compression test
compression test
can you please advise whether I would obtain accurate compression results by spinning a removed engine on the starter with fully charged battery and all plugs removed and with no carb fitted?
Re: compression test
Compression readings should be valid but your biggest problem is securing the engine against torque reaction from the starter motor. At best the engine will rock which will unseat the compression tester, at worst the engine will fall over
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Re: compression test
But if you lay it on it,s side, perhaps against a block of wood, an then stand on it while cranking it will be fine - I know, I ,ve done it.
Re: compression test
Just wondering where oil in the sump might flow...Dave Clark wrote:But if you lay it on it,s side...
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Re: compression test
Details, details .
There will be enough oil flowing around to do a compression test, surely ?
Never seemed to do any harm when I tried it anyway. (But when I last resorted to this I think I was about 21, so probably didn,t even think about it !!)
There will be enough oil flowing around to do a compression test, surely ?
Never seemed to do any harm when I tried it anyway. (But when I last resorted to this I think I was about 21, so probably didn,t even think about it !!)
- Neil Evans
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Re: compression test
Could always ratchet strap it to a bench leg or other suitable post...
Club Technical Information Officer
A30/A35 Club Member A191 (since 1972)
Father of the club's only love child
A30/A35 Club Member A191 (since 1972)
Father of the club's only love child
Re: compression test
Yes you would probably get away with it 90% of the time...Dave Clark wrote:Never seemed to do any harm when I tried it anyway.
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Re: compression test
i've fired them up on the floor with no restraints
Nick Bayliss
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)
Club's A35 (Saloon) Registrar, South Midlands Area Contact
Email, a35@austina30a35ownersclub.co.uk
Connected with A30/A35's for 63 years
A30/A35 Member A1372 (since 1981)
Re: compression test
Sounds dodgy to me especially if the fuel supply gets damaged. An old friend temporarily fed an A-Series from a metal can which he kicked over resulting in a fire. His wooden garage burnt down taking his Mini with it...A40FARINAGURU wrote:i've fired them up on the floor with no restraints
Re: compression test
I had already tested 4 removed engines without any restraint without them moving and remaining upright; my question was actually to establish whether they spun fast enough to obtain accurate compression tests? it appears the answer is yes.
Re: compression test
No you never mentioned that question. What makes you think it would spin slower whether installed or removed from the car16Cabulrd wrote:...my question was actually to establish whether they spun fast enough to obtain accurate compression tests?
Re: compression test
Because nutty as I can be I thought you removed one plug at a time and started the engine to get an accurate compression, I'm 79 and obviously am losing the plot. I must be as at my age to take on two major restorations, but at least it gets me away from her indoors.
Re: compression test
Good on you...16Cabulrd wrote:... but at least it gets me away from her indoors.
Re: compression test
If all the other plugs are out then there should be no problem with oil starvation or the starter having to work too hard to spin it. Inlet configuration should not matter because compression measured with both valve closed. Or am I wrong again?
Re: compression test
Sounds fine to me. If you discover a cylinder down on compression, an additional Wet Compression Test can help diagnose the problem:
http://www.freeasestudyguides.com/compr ... g-oil.html
http://www.freeasestudyguides.com/compr ... g-oil.html