would be better use of time me thinks
Could not agree more 
Craig
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02GF74
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| posted on 14/1/09 at 11:33 AM |
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quote:
Originally posted by tomgregory2000
why do you want to put the head from a 1.6 on a 2L?
Tommy
oops - brain is not working - I meant 1.8 l head.
1.8 and 2.0 have same size valves.
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zetec
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| posted on 14/1/09 at 11:33 AM |
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Agree just skim the head...only slight issue with this is if you fit too high a lift cam you will have piston contact. Normal first stage is cam
change with gas flowed head on standard CR with TBS, then moving onto pocketed pistons and even more lift on cam.
" I only registered to look at the pictures, now I'm stuck with this username for the rest of my life!"
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coozer
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| posted on 14/1/09 at 12:18 PM |
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Combustion chamber sizes and shapes are different across the 1.6, 1.8, 2.0 range.
Be carefull there is no clash of pistons on head or valves on pistons.
1972 V8 Jago
1980 Z750
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martyn_16v
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| posted on 14/1/09 at 08:41 PM |
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A CR of 10.9 isn't in itself a problem, VAG 16v engines tend to be around there as standard (9A engine is 10.8 for example).
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paulf
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| posted on 14/1/09 at 09:38 PM |
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The gasket sealing rings may be in the wrong area and there would be a step with a sharp edge between the head and block faces.I had considered doing
the opposite with a 2.0 head on an 1800 to reduce compression for a turbo but decided against it for those reasons.
Paul.
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scutter
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| posted on 15/1/09 at 08:33 AM |
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As i've the same situation waiting to happen, I've ask on
Turbosport to see what the response is.
ATB Dan.
The less I worked, the more i liked it.
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