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compression?
https://www.ausmini.com/forums/viewtopic.php?f=2&t=77349
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Author:  JC [ Fri Jun 29, 2012 3:49 pm ]
Post subject:  compression?

Engine is a 998. Vendor reckons cylinder head had been converted to unleaded. I'm seeing 100 across all four cylinders. Sounds low to me?

Author:  Mike_Byron [ Fri Jun 29, 2012 4:03 pm ]
Post subject: 

No - it really depends on how you are testing it - that is; exactly how you perform the tests and with what instrument. The fact that it is even across the cylinders is actually a good thing.

Did squirts of oil down the plug holes bring it up significantly ???

Mike

Author:  awdmoke [ Fri Jun 29, 2012 4:33 pm ]
Post subject: 

Early unleaded heads had compression to suit 90 RON ULP, so on a cold engine that sounds fine.

Author:  JC [ Fri Jun 29, 2012 6:51 pm ]
Post subject: 

We'll it's got me knackered why it won't start. Got fuel, spark and (enough) compression.

Author:  Morris 1100 [ Fri Jun 29, 2012 6:53 pm ]
Post subject: 

Does it have spark at the tips of the plugs or just at the plug leads?

Author:  JC [ Fri Jun 29, 2012 7:43 pm ]
Post subject: 

We'll it's got me knackered why it won't start. Got fuel, spark and (enough) compression.

Author:  JimL [ Fri Jun 29, 2012 7:58 pm ]
Post subject: 

Image

i had a similar problem, checked and re-checked all those aspects and turns out (rather embarrassingly) the timing was way out to begin with

Author:  JC [ Fri Jun 29, 2012 8:42 pm ]
Post subject: 

I would believe it. is there a How to on checking timing?

Author:  Convertible Mini [ Fri Jun 29, 2012 9:30 pm ]
Post subject:  No Start

Try pulling the Choke out.

Author:  JC [ Fri Jun 29, 2012 10:11 pm ]
Post subject: 

You're a funny guy Tony.

Author:  Irish Yobbo [ Sat Jun 30, 2012 9:45 am ]
Post subject: 

Well, as a comparison I get 140-145psi on my untouched 998. You can put a bit of oil down in the cylinders and try again, if the compression rises it is the rings.

As said earlier though, it's hard to know how accurate the gauges are. I'd look at timing and fuelling first, get it running, than look at the compression.

Author:  JC [ Sat Jun 30, 2012 10:36 am ]
Post subject: 

I reckon its timing too, but I've no idea how to check. Help is on the way apparently...

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