Compression tester

[moggiethouable]

Before I plumb for some piece of fragile tat that breaks when I remove it from the box, can someone recommend a good compression tester please?
Thanks.

[philthehill]

This is the make and type of compression tester I use and it has given good service over many years.
https://www.ebay.co.uk/itm/326785013031 ... R6TeuPfgZg

[svenedin]

I have the Draper 35880 which is very good and has a hard case to keep it in. It is a tool that I use so infrequently that it would have made more sense to borrow one really.

Stephen

[Mervin]

Like Phil, I have a Gunson's compression tester, similar to that linked. However, it's very old with the scale in lbf/in2, not bar. Although rarely used it has done good service over the years. I did use it aout 6 months ago to check my Minor's cylinder compressions, all four around 160/165p.s.i..

[philthehill]

It really does not matter if the reading is read as lb/sq in or bar - what you are looking for is a good pressure and even readings across all cylinders.
12 bar/168lb.sq in is a good reading.

[moggiethouable]

Many thanks.
What it should read was my next question.
I don't know why but I like the look of the Draper unit and have had good service from other Draper tools.
Onwards and upwards.

[Mervin]

"It really does not matter if the reading is read as lb/sq in or bar" It does to me Phil, I'm old school
It wouldn't surprise me if my old gauge is better quality than the modern equivalent - even Gunson's (made in Taiwan).

[moggiethouable]

I have ordered the Draper 35885 which covers 4 sizes of thread.
It will as suggested by Stephen probably be used once in a blue moon, I could rent it out to the neighbours of course.
I have within a stones throw a TVR an MGA an E type a Mini a MK1 landy and a few specials too.
Thanks again.

[philthehill]

Mervin
Being old schools does not make the compression reading any higher. It is what it is.
Phil

[mike1864]

Checking back through my maintenance log (for the Minor I still run), I found this entry from 48 years ago. It shows that measuring every 2-4k miles can tell a useful story. In this case, new piston rings, please! The floating dots at 57.2k miles show that - when fitted - the new rings brought them all up to 132 psi (+/- 3psi). It had an 803cc in those days, doing 11,000 miles/annum. Nowadays, and with it's recently installed (1979 ) 1098, it's more like 1000 mpa.

IMG_4385[1].JPG (1.49 MiB) Viewed 3940 times

[Sleeper]

Wonder why 2 was so low??

John ;-)

[moggiethouable]

Thanks for the chart, that's interesting.
Coloured lines like that just highlight my colour blindness, but I get the gist.
I think I should do something similar when I get my tester delivered.

[mike1864]

Wonder why 2 was so low??

John ;-)

My 48 year old notes show I replaced the middle 3 of its 5 rings.
Incidentally I sold that engine to a Southampton student in 1979. Has anyone still got it (No. 221137)?