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Tripyrenees
Firing on two.
Joined: December 17th, 2012, 10:03 pm Posts: 966 Location: Luscan, Pyrenees, FRANCE
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Re: 1955 Traction Avant 11cv
So I have done the compression test working from left to right 1, 2, 3, 4
Published ratio is 6.2/1 and compression circa 7.7bar or 111 psi with flat top pistons (I have domed pistons so this should lift the ratio slightly)
Cylinder 1 - 8.8 bar (127.6psi) Cylinder 2 - 9.2 bar (133.4psi) Cylinder 3 - 9.0 bar (130.5psi) Cylinder 4 - 8.0 bar (116.0psi)
So I am a bit low on number 4 - why could this be.
I am super worried about the seal on the base of the cylinder sleeve, not that I have done it wrong, just because I have never done this before. But then that should not have an effect on the compression. Maybe the piston rings are lined up with the gaps?? Just guessing here so any advice would be appreciated.
Otherwise the figures seem OK to me.
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March 24th, 2015, 2:04 pm |
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subarupete
Firing on two.
Joined: March 5th, 2009, 6:23 pm Posts: 2174 Location: Near Monmouth
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Re: 1955 Traction Avant 11cv
Does the engine need "Running In"?
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March 24th, 2015, 2:22 pm |
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Tripyrenees
Firing on two.
Joined: December 17th, 2012, 10:03 pm Posts: 966 Location: Luscan, Pyrenees, FRANCE
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Re: 1955 Traction Avant 11cv
Yes, it will do - done 100km so far. I am just paranoid - I have ordered a CO2 detector to check any combustable gases in the coolant and also a leak down tester
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March 24th, 2015, 2:33 pm |
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knightley
Firing on two.
Joined: June 19th, 2010, 8:40 pm Posts: 761 Location: Kingswood, S.Glos.
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Re: 1955 Traction Avant 11cv
Could be a slightly leaking valve on no.4. Did you lap the valves in?
_________________ John Jordan
It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a d'olly.
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March 24th, 2015, 3:30 pm |
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Tripyrenees
Firing on two.
Joined: December 17th, 2012, 10:03 pm Posts: 966 Location: Luscan, Pyrenees, FRANCE
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Re: 1955 Traction Avant 11cv
New valves and valve seats done by the machine shop - I would hope they would have done that but no I did not do it as they were fitted when I got the head back.
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March 24th, 2015, 3:57 pm |
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ChrisW
Firing on two.
Joined: February 21st, 2012, 9:01 pm Posts: 1136 Location: Avranches, Sud Manche, France
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Re: 1955 Traction Avant 11cv
Must admit that I always checked the heads I did on racing Mini's and the Dyane by turning the head upside down and filling the valve area with WD40 leaving over night and checking the next day by looking into the exhaust/inlet port for WD40
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March 24th, 2015, 9:10 pm |
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Vasil Ami
Firing on two.
Joined: December 6th, 2013, 9:55 pm Posts: 115
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Re: 1955 Traction Avant 11cv
You got a point there ChrisW WD40 is very thin and is a good valve seal checker.
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March 24th, 2015, 11:50 pm |
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lpgo
Firing on 1-2 Spark
Joined: November 8th, 2009, 5:42 pm Posts: 2847 Location: NL
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Re: 1955 Traction Avant 11cv
_________________
Russell wrote: Hi Geo, you've been one of the sites biggest attractions in recent years. Russ
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March 24th, 2015, 11:59 pm |
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ken
Agony Aunt - You have a car problem? Speak to Ken
Joined: March 6th, 2009, 1:40 am Posts: 3675
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Re: 1955 Traction Avant 11cv
Vasil, diesel fuel is cheaper, also seems to be of similar viscosity to WD40... @ Chris, did you check the valve clearances prior to the compression test? Whenever I've rebuilt an engine, I usually do the 'initial break-in' runs plus some more mileage, then check and adjust the clearances before a compression test
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March 25th, 2015, 12:41 am |
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Tripyrenees
Firing on two.
Joined: December 17th, 2012, 10:03 pm Posts: 966 Location: Luscan, Pyrenees, FRANCE
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Re: 1955 Traction Avant 11cv
Just a quick compression test first.
I will take off the rocker cover and re-tighten the head bolts (loosen and torque back up) and I will also re-adjust the valve clearances now it has run a while.
As I mentioned - I am just being paranoid as it is my first full engine rebuild.
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March 25th, 2015, 8:55 am |
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