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        General >> Give/Need advice to/from others >> gudgeon pin?
        
(Message started by: sierra3dr on Oct 28th, 2009, 10:33am)
Title: gudgeon pin?
Post by sierra3dr on Oct 28th, 2009, 10:33am
Hi gang,
as I am aiming to supercharge a 2.3er,the needed compression reduction will be required. So,I am contemplating to putting in dished pistons. Do I have it correct,in the Engine Data 2.3 (http://www.fordscorpio.co.uk/images/engdata2.3.htm) that the gudgeon pin is 20,589 - 20,609mm (Bore diameter, small end)?
Title: Re: gudgeon pin?
Post by Scorpio_Mike on Oct 28th, 2009, 10:42am
You can reduce the CR by having the tops of the pistons machined - this is what I did when I turbo'd an XR3 many moons ago.
Much cheaper than a new set of pistons  :)
Title: Re: gudgeon pin?
Post by sierra3dr on Oct 29th, 2009, 12:21am
ooo...thanks Mike,I like the sound of that. But,when you say machined,you do mean a dish is created in the pistons,and not skimmed?
Title: Re: gudgeon pin?
Post by Matt on Oct 29th, 2009, 9:44am
both can be done but old school method mike is talking about it just slicing off the top of the piston (skimming not dishing). another cheep way of doing it is have a thicker headgasket made, but you need to watch the timing chain then!

you may need to look at upping the injectors, not sure the 2.3 will flow enough
Title: Re: gudgeon pin?
Post by Scorpio_Mike on Oct 29th, 2009, 10:48pm
Yes, skimming is what I meant ! Turboing my XR3 was my 1984 summer holiday project  8)
From memory - this is 25yrs ago - I only had to get a few thou taken off each piston crown.
I will try to find the turbo kit installation manual - think it is in the attic. The spec for the piston machining is somewhere in the manual.

I recall it involved using a depth gauge micrometer to measure the piston heights at TDC so had to be done with the pistons & crank still in the block - which me and a mate put in his car boot and we took it to the local FMD to borrow the tool  ;)
Having taken the measurements the pistons were removed and taken to a local machine shop for skimming. Collect pistons and reassemble. Simples.
Each cylinder should then have the same CR & swept volume.
Title: Re: gudgeon pin?
Post by sierra3dr on Oct 30th, 2009, 1:22am

on 10/29/09 at 09:44:59, Matt wrote:
both can be done but old school method mike is talking about it just slicing off the top of the piston (skimming not dishing). another cheep way of doing it is have a thicker headgasket made, but you need to watch the timing chain then!
Due to such methods,equivalent to decompression plates,it rids the squish area
The most important thing when
trying to change the compression
ratio is to try and keep the
designed squish area correct. The
squish area exists between the
piston’s upper/outer edges and
the cylinder head when the piston
is positioned at exactly top dead
centre. This section is designed
to squeeze the mixture towards
the centre of the combustion
chamber as the piston reaches
the top of its stroke. This creates a
nice mixture swirl that distributes
the fuel evenly throughout
the combustion chamber and
lessens the risk of pockets of fuel
forming around the outer edges
of the cylinder, which can lead to
inefficiency and, in worst cases,
detonation due to heat.
Squish effect is the main
reason a decompression plate is
accepted as the worst possible
way to adjust the compression
ratio. By its very nature it will
increase the gap between the
piston crown and the head, and
decrease or totally eradicate the
squish band, not to mention
the extra sealing face it
introduces (plate to block),
which gives another area of
potential compromise.

on 10/29/09 at 09:44:59, Matt wrote:
you may need to look at upping the injectors, not sure the 2.3 will flow enough

now that's interesting,thanks

on 10/29/09 at 22:48:20, Scorpio_Mike wrote:
Each cylinder should then have the same CR & swept volume.

I'm aiming for the >hybrid 8v+2.3 block setup< (http://www.crustworld.co.uk/pdf/dohchybrid.pdf) with a supercharger
Looking at the formula
573.76 + 58.38 ÷ 58.38= 10.83 ,I've established that to obtain a 7:10.1 for a SC/turbo application,I would need to add 35.62 cubic centimeter to 58.38.
The 35.62 would come from a dished piston hopefully
Title: Re: gudgeon pin?
Post by Matt on Oct 30th, 2009, 11:11am
interesting project   ;D
Title: Re: gudgeon pin?
Post by sierra3dr on Oct 31st, 2009, 12:34am
Oh I,what's the big grin for? :) Does the 8v+2.3 block appear daft?
Title: Re: gudgeon pin?
Post by pinto on Oct 31st, 2009, 8:50am
If you're going to supercharge a 2.3, you're best off sticking to the standard 16v head anyway - it had the lowest CR of the whole I4 DOHC family (including the 8v) :)

Standard pistons on the 2.3 are dished already.

Unless you're planing to run more than 0.75 bar (10psi) then the stock twinky will take that anyway - just make sure you keep the fueling nice and rich on boost :)
Title: Re: gudgeon pin?
Post by sierra3dr on Oct 31st, 2009, 11:15am
hello Jeff,thanks for that. The head I have sold,due to the PATS problem. So the 2.3 pistons are dished already,I should have known that :) the block is upside down at the moment.
Neil is running his twinky in double figures @7.10:1,so I'm aiming for that region
Title: Re: gudgeon pin?
Post by pinto on Oct 31st, 2009, 4:55pm
I should think you are steve lol - do you have any idea how much money neil has plowed into that car over the years ? think concours cossie, several times over  ;)

The pistons he had custom made by JE in the states IIRC - cost £200 each ?  mind you, this does let him run up to 28psi of boost ;D

Unless you plan on big, big money here, you'll never get the 7.1 CR without a decompressor plate.  You need to speak to Ferriday Engineering, who can laser cut you a nice copper or alloy one :)

http://www.ferriday.co.uk/cnc/decompression_plates.shtml

Bear in mind what they say about vernier pulleys tho - they certainly wont be available for the 8v twinky head you're using.

Next up, how are you going to cope with the fueling issues of using an EEC IV ? it has no concept of boost and no lamda to help out, so you'll be looking at agricultural (using a boost switch/5th injector) or probably much more sensible, running the whole shebang on an emerald ECU... in which case you might as well kept the 16v head lol :)
Title: Re: gudgeon pin?
Post by sierra3dr on Nov 1st, 2009, 8:13am

on 10/31/09 at 16:55:04, pinto wrote:
do you have any idea how much money neil has plowed into that car over the years ? think concours cossie, several times over  ;)
Good god!!!

on 10/31/09 at 16:55:04, pinto wrote:
The pistons he had custom made by JE in the states IIRC - cost £200 each ?  mind you, this does let him run up to 28psi of boost ;D
Well,probably not that extreme. The pistons in the 2.3 block are flat,from a Galaxy.
Federal-Mogul sell dished pistons,but the gudgeon pin diameter are too large on most

on 10/31/09 at 16:55:04, pinto wrote:
you'll never get the 7.1 CR without a decompressor plate.  You need to speak to Ferriday Engineering, who can laser cut you a nice copper or alloy one :)

http://www.ferriday.co.uk/cnc/decompression_plates.shtml

Not the direction I prefer,perhaps other Ford pistons might work


on 10/31/09 at 16:55:04, pinto wrote:
Bear in mind what they say about vernier pulleys tho - they certainly wont be available for the 8v twinky head you're using.

[quote author=pinto link=board=Advice;num=1256726014;start=0#10 date=10/31/09 at 16:55:04]Next up, how are you going to cope with the fueling issues of using an EEC IV ? it has no concept of boost and no lamda to help out, so you'll be looking at agricultural (using a boost switch/5th injector) or probably much more sensible, running the whole shebang on an emerald ECU...
Yeh,I was enquiring on FSOC whether the EEC-IV maps can be opened with the necessary software,like MJLJ. Lambda is already there.

on 10/31/09 at 16:55:04, pinto wrote:
in which case you might as well kept the 16v head lol :)

Oh well,I'll improvise with what I have :)
Title: Re: gudgeon pin?
Post by pinto on Nov 1st, 2009, 9:41pm
Well, if you wont run the decompressor plate, the only option left is to have the combustion bowls machined in the head to increase the cc of each (usually a trick used for v6 engines which cant be made to work easily with decompression plate)

Ferriday can do that too  ;D
Title: Re: gudgeon pin?
Post by sierra3dr on Nov 2nd, 2009, 6:19am

on 11/01/09 at 21:41:45, pinto wrote:
Well, if you wont run the decompressor plate, the only option left is to have the combustion bowls machined in the head to increase the cc of each (usually a trick used for v6 engines which cant be made to work easily with decompression plate)

Ferriday can do that too  ;D

That's interesting,thanks Jeff


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