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Mayflower compression
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Rollmop



Joined: 23 Dec 2016
Posts: 14
Location: Market Drayton, Shropshire

PostPosted: Mon Oct 26, 2020 12:39 pm    Post subject: Mayflower compression Reply with quote

Has anyone had a compression test done on a Triumph Mayflower engine?
I tested mine to check the cylinder head gasket and get a reading of 73 to 75 psi across the four cylinders. None of the Triumph technical manuals I have seen give a pressure value, is around 75 psi about right for a low mileage engine? Any info/experience would be much appreciated.
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Failure is not an option - in my case it is usually a feature.
1971 Herald convertible
1952 Triumph Mayflower
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Ray White



Joined: 02 Dec 2014
Posts: 3993
Location: Derby

PostPosted: Mon Oct 26, 2020 2:37 pm    Post subject: Re: Mayflower compression Reply with quote

Rollmop wrote:
Has anyone had a compression test done on a Triumph Mayflower engine?
I tested mine to check the cylinder head gasket and get a reading of 73 to 75 psi across the four cylinders. None of the Triumph technical manuals I have seen give a pressure value, is around 75 psi about right for a low mileage engine? Any info/experience would be much appreciated.


I would think that is a bit low but the main thing is that they are all more or less equal.
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Sid



Joined: 20 Sep 2017
Posts: 69
Location: From whence cometh the mighty Lagonda

PostPosted: Mon Oct 26, 2020 10:04 pm    Post subject: Reply with quote

To calculate the compression in PSI, and if you know the compression ratio, multiply the first figure by 14.
edit....which is 6.8:1, therefore a compression of 95psi.
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Rick
Site Admin


Joined: 27 Apr 2005
Posts: 21546
Location: UK

PostPosted: Tue Oct 27, 2020 12:43 pm    Post subject: Re: Mayflower compression Reply with quote

Ray White wrote:
Rollmop wrote:
Has anyone had a compression test done on a Triumph Mayflower engine?
I tested mine to check the cylinder head gasket and get a reading of 73 to 75 psi across the four cylinders. None of the Triumph technical manuals I have seen give a pressure value, is around 75 psi about right for a low mileage engine? Any info/experience would be much appreciated.


I would think that is a bit low but the main thing is that they are all more or less equal.


Agreed, if it runs and drives ok I wouldn't be concerned.

RJ
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Various 1920s-1960s - Austin, Morris, Commer, Dodge etc.
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ukdave2002



Joined: 23 Nov 2007
Posts: 3608
Location: South Cheshire

PostPosted: Tue Oct 27, 2020 3:59 pm    Post subject: Reply with quote

Sid wrote:
To calculate the compression in PSI, and if you know the compression ratio, multiply the first figure by 14.
edit....which is 6.8:1, therefore a compression of 95psi.

The test need so be completed with the throttle wide open, otherwise it will read low.

Dave
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Rollmop



Joined: 23 Dec 2016
Posts: 14
Location: Market Drayton, Shropshire

PostPosted: Fri Oct 30, 2020 12:43 pm    Post subject: Reply with quote

Thanks for the CR formula. Once you see it it is a very obvious calculation, atmospheric pressure x compression factor. I will leave it for now but next year may have the head off to check the pistons, bores etc
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1952 Triumph Mayflower
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