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 Engine compression 
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viking bastard
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Joined: April 18th, 2009, 11:43 am
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Location: Meneac, Bretagne France
Post Re: Engine compression
I've never disputed that compression test is done with warm engine (working temp) If you read above, I said ALSO.
I start compression test cold in order to view the sitiuation when engines are struggeling to start. Low compression yes in general lead to starting problems.
As we all know warm metal changes so the picture is altered when doing a compression test.

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March 17th, 2011, 9:36 am
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Firing on two.
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Post Re: Engine compression
:roll: :roll: :roll:

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March 17th, 2011, 9:58 am
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Joined: December 9th, 2008, 7:50 pm
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Post Re: Engine compression
Without wanting to get drawn into an argument, I was wondering this last night, Viking. If you were to test a warm engine's compression with WOT, and find it was good/acceptable, and then repeat the test when cold with closed throttle, and find it was lacking (what sort of readings would you expect, btw, from a good engine?), what would your course of action be? Are there common faults which would lead to the situation? Is it something you see often?


March 17th, 2011, 10:03 am
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Post Re: Engine compression
Luke wrote:
Without wanting to get drawn into an argument, I was wondering this last night, Viking. If you were to test a warm engine's compression with WOT, and find it was good/acceptable, and then repeat the test when cold with closed throttle, and find it was lacking (what sort of readings would you expect, btw, from a good engine?), what would your course of action be? Are there common faults which would lead to the situation? Is it something you see often?


Good question :lol:

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March 17th, 2011, 10:08 am
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viking bastard
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Joined: April 18th, 2009, 11:43 am
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Location: Meneac, Bretagne France
Post Re: Engine compression
It is going to be difficult for the establishment to swallow.

A warm engine with low compression (120 psi or there about) may run ok cruising around, have little starting problems and idle ok to a point.

Doing the same test cold will give a different picture (100 psi or there about) since many 2cv are having starting difficulties (when cold, summer or winter) it make sense to recommend a new set of piston and barrels. Naturally only conclude this if all other starting problems/faults are eliminated (ignition and carby etc including valves and guides.)
Obviously the result of fitting new piston and barrels will improve the performance immensely both at cold starts and cruising.
To me, it is not enough to judge the state of the engine at working temp. Yes it gives you a picture of wear and tear, which is important but I like to include cold engine test to give a different picture.


Keep :lol:

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March 17th, 2011, 12:33 pm
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Joined: July 21st, 2010, 7:12 pm
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Post Re: Engine compression
:?: :roll:

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March 17th, 2011, 12:36 pm
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viking bastard
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Post Re: Engine compression
602 wrote:
:?: :roll:


I knew this was coming. What is it that you don't understand?

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March 17th, 2011, 12:37 pm
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Post Re: Engine compression
2CViking wrote:
602 wrote:
:?: :roll:


I knew this was coming. What is it that you don't understand?


Your logic!

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March 17th, 2011, 12:41 pm
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Post Re: Engine compression
:lol: conspiracy theory now!
>sigh<
off to the shed to make a leak down tester might even paint the shell if the sun stays out.

Sean

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March 17th, 2011, 12:53 pm
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viking bastard
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Post Re: Engine compression
Logic is for people lacking imagination :mrgreen:

http://en.wikipedia.org/wiki/Logic

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March 17th, 2011, 12:55 pm
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