Jump to content


Photo
- - - - -

Compression Test Results - Lets Get Weird.


  • Please log in to reply
26 replies to this topic

#1 happydude2012

happydude2012

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 266 posts
  • Location: the moon

Posted 06 August 2018 - 08:58 AM

Ok so did a compression test with me pal this morning 

We checked 4 times on each cylinder - results as follows/

 

 

1) 120

2) 120

3) 140  ??? what the hell

4)  120

 

So on a car that runs sweet as a nut (except for the weird tapping on rockers 1 and 2) and has smooth idol, smooth revving and no major issues - ive got cylinder 3 at 140 with everything else at 120.

 

10% of 120 being 132, im just outside the limit on 3.

 

This was a dry test by the way at normal running temp./

 

Any ideas lads?


Edited by happydude2012, 06 August 2018 - 09:03 AM.


#2 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 3,232 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 06 August 2018 - 09:04 AM

What were the conditions?

 

Hot or cold?

 

With a drop of oil or not?



#3 happydude2012

happydude2012

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 266 posts
  • Location: the moon

Posted 06 August 2018 - 09:06 AM

hotish - did about a mile before the test - with no oil - i mean oil in the car, just not down the bores


Edited by happydude2012, 06 August 2018 - 09:07 AM.


#4 Steve220

Steve220

    Up Into Fourth

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 3,232 posts
  • Location: Shropshire
  • Local Club: RAF Mini Club

Posted 06 August 2018 - 09:09 AM

Worth getting a drop of oil in each cylinder and trying it again.



#5 Moke Spider

Moke Spider

    Crazy About Mini's

  • TMF Team
  • PipPipPipPipPipPipPipPipPipPip
  • 7,587 posts
  • Location: NSW
  • Local Club: South Australian Moke Club

Posted 06 August 2018 - 09:19 AM

Personally, I don't rate compression tests (nor leak down tests).

 

There are so many variables and it does not remotely simulate what's happen when the engine is running.

 

I wouldn't loose any sleep over those figures.



#6 unburntfuelinthemorning

unburntfuelinthemorning

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 219 posts
  • Location: Bedfordshire

Posted 06 August 2018 - 09:46 AM

I presume oil finding its way into number three will give you a higher reading than the others - or it may be nothing.  Have you tried shining a decent torch through the spark plug hole to see what's inside?



#7 happydude2012

happydude2012

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 266 posts
  • Location: the moon

Posted 06 August 2018 - 10:27 AM

if i run the engine to running temp and use a drop of oil down the bores - how much oil are we tallking? 5ml?10ml?

ready to do it so if someone could drop me a line with that knowledge ill crack on.

ive enlisted the Mrs to help ha ha 



#8 happydude2012

happydude2012

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 266 posts
  • Location: the moon

Posted 06 August 2018 - 11:25 AM

ok - put a nice clean drop of 20/50 down the spark plug bores - results taken immediately as follows.

 

1 = 180

2 = 180

3 = 150

4 = 180

 

then i did 4 more sweeps - all showed the following

 

1 = 140

2 = 140

3 = 140

4 = 140

 

so guess i dont have a major problem here - apart from the cloud of smoke when i restarted the car because i put oil down the holes.

 

pheeewwwwwwwww.

 

now onto the next nonsensical problem that isnt a problem.



#9 Retroman

Retroman

    Super Mini Mad

  • Traders
  • PipPipPipPipPipPip
  • 607 posts
  • Location: Sunny Sabden
  • Local Club: CDMC

Posted 06 August 2018 - 11:28 AM

yes Rowan

 

You will have to count the flies in your teeth with mirror hahha



#10 ACDodd

ACDodd

    Camshaft & Stage Two Head

  • Mini Docs
  • PipPipPipPipPipPipPipPip
  • 1,949 posts

Posted 06 August 2018 - 12:04 PM

If it's not burning oil, it just needs a valve job. Your engines telling you it needs maintenance.


Ac

#11 happydude2012

happydude2012

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 266 posts
  • Location: the moon

Posted 06 August 2018 - 12:10 PM

Hi AC , not burning oil to my knowledge - well, no evidence of that anyway - i get a barely noticeable puff on cold start and the its clear all the way.

- valve job? would you explain that in dingbat terms just for me?

 

yes Rowan

 

You will have to count the flies in your teeth with mirror hahha

whos rowan? ha ha - wrong thread??



#12 ACDodd

ACDodd

    Camshaft & Stage Two Head

  • Mini Docs
  • PipPipPipPipPipPipPipPip
  • 1,949 posts

Posted 06 August 2018 - 04:11 PM

Remove the cylinder head and have the valves re seated to restore the lost valve seal. Engine will run better and with more power once valve seal is restored.

Ac

#13 russo

russo

    Mini Mad

  • Members
  • PipPipPipPip
  • 168 posts
  • Location: Nelson
  • Local Club: Minis In Nelson Inc.

Posted 06 August 2018 - 09:16 PM

Just sayin, if it ain't broken.....................don't fix it.



#14 Retroman

Retroman

    Super Mini Mad

  • Traders
  • PipPipPipPipPipPip
  • 607 posts
  • Location: Sunny Sabden
  • Local Club: CDMC

Posted 06 August 2018 - 09:30 PM

 

 

yes Rowan

 

You will have to count the flies in your teeth with mirror hahha

whos rowan? ha ha - wrong thread??

   Who's that in your armchair on the roof...? Rowan Atkinson...your avatar



#15 happydude2012

happydude2012

    Mini Mad

  • TMF+ Member
  • PipPipPipPip
  • 266 posts
  • Location: the moon

Posted 07 August 2018 - 07:29 AM

 

 

 

yes Rowan

 

You will have to count the flies in your teeth with mirror hahha

whos rowan? ha ha - wrong thread??

   Who's that in your armchair on the roof...? Rowan Atkinson...your avatar

 

 

ha ha ha  - of course! 






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

Mini Spares