HOW CAN I TELL IF I GOT LOW COMP PISTON`S OR NOT???
04-07-2004, 11:29 PM
#43
Norris Motorsport
LOL, indeed it is actually quite normal!!! 
Time for my favorite quote:
"There nothing like a determined idiot to destroy an engine"
(Remeber the guy who tried to tow start his car because it wouldnt turn over on the starter)
Time for my favorite quote:
"There nothing like a determined idiot to destroy an engine"
(Remeber the guy who tried to tow start his car because it wouldnt turn over on the starter)
04-07-2004, 11:36 PM
#46
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Originally Posted by DOO
Originally Posted by Stu @ M Developments
Glenn.
If you do a copmpression test and its low at say 120PSI. How will that tell you its a low comp set of pistons?
How do you know the valve's arent leaking or the piston rings not worn? Maybe even the followers are knackered and causing a low reading.
If you do a copmpression test and its low at say 120PSI. How will that tell you its a low comp set of pistons?
How do you know the valve's arent leaking or the piston rings not worn? Maybe even the followers are knackered and causing a low reading.
so i don`t think anything would be wrong.
so is it worth doing a comp test or not
Do a compression test m8 and check your figures against ford.
It wont hurt to try it.
04-07-2004, 11:39 PM
#47
15K+ Super Poster!!
Originally Posted by Glenn5
Originally Posted by DOO
Originally Posted by Stu @ M Developments
Glenn.
If you do a copmpression test and its low at say 120PSI. How will that tell you its a low comp set of pistons?
How do you know the valve's arent leaking or the piston rings not worn? Maybe even the followers are knackered and causing a low reading.
If you do a copmpression test and its low at say 120PSI. How will that tell you its a low comp set of pistons?
How do you know the valve's arent leaking or the piston rings not worn? Maybe even the followers are knackered and causing a low reading.
so i don`t think anything would be wrong.
so is it worth doing a comp test or not
Do a compression test m8 and check your figures against ford.
It wont hurt to try it.
Me thinks you are missing the point somewhat
04-07-2004, 11:42 PM
#48
Norris Motorsport
Glenn5,
You'll find the cosworth specification is quoted as:
Compression test results: Minimum 8 bar.
How does that help identify whether the engine is high or low comp.
I've seen low comp engines make 10bar and std comp engines make 7 bar???
What would you do then? lol
You'll find the cosworth specification is quoted as:
Compression test results: Minimum 8 bar.
How does that help identify whether the engine is high or low comp.
I've seen low comp engines make 10bar and std comp engines make 7 bar???
What would you do then? lol
04-07-2004, 11:49 PM
#49
I forsee a new trend here....
Engine everrevved / run low on oil / belt timed wrong blah blah....... checked out, none or very little compression as expected....
Owner: No problemo at all.... il just sell the engine now and its woirth more than it was before i fooked it. . dead easy.
For sale:
"Low Comp" YB powerunit
Goodnight folks
Engine everrevved / run low on oil / belt timed wrong blah blah....... checked out, none or very little compression as expected....
Owner: No problemo at all.... il just sell the engine now and its woirth more than it was before i fooked it. . dead easy.
For sale:
"Low Comp" YB powerunit
Goodnight folks
04-07-2004, 11:53 PM
#51
PassionFord Post Whore!!
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Originally Posted by Stu @ M Developments
I forsee a new trend here....
Engine everrevved / run low on oil / belt timed wrong blah blah....... checked out, none or very little compression as expected....
Owner: No problemo at all.... il just sell the engine now and its woirth more than it was before i fooked it. . dead easy.
For sale:
"Low Comp" YB powerunit
Goodnight folks
Engine everrevved / run low on oil / belt timed wrong blah blah....... checked out, none or very little compression as expected....
Owner: No problemo at all.... il just sell the engine now and its woirth more than it was before i fooked it. . dead easy.
For sale:
"Low Comp" YB powerunit
Goodnight folks
05-07-2004, 01:43 PM
#55
Professional Waffler
Originally Posted by Stu @ M Developments
A simple cambelt change i believe!!
(No doubtr because us tuners charge too much or werent trusted to know how to do it properly
)
Ouch!!
(No doubtr because us tuners charge too much or werent trusted to know how to do it properly
)Ouch!!
looks like something i would do
05-07-2004, 01:54 PM
#56
Testing the future
by 'low compression pistons', is there not a general type that are used in yb's? do they have a different shaped bowl or something (like 4x4 pistons vs. 2wd) that can be seen with an endoscope?
or the bowl is deeper and can be measured using a dial gauge or something?
or can you use a known fuel, at known engine speed, with a known boost, a known ACT, known cams etc and from the ignition advance you can tell roughly the compression ratio from when you start to hear det? it's not gonna be precise and be able to tell you the c/r, but it might be able to indicate if it's lower than std?
just bunging some ideas in. have a test report to write at work ad am finding it extremely boring.
or the bowl is deeper and can be measured using a dial gauge or something?
or can you use a known fuel, at known engine speed, with a known boost, a known ACT, known cams etc and from the ignition advance you can tell roughly the compression ratio from when you start to hear det? it's not gonna be precise and be able to tell you the c/r, but it might be able to indicate if it's lower than std?
just bunging some ideas in. have a test report to write at work ad am finding it extremely boring.
05-07-2004, 02:01 PM
#57
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PMSL @ this thread
As far as i understand it (and im sure i understand properly) then a compression test isnt going to tell you what compression ratio you have or even any sort of indication of wether you have low comp pistons...
I think you are missunderstanding the question mate.. i fully accept that the compression test will give an indication as to the health of the engine.. and the compression on each cylinder. BUT that wasnt what DOO wanted to know.. he wanted the compression ratio of the engine.. and to do this you must take the head off.(unless you have x-ray vision)
CheeRS
Phil
As far as i understand it (and im sure i understand properly) then a compression test isnt going to tell you what compression ratio you have or even any sort of indication of wether you have low comp pistons...
You could still do a comp test 2 see what the figures are if there all the same across all cyls and are low or high will help denote health of engine and will help explain whether low comp or std it wont give a comp ratio but will help
CheeRS
Phil
05-07-2004, 02:33 PM
#58
Testing the future
he wanted the compression ratio of the engine
there must be some relatively simple way of finding out if the compression is lower than std. without being sophisticated enough to be able to tell you what the actual c/r is?
05-07-2004, 02:38 PM
#59
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no he didn't. he wanted to know if 'low compression' pistons had been fitted.
there must be some relatively simple way of finding out if the compression is lower than std. without being sophisticated enough to be able to tell you what the actual c/r is?
there must be some relatively simple way of finding out if the compression is lower than std. without being sophisticated enough to be able to tell you what the actual c/r is?
but my point remains that the 'compression test' is in no way related to the c/r or the fact that the car my have 'low compression' pistons
05-07-2004, 02:47 PM
#61
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think that we all (except glenn5 who is probably too small to admit that he was wrong) can understand your point on that one mate.
there must be some relatively simple way of finding out if the compression is lower than std. without being sophisticated enough to be able to tell you what the actual c/r is?
Never mind hey keep for in buisness with head sets
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