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Harley Dropped
Joined: 26 Nov 2007 Posts: 394 Location: Braidwood - Australia
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Posted: Thu Aug 19, 2010 1:13 pm Post subject: |
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Olli wrote: | Yeah, you can sure find those for 2cv6, but how is with old 425cc?
Also I can go machine my cylinders to my friends place at free.
Does anyone know how much is example this 7,5:1 in bars? My
engine has only 6bar in bolth sides, and it does not mess oil so piston
rings does not leak so much.
-Olli |
Calculating Compression ratio is better left to rocket scientists and witch doctors...
This article explains in-depth how and what it is: Article
And here is a calculator to accompany it: Calculator
Correct ratio pistons are more effective at their given ratio compared to shortened barrels, as this alters the combustion chambers 'squish area', a small area or ring around the edge of the combustion chamber. Some performance engineers say this area must not be messed with treat it like your in-laws, respect it but don't f@ck with it
Unfortunately I don't have the mind to give you the answer, but I hope this has helped. Talk to the people who machined your heads they will be able to help.
Keep the pics inc.
Harley _________________ Check out my Dinosaur www.youtube.com/watch?v=RPF_uU61als
Spot my 2cv www.youtube.com/watch?v=Zoq68CPLq4M |
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Olli Soviet-Finn Photoshoper
Joined: 25 May 2007 Posts: 2146 Location: Soviet-Finland
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Posted: Thu Aug 19, 2010 4:48 pm Post subject: |
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Thanks Harley!
I will check those links later, but anyway I think my only change is to do
something and check what happent.
Harley wrote: |
Talk to the people who machined your heads they will be able to help.
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As usual, I can talk with my self
Got all rockers ready today! About 1 - 1,5h work with each.
I made one extra arm which is lighter and better polished than rest.
-Olli _________________ www.ollierkkila.com |
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woody Dropped
Joined: 01 Jul 2007 Posts: 151 Location: Chaudfontaine Belgium
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Posted: Thu Aug 19, 2010 8:19 pm Post subject: |
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woooawww |
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Chewie Dropped
Joined: 29 May 2009 Posts: 112 Location: Eggenfelden, Germany
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Posted: Sun Aug 22, 2010 2:12 pm Post subject: |
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Hey looks great :-)
you should sell some of theese replica RAF carburator manifolds ... I would buy one _________________ Thatīs not broken ... thats normal
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Olli Soviet-Finn Photoshoper
Joined: 25 May 2007 Posts: 2146 Location: Soviet-Finland
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Posted: Thu Sep 02, 2010 9:55 pm Post subject: |
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I'm trying to make some of those manifolds and exhausts at next winter.
Today I cleaned pair of 15,5mm's to replace those huge 17mm's what there is now.
-Olli _________________ www.ollierkkila.com |
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dyanut Dropped
Joined: 05 Aug 2007 Posts: 177 Location: North Yorkshire
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Posted: Thu Sep 02, 2010 11:22 pm Post subject: |
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Ollie,
do you know what the nominal compression ratio of your engine is?
602 pistons often have the compression ratio marked on the piston crown, but I don't know if this applied to the older models...
Fwiw, 6 bar seems quite low, as a 602 engine with 8.5:1 pistons will show around 10 bar at cranking speed, with 9.0:1 pistons producing almost 12 bar.
Using the following 'rule of thumb', it seems probable that your pistons may be the early 6.2:1 version, since 6 bar = 90 psi.
Then 90/15 = 6
"Generally, cylinder pressure for common automotive designs should at least equal 10 bar, or, roughly estimated in pounds per square inch (psi) as between 15 and 20 times the compression ratio, "
If you're worried about reducing the clearance between the pistons and the heads at the squish band, you can use plasticine to check the gap.
Another trick I used when I first started building race engines was to pour molten candle wax into the combustion chambers with the pistons at top dead centre.
Let it cool and set, then there's a nice casting available for dissection.
My guess is that you should be able to remove 'around' 0.5mm from the barrels' top spigots without clearance problems.
Whether the crankshaft will stand up to the increased output is another matter, same story for the valve seats regarding coping with the extra stress...
Ken
Olli wrote: | Yeah, you can sure find those for 2cv6, but how is with old 425cc?
Also I can go machine my cylinders to my friends place at free.
Does anyone know how much is example this 7,5:1 in bars? My
engine has only 6bar in bolth sides, and it does not mess oil so piston
rings does not leak so much.
-Olli |
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Malte Lowered
Joined: 11 Dec 2007 Posts: 534 Location: Germany
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Posted: Fri Sep 03, 2010 12:31 pm Post subject: |
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Olli wrote: | I'm trying to make some of those manifolds and exhausts at next winter.
Today I cleaned pair of 15,5mm's to replace those huge 17mm's what there is now.
-Olli |
6pack for 440 mopar? :) _________________ in rust we trust... |
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Olli Soviet-Finn Photoshoper
Joined: 25 May 2007 Posts: 2146 Location: Soviet-Finland
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Posted: Fri Nov 12, 2010 10:52 am Post subject: |
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Ok, after some other projects this continues!
Motor madness in getting deep.
Now I have some problems to install manifold:
So whats going on here is: 602cc "12hp".
I got old Ami6 case from JoZeF, thanks! So I can get old engine look
and 70mm stroke, instead of 62mm. Also 2cv6 cylinders will fit straight
on case.
But cylinders does not fit on 12hp heads. Outer diameter of 425cc cylinder
in 80mm and 2cv6 is 82mm.
I took heads to machining company. Here you can see 2cv6 cylinder
sitting on 12hp head.
Needs still some grinding to get it nicely shaped.
Also I got problems with pushrod tubes. In 12hp head they are very short and outer diameter 16mm (2cv6 18mm).
First I was thinking to extend the tubes but as they are so small I was
thinking that it may bring me some problems. So I drill old tubes off
with 18mm drill and swap tubes from 2cv6 head. I can tell that, this was
no easiest project but I'm very satisfied with result. Tubes sit really thick
in their new home.
Push rods and their cups on block seem to be usable from 2cv6.
Next step is to finnish this head bussines, see that engine rolls nicely
around, valves work etc and then case on pieces: wash and check.
-Olli _________________ www.ollierkkila.com |
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dule Lowered
Joined: 06 Jan 2008 Posts: 590 Location: Zagreb, Croatia
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Posted: Fri Nov 19, 2010 7:41 am Post subject: |
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are you still going with RAF intake replica that you've made? |
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Olli Soviet-Finn Photoshoper
Joined: 25 May 2007 Posts: 2146 Location: Soviet-Finland
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Posted: Fri Nov 19, 2010 6:01 pm Post subject: |
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I'm not sure yet what I will use. One I made will not fit in this engine anyway.
-Olli _________________ www.ollierkkila.com |
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dule Lowered
Joined: 06 Jan 2008 Posts: 590 Location: Zagreb, Croatia
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Posted: Wed Jun 08, 2011 10:14 am Post subject: |
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any news? I've started to think about dual carb for my 602 with that vintage looking manifold, what do you think, would a pair of single barrel stock solex carbs do the job? |
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JoZeF Grave Digger
Joined: 25 May 2007 Posts: 1734
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Posted: Wed Jun 08, 2011 11:00 am Post subject: |
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Apparently, with 2 single choke 2cv carbs on a 602 with a hotter cam, yes, it does _________________ "That bumper fits there like sunglasses on pig" O.E.
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dule Lowered
Joined: 06 Jan 2008 Posts: 590 Location: Zagreb, Croatia
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Posted: Thu Jun 09, 2011 7:33 pm Post subject: |
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tnx |
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PerI Snailer
Joined: 13 Nov 2008 Posts: 85 Location: Landvik, Norway
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Posted: Wed Feb 06, 2013 12:17 am Post subject: |
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Found this in my parents photo album recently
From world meeting in 1985, Cheltenham UK
_________________ '71 2cv 6 · '74 Ami Super Berline · '70 Ami 6 Service (project) · 2(3) AZU projects · 2cv since '93 · C5 v6.24 · GPicasso 2.0 hdi · 307cc |
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oliver pickard Snailer
Joined: 18 Jul 2011 Posts: 11
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Posted: Mon Mar 17, 2014 8:44 pm Post subject: |
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i totally dig this project its totally awesome, any news on what has been going on with it? |
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