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My Engine No Compression


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#1 minigem

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Posted 01 September 2007 - 08:32 PM

Can anyone help me my engine sounded awful and seemed to be fireing on only 2 cylinders. We checked the ignition and it was fine so we checked the compression and found cylinders 3 and 4 at 195 and 190 but cylinders 1 and 2 were reading nothing and the spark plugs were oily.
We checked the valve clearences ..with valve number 8 open we checked number 1 clearence as to the book and so on all correct.
So am I thinking correctly that the head gasket has gone or worse the head has a crack in it.
The head is a 12G295 Cooper head with 'S' valves fitted which are bigger than the other valves on another 12g295 head we have.
We are going to take the head off in the next few days,but if its cracked will I see it or will I have to have it tested ?


Clare. :D

#2 Broomer

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Posted 01 September 2007 - 08:33 PM

piston could of picked up.

#3 Bungle

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Posted 01 September 2007 - 08:51 PM

normal test is to squart some oil down the bores and re test

#4 Sprocket

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Posted 01 September 2007 - 10:23 PM

head gasket

#5 mini_kel

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Posted 01 September 2007 - 10:28 PM

As above

#6 Sprocket

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Posted 02 September 2007 - 05:34 PM

piston could of picked up.



Keep thinking about what you are saying.


What are you saying???? :wub:

#7 steveobennet

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Posted 02 September 2007 - 06:40 PM

think he means packed up, sprocket

#8 Dan

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Posted 02 September 2007 - 08:12 PM

If one cylinder was low then it could be a piston, it's really unlikely that two have gone. Most likely is the head gasket between cylinders. Sure you numbered the cylinders from the right end? It's more common to fail between #3 & #4. It is an old head though and so could be cracked, only way to find out is to lift it and see. All 295s are getting on a bit now. This one is normally a really obvious gasket failure when you eventually get to the gasket, like a dirty great hole in it so it should be easy to spot.

#9 mini_kel

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Posted 02 September 2007 - 08:15 PM

If one cylinder was low then it could be a piston, it's really unlikely that two have gone. Most likely is the head gasket between cylinders. Sure you numbered the cylinders from the right end? It's more common to fail between #3 & #4. It is an old head though and so could be cracked, only way to find out is to lift it and see. All 295s are getting on a bit now. This one is normally a really obvious gasket failure when you eventually get to the gasket, like a dirty great hole in it so it should be easy to spot.


I`ve always found they fail between 2 & 3!

Edited by mini_kel, 02 September 2007 - 08:15 PM.


#10 minigem

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Posted 02 September 2007 - 08:22 PM

Thanks boys it was :o the gasket ,the bit between the cylinders was missing completely so you were very correct.

Bad news though, as my other half, while torqueing the head down snapped a stud. The air was very blue for a while :D and I heard lots of fence kicking which helped him calm down.

So it looks like I maybe getting a 1275 soon......not that I am complaining of course :wub:


Clare

#11 Sprocket

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Posted 02 September 2007 - 10:22 PM

think he means packed up, sprocket


Ah well fair enough.

"The piston has picked up" normaly describes the following - the piston has picked up some metal swarf and scored the bores

Edited by Mini Sprocket, 02 September 2007 - 10:23 PM.


#12 minigem

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Posted 03 September 2007 - 05:24 PM

Forget it he managed to get the stud out and fitted a new one and has got it running so I won't be getting a 1275 now :) .
Fantastic forum very helpful I will be back again I expect.


Clare :lol:




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